Patent Application
20230285504
The present application claims the benefit of U562/978,786 filed Feb. 19, 2020, which is incorporated by reference in its entirety for all purposes.
The present application contains sequence in a txt filed named 695302SEQLST.TXT of 20,212 bytes created Feb. 17, 2021, which is incorporated by reference.
Tat-NR2B9c (also known as NA-1 or nerinetide) is an agent that inhibits PSD-95, thus disrupting binding to N-methyl-D-aspartate receptors (NMDARs) and neuronal nitric oxide synthases (nNOS) and reducing excitoxicity induced by cerebral ischemia. Treatment reduces infarction size and functional deficits in models of cerebral injury and neurodegenerative diseases. Tat-NR2B9c has undergone a successful phase II trial (see WO 2010144721 and Aarts et al., Science 298, 846-850 (2002), Hill et al., Lancet Neurol. 11:942-950 (2012)).
Restoration of the blood supply by chemical or mechanical reperfusion can reduce more extensive brain tissue injured by salvaging a reversibly damage penumbra of tissue. However, for some subjects, reperfusion may cause additional damage, i.e., reperfusion injury, by a distinct mechanism that the initial ischemia and resulting excitotoxicity. This mechanism is inflammatory in nature and can involve any or all of leukocyte infiltration, platelet and complement activation, post-ischemic hyperperfusion, and breakdown of the blood—brain barrier.
The invention provides a method of inhibiting reperfusion injury in a subject having ischemia comprising administering to the subject an active agent that inhibits PSD-95 at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow by reperfusion. Optionally, the reperfusion is mechanical reperfusion. Optionally, the reperfusion is by administration of a thrombolytic agent. Optionally, restoration of flow is determined by imaging. Optionally, the imaging is by MRI or CT imaging. Optionally, the reperfusion is by endovascular thrombectomy. Optionally, the n is administered not more than 5, 10 or 15 minutes after puncture to initiate endovascular thrombectomy. Optionally, the active agent that inhibits PSD-95 is administered not more than 5 minutes after the puncture. Optionally, the active agent that inhibits PSD-95 is administered before the puncture. Optionally, the ischemia is cerebral ischemia. Optionally, the subject has stroke. Optionally, the subject has acute ischemic stroke. Optionally, the subject receives an active agent that inhibits PSD-95, thereafter is qualified for reperfusion and thereafter receives reperfusion. Optionally, the method is performed on a population of at least 100 subjects, each of which receive the active agent that inhibits PSD-95 at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow by reperfusion.
The invention further provides a method of treating a population of subjects receiving endovascular thrombectomy for ischemic stroke comprising administering both an active agent that inhibits PSD-95 cleavable by plasmin and a thrombolytic agent to some of the subjects, wherein the active agent that inhibits PSD-95 is administered at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow by reperfusion before the thrombolytic agent, and administering the active agent that inhibits PSD-95 or the thrombolytic agent but not both to the other subjects of the population. Optionally, the subjects receiving the active agent that inhibits PSD-95 and thrombolytic agent do so before the subjects receive endovascular thrombectomy. Optionally, the subjects receiving the active agent that inhibits PSD-95 or thrombolytic agent but not both do before the subjects receive endovascular thrombectomy. Optionally, in the subjects receiving both the active agent that inhibits PSD-95 and thrombolytic agent the active agent that inhibits PSD-95 is administered at least 10 minutes before the thrombolytic agent, and the active agent that inhibits PSD-95 or the thrombolytic agent but not both is administered to the other subjects.
In any of the above methods, the active agent that inhibits PSD-95 comprises a peptide comprising [E/D/N/Q]-[S/T]-[D/E/Q/N]-[V/L] (SEQ ID NO:1) at the C-terminus or X1-[T/S]-X2-V (SEQ ID NO:2) at the C-terminus, wherein [T/S] are alternative amino acids, X1 is selected from among E, Q, and A, or an analogue thereof, X2 is selected from among A, Q, D, N, N-Me-A, N-Me-Q, N-Me-D, and N-Me-N or an analog thereof, and an internalized peptide linked to the N-terminus of the inhibitor peptide. Optionally, the active agent that inhibits PSD-95 linked to the internalization peptide is Tat-NR2B9c. Optionally, the thrombolytic agent is tPA.
A “pharmaceutical formulation” or composition is a preparation that permits an active agent to be effective, and lacks additional components which are toxic to the subjects to which the formulation would be administered.
Use of upper case one letter amino acid codes can refer to either D or L amino acids unless the context indicates otherwise. Lower case single letter codes are used to indicate D amino acids. Glycine does not have D and L forms and thus can be represented in either upper or lower case interchangeably.
Numeric values such as concentrations or pH's are given within a tolerance reflecting the accuracy with which the value can be measured. Unless the context requires otherwise, fractional values are rounded to the nearest integer. Unless the context requires otherwise, recitation of a range of values means that any integer or subrange within the range can be used.
The terms “disease” and “condition” are used synonymously to indicate any disruption or interruption of normal structure or function in a subject.
Indicated dosages should be understood as including the margin of error inherent in the accuracy with which dosages can be measured in a typical hospital setting
The terms “isolated” or “purified” means that the object species (e.g., a peptide) has been purified from contaminants that are present in a sample, such as a sample obtained from natural sources that contain the object species. If an object species is isolated or purified it is the predominant macromolecular (e.g., polypeptide) species present in a sample (i.e., on a molar basis it is more abundant than any other individual species in the composition), and preferably the object species comprises at least about 50 percent (on a molar basis) of all macromolecular species present. Generally, an isolated, purified or substantially pure composition comprises more than 80 to 90 percent of all macromolecular species present in a composition. Most preferably, the object species is purified to essential homogeneity (i.e., contaminant species cannot be detected in the composition by conventional detection methods), wherein the composition consists essentially of a single macromolecular species. The term isolated or purified does not necessarily exclude the presence of other components intended to act in combination with an isolated species. For example, an internalization peptide can be described as isolated notwithstanding that it is linked to an active peptide.
A “peptidomimetic” refers to a synthetic chemical compound which has substantially the same structural and/or functional characteristics of a peptide consisting of natural amino acids. The peptidomimetic can contain entirely synthetic, non-natural analogues of amino acids, or can be a chimeric molecule of partly natural peptide amino acids and partly non-natural analogs of amino acids. The peptidomimetic can also incorporate any amount of natural amino acid conservative substitutions as long as such substitutions also do not substantially alter the mimetic's structure and/or inhibitory or binding activity. Polypeptide mimetic compositions can contain any combination of nonnatural structural components, which are typically from three structural groups: a) residue linkage groups other than the natural amide bond (“peptide bond”) linkages; b) non-natural residues in place of naturally occurring amino acid residues; or c) residues which induce secondary structural mimicry, i.e., to induce or stabilize a secondary structure, e.g., a beta turn, gamma turn, beta sheet, alpha helix conformation, and the like. In a peptidomimetic of a chimeric peptide comprising an active peptide and an internalization peptide, either the active moiety or the internalization moiety or both can be a peptidomimetic.
The term “specific binding” refers to binding between two molecules, for example, a ligand and a receptor, characterized by the ability of a molecule (ligand) to associate with another specific molecule (receptor) even in the presence of many other diverse molecules, i.e., to show preferential binding of one molecule for another in a heterogeneous mixture of molecules. Specific binding of a ligand to a receptor is also evidenced by reduced binding of a detectably labeled ligand to the receptor in the presence of excess unlabeled ligand (i.e., a binding competition assay).
Excitotoxicity is the pathological process by which neurons and surrounding cells are damaged and killed by the overactivation of receptors for the excitatory neurotransmitter glutamate, such as the NMDA receptors, e.g., NMDA receptors bearing the NMDAR 2B subunit.
The term “subject” includes humans and veterinary animals, such as mammals, as well as laboratory animal models, such as mice or rats used in preclinical studies.
A tat peptide means a peptide comprising or consisting of RKKRRQRRR (SEQ ID NO:3), in which no more than 5 residues are deleted, substituted or inserted within the sequence, which retains the capacity to facilitate uptake of a linked peptide or other agent into cells. Preferably any amino acid changes are conservative substitutions. Preferably, any substitutions, deletions or internal insertions in the aggregate leave the peptide with a net cationic charge, preferably similar to that of the above sequence. Such can be accomplished for example, by not substituting any R or K residues, or retaining the same total of R and K residues. The amino acids of a tat peptide can be derivatized with biotin or similar molecule to reduce an inflammatory response.
Co-administration of a pharmacological agents means that the agents are administered sufficiently close in time for detectable amounts of the agents to present in the plasma simultaneously and/or the agents exert a treatment effect on the same episode of disease or the agents act co-operatively, or synergistically in treating the same episode of disease. For example, an anti-inflammatory agent acts cooperatively with an agent including a tat peptide when the two agents are administered sufficiently proximately in time that the anti-inflammatory agent can inhibit an anti-inflammatory response inducible by the internalization peptide.
Statistically significant refers to a p-value that is <0.05, preferably <0.01 and most preferably <0.001.
An episode of a disease means a period when signs and/or symptoms of the disease are present interspersed by flanked by longer periods in which the signs and/or symptoms or absent or present to a lesser extent.
If administration of a drug is not instantaneous, intervals are calculated from or to the initial point of its administration, unless explicitly stated otherwise. Depending on the context, timing of reperfusion can refer to either initiation as by administration of a thrombolytic agent or groin puncture to initiate endovascular thrombectomy or to restoration of blood flow, which is typically determined by imaging.
The term “NMDA receptor,” or “NMDAR,” refers to a membrane associated protein that is known to interact with NMDA including the various subunit forms described below. Such receptors can be human or non-human (e.g., mouse, rat, rabbit, monkey).
The invention is based in part on the observation that the peptide inhibitor of PSD-95, Tat-NR2B9c, and related peptides can inhibit damage resulting from reperfusion, i.e., reperfusion injury, when administered before blood flow is restored. This role is in addition to the role of active agents that inhibits PSD-95 inhibiting damage resulting from ischemia and resulting excitotoxicity. The relative timing of administering active agents that inhibits PSD-95 and reperfusion by thrombolytic agents is additionally influenced by degradation of plasmin-sensitive active agents by plasmin induced by thrombolytic agents if the active agents that inhibit PSD-95 and plasmin are co-resident in the plasma. Plasmin-degradation can be reduced or avoided and the benefit of inhibiting reperfusion injury obtained by administering an active agent that inhibits PSD-95 before restoration of blood flow by reperfusion, preferably at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow by reperfusion.
Active agents of the invention specifically binding to PSD-95 so as to inhibit its binding to NMDA Receptor 2 subunits including NMDAR2B and/or NOS. Such active agents can include a peptide that binds to PSD-95 and inhibits its binding to NMDA Receptor 2 subunits including NMDAR2B and/or NOS and an internalization peptide to facilitate passage of the peptide inhibitor across cell membranes and the blood brain barrier. Such agents include an above normal representation of basic residues R and K. When the agents are formed of conventional L amino acids, the overrepresentation of R and K residues renders them particularly susceptible to plasmin cleavage at sites between and R and K residue and the proximate residue on the C-terminal side.
Some peptide inhibitors have an amino acid sequence comprising [E/D/N/Q]-[S/T]-[D/E/Q/N]-[V/L] (SEQ ID NO:1) at their C-terminus. Exemplary peptides comprise: ESDV (SEQ ID NO:4), ESEV (SEQ ID NO:5), ETDV (SEQ ID NO:6), ETAV (SEQ ID NO:7), ETEV (SEQ ID NO:8), DTDV (SEQ ID NO:9), and DTEV (SEQ ID NO:10) as the C-terminal amino acids. Some peptides have an amino acid sequence comprising [I]-[E/D/N/QHS/THD/E/Q/NHV/L] (SEQ ID NO:83) at their C-terminus. Exemplary peptides comprise: IESDV (SEQ ID NO:11), IESEV (SEQ ID NO:12), IETDV (SEQ ID NO:13), IETAV (SEQ ID NO:14), IETEV (SEQ ID NO:15), IDTDV (SEQ ID NO:16), and IDTEV (SEQ ID NO:17) as the C-terminal amino acids. Some inhibitor peptides having an amino acid sequence comprising [E/D/N/Q]-[S/THD/E/Q/NHV/L] (SEQ ID NO:1) at their C-terminus or X1-[T/S]-X2-V (SEQ ID NO:2) at the C-terminus, wherein [T/S] are alternative amino acids, X1 is selected from among E, Q, and A, or an analogue thereof, X2 is selected from among A, Q, D, N, N-Me-A, N-Me-Q, N-Me-D, and N-Me-N or an analog thereof (see Bach, J. Med. Chem. 51, 6450-6459 (2008) and WO 2010/004003). Some inhibitor peptides having an amino acid sequence comprising X3-[T/S]-4V (SEQ ID NO:18) at the C-terminus, wherein [T/S] are alternative amino acids, X3 is selected from among E, Q, A, or D or an analogue thereof, X4 is selected from among A, Q, D, E, N, N-Me-A, N-Me-Q, N-Me-D, N-Me-E, and N-Me-N or an analog thereof. Optionally the peptide is N-alkylated in the P3 position (third amino acid from C-terminus, i.e. position occupied by [T/S]). The peptide can be N-alkylated with a cyclohexane or aromatic substituent, and further comprises a spacer group between the substituent and the terminal amino group of the peptide or peptide analogue, wherein the spacer is an alkyl group, preferably selected from among methylene, ethylene, propylene and butylene. The aromatic substituent can be a naphthalen-2-yl moiety or an aromatic ring substituted with one or two halogen and/or alkyl group. Some inhibitor peptides having an amino acid sequence comprising I-X1-[T/S]-X2-V (SEQ ID NO:19) at the C-terminus, wherein [T/S] are alternative amino acids, X1 is selected from among E, Q, and A, or an analogue thereof, X2 is selected from among A, Q, D, N, N-Me-A, N-Me-Q, N-Me-D, and N-Me-N or an analog thereof. Some inhibitor peptides having an amino acid sequence comprising I-X3-[T/S]-X4-V (SEQ ID NO:20) at the C-terminus, wherein [T/S] are alternative amino acids, X3 is selected from among E, Q, A, or D or an analogue thereof, X4 is selected from among A, Q, D, E, N, N-Me-A, N-Me-Q, N-Me-D, N-Me-E, and N-Me-N or an analog thereof. Exemplary inhibitor peptides have sequences IESDV (SEQ ID NO:11), IETDV (SEQ ID NO:13), KLSSIESDV (SEQ ID NO:21), and KLSSIETDV (SEQ ID NO:22). Inhibitor peptides usually have 3-25 amino acids (without an internalization peptide), peptide lengths of 5-10 amino acids, and particularly 9 amino acids (also without an internalization peptide) are preferred.
Internalization peptides are a well-known class of relatively short peptides that allow many cellular or viral proteins to traverse membranes. They can also promote passage of linked peptides across cell membranes or the blood brain barrier. Internalization peptides, also known as cell membrane transduction peptides, protein transduction domains, brain shuttles or cell penetrating peptides can have e.g., 5-30 amino acids. Such peptides typically have a cationic charge from an above normal representation (relative to proteins in general) of arginine and/or lysine residues that is believed to facilitate their passage across membranes. Some such peptides have at least 5, 6, 7 or 8 arginine and/or lysine residues. Examples include the antennapedia protein (Bonfanti, Cancer Res. 57, 1442-6 (1997)) (and variants thereof), the tat protein of human immunodeficiency virus, the protein VP22, the product of the UL49 gene of herpes simplex virus type 1, Penetratin, SynB1 and 3, Transportan, Amphipathic, gp41NLS, polyArg, and several plant and bacterial protein toxins, such as ricin, abrin, modeccin, diphtheria toxin, cholera toxin, anthrax toxin, heat labile toxins, and Pseudomonas aeruginosa exotoxin A (ETA). Other examples are described in the following references (Temsamani, Drug Discovery Today, 9(23):1012-1019, 2004; De Coupade, Biochem J., 390:407-418, 2005; Saalik Bioconjugate Chem. 15: 1246-1253, 2004; Zhao, Medicinal Research Reviews 24(1):1-12, 2004; Deshayes, Cellular and Molecular Life Sciences 62:1839-49, 2005); Gao, ACS Chem. Biol. 2011, 6, 484-491, SG3 (RLSGMNEVLSFRWL (SEQ ID NO:23)), Stalmans PLoS ONE 2013, 8(8) e71752, 1-11 and supplement; Figueiredo et al., IUBMB Life 66, 182-194 (2014); Copolovici et al., ACS Nano, 8, 1972-94 (2014); Lukanowski Biotech J. 8, 918-930 (2013); Stockwell, Chem. Biol. Drug Des. 83, 507-520 (2014); Stanzl et al. Accounts. Chem. Res/46, 2944-2954 (2013); Oller-Salvia et al., Chemical Society Reviews 45: 10.1039/c6cs00076b (2016); Behzad Jafari et al., (2019) Expert Opinion on Drug Delivery, 16:6, 583-605 (2019) (all incorporated by reference). Still other strategies use additional methods or compositions to enhance delivery of cargo molecules such as the PSD-95 inhibitors to the brain (Dong, Theranostics 8(6): 1481-1493 (2018)).
A preferred internalization peptide is tat from the HIV virus. A tat peptide reported in previous work comprises or consists of the standard amino acid sequence YGRKKRRQRRR (SEQ ID NO:24) found in HIV Tat protein. RKKRRQRRR (SEQ ID NO:3) and GRKKRRQRRR (SEQ ID NO:25) can also be used. If additional residues flanking such a tat motif are present (beside the pharmacological agent) the residues can be for example natural amino acids flanking this segment from a tat protein, spacer or linker amino acids of a kind typically used to join two peptide domains, e.g., gly (ser)4 (SEQ ID NO:26), TGEKP (SEQ ID NO:27), GGRRGGGS (SEQ ID NO:28), or LRQRDGERP (SEQ ID NO:29) (see, e.g., Tang et al. (1996), J. Biol. Chem. 271, 15682-15686; Hennecke et al. (1998), Protein Eng. 11, 405-410)), or can be any other amino acids that do not significantly reduce capacity to confer uptake of the variant without the flanking residues. Preferably, the number of flanking amino acids other than an active peptide does not exceed ten on either side of YGRKKRRQRRR (SEQ ID NO:24). However, preferably, no flanking amino acids are present. One suitable tat peptide comprising additional amino acid residues flanking the C-terminus of YGRKKRRQRRR (SEQ ID NO:24) or other inhibitor peptide is YGRKKRRQRRRPQ (SEQ ID NO:30). Other tat peptides that can be used include GRKKRRQRRRPQ (SEQ ID NO:31 and GRKKRRQRRRP (SEQ ID NO:32).
Variants of the above tat peptide having reduced capacity to bind to N-type calcium channels are described by WO/2008/109010. Such variants can comprise or consist of an amino acid sequence XGRKKRRQRRR (SEQ ID NO:33), in which X is an amino acid other than Y or can comprise or consist of an amino acid sequence GRKKRRQRRR (SEQ ID NO:25). A preferred tat peptide has the N-terminal Y residue substituted with F. Thus, a tat peptide comprising or consisting of FGRKKRRQRRR (SEQ ID NO:34) is preferred. Another preferred variant tat peptide consists of GRKKRRQRRR (SEQ ID NO:25). Another preferred tat peptide comprises or consists of RRRQRRKKRG (SEQ ID NO:35) or RRRQRRKKRGY (SEQ ID NO:36). Other tat derived peptides that facilitate uptake of a pharmacological agent without inhibiting N-type calcium channels include those presented below.
X can represent a free amino terminus, one or more amino acids, or a conjugated moiety.
A preferred active agent is Tat-NR2B9c, also known as NA-1 or nerinetide, having the amino acid sequence YGRKKRRQRRRKLSSIESDV (SEQ ID NO:54). Another preferred agent is YGRKKRRQRRRKLSSIETDV (SEQ ID NO:55). Some active agents, such as nerinetide, are peptides of all-L amino acids.
Some active agents include D-amino acids to reduce or eliminate plasmin-mediated cleavage of a peptide. In such agents, at least the four C-terminal residues of the inhibitor peptide and preferably the five C-terminal residues of the inhibitor peptide are L amino acids, and at least one of the remaining residues in the inhibitor peptide and internalization peptide is a D residue. Positions for inclusion of D residues can be selected such that D residues appear immediately after (i.e., on the C-terminal side) of any basic residue (i.e., arginine or lysine). Plasmin acts by cleaving the peptide bond on the C-terminal side of such basic residues. Inclusion of D residues flanking sites of cleavage, particularly on the C-terminal side of basic residues reduces or eliminates peptide cleavage. Any or all of residues on the C-terminal side of basic residues can be D residues. Any basic residues can also be D amino acids.
Some inhibitor peptides include at least one D-amino acid in both the internalization peptide and inhibitor peptide. Some active agents include inhibitor peptides including D-amino acids at each position of the internalization peptide. Some active agents include D-amino acids at each position of the inhibitor peptide except the four or five C-terminal residues, which are L-amino acids. Some inhibitor peptides include D-amino acids at each position of the internalization peptide, and each position of the inhibitor peptide except the last four or five C-terminal amino acid residues, which are L-amino acids.
Tat-NR2B9c has the amino acid sequence YGRKKRRQRRRKLSSIESDV (SEQ ID NO:54). In an exemplary active agent, the first eleven amino acids (internalization peptide) are D-amino acids, and the last nine amino acids (inhibitor peptide) L-amino acids (D-Tat-L-NR2B9c). Some active agents are variants of YGRKKRRQRRRKLSSIESDV (SEQ ID NO:54) in which ESDV (SEQ ID NO:4) or IESDV (SEQ ID NO:11) are L-amino acids and at least one of the remaining amino acids is a D-amino acid. In some active agents at least the L or K residue at the eighth and ninth position from the C-terminus, or both, is or are D residues. In some active agents, at least one of the R, R, Q, R, R residues occupying the 6th, 7th, 8th, 10th, and 11th positions from the N-terminus is a D residue. In some active agents all of these residues are D-residues. In some active agents, each of residues 4-8 and 10-13 residues are D-amino acids. In some active agents, each of residues 4-13 or 3-13 are D-amino acids. In some active agents, each of the eleven residues of the internalization peptide is a D-amino acid. Some exemplary active agents include ygrkkrrqrrrklssIESDV (SEQ ID NO:56), ygrkkrrqrrrklssiESDV (SEQ ID NO:57) ygrkkrrqrrrklsSIESDV (SEQ ID NO:58) ygrkkrrqrrrkISSIESDV (SEQ ID NO:59) ygrkkrrqrrrkssIESDV (SEQ ID NO:60), ygrkkrrqrrrksIESDV (SEQ ID NO:61), and ygrkkrrqrrrkIETDV (SEQ ID NO:62). Other active agents include variants of the above sequences in which the S at the third position from the C-terminal is replaced with T: ygrkkrrqrrrklssIETDV (SEQ ID NO:63), ygrkkrrqrrrklssiETDV (SEQ ID NO:64) ygrkkrrqrrrklsSIETDV (SEQ ID NO:65) ygrkkrrqrrrklSSIETDV (SEQ ID NO:66) ygrkkrrqrrrkssIETDV (SEQ ID NO:67), ygrkkrrqrrrksIETDV (SEQ ID NO:68), and ygrkkrrqrrrkIETDV (SEQ ID NO:69). Active agents include ygrkkrrqrrrIESDV (SEQ ID NO:70) (D-Tat-L-2B5c) and ygrkkrrqrrrIETDV (SEQ ID NO:71).
The invention also includes an active agent comprising an internalization peptide linked, e.g., as a fusion peptide, to an inhibitor peptide, which inhibits PSD-95 binding to NOS, wherein the internalization peptide has an amino acid sequence comprising YGRKKRRQRRR (SEQ ID NO:24), GRKKRRQRRR (SEQ ID NO:25), or RKKRRQRRR (SEQ ID NO:3) and the inhibitor peptide has a sequence comprising KLSSIESDV (SEQ ID NO:21), or a variant thereof with up to 1, 2, 3, 4, or 5 substitutions or deletions total in the internalization peptide and inhibitor peptide. In such active agents at least the four or five C-terminal amino acids of the inhibitor peptide are L-amino acids, and a contiguous segment of amino acids including all of the R and K residues and the residue immediately C-terminal to the most C-terminal R or K residue are D-amino acids. Thus, in a peptide having the sequence YGRKKRRQRRRKLSSIESDV (SEQ ID NO:54), a contiguous segment from the first R to the L residue are D-amino acids.
One example of permitted substitutions is provided by the motif [E/D/N/Q]-[S/T]-[D/E/Q/N]-[V/L] (SEQ ID NO:1) at the C-terminus of the inhibitor peptide. For example, the third amino acid from the C-terminus can be S or T. Preferably each of the five C-terminal amino acids of the inhibitor peptide are L-amino acids. Preferably every other amino acid is a D-amino acid as in the active agent ygrkkrrqrrrklssIESDV (SEQ ID NO:56), wherein the lower case letter are D-amino acids and the upper case letters are L-amino acids.
Preferred active agents with D-amino acids have enhanced stability in rat or human plasma compared with Tat-NR2B9c or an otherwise identical all L-active agent. Stability can be measured as in the examples. Preferred active have enhanced plasmin resistance compared with Tat-NR2B9c or an otherwise identical all L active agent. Plasmin resistance can be measured as in the examples. Active agents preferably bind to PSD-95 within 1.5-fold, 2-fold, 3 fold or 5-fold of Tat-NR2B9c (all L) or an otherwise identical all L peptide or have indistinguishable binding within experimental error. Preferred active agents compete for binding with Tat-NR2B9c for binding to PSD-95 (e.g., a ten-fold excess of active agent reduces Tat-NR2B9c binding) by at least 10%, 25% or 50%. Competition provides an indication that the active agent binds to the same or overlapping binding site as Tat-NR2B9c. Possession of the same or overlapping binding sites can also be shown by alanine mutagenesis of PSD-95. If mutagenesis of the same or overlapping set of residues reduces binding of an active agent and Tat-NR2B9c, then the active agent and TAT-NR2B9c bind to the same or overlapping sites on PSD-95.
Active agents of the invention can contain modified amino acid residues for example, residues that are N-alkylated. N-terminal alkyl modifications can include e.g., N-Methyl, N-Ethyl, N-Propyl, N-Butyl, N-Cyclohexylmethyl, N-Cyclyhexylethyl, N-Benzyl, N-Phenylethyl, N-phenylpropyl, N-(3, 4-Dichlorophenyl)propyl, N-(3,4-Difluorophenyl)propyl, and N-(Naphthalene-2-yl)ethyl). Active agents can also include retro peptides. A retro peptide has a reverse amino acid sequence. Peptidomimetics also include retro inverso peptides in which the order of amino acids is reversed from so the originally C-terminal amino acid appears at the N-terminus and D-amino acids are used in place of L-amino (e.g., acids vdseisslkrrrqrrkkrgy (SEQ ID NO:72), also known as RI-NA-1).
Appropriate pharmacological activity of peptides, peptidomimetics or other agent can be confirmed if desired, using previously described rat models of stroke before testing in the primate and clinical trials described in the present application. Peptides or peptidomimetics can also be screened for capacity to inhibit interactions between PSD-95 and NMDAR 2B using assays described in e.g., US 20050059597, which is incorporated by reference. Useful peptides or other agents typically have IC50 values of less than 50 μM, 25 μM, 10 μM, 0.1 μM or 0.01 μM in such an assay. Preferred peptides or other agents typically have an IC50 value of between 0.001-1 μM, and more preferably 0.001-0.05, 0.05-0.5 or 0.05 to 0.1 μM. When a peptide or other agent is characterized as inhibiting binding of one interaction, e.g., PSD-95 interaction to NMDAR2B, such description does not exclude that the peptide or agent also inhibits another interaction, for example, inhibition of PSD-95 binding to nNOS.
Peptides such as those just described can optionally be derivatized (e.g., acetylated, phosphorylated, myristoylated, geranylated, pegylated and/or glycosylated) to improve the binding affinity of the inhibitor, to improve the ability of the inhibitor to be transported across a cell membrane or to improve stability. As a specific example, for inhibitors in which the third residue from the C-terminus is S or T, this residue can be phosphorylated before use of the peptide.
Internalization peptides can be attached to pharmacological agents by conventional methods. For example, the agents can be joined to internalization peptides by chemical linkage, for instance via a coupling or conjugating agent. Numerous such agents are commercially available and are reviewed by S. S. Wong, Chemistry of Protein Conjugation and Cross-Linking, CRC Press (1991). Some examples of cross-linking reagents include J-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) or N,N′-(1,3-phenylene) bismaleimide; N,N′-ethylene-bis-(iodoacetamide) or other such reagent having 6 to 11 carbon methylene bridges (which relatively specific for sulfhydryl groups); and 1,5-difluoro-2,4-dinitrobenzene (which forms irreversible linkages with amino and tyrosine groups). Other cross-linking reagents include p,p′-difluoro-m, m′-dinitrodiphenylsulfone (which forms irreversible cross-linkages with amino and phenolic groups); dimethyl adipimidate (which is specific for amino groups); phenol-1,4-disulfonylchloride (which reacts principally with amino groups); hexamethylenediisocyanate or diisothiocyanate, or azophenyl-p-diisocyanate (which reacts principally with amino groups); glutaraldehyde (which reacts with several different side chains) and disdiazobenzidine (which reacts primarily with tyrosine and histidine).
A linker, e.g., a polyethylene glycol linker, can be used to dimerize the active moiety of the peptide or the peptidomimetic to enhance its affinity and selectivity towards proteins containing tandem PDZ domains. See e.g., Bach et al., (2009) Angew. Chem. Int. Ed. 48:9685-9689 and WO 2010/004003. A PL motif-containing peptide is preferably dimerized via joining the N-termini of two such molecules, leaving the C-termini free. Bach further reports that a pentamer peptide IESDV (SEQ ID NO:11) from the C-terminus of NMDAR 2B was effective in inhibiting binding of NMDAR 2B to PSD-95. IETDV (SEQ ID NO:13) can also be used instead of IESDV (SEQ ID NO:11). Optionally, about 2-10 copies of a PEG can be joined in tandem as a linker. Optionally, the linker can also be attached to an internalization peptide or lipidated to enhance cellular uptake. Examples of illustrative dimeric inhibitors are shown below (see Bach et al., PNAS 109 (2012) 3317-3322). Any of the PSD-95 inhibitors disclosed herein can be used instead of IETDV (SEQ ID NO:13), and any internalization peptide or lipidating moiety can be used instead of tat. Other linkers to that shown can also be used.
Internalization peptides can also be linked to inhibitor peptide as fusion peptides, preferably with the C-terminus of the internalization peptide linked to the N-terminus of the inhibitor peptide leaving the inhibitor peptide with a free C-terminus.
Instead of or as well as linking a peptide to an internalization peptide, such a peptide can be linked to a lipid (lipidation) to increase hydrophobicity of the conjugate relative to the peptide alone and thereby facilitate passage of the linked peptide across cell membranes and/or across the brain barrier. Lipidation is preferably performed on the N-terminal amino acid but can also be performed on internal amino acids, provided the ability of the peptide to inhibit interaction between PSD-95 and NMDAR 2B is not reduced by more than 50%. Preferably, lipidation is performed on an amino acid other than one of the five most C-terminal amino acids. Lipids are organic molecules more soluble in ether than water and include fatty acids, glycerides and sterols. Suitable forms of lipidation include myristoylation, palmitoylation or attachment of other fatty acids preferably with a chain length of 10-20 carbons, such as lauric acid and stearic acid, as well as geranylation, geranylgeranylation, and isoprenylation. Lipidations of a type occurring in posttranslational modification of natural proteins are preferred. Lipidation with a fatty acid via formation of an amide bond to the alpha-amino group of the N-terminal amino acid of the peptide is also preferred. Lipidation can be by peptide synthesis including a prelipidated amino acid, be performed enzymatically in vitro or by recombinant expression, by chemical crosslinking or chemical derivatization of the peptide. Amino acids modified by myristoylation and other lipid modifications are commercially available. Use of a lipid instead of an internalization peptide reduces the number of K and R residues providing sites of plasmin cleavage. Some exemplary lipidated molecules include KLSSIESDV (SEQ ID NO:21), kISSIESDV (SEQ ID NO:73), ISSIESDV (SEQ ID NO:74), LSSIESDV (SEQ ID NO:75), SSIESDV (SEQ ID NO:76), SIESDV (SEQ ID NO:77), IESDV (SEQ ID NO:11), KLSSIETDV (SEQ ID NO:22), kISSIETDV (SEQ ID NO:78), ISSIETDV (SEQ ID NO:79), LSSIETDV (SEQ ID NO:80), SSIETDV (SEQ ID NO:81), SIETDV (SEQ ID NO:82), IETDV (SEQ ID NO:13) with lipidation preferably at the N-terminus.
Inhibitor peptides, optionally fused to internalization peptides, can be synthesized by solid phase synthesis or recombinant methods. Peptidomimetics can be synthesized using a variety of procedures and methodologies described in the scientific and patent literature, e.g., Organic Syntheses Collective Volumes, Gilman et al. (Eds) John Wiley & Sons, Inc., NY, al-Obeidi (1998) Mol. Biotechnol. 9:205-223; Hruby (1997) Curr. Opin. Chem. Biol. 1:114-119; Ostergaard (1997) Mol. Divers. 3:17-27; Ostresh (1996) Methods Enzymol. 267:220-234.
Peptides of the type described above are typically made by solid state synthesis. Because solid state synthesis uses trifluoroacetate (TFA) to remove protecting groups or remove peptides from a resin, peptides are typically initially produced as trifloroacetate salts. The trifluoroacetate can be replaced with another anion by for example, binding the peptide to a solid support, such as a column, washing the column to remove the existing counterion, equilibrating the column with a solution containing the new counterion and then eluting the peptide, e.g., by introducing a hydrophobic solvent such as acetonitrile into the column. Replacement of trifluoroacetate with acetate can be done with an acetate wash as the last step before peptide is eluted in an otherwise conventional solid state synthesis. Replacing trifluoroacetate or acetate with chloride can be done with a wash with ammonium chloride followed by elution. Use of a hydrophobic support is preferred and preparative reverse phase HPLC is particularly preferred for the ion exchange. Trifluoroacetate can be replaced with chloride directly or can first be replaced by acetate and then the acetate replaced by chloride.
Counterions, whether trifluoroacetate, acetate or chloride, bind to positively charged atoms on Tat-NR2B9c and D-variants thereof, particularly the N-terminal amino group and amino side chains arginine and lysine residues. Although practice of the invention, it is not dependent on understanding the exact stoichiometry of peptide to anion in a salt of Tat-NR2B9c and its D-variants, it is believed that up to about 9 counterion molecules are present per molecule of salt.
Although replacement of one counterion by another takes place efficiently, the purity of the final counterion may be less than 100%. Thus, reference to a chloride salt of Tat-NR2B9c or its D-variants described herein means that in a preparation of the salt, chloride is the predominant anion by weight (or moles) over all other anions present in the aggregate in the salt. In other words, chloride constitutes greater than 50% and preferably greater than 75%, 95%, 99%, 99.5% or 99.9% by weight or moles of the all anions present in the salt or formulation thereof. In such a salt or formulation prepared from the salt, acetate and trifluoroacetate in combination and individually constitutes less than 50%, 25%, 5%, 1%, 0.5% or 0.1 of the anions in the salt or formulation.
Active agents can be incorporated into liquid formulation or lyophilized formulations. A liquid formulation can include a buffer, salt and water. A preferred buffer is sodium phosphate. A preferred salt is sodium chloride. The pH can be e.g., pH7.0 or about physiological.
Lyophilized formulations can be prepared from a prelyophilized formulation comprising an active agent, a buffer, a bulking agent and water. Other components, such as cryo or lyopreservatives, a tonicity agent pharmaceutically acceptable carriers and the like may or may be present. A preferred buffer is histidine. A preferred bulking agent is trehalose. Trehalose also serves as a cryo and lyo-preservative. An exemplary prelyophilized formulation comprises the active agent, histidine (10-100 mM, 15-100 mM 15-80 mM, 40-60 mM or 15-60 mM, for example, 20 mM or optionally 50 mM, or 20-50 mM)) and trehalose (50-200 mM, preferably 80-160 mM, 100-140 mM, more preferably 120 mM). The pH is 5.5 to 7.5, more preferably, 6-7, more preferably 6.5. The concentration of active agent is 20-200 mg/ml, preferably 50-150 mg/ml, more preferably 70-120 mg/ml or 90 mg/ml. Thus, an exemplary prelyophilized formulation is 20 mM histidine, 120 mM trehalose, and 90 mg/ml chloride salt of active agent. Optionally an acetylation scavenger, such as lysine can be included, as described in U.S. Pat. No. 10,206,878, to further reduce any residual acetate or trifluoroacetate in the formulation
After lyophilization, lyophilized formulations have a low-water content, preferably from about 0%-5% water, more preferably below 2.5% water by weight. Lyophilized formulations can be stored in a freezer (e.g., −20 or −70° C.), in a refrigerator (0-40° C.) or at room temperature (20-25° C.).
Active agents are reconstituted in an aqueous solution, preferably water for injection or optionally normal saline (0.8-1.0% saline and preferably 0.9% saline). Reconstitution can be to the same or a smaller or larger volume than the prelyophilized formulation. Preferably, the volume is larger post-reconstitution than before (e.g., 3-6 times larger). For example, a prelyophilization volume of 3-5 ml can be reconstituted as a volume of 10 mL, 12 mL, 13.5 ml, 15 mL or 20 mL or 10-20 mL among others. After reconstitution, the concentration of histidine is preferably 2-20 mM, e.g., 2-7 mM, 4.0-6.5 mM, 4.5 mM or 6 mM; the concentration of trehalose is preferably 15-45 mM or 20-40 mM or 25-27 mM or 35-37 mM. The concentration of lysine is preferably 100-300 mM, e.g., 150-250 mM, 150-170 mM or 210-220 mM. The active agent is preferably at a concentration of 10-30 mg/ml, for example 15-30, 18-20, 20 mg/ml of active agent or 25-30, 26-28 or 27 mg/mL active agent. An exemplary formulation after reconstitution has 4-5 mM histidine, 26-27 mM trehalose, 150-170 mM lysine and 20 mg/ml active agent (with concentrations rounded to the nearest integer). A second exemplary formulation after reconstitution has 5-7 mM histidine, 35-37 mM trehalose, 210-220 mM lysine and 26-28 mg/ml active agent (with concentrations rounded to the nearest integer). The reconstituted formulation can be further diluted before administration such as by adding into a fluid bag containing normal saline.
The present methods are useful for treating conditions resulting from ischemia, particularly ischemia of the CNS, and more particularly ischemic stroke. Treatment with a thrombolytic agent or mechanical reperfusion acts to remove a blockage in a blood vessel causing ischemia. Treatment with an active agent that inhibits PSD-95 acts to reduce damaging effects of ischemia.
A stroke is a condition resulting from impaired blood flow in the CNS regardless of cause. Potential causes include embolism, hemorrhage and thrombosis. Some neuronal cells die immediately as a result of impaired blood flow. These cells release their component molecules including glutamate, which in turn activates NMDA receptors, which raise intracellular calcium levels, and intracellular enzyme levels leading to further neuronal cell death (the excitotoxicity cascade). The death of CNS tissue is referred to as infarction. Infarction Volume (i.e., the volume of dead neuronal cells resulting from stroke in the brain) can be used as an indicator of the extent of pathological damage resulting from stroke. The symptomatic effect depends both on the volume of an infarction and where in the brain it is located. Disability index can be used as a measure of symptomatic damage, such as the Rankin Stroke Outcome Scale (Rankin, Scott Med J; 2:200-15 (1957)) and the Barthel Index. The Rankin Scale is based on assessing directly the global conditions of a patient as follows.
The Barthel Index is based on a series of questions about the patient's ability to carry out 10 basic activities of daily living resulting in a score between 0 and 100, a lower score indicating more disability (Mahoney et al, Maryland State Medical Journal 14:56-61 (1965)).
Alternatively stroke severity/outcomes can be measured using the NIH stroke scale, available at world wide web ninds.nih.gov/doctors/NIH Stroke ScaleJBooklet.pdf.
The scale is based on the ability of a patient to carry out 11 groups of functions that include assessments of the patient's level of consciousness, motor, sensory and language functions.
An ischemic stroke refers more specifically to a type of stroke that caused by blockage of blood flow to the brain. The underlying condition for this type of blockage is most commonly the development of fatty deposits lining the vessel walls. This condition is called atherosclerosis. These fatty deposits can cause two types of obstruction. Cerebral thrombosis refers to a thrombus (blood clot) that develops at the clogged part of the vessel “Cerebral embolism” refers generally to a blood clot that forms at another location in the circulatory system, usually the heart and large arteries of the upper chest and neck. A portion of the blood clot then breaks loose, enters the bloodstream and travels through the brain's blood vessels until it reaches vessels too small to let it pass. A second important cause of embolism is an irregular heartbeat, known as arterial fibrillation. It creates conditions in which clots can form in the heart, dislodge and travel to the brain. Additional potential causes of ischemic stroke are hemorrhage, thrombosis, dissection of an artery or vein, a cardiac arrest, shock of any cause including hemorrhage, and iatrogenic causes such as direct surgical injury to brain blood vessels or vessels leading to the brain or cardiac surgery. Ischemic stroke accounts for about 83 percent of all cases of stroke.
Transient ischemic attacks (TIAs) are minor or warning strokes. In a TIA, conditions indicative of an ischemic stroke are present and the typical stroke warning signs develop. However, the obstruction (blood clot) occurs for a short time and tends to resolve itself through normal mechanisms. Patients undergoing heart surgery are at particular risk of transient cerebral ischemic attack.
Hemorrhagic stroke accounts for about 17 percent of stroke cases. It results from a weakened vessel that ruptures and bleeds into the surrounding brain. The blood accumulates and compresses the surrounding brain tissue. The two general types of hemorrhagic strokes are intracerebral hemorrhage and subarachnoid hemorrhage. Hemorrhagic stroke result from rupture of a weakened blood vessel ruptures. Potential causes of rupture from a weakened blood vessel include a hypertensive hemorrhage, in which high blood pressure causes a rupture of a blood vessel, or another underlying cause of weakened blood vessels such as a ruptured brain vascular malformation including a brain aneurysm, arteriovenous malformation (AVM) or cavernous malformation. Hemorrhagic strokes can also arise from a hemorrhagic transformation of an ischemic stroke which weakens the blood vessels in the infarct, or a hemorrhage from primary or metastatic tumors in the CNS which contain abnormally weak blood vessels. Hemorrhagic stroke can also arise from iatrogenic causes such as direct surgical injury to a brain blood vessel. An aneurysm is a ballooning of a weakened region of a blood vessel. If left untreated, the aneurysm continues to weaken until it ruptures and bleeds into the brain. An arteriovenous malformation (AVM) is a cluster of abnormally formed blood vessels. A cavernous malformation is a venous abnormality that can cause a hemorrhage from weakened venous structures. Any one of these vessels can rupture, also causing bleeding into the brain. Hemorrhagic stroke can also result from physical trauma. Hemorrhagic stroke in one part of the brain can lead to ischemic stroke in another through shortage of blood lost in the hemorrhagic stroke.
One patient class amenable to treatments are patients undergoing a surgical procedure that involves or may involve a blood vessel supplying the brain, or otherwise on the brain or CNS. Some examples are patients undergoing cardiopulmonary bypass, carotid stenting, diagnostic angiography of the brain or coronary arteries of the aortic arch, vascular surgical procedures and neurosurgical procedures. Additional examples of such patients are discussed in section IV above. Patients with a brain aneurysm are particularly suitable. Such patients can be treated by a variety of surgical procedures including clipping the aneurysm to shut off blood, or performing endovascular surgery to block the aneurysm with small coils or introduce a stent into a blood vessel from which an aneurysm emerges, or inserting a microcatheter. Endovascular procedures are less invasive than clipping an aneurysm and are associated with a better patient outcome but the outcome still includes a high incidence of small infarctions. Such patients can be treated with an inhibitor of PSD95 interaction with NMDAR 2B and particularly the agents described above. The timing of administration relative to performing surgery can be as described above for the clinical trial.
Another class of subjects is those with ischemic strokes who are candidates for endovascular thrombectomy to remove the clot, such as the ESCAPE-NA1 trial (NCT02930018). Drug can be administered before or after the surgery to remove the clot, and is expected to improve outcome from both the stroke itself and any potential iatrogenic strokes associated with the procedures as discussed supra. Another example is those who have been diagnosed with a potential stroke without the use of imaging criteria and receive treatment within hours of the stroke, preferably within the first 3 hours but optionally the first 6, 9 or 12 hour after stroke onset (similar to NCT02315443).
VI. Co-Administration of Active Agent that Inhibits PSD-95 with Reperfusion
Plaques and blood clots (also known as emboli) causing ischemia can be dissolved, removed or bypassed by both pharmacological and physical means. The dissolving, removal of plaques and blood clots and consequent restoration of blood flow is referred to as reperfusion. One class of agents acts by thrombolysis. Thrombolytic agents work by promoting production of plasmin from plasminogen. Plasmin clears cross-linked fibrin mesh (the backbone of a clot), making the clot soluble and subject to further proteolysis by other enzymes, and restores blood flow in occluded blood vessels. Examples of thrombolytic agents include tissue plasminogen activator t-PA, alteplase) (ACTIVASE®, reteplase) (RETAVASE®, tenecteplase) (TNKase®, anistreplase) (EMINASE®, streptokinase (KABIKINASE®, STREPTASE®), and urokinase) (ABBOKINASE®).
Another class of drugs that can be used for reperfusion is vasodilators. These drugs act by relaxing and opening up blood vessels thus allowing blood to flow around an obstruction. Some examples of types of vasodilator agents include alpha-adrenoceptor antagonists (alpha-blockers), Angiotensin receptor blockers (ARBs), β-2-adrenoceptor agonists, calcium-channel blockers (CCBs), centrally acting sympatholytics, direct acting vasodilators, endothelin receptor antagonists, ganglionic blockers, nitrodilators, phosphodiesterase inhibitors, potassium-channel openers, and renin inhibitors.
Another class of drugs that can be used for reperfusion is hypertensive agents (i.e., drugs raising blood pressure), such as epinephrine, phenylephrine, pseudoephedrine, norepinephrine; norephedrine; terbutaline; salbutamol; and methylephedrine. Increased perfusion pressure can increase flow of blood around an obstruction.
Mechanical methods of reperfusion include angioplasty, catheterization, and artery bypass graft surgery, stenting, embolectomy, endarterectomy or endovascular thrombectomy. Such procedures restore plaque flow by mechanical removal of a plaque, holding a blood vessel open, so blood can flow around a plaque or bypassing a plaque.
Other mechanical methods of reperfusion include use of a device that diverts blood flow from other areas of the body to the brain. An example is a catheter partially occluding the aorta, such as the CoAxia NeuroFlo™ catheter device, which has recently been subjected to a randomized trial and may get FDA approval for stroke treatment. This device has been used on subjects presenting with stroke up to 14 hours after onset of ischemia.
The present methods provide regimes for administering both reperfusion and an active agent that inhibits PSD-95, such that they can both contribute to treatment. Such regimes administer PSD-95 in sufficient time before restoration of blood flow by reperfusion such that the active agent that inhibits PSD-95 can inhibit damage from reperfusion as described in the Background section. Such regimes also avoid administering a plasmin-sensitive active agent that inhibits PSD-95 and a thrombolytic agent sufficiently proximal in time that there is substantial co-residency in the plasma of both the active agent that inhibits PSD-95 and plasmin induced by the thrombolytic agent resulting in cleavage of the active agent that inhibits PSD-95 and reduced or eliminated activity of the active agent that inhibits PSD-95. Although in much of the description that follows Tat-NR2B9c is referred to as an exemplary active agent, the same methods should be understood as referring to other active agents that inhibit PSD-95 as described herein.
For inhibiting damage from reperfusion or reperfusion injury, an active agent that inhibits PSD-95 should be administered before restoration of blood flow by reperfusion Restoration of blood flow can be determined by MRI or CT imaging or TICI (thrombolysis in cerebral infarction) imaging. Preferably, the active agent that inhibits PSD-95 should be administered at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 min before restoration of blood flow. For endovascular thrombectomy, groin puncture can be used as a point of initiating reperfusion (prior to restoration of blood flow). In this case, an active agent that inhibits PSD-95 is preferably administered not later than 5 minutes after groin puncture, and more preferably before groin puncture.
Tat-NR2B9c has a plasma half-life in human plasma of about ten minutes. This does not mean that Tat-NR2B9c is normally half-degraded after ten minutes in plasma, but rather than Tat-NR2B9c is moved out of the plasma with a half-life of ten minutes. Alteplase (a recombinant form of tPA) has a half-life in human plasma of only about five minutes. But more significant for present purposes is the half-life of plasmin, which is induced by alteplase and other thrombolytic agents and is responsible for cleavage of Tat-NR2B9c. Plasmin has been reported to have a half-life in human plasma of about 4-8 hr.
It follows from the respective half-lives of Tat-NR2B9c and plasmin that interaction between the two can be avoided by administering Tat-NR2B9c at least one plasma half-life of Tat-NR2B9c (i.e., about ten minutes) before administering the thrombolytic agent. A greater interval of 2 or 3 half-lives, such that Tat-NR2B9c is administered at least 20 or 30 minutes before a thrombolytic agent still further reduces co-residency in the plasma and consequent potential for inactivation of Tat-NR2B9c and the thrombolytic agent. For administration of Tat-NR2B9c over a ten minute period, as is typical, administration of a thrombolytic agent ten minutes after the end of Tat-NR2B9c administration is equivalent to administering the thrombolytic agent twenty minutes after the start of Tat-NR2B9c administration. Likewise administering 20 minutes after the end is equivalent to administering 30 minutes after the start and so forth. Administering Tat-NR2B9c even further in advance of a thrombolytic agent, such as at least 45 min, 1 hr, 2 hr, 3 hr, 5 hr reduces potential for inactivation of Tat-NR2B9c still further. Cleavage can also be avoided by administering an active agent that inhibits PSD-95 at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow, i.e., the same interval as allows the active agent that inhibits PSD-95 to inhibit reperfusion injury.
An active agent that inhibits PSD-95 and a thrombolytic agent should not be administered together either as a single composition or co-administered separate compositions.
In subjects with or suspected of having ischemia, who have not yet received any treatment, and in which the relative order of treatments can be controlled, it is preferable to treat with an active agent that inhibits PSD-95 first and then wait a suitable interval as discussed above to administer a thrombolytic agent notwithstanding conventional wisdom in the field that thrombolytic agents should be administered as soon as possible to mitigate on-going death of neuronal cells, and at least before 3 hours or 4.5 hour after onset of stroke. The interval between administering an active agent that inhibits PSD-95 and a thrombolytic agent can be used for performing additional testing to confirm presence of ischemic stroke and eliminate presence or risk of hemorrhagic stroke or other hemorrhage for which administration of a thrombolytic agent would be counter-indicated. Prior administration of the active agent that inhibits PSD-95 also had the advantage of prolonging the window in which the thrombolytic agent is likely to be effective after onset of ischemia. In the absence of an active agent that inhibits PSD-95 the window is only about 3-4.5 hr but it can be prolonged by a PSD-95 inhibit to at least 5, 6, 9, 12 or 24 hours.
If it has already been determined that a subject has ischemic stroke and is eligible for treatment with a thrombolytic agent (e.g., lack of hemorrhage), then it can be preferable to administer an active agent that inhibits PSD-95 before restoration of blood flow by reperfusion even if this means the thrombolytic agent is administered after the 3 or 4.5 hour time point beyond which conventional wisdom would consider it ineffective.
Populations of subjects undergoing treatment population can represent for example subjects treated by the same physician or by the same institution. Such a population can include at least 10, 50, 100 or 500 subjects. In some populations, each subject receives an active agent that inhibits PSD-95 at an interval of at least 10, 15, 20, 22, 25, 30, 40, 50 or 60 minutes before restoration of blood flow by reperfusion. Subjects in such populations can vary in the form of reperfusion received, such as by mechanical means, thrombolytic agent, hypertensive agent or vasodilator. In some populations, no subject receives an active agent that inhibits PSD-95 at less than the interval before restoration of blood flow by reperfusion therapy.
Both treatment with an active agent and reperfusion therapy independently have ability to reduce infarction size and functional deficits due to ischemia and reperfusion. When used in combination according to the present methods, the reduction in infarction size and/or functional deficits is preferably greater than that from use of either agent or procedure alone administered under a comparable regime other than for the combination (i.e., co-operative). More preferably, the reduction in infarction side and/or functional deficits is at least additive or preferably more than additive (i.e., synergistic) of reductions achieved by the agents (or reperfusion procedure) alone under a comparable regime except for the combination. In some regimes, the reperfusion therapy is effective in reducing infarction size and/or functional times at a time post onset of ischemia (e.g., more than 4.5 hr) when it would be ineffective but for the concurrent or prior administration of the active agent that inhibits PSD-95. Put another way, when a subject is administered an active agent and reperfusion therapy, the reperfusion therapy is preferably at least as effective as it would be if administered at an earlier time without the active agent. Thus, the active agent effectively increases the efficacy of the reperfusion therapy by reducing one or more damaging effects of ischemia before or as reperfusion therapy takes effects. The active agent can thus compensate for delay in administering the reperfusion therapy whether the delay be from delay in the subject recognizing the danger of his or her initial symptoms delays in transporting a subject to a hospital or other medical institution or delays in performing diagnostic procedures to establish presence of ischemia and/or absence of hemorrhage or unacceptable risk thereof. Statistically significant combined effects of an active agent and reperfusion therapy including additive or synergistic effects can be demonstrated between populations in a clinical trial or between populations of animal models in preclinical work.
An active agent is administered in an amount, frequency and route of administration effective to cure, reduce or inhibit further deterioration of at least one sign or symptom of a disease in a subject having the disease being treated. A therapeutically effective amount (before administration) or therapeutically effective plasma concentration after administration means an amount or level of active agent sufficient significantly to cure, reduce or inhibit further deterioration of at least one sign or symptom of the disease or condition to be treated in a population of subjects (or animal models) suffering from the disease treated with an agent of the invention relative to the damage in a control population of subjects (or animal models) suffering from that disease or condition who are not treated with the agent. The amount or level is also considered therapeutically effective if an individual treated subject achieves an outcome more favorable than the mean outcome in a control population of comparable subjects not treated by methods of the invention. A therapeutically effective regime involves the administration of a therapeutically effective dose at a frequency and route of administration needed to achieve the intended purpose.
For a subject suffering from stroke or other ischemic condition, the active agent is administered in a regime comprising an amount frequency and route of administration effective to reduce the damaging effects of stroke or other ischemic condition. When the condition requiring treatment is stroke, the outcome can be determined by infarction volume or disability index, and a dosage is considered therapeutically effective if an individual treated subject shows a disability of two or less on the Rankin scale and 75 or more on the Barthel scale, or if a population of treated subjects shows a significantly improved (i.e., less disability) distribution of scores on a disability scale than a comparable untreated population, see Lees et al., N. Engl. J. Med. 2006; 354:588-600. A single dose of agent can be sufficient for treatment of stroke.
The invention also provides methods and formulations for the prophylaxis of a disorder in a subject at risk of that disorder. Usually such a subject has an increased likelihood of developing the disorder (e.g., a condition, illness, disorder or disease) relative to a control population. The control population for instance can comprise one or more individuals selected at random from the general population (e.g., matched by age, gender, race and/or ethnicity) who have not been diagnosed or have a family history of the disorder. A subject can be considered at risk for a disorder if a “risk factor” associated with that disorder is found to be associated with that subject. A risk factor can include any activity, trait, event or property associated with a given disorder, for example, through statistical or epidemiological studies on a population of subjects. A subject can thus be classified as being at risk for a disorder even if studies identifying the underlying risk factors did not include the subject specifically. For example, a subject undergoing heart surgery is at risk of transient cerebral ischemic attack because the frequency of transient cerebral ischemic attack is increased in a population of subjects who have undergone heart surgery as compared to a population of subjects who have not.
Other common risk factors for stroke include age, family history, gender, prior incidence of stroke, transient ischemic attack or heart attack, high blood pressure, smoking, diabetes, carotid or other artery disease, atrial fibrillation, other heart diseases such as heart disease, heart failure, dilated cardiomyopathy, heart valve disease and/or congenital heart defects; high blood cholesterol, and diets high in saturated fat, trans fat or cholesterol.
In prophylaxis, an active agent or procedure is administered to a subject at risk of a disease but not yet having the disease in an amount, frequency and route sufficient to prevent, delay or inhibit development of at least one sign or symptom of the disease. A prophylactically effective amount before administration or plasma level after administration means an amount or level of agent sufficient significantly to prevent, inhibit or delay at least one sign or symptom of the disease in a population of subjects (or animal models) at risk of the disease relative treated with the agent compared to a control population of subjects (or animal models) at risk of the disease not treated with an active agent of the invention. The amount or level is also considered prophylactically effective if an individual treated subject achieves an outcome more favorable than the mean outcome in a control population of comparable subjects not treated by methods of the invention. A prophylactically effective regime involves the administration of a prophylactically effective dose at a frequency and route of administration needed to achieve the intended purpose. For prophylaxis of stroke in a subject at imminent risk of stroke (e.g., a subject undergoing heart surgery), a single dose of agent is usually sufficient.
Depending on the agent, administration can be parenteral, intravenous, intrapulmonary, nasal, oral, subcutaneous, intra-arterial, intracranial, intrathecal, intraperitoneal, topical, intranasal or intramuscular.
For intravenous administration, the claimed agents can be administered without anti-inflammatory e.g., up to 3 mg/kg, 0.1-3 mg/kg, 2-3 mg/kg or 2.6 mg/kg, or at higher dosages, e.g., at least 5, 10, 15, 20 or 25 mg/kg with an anti-inflammatory. For routes such as subcutaneous, intranasal, intrapulmonary or intramuscular, the dose can be up to 10, 15, 20 or 25 mg/kg with or without an anti-inflammatory. The need for an-inflammatory at higher doses can alternatively be reduced or eliminated by administration of the active agent over a longer time period (e.g., administration in less than 1 minute, 1-10 minutes, and greater than ten minutes constitute alternative regimes in which for constant dosage histamine release and need for an anti-inflammatory is reduced or eliminated with increased time period).
The active agents can be administered as a single dose or as a multi-dose regime. A single dose regime can be used for treatment of an acute condition, such as acute ischemic stroke, to reduce infarction and cognitive deficits. Such a dose can be administered before onset of the condition if the timing of the condition is predictable such as with a subject undergoing neurovascular surgery, or within a window after the condition has developed (e.g., up to 1, 3, 6 or 12 hours later).
A multi-dose regime can be designed to maintain the active agent at a detectable level in the plasma over a prolonged period of time, such as at least 1, 3, 5 or 10 days, or at least a month, three months, six months or indefinitely. For example, the active agents can be administered every hour, 2, 3, 4, 6, or 12 times per day, daily, every other day, weekly and so forth. Such a regime can reduce initial deficits from an acute condition as for single dose administration and thereafter promote recovery from such deficits as still develop. Such a regime can also be used for treating chronic conditions, such as Alzheimer's and Parkinson's disease. Active agents are sometimes incorporated into a controlled release formulation for use in a multi-dose regime. Alternatively, multiple smaller doses could be administered over a shorter period to achieve neuroprotection without triggering histamine release, or given as a slow infusion if administered intravenously.
Active agents can be prepared with carriers that protect the compound against rapid elimination from the body, such as controlled formulations or coatings. Such carriers (also known as modified, delayed, extended or sustained release or gastric retention dosage forms, such as the DEPOMED GR™ system in which agents are encapsulated by polymers that swell in the stomach and are retained for about eight hours, sufficient for daily dosing of many drugs). Controlled release systems include microencapsulated delivery systems, implants and biodegradable, biocompatible polymers such as collagen, ethylene vinyl acetate, polyanhydrides, polyglycolic acid, polyorthoesters, polylactic acid, matrix controlled release devices, osmotic controlled release devices, multiparticulate controlled release devices, ion-exchange resins, enteric coatings, multilayered coatings, microspheres, nanoparticles, liposomes, and combinations thereof. The release rate of an active agent can also be modified by varying the particle size of the active agent: Examples of modified release include, e.g., those described in U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809; 3,598,123; 4,008,719; 5,674,533; 5,059,595; 5,591,767; 5,120,548; 5,073,543; 5,639,476; 5,354,556; 5,639,480; 5,733,566; 5,739,108; 5,891,474; 5,922,356; 5,972,891; 5,980,945; 5,993,855; 6,045,830; 6,087,324; 6,113,943; 6,197,350; 6,248,363; 6,264,970; 6,267,981; 6,376,461; 6,419,961; 6,589,548; 6,613,358; and 6,699,500.
V. Co-Administration with Anti-Inflammatories
Depending on the dose and route of administration the active agents of the invention can induce an inflammatory response characterized by mast cell degranulation and release of histamine and its sequelae. For example, dosages of at least 3 mg/kg are associated with histamine release for IV administration, and at least 10 mg/kg for other routes.
A wide variety of anti-inflammatory agents are readily available to inhibit one or more aspects of the of the inflammatory response. A preferred class of anti-inflammatory agent is mast cell degranulation inhibitors. This class of compounds includes cromolyn (5,5′-(2-hydroxypropane-1,3-diyl)bis(oxy)bis(4-oxo-4H-chromene-2-carboxylic acid) (also known as cromoglycate), and 2-carboxylatochromon-5′-yl-2-hydroxypropane derivatives such as bis(acetoxymethyl), disodium cromoglycate, nedocromil (9-ethyl-4,6-dioxo-10-propyl-6,9-dihydro-4H-pyrano[3,2-g]quinoline-2,8-di-carboxylic acid) and tranilast (2-{[(2E)-3-(3,4-dimethoxyphenyl)prop-2-enoyl]amino}), and lodoxamide (2-[2-chloro-5-cyano-3-(oxaloamino)anilino]-2-oxoacetic acid). Reference to a specific compound includes pharmaceutically acceptable salts of the compound Cromolyn is readily available in formulations for nasal, oral, inhaled or intravenous administration. Although practice of the invention is not dependent on an understanding of mechanism, it is believed that these agents act at an early stage of inflammatory response induced by an internalization peptide and are thus most effective at inhibiting development of its sequelae including a transient reduction in blood pressure. Other classes of anti-inflammatory agent discussed below serve to inhibit one or more downstream events resulting from mast cell degranulation, such as inhibiting histamine from binding to an H1 or H2 receptor, but may not inhibit all sequelae of mast cell degranulation or may require higher dosages or use in combinations to do so. Table 1 below summarizes the names, chemical formulate and FDA status of several mast cell degranulation inhibitors that can be used with the invention.
Another class of anti-inflammatory agent is anti-histamine compounds. Such agents inhibit the interaction of histamine with its receptors thereby inhibiting the resulting sequelae of inflammation noted above. Many anti-histamines are commercially available, some over the counter. Examples of anti-histamines are azatadine, azelastine, burfroline, cetirizine, cyproheptadine, doxantrozole, etodroxizine, forskolin, hydroxyzine, ketotifen, oxatomide, pizotifen, proxicromil, N,N′-substituted piperazines or terfenadine. Anti-histamines vary in their capacity to block anti-histamine in the CNS as well as peripheral receptors, with second and third generation anti-histamines having selectivity for peripheral receptors. Acrivastine, Astemizole, Cetirizine, Loratadine, Mizolastine, Levocetirizine, Desloratadine, and Fexofenadine are examples of second and third generation anti-histamines. Anti-histamines are widely available in oral and topical formulations. Some other anti-histamines that can be used are summarized in Table 2 below.
Another class of anti-inflammatory agent useful in inhibiting the inflammatory response is corticosteroids. These compounds are transcriptional regulators and are powerful inhibitors of the inflammatory symptoms set in motion by release of histamine and other compounds resulting from mast cell degranulation. Examples of corticosteroids are Cortisone, Hydrocortisone (Cortef), Prednisone (Deltasone, Meticorten, Orasone), Prednisolone (Delta-Cortef, Pediapred, Prelone), Triamcinolone (Aristocort, Kenacort), Methylprednisolone (Medrol), Dexamethasone (Decadron, Dexone, Hexadrol), and Betamethasone (Celestone). Corticosteriods are widely available in oral, intravenous and topical formulations.
Nonsteroidal anti-inflammatory drugs (NSAIDs) can also be used. Such drugs include aspirin compounds (acetylsalicylates), non-aspirin salicylates, diclofenac, diflunisal, etodolac, fenoprofen, flurbiprofen, ibuprofen, indomethacin, ketoprofen, meclofenamate, naproxen, naproxen sodium, phenylbutazone, sulindac, and tometin. However, the anti-inflammatory effects of such drugs are less effective than those of anti-histamines or corticosteroids. Stronger anti-inflammatory drugs such as azathioprine, cyclophosphamide, leukeran, and cyclosporine can also be used but are not preferred because they are slower acting and/or associated with side effects. Biologic anti-inflammatory agents, such as TYSABRI® or HUMIRA®, can also be used but are not preferred for the same reasons.
Different classes of drugs can be used in combinations in inhibiting an inflammatory response. A preferred combination is a mast cell degranulation inhibitor and an anti-histamine.
In methods in which an inhibitor peptide linked to an internalization peptide is administered with an anti-inflammatory agent, the two entities are administered sufficiently proximal in time that the anti-inflammatory agent can inhibit an inflammatory response inducible by the internalization peptide. The anti-inflammatory agent can be administered before, at the same time as or after the active agent. The preferred time depends in part on the pharmacokinetics and pharmacodynamics of the anti-inflammatory agent. The anti-inflammatory agent can be administered at an interval before the active agent such that the anti-inflammatory agent is near maximum serum concentration at the time the active agent is administered. Typically, the anti-inflammatory agent is administered between 6 hours before the active agent and one hour after. For example, the anti-inflammatory agent can be administered between 1 hour before and 30 min after the active agent. Preferably the anti-inflammatory agent is administered between 30 minutes before and 15 minutes after the active agent, and more preferably within 15 minutes before and the same time as the active agent. In some methods, the anti-inflammatory agent is administered before the active agent within a period of 15, 10 or 5 minutes before the active agent is administered. In some methods, the anti-inflammatory agent is administered 1-15, 1-10 or 1-5 minutes before the active agent.
When an anti-inflammatory agent is said to be able to inhibit the inflammatory response of an inhibitor peptide linked to an internalization peptide what is meant is that the two are administered sufficiently proximate in time that the anti-inflammatory agent would inhibit an inflammatory response inducible by the active agent linked to the internalization peptide if such a response occurs in a particular subject, and does not necessarily imply that such a response occurs in that patient. Some patients are treated with a dose of active agent linked to an internalization peptide that is associated with an inflammatory response in a statistically significant number of subjects in a controlled clinical or nonclinical trial. It can reasonably be assumed that a significant proportion of such subjects although not necessarily all develop an anti-inflammatory response to the active agent linked to the internalization peptide. In some subjects, signs or symptoms of an inflammatory response to the inhibitor peptide linked to the internalization peptide are detected or detectable.
In clinical treatment of an individual subject, it is not usually possible to compare the inflammatory response from an inhibitor peptide linked to an internalization peptide in the presence and absence of an anti-inflammatory agent. However, it can reasonably be concluded that the anti-inflammatory agent inhibits an anti-inflammatory response inducible by the internalization peptide if significant inhibition is seen under the same or similar conditions of co-administration in a controlled clinical or pre-clinical trial. The results in the subject (e.g., blood pressure, heart rate, hives) can also be compared with the typical results of a control group in a clinical trial as an indicator of whether inhibition occurred in the individual subject. Usually, the anti-inflammatory agent is present at a detectable serum concentration at some point within the time period of one hour after administration of the active agent. The pharmacokinetics of many anti-inflammatory agents is widely known and the relative timing of administration of the anti-inflammatory agent can be adjusted accordingly. The anti-inflammatory agent is usually administered peripherally, i.e., segregated by the blood brain barrier from the brain. For example, the anti-inflammatory agent can be administered orally, nasally, intravenously or topically depending on the agent in question. If the anti-inflammatory agent is administered at the same time as the active agent, the two can be administered as a combined formulation or separately.
In some methods, the anti-inflammatory agent is one that does not cross the blood brain barrier when administered orally or intravenously at least in sufficient amounts to exert a detectable pharmacological activity in the brain. Such an agent can inhibit mast cell degranulation and its sequelae resulting from administration of the active agent in the periphery without itself exerting any detectable therapeutic effects in the brain. In some methods, the anti-inflammatory agent is administered without any co-treatment to increase permeability of the blood brain barrier or to derivatize or formulate the anti-inflammatory agent so as to increase its ability to cross the blood brain barrier. However, in other methods, the anti-inflammatory agent, by its nature, derivatization, formulation or route of administration, may by entering the brain or otherwise influencing inflammation in the brain, exert a dual effect in suppressing mast-cell degranulation and/or its sequelae in the periphery due to an internalization peptide and inhibiting inflammation in the brain. Strbian et al., WO 04/071531 have reported that a mast cell degranulation inhibitor, cromoglycate, administered i.c.v. but not intravenously has direct activity in inhibiting infarctions in an animal model.
In some methods, the subject is not also treated with the same anti-inflammatory agent co-administered with the active agent in the day, week or month preceding and/or following co-administration with active agent. In some methods, if the subject is otherwise being treated with the same anti-inflammatory agent co-administered with the active agent in a recurring regime (e.g., same amount, route of delivery, frequency of dosing, timing of day of dosing), the co-administration of the anti-inflammatory agent with the active agent does not comport with the recurring regime in any or all of amount, route of delivery, frequency of dosing or time of day of dosing. In some methods, the subject is not known to be suffering from an inflammatory disease or condition requiring administration of the anti-inflammatory agent co-administered with the active agent in the present methods. In some methods, the subject is not suffering from asthma or allergic disease treatable with a mast cell degranulation inhibitor. In some methods, the anti-inflammatory agent and pharmacological agent are each administered once and only once within a window as defined above, per episode of disease, an episode being a relatively short period in which symptoms of disease are present flanked by longer periods in which symptoms are absent or reduced.
The anti-inflammatory agent is administered in a regime of an amount, frequency and route effective to inhibit an inflammatory response to an internalization peptide under conditions in which such an inflammatory response is known to occur in the absence of the anti-inflammatory. An inflammatory response is inhibited if there is any reduction in signs or symptoms of inflammation as a result of the anti-inflammatory agent. Symptoms of the inflammatory response can include redness, rash such as hives, heat, swelling, pain, tingling sensation, itchiness, nausea, rash, dry mouth, numbness, airway congestion. The inflammatory response can also be monitored by measuring signs such as blood pressure, or heart rate. Alternatively, the inflammatory response can be assessed by measuring plasma concentration of histamine or other compounds released by mast cell degranulation. The presence of elevated levels of histamine or other compounds released by mast cell degranulation, reduced blood pressure, skin rash such as hives, or reduced heart rate are indicators of mass cell degranulation. As a practical matter, the doses, regimes and routes of administration of most of the anti-inflammatory agents discussed above are available in the Physicians' Desk Reference and/or from the manufacturers, and such anti-inflammatories can be used in the present methods consistent with such general guidance.
Although the invention has been described in detail for purposes of clarity of understanding, certain modifications may be practiced within the scope of the appended claims. All publications, accession numbers, and patent documents cited in this application are hereby incorporated by reference in their entirety for all purposes to the same extent as if each were so individually denoted. To the extent more than one sequence is associated with an accession number at different times, the sequences associated with the accession number as of the effective filing date of this application is meant. The effective filing date is the date of the earliest priority application disclosing the accession number in question. Unless otherwise apparent from the context any element, embodiment, step, feature or aspect of the invention can be performed in combination with any other.
Nerinetide is an eicosapeptide neuroprotectant generated to target the neuronal scaffolding postsynaptic density protein-95 (PSD-95), an abundant synaptic protein acting as a hub for neurotoxic signalling1. It was recently shown in the phase 3 ESCAPE-NA1 trial2 (clinicaltrials.gov NCT) to be a promising adjunct to endovascular thrombectomy (EVT) in certain patients suffering from an acute ischemic stroke (AIS) due to a large vessel arterial occlusion (LVO). In ESCAPE-NA1, participants were enrolled with AIS due to LVO within a 12-hour treatment window and vascular imaging suggestive of an ischemic penumbra, stratified by intravenous alteplase treatment. The study showed improved functional independence, reduced mortality, and reduced infarct volume in the nerinetide group that did not receive alteplase, whereas patients that received alteplase did not benefit. The latter finding is hypothesized to occur due to cleavage of nerinetide by plasmin, the product of alteplase3, an observation was supported by measurements of reduced blood nerinetide concentrations in the alteplase stratum2.
Nerinetide binds the second PDZ domain of PSD-95 protein with high affinity (EC50 ˜7 nM)5, thereby perturbing the protein-protein interactions of PSD-95 with N-Methyl-D-Aspartate glutamate receptors (NMDARs; IC50 ˜1-8 uM) and with the neurotoxic signaling protein neuronal nitric oxide synthase (nNOS; IC50˜200 nM). This perturbation of the co-association of NMDARs with nNOS reduces the efficiency with which NMDARs can trigger the formation of nitric oxide (NO) during excitotoxicity1,4 thus interrupting a leading mechanism of ischemic stroke damage6. The production of NO and simultaneous production of superoxide anion in mitochondria during ischemia provides a permissive environment for the formation of peroxynitrite (ONOO—), a potent oxidant which damages DNA, lipids and proteins6,7. NO and related reactive nitrogen species (RNS) such as peroxynitrite are produced in significant quantities after ischemia-reperfusion, and are believed to be major mediators of reperfusion injury of ischemic tissues8-10.
Among the pre-specified exploratory analyses in ESCAPE-NA1 were explorations of the impact of various time intervals between stroke onset and dosing with nerinetide. As a complementary approach, we also explored the temporality of dosing with nerinetide in relation to reperfusion, a critical prognostic event and the postulated start of the oxidative stress of reperfusion injury. We therefore analyzed the effect of timing of nerinetide dosing on outcome throughout the 12 hour trial enrollment period, as well as the timing of dosing during critical intervals between qualifying imaging and reperfusion.
The details of the ESCAPE-NA1 methodology are published2. In-brief, the trial was conducted at 48 sites globally. Adult patients aged 18 or greater with a disabling ischemic stroke (baseline National Institutes of Health Stroke Scale (NIHSS) score11>5), CT evidence of a small-to-moderate ischemic core (ASPECTS 5-10)12 and CTA evidence of LVO with a moderate-to-good collateral circulation13,14 were enrolled in a window of up to 12 hours after the onset of stroke symptoms (last-seen-well time). Enrollment was stratified on the use of intravenous alteplase (yes/no) and declared initial thrombectomy device (stent-retriever or aspiration device). Randomized minimization was conducted within strata aimed to achieve distribution balance with regard to age, sex, baseline NIHSS, site of arterial occlusion, baseline ASPECTS and clinical site. Nerinetide and placebo vials were visually identical other than a unique vial number so that all trial personnel and patients were fully masked to treatment allocation.
After qualifying imaging, patients were treated with rapid EVT using currently available devices. Patients received intravenous alteplase15 according to usual care following national or regional guidelines, before or during EVT, at a primary hospital prior to transfer or at the endovascular center. Treatment with alteplase was not a requirement for the study and interpretation of treatment guidelines was at the discretion of the treating team. Patients received trial drug (1:1 nerinetide:placebo), as a single dose of 2.6 mg/kg to a maximum dose of 270 mg as soon as possible after randomization. Time targets were imaging to randomization 30 minutes, imaging to study drug administration 60 minutes, and imaging to arterial access/puncture 60 minutes. Targets from imaging to reperfusion were 90th percentile 90 minutes and a median at 75 minutes.16,17 Times (min) for workflow are summarized in Table 3.
The primary outcome was good outcome at 90 days as defined by a score of 0-2 on the modified Rankin scale (mRS) (range, 0 [no symptoms] to 6 [death]) for the assessment of neurologic functional disability18-20. Secondary 90 day efficacy outcomes included neurological outcome as defined by the NIHSS of 0-2, functional independence in activities of daily living as defined by a Barthel Index score of 95, and mortality rates. Tertiary outcomes included assessments of stroke volumes on 24-hour imaging (MR or CT brain). Imaging interpretation was conducted at a central core laboratory and clinical data were verified by independent monitors. Infarct volumes were measured by summation of manual planimetric demarcation of infarct on axial imaging (636/1099 (57.9%) on CT and 463/1099 (42.1%) on MRI).
As the ESCAPE-NA1 study showed that the entire beneficial effect of nerinetide was restricted to patients who were not treated with alteplase, all analyses (unless otherwise indicated) are limited to subjects enrolled in the no-alteplase stratum. Analyses of efficacy in this stratum were conducted as per the primary analysis of ESCAPE-NA1 on the intention-to-treat (ITT) population, and comprised a logistic regression providing an adjusted estimate of effect size including treatment, the stratification variable of declared initial endovascular approach, and the baseline covariates of age, sex, baseline NIHSS score, baseline ASPECTS, occlusion location and clinical site. Analyses of secondary efficacy outcomes were conducted similarly to the primary analysis. To determine the impact of time metrics of interest on the efficacy of nerinetide (e.g., Onset to randomization, CT to reperfusion, Randomization to reperfusion, and Drug administration to reperfusion), the metrics variables were included in the regression analysis that was otherwise conducted like the primary analysis. Deceased patients were included in the ITT population with a mRS score of 6, a Barthel Index of 0 and NIHSS of 42. Missing primary outcomes (n=9) were imputed as the worst possible score, counted as poor outcome (mRS 3-6 dichotomy) and for mortality analysis, imputed as deaths. All analyses were performed with the use of STATA software (v16.0).
Patients in the no-alteplase stratum in ESCAPE-NA1 (n=445) were randomized over a 12 hours window from stroke onset in a median time of 272 minutes (IQR: 148-548 minutes). This was significantly longer than patients in the alteplase stratum, in whom the median time to enrollment was 158 minutes (IQR: 110-234 minutes). The difference was because patients who received alteplase were generally enrolled within a window corresponding to the alteplase treatment guidelines (up to 4.5 hours from symptom onset) whereas participants in the no-alteplase group were enrolled over the 12 hour window dictated by the trial protocol. This resulted in approximately half of no-alteplase subjects being enrolled after 4.5 hours.
In patients selected for EVT in the no-alteplase stratum, the time from stroke onset to randomization was an independent predictor of favorable outcome, confirming the importance of treating stroke in a timely manner (adj OR=0.998; Cl95 0.997-0.999; p=0.016). Overall, participants exhibited higher rates of functional independence when they were enrolled in the earlier time windows of the trial (
Effect of Time from Qualifying CT to Initial Reperfusion on the Effectiveness of Nerinetide
Analysis of workflow data from ESCAPE″, the predecessor trial to ESCAPE-NA1, showed that imaging-to-reperfusion time is a significant predictor of functional outcome. Specifically, every 30-minute increase in computed tomography to-reperfusion time reduced the probability of achieving a functionally independent outcome (90-day modified Rankin Scale 0-2) by 8.3%16. We therefore evaluated whether CT to reperfusion times also impacted the effectiveness of nerinetide. The interval from qualifying imaging until initial reperfusion was an independent predictor of clinical outcome (adj. OR=0.989; Cl95 0.982-0.997; p=0.006), confirming the prior findings' on the importance of this workflow interval to outcome. To investigate its impact on the effects of nerinetide, we dichotomized the participants into those whose CT to reperfusion interval was less than the median of 73.5 minutes (“short” interval) and compared outcomes with those whose interval was more than the median (“long” interval; >=73.5 minutes). This revealed that nerinetide was ineffective in improving functional outcome in participants with short CT to reperfusion intervals (
The Time from Dosing to Initial Reperfusion is a Critical Determinant of Nerinetide's Effectiveness.
Since workflow is designed to address the time-sensitive nature of AIS, we sought to understand why longer workflow times were associated with better outcomes with nerinetide. Dosing with study drug in ESCAPE-NA1 could only take place after the completion of qualifying imaging, enrollment screening, the obtaining of consent and randomization. Therefore, depending on the speed with which the workflow unfolded, study drug was given at various times beginning from qualifying imaging and up until the closure of arterial access following the EVT procedure2. Since reperfusion is a major determinant of prognosis in EVT21 and reperfusion injury is an anticipated target of therapy with nerinetide, we hypothesized that the interval from dosing to initial reperfusion would have an impact on clinical outcome. The time of initial reperfusion was defined as that at which the physician performing the thrombectomy indicated a partial or complete restoration of blood flow to the affected hemisphere.
In the no-alteplase stratum, the median time from initiation of dosing with study drug until initial reperfusion was 22 minutes (IQR: 9-41 minutes). This was in the context of a median qualifying CT scan to initial reperfusion time of 73.5 minutes (IQR: 56.5 to 100 minutes), suggesting that study drug was generally administered late in the workflow, and closer to the time of reperfusion in most patients. Much of the time from qualifying imaging to infusion start (median 49 minutes) was taken by enrollment activities, specifically the obtaining of consent (median of 26.5 minutes), randomization (median of 8 minutes) and time to prepare for infusion (median of 11 minutes).
The interval from study drug initiation until initial reperfusion was an independent predictor of clinical outcome (adj. OR=0.990; Cl95 0.980-0.999; p=0.039). To explore the impact of nerinetide we dichotomized the participants into those whose infusion began less than the median of 22 minutes (“short” interval), as compared with those who started study drug at or more than 22 minutes from initial reperfusion (“long” interval). Nerinetide showed no benefit in short interval patients (
The larger absolute effect of nerinetide when it was given at 22 or more minutes from initial reperfusion as compared with effect in the whole no-alteplase stratum (16.25% vs. 9.65%, respectively) suggests that attending to this workflow metric might maximize a benefit of nerinetide. Reperfusion is already sought as expeditiously as possible for each patient, but the procedure time may vary due to patient and environmental factors that are difficult to control. We therefore examined whether the time of groin puncture might be used as a practical target to guide dosing.
The interval from dosing to groin puncture was distributed symmetrically around a mean time of −4.23 minutes and median of −5 minutes, indicating that the most common time of drug infusion start was approximately 4-5 minutes after groin puncture. Performing the primary analysis on subjects who received study drug more than 5 minutes after groin puncture failed to demonstrate a benefit of nerinetide (
Time from CT to the Initiation of Alteplase May Inform Future Timing of Nerinetide Administration in Clinical Use
Because nerinetide is an experimental agent it could not be administered in ESCAPE-NA1 until consent for study participation was obtained (median time: 28 min) and randomization (median time: 8 minutes) was completed. The median time from qualifying CT to study drug infusion in the trial was 50 minutes of which 34 minutes were taken by study-related procedures. Workflow in the trial was such that these procedures occurred in parallel with standard-of-care processes to not delay the access of participants to EVT. Since the interval between nerinetide administration and reperfusion (median 22 minutes) appears to impact its effectiveness, we postulated that estimates of its potential effectiveness in usual clinical practice may have been under-estimated in ESCAPE-NA1 due to enrollment of 50% of patients who were dosed less than 22 minutes from reperfusion and who therefore had low response to nerinetide. Based on the distribution of patient treatment times in the trial, a saving of 34 minutes would have shifted many participants into the high response group who were dosed more than 22 minutes from reperfusion. These assumptions may be validated by examining the time from qualifying CT scan to the initiation of alteplase, which does not require consent. We analyzed subjects dosed with alteplase at the EVT hospital (N=443), excluding those who received alteplase at a referring hospital before arrival and qualifying imaging. In this subgroup, the median time from qualifying CT imaging to the initiation of alteplase was 15 minutes (IQR: 8-23) as compared with the 50 minutes to study drug. Based on these timelines, dosing nerinetide under a standard-of-care scenario would have shifted many participants into the high response group.
Our exploratory re-analyses of the ESCAPE-NA1 trial data provide evidence that nerinetide is of benefit to patients throughout the 12 hour enrollment period of the trial provided that the participant had not received alteplase. We have also confirmed previous findings that an important workflow metric is the time from qualifying CT to initial reperfusion, with faster workflows being generally associated with better functional outcomes. Our analyses also show that generally, when nerinetide is given late in the workflow, it is less effective. Specifically, nerinetide was ineffective in improving functional outcome in participants with short CT to reperfusion intervals, and this was likely because in such patients, dosing with nerinetide occurred close to-, or after, reperfusion. Our data suggest that nerinetide is not effective if it is given too late (for example, in some patient initiated less than about 22 minutes from reperfusion), and this was likely the case when CT to reperfusion intervals were short. We have also demonstrated that these findings can be operationalized clinically by targeting drug administration to start at less than 5 minutes after groin puncture. Finally, we showed that given the usual care workflows in EVT centers, the use of nerinetide under a standard-of-care scenario would result in a large majority of subject being treated in a timeframe where the clinical benefit of nerinetide may be maximized.
Participants in ESCAPE-NA1 in the no-alteplase stratum who were treated with nerinetide in longer intervals from reperfusion exhibited absolute effect sizes of approximately 16%, and relative improvements over placebo of between 40% and 50%. This may be explained by the chemical nature, mechanism of action and pharmacokinetics of nerinetide. Nerinetide is administered intravenously over a 10 minute (+/−1 minute) period and has a plasma half-life of 5-10 minutes3. It is redistributed into tissues3 and must cross the blood-brain barrier, penetrate into neurons and disrupt the association of nNOS with NMDARs to inhibit NO production. However, it is not a free radical scavenger or antioxidant and therefore would not be anticipated to inactivate reactive oxygen or nitrogen species that have been already produced by reperfusion. By this reasoning, in the setting of ischemia-reperfusion nerinetide is predicted to be most effective when given before reperfusion begins.
This finding has substantial implications for nerinetide as a standard-of-care treatment for patients selected for EVT. The effect size of nerinetide may be maximized by treating patients as soon as possible. Additionally in such a scenario, nerinetide can also be administered to patients who are also selected for alteplase treatment. Due to the short plasma half-life of nerinetide it is anticipated to distribute into tissues, where it would not be cleaved by plasmin, rapidly enough to enable treatment with thrombolytic agents soon after its administration.
In conclusion, the study provides evidence nerinetide benefits patients not receiving alteplase who are selected for EVT for 12 hours after stroke onset, but the benefit is greatest if nerinetide administration occurs as rapidly as possible after the qualifying imaging.
This example investigates cleavage of nerinetide by plasmin and describes variant active agents inhibiting PSD-95 resistant to plasmin cleavage.
Results
Nerinetide is Cleaved by Plasmin
Nerinetide does not have any intrinsic fibrinolytic activity and does not affect the activity of thrombolytics such as alteplase or tenecteplase but the converse is different. Plasmin, a serine protease, is activated by thrombolytics to dissolve fibrin blood clots and persists for several hours (Chandler et al., Haemostasis 30, 204-218 (2000). Plasmin has a cleavage specificity on the C-terminal side of basic residues, and so may occur after residues 3, 4, 5, 6, 7, 9, 11 and 12 from the N-terminus of nerinetide. Cleavage products consistent with these sites of cleavage were observed after incubating nerinetide (18 mg/mL) with plasmin (1 mg/mL) in phosphate-buffered saline at 37° C. and analyzing the samples by LC/MS (
Since the effect of nerinetide in the ESCAPE-NA1 trial was negated by alteplase, we next evaluated the effects of alteplase on pharmacokinetics (PK) of nerinetide in rats. Alteplase was administered at 0.9 mg/kg (human dose) and at 5.4 mg/kg (6 times the human dose) in an infusion that simulated the clinical protocol (10% bolus followed by a 60 min infusion of the remainder). Nerinetide was administered as an intravenous bolus at the start of the alteplase infusion at 7.6 mg/kg. This is the dose most commonly used in rats in prior stroke studies (5, 7, 15) and that leads to a Cmax in rats similar to that produced in humans receiving 2.6 mg/kg, the dose used in ESCAPE-NAL The co-administration of nerinetide with the human dose of alteplase resulted in a non-significant reduction of the Cmax and AUC of nerinetide (
The cleavage of full-length nerinetide by high dose alteplase was incomplete, raising the possibility that some active drug could still remain to achieve neuroprotection. This was supported in rats by a dose-response study of nerinetide in a model of transient middle cerebral artery occlusion (tMCAO). Nerinetide and lodoxamide was administered to rats intravenously as a bolus injection, 60 minutes after tMCAo.
Dose separation restores the treatment benefit of nerinetide
In both rat and human at the human equivalent concentrations, the half-life of nerinetide was approximately 5-10 minutes (
To test this, male Sprague-Dawley rats (10-12 weeks old; 270-310 g; Charles River, Montreal, QC, Canada) were subjected to embolic middle cerebral artery occlusion (eMCAO), produced by the introduction of an autologous blood thrombus into the middle cerebral artery. Reperfusion was achieved by treatment with intravenous alteplase at a total dose of 5.4 mg/kg beginning at 90 minutes after ischemia onset. Alteplase was administered using the human injection protocol in which 10% of the total dose is given as a bolus, with the remainder 90% of the dose being given over a 60-minute infusion. The dose of alteplase was 6 times the human dose, in anticipation that the rat fibrinolytic system may be less sensitive to human recombinant tPA. This dose was chosen because in pilot studies, higher doses of alteplase (10×human dose) produced unacceptable mortality rates due to hemorrhagic conversions of strokes. Nerinetide was administered either 30 minutes prior to, or concurrently with, the start of the alteplase administration (
Nerinetide alone, administered 60 minutes after eMCAO, reduced infarction volume by 59.2% (from 427±27 mm3 to 175±40 mm3) whereas alteplase alone reduced infarction volume by 26% when given at 60 min and 18% when given at 90 minutes after eMCAO (
We conducted further PK studies to probe the necessary dose-separation interval to mitigate degradation. These studies were conducted in cynomolgus macaques (Macaca fascicularis) to maximize their relevance to humans. Nerinetide was given as a 10-minute intravenous infusion at a dose of 2.6 mg/kg. This dosing regimen was neuroprotective in macaques exposed to stroke by LVO (Cook et al., Nature 483, 213-217 (2012)) and was used in both the Phase 2 ENACT trial (Lancet Neurol 11, 942-950 (2012)) and the ESCAPE-NA1 trial (Lancet 395, 878-887 (2020)). We examined the scenarios in which alteplase administration was started simultaneously with the nerinetide infusion start, at the end of the 10-minute nerinetide infusion, or 10 minutes after the end of nerinetide infusion. Alteplase (1 mg/kg) was administered through a separate intravenous line as a 10% bolus, followed by an infusion of the remaining 90% over 1 hour, as per its clinical use.
The co-administration of nerinetide with alteplase resulted in a 47.4% reduction of the Cmax and 53.9% reduction in the AUC of nerinetide (
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/051408 | 2/19/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62978786 | Feb 2020 | US |
