Patent Application
20080153819
1. Field of the Invention
The present invention is directed to the prevention and treatment of diabetic macular edema and/or pathologic ocular angiogenesis, specifically exudative age-related macular degeneration and proliferative diabetic retinopathy. In particular, the present invention is directed to the use of certain formulations of a neuroprotectant and a Receptor Tyrosine Kinase inhibitor to treat such disorders.
2. Description of the Related Art
Diabetes mellitus is characterized by persistent hyperglycemia that produces reversible and irreversible pathologic changes within the microvasculature of various organs. Diabetic retinopathy (DR), therefore, is a retinal microvascular disease that is manifested as a cascade of stages with increasing levels of severity and a worsening prognosis for vision. Retinal neuronal damage during diabetes mellitus may result secondary to the microangiopathy, or as some evidence suggests, it may be a direct result of hyperglycemia on retinal neurons. DR is broadly classified into 2 major clinical stages: nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR), where the term “proliferative” refers to the presence of preretinal neovascularization (PNV) emanating from the retina into the vitreous. NPDR encompasses a range of clinical subcategories which include initial “background” DR, where small multifocal changes are observed within the inner retina (e.g., microaneurysms, “dot-blot” hemorrhages, and nerve fiber layer infarcts), through preproliferative DR, which immediately precedes the development of posterior segment neovascularization (PSNV). Diabetic macular edema (DME) can be seen during either stage of DR, however, it often is observed in the latter stages of NPDR and is a prognostic indicator for progression into the most severe stage, PDR.
Although PDR is the major cause of legal blindness in patients with diabetes mellitus, macular edema is the most common cause of vision loss. Nonproliferative diabetic retinopathy (NPDR) and subsequent macular edema are associated, in part, with retinal ischemia that results from the retinal microvasculopathy induced by persistent hyperglycemia. Data accumulated from animal models and empirical human studies show that retinal ischemia is often associated with increased local levels of proinflammatory and/or proangiogenic growth factors and cytokines, such as prostaglandin E2, vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1), etc. These molecules can alter the retinal microvasculature and cause pathologic changes such as extracellular matrix remodeling, retinal vascular leakage leading to edema, and ultimately pathologic ocular angiogenesis. The cumulative impact of these diabetic changes (altered growth factor production, hypoxia, increased sorbitol metabolism, change in redox potential, advanced glycosylation endproducts, etc.) can lead to apoptotic cell death of endothelial cells, pericytes and neuronal cells within the retina.
Diabetic macular edema and leakage from preretinal neovascular membranes are primarily associated with abnormally enhanced vascular leakage leading to interstitial edema. In addition, removal of fluid from the diabetic retina may be impaired. Fluid removal is mediated in large part by the retina pigmented epithelium (RPE), where these outer retinal cells actively pump ions and fluid away from the photoreceptors. Dysfunctional RPE pumping mechanisms may also be associated with exudative or wet AMD. The term “exudative” refers to the increased vascular permeability of the pathologic new choroidal vessels, where the enhanced vascular permeability leads to subretinal fluid accumulation and intraretinal edema. Moreover, retinal edema can be observed in various other posterior segment diseases, such as posterior uveitis, branch or central retinal vein occlusion, surgically induced inflammation, endophthalmitis (sterile and non-sterile), scleritis, and episcleritis, etc. Regardless of disease etiology, when the edema involves the fovea, visual acuity is threatened.
Although posterior segment NV (PSNV) and macular/retinal edema are major causes of vision loss in adults, viable, approved treatment options are currently limited. The approved treatments for exudative AMD are photodynamic therapy with VISUDYNE® (QLT/Novartis) and intravitreal injection of Macugen® (pegaptanib) (Eyetech/Pfizer) or Lucentis® (ranibizumab) (Genentech). Laser photocoagulation alone or photodynamic therapy (PDT) with VISUDYNE® are therapies that involve laser-induced occlusion of the affected vasculature, which can result in localized damage to the retina. Macugen® (Eyetech/Pfizer) is an anti-VEGF aptamer that binds to VEGF165 preventing ligand-receptor interaction and is labeled for intravitreal injections every 4 weeks. Lucentis® (Genentech) is a humanized anti-VEGF antibody fragment that also binds directly to all isoforms of human VEGF and is labeled for intravitreal injections every 6 weeks. Phase III trial results demonstrate the ability of Lucentis® to not only stabilize, but improve visual acuity in up to 35-40% of patients treated at 24 months. Late stage clinical trials are on-going in patients with diabetic macular edema using both Macugen® and Lucentis®. A variety of other pharmacologic therapies are undergoing clinical evaluation for exudative AMD, such as RETAANE® 15 mg (anecortave acetate suspension, Alcon Research, Ltd.), Envision (squalamine, Genera), the VEGF R1R2 Trap, (Regeneron), Cand5 (anti-VEGF siRNA, Acuity), Sirna-027 (anti-VEGFR1 siRNA, SIRNA/Allergan), a topical receptor tyrosine kinase antagonist (TargeGen), sirolimus (rapamycin, MacuSight), etc. Several of these agents also are under investigation for use in DME.
Grid and pan retinal laser photocoagulation are the only proven options currently available for patients with diabetic macular edema or PDR, respectively. Multifocal laser photocoagulation may reduce retinal ischemia and inhibit angiogenesis by destroying healthy tissue and thus decreasing the sum metabolic demand of the retina. It also may modulate the expression and production of various cytokines and trophic factors. Unfortunately, laser photocoagulation is a cytodestructive procedure and the visual field of the treated eye is irreversibly compromised. Surgical interventions, such as vitrectomy and removal of preretinal membranes, are widely used with or without laser treatment. Similar to the exudative AMD trials, various pharmacologic agents are in clinical trials for DME, such as ARXXANT™ (ruboxystaurin mesylate, Lilly), RETISERT™ (fluocinolone acetonide, Bausch & Lomb), Posurdex (fluocinolone acetonide erodible implant, Occulex/Allergan), I-vation (nonerodible Dexamethasone implant, Occulex), Medidur (fluocinolone acetonide erodible implant, Alimera), etc. Intravitreal or periocular injection of triamcinolone acetonide, a corticosteroid (Kenalog®, Schering-Plough), and intravitreal Avastin® (anti-VEGF Mab, Genentech) are also being used “off-label” for the treatment of both macular edema and wet AMD.
Subgroups of endothelial-selective Receptor Tyrosine Kinases (RTKs) are critical signaling mediators during microvascular biology and disease. RTKs comprise a large family of transmembrane receptors that mediate intracellular signaling via autophosphorylation of tyrosine residues following ligand binding. Signaling through RTKs appears to determine microvascular endothelial cell phenotype, homeostasis, and survival. Key growth factor pathways known for the retinal and choroidal vascular beds are vascular endothelial growth factor (VEGF), angiopoietins, ephrins, fibroblast growth factor-2 (bFGF), platelet-derived growth factor, etc. For example, VEGF binds the high affinity membrane-spanning tyrosine kinase receptors VEGFR-1 (Flt-1), VEGFR-2 (KDR or Flk-1), and VEGFR-3 (Flt-4). Cell culture and gene knockout experiments indicate that VEGFR-2 and -1 are most important for endothelial physiology, vasculogenesis, and pathologic angiogenesis. More specifically, VEGFR-2 has been shown to be responsible for endothelial cell migration, proliferation, and barrier function in culture. VEGFR-2 is upregulated during retinal ischemia and pathologic ocular angiogenesis in animal models, whereas KDR blockade inhibits these abnormalities. Similarly, Angiopoietin 1 and 2 bind Tie-2, where Tie-2 signaling appears to be important in both normal vascular development and pathologic angiogenesis (ref. Hacket S F et al. J Cell Physiol 2000 184:275-284) and works in concert with VEGF signaling. Protein kinases and RTKs have been targeted for designing novel pharmacologic strategies for a variety of human conditions, such as cancer and posterior segment disease (Lawrence 1998; Gschwind 2004). Consequently, numerous pharmaceutical companies have developed medicinal chemistry efforts to design both selective and multi-targeted RTK inhibitors (Traxler 2001; Murakata 2002). Highly specific inhibitors of VEGFR-2, or KDR, have been designed and demonstrate potent and efficacious inhibition of tumor-induced angiogenesis (Shaheen 2001; Boyer 2002, Bilodeau 2002; Manley 2002; and Curtin 2004). The RTKi compound, SU11248 (Sutent®, Pfizer) was recently approved for oral use in cancer treatment. This compound was selected based on the performance of inhibitors with varying kinase selectivities in a transgenic mouse model of pancreatic islet cell carcinogenesis (Inoue 2002; McMahon 2002). In this model, the combination of a selective KDR inhibitor (SU5416) plus Gleevec, a PDGFR and KIT inhibitor, produced responses greater than either agent given individually (Bergers 2003). These responses included regressions of established tumors and were attributed to simultaneous inhibition of VEGF signaling in endothelial cells and PDGF signaling in pericytes, since a disruption of endothelial cell-pericyte association was observed. Significantly, no such disruption of endothelial cell-pericyte junctions was seen in the non-tumor vasculature from these animals.
It has been discovered that it is preferable to selectively inhibit a specific combination or combinations of Receptor Tyrosine Kinase (RTK) receptors. For example, co-pending application No. US 2006/0189608 discusses the use of RTK inhibitors that block tyrosine autophosphorylation of VEGFR-1 (Flt-1), VEGFR-2 (KDR), VEGFR-3 (Flt-4), Tie-2, PDGFR, c-KIT, Flt-3, and CSF-1R with an IC50 value of from 0.1 nM to 250 nM for each of these receptors, to inhibit ocular neovascularization and/or retinal edema.
While these compounds appear to be effective for inhibiting the progression of retinal microvascular pathology, patients suffering from these disorders may require treatment with additional therapeutic agents to address neurodegeneration of the retinal tissues.
An effective combination pharmacologic therapy for pathologic ocular angiogenesis and/or macular edema that provides neuroprotection to the retinal tissues would provide substantial efficacy to the patient, thereby avoiding invasive surgical or damaging laser procedures. Effective treatment of the pathologic ocular angiogenesis and edema, while providing neuroprotection to the retinal tissues, would improve the patient's quality of life and productivity within society. Also, societal costs associated with providing assistance and health care to the blind could be dramatically reduced.
The present invention overcomes these and other drawbacks of the prior art by providing methods for inhibiting increased vascular permeability and/or pathologic ocular angiogenesis and providing neuroprotection of the affected retina via administration of a combination of one or more molecules that potently inhibit select receptor tyrosine kinases (RTKs) or vascular endothelial growth factor (VEGF) and one or more neuroprotectants, such as β-adrenergic receptor antagonists (also referred to herein as beta blockers), 5HT1A receptor agonists, Nrf-2 acting agents, geranylgeranyl transferase inhibitors, statins, or antioxidants.
The following drawing forms part of the present specification and is included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to this drawing in combination with the detailed description of specific embodiments presented herein.
According to the methods of the present invention, a composition comprising a neuroprotective agent and a composition comprising a receptor tyrosine kinase inhibitor (RTKi) or an anti-VEGF molecule are administered to a patient suffering from diabetic macular edema and/or ocular angiogenesis in order to prevent the loss of visual acuity associated with such conditions and to provide neuroprotection to retinal tissues. The neuroprotective agent and the RTKi/anti-VEGF may be administered together in the same composition, or they may be administered separately, in different compositions. It is further contemplated that the compositions and methods described herein will be useful in treating any disorder affecting the retinal tissues, including, but not limited to age-related macular degeneration, proliferative or non-proliferative diabetic retinopathy, disorders resulting from increase neovascularization in the retinal tissues, macular edema, etc. The skilled artisan will be well aware of the retinal disorders which may be treating using the compositions and methods disclosed herein.
It is important that the RTKi compounds for use in the methods of the invention exhibit a receptor binding profile where multiple receptors in the RTK family are blocked by a single compound. One preferred group of receptors for which tyrosine autophosphorylation is blocked includes VEGF receptor 1 (Flt-1), VEGF receptor 2 (KDR), VEGF receptor 3 (Flt-4), Tie-2, PDGFR, c-KIT, Flt-3, and CSF-1R. Additional preferred binding profiles include the following: a) Tie-2, PDGFR, and VEGF receptor 2 (KDR); b) VEGF receptor 2 (KDR), VEGF receptor 1 (Flt-1), PDGFR, and Tie-2; c) VEGF receptor 2 (KDR), VEGF receptor 1 (Flt-1), and Tie-2; d) VEGF receptor 2 (KDR), VEGF receptor 1 (Flt-1), and PDGFR; e) VEGF receptor 2 (KDR) and Tie-2; f) VEGF receptor 2 (KDR) and PDGFR; and g) VEGF receptor 2 (KDR), Tie-2, and PDGFR.
Preferred RTKi compounds for use in the methods of the present invention are potent, competitive inhibitors of the ATP binding site for a select group of RTKs. That is, preferred agents simultaneously block tyrosine autophosphorylation of VEGFR-1 (Flt-1), VEGFR-2 (KDR), VEGFR-3 (Flt-4), TIE-2, PDGFR, c-KIT, FLT-3, and CSF-1R, or some combination of two or more of these receptors, at low nM concentrations. Preferably, RTKi compounds for use in the methods of the invention exhibit an IC50 range between 0.1 nM and 250 nM for each of these receptors. More preferred RTKi compounds exhibit an IC50 range between 0.1 nM and 100 nM for at least six of these receptors. Most preferred RTKi compounds possess an IC50 range between 0.1 nM and 10 nM for at least four of these receptors.
In one preferred aspect, for each grouping of receptors listed in a)-g) above, the IC50 value of each receptor in each group will be from 0.1 nM to 200 nM. In another preferred aspect, the IC50 value of each receptor in each group will be from 0.1 nM to 100 nM. In yet another preferred embodiment, at least one receptor in each preferred group of receptors listed in a)-f) above will exhibit an IC50 value of less than 10 nM. In yet another preferred embodiment, two or more receptors in each preferred group of receptors listed in a)-g) above will exhibit an IC50 value of less than 10 nM.
Preferred RTKi compounds for use in the compositions and methods of the invention include, but are not limited to, the compounds listed in Table 1:
Preferred RTKi compounds for use in the methods of the invention include Compounds 86 and 88-111. The most preferred RTKi compound for use in the methods of the invention is Compound 86.
Other preferred RTKi compounds for use in the methods described herein may be identified using assays described herein, the performance of which will be routine to the skilled artisan.
Vascular growth in the retina leads to visual degeneration culminating in blindness. Vascular endothelial growth factor (VEGF) accounts for most of the angiogenic activity produced in or near the retina in diabetic retinopathy. Ocular VEGF mRNA and protein are elevated by conditions such as retinal vein occlusion in primates and decreased pO2 levels in mice that lead to neovascularization. Intraocular injections of either anti-VEGF monoclonal antibodies or VEGF receptor immunofusions inhibit ocular neovascularization in rodent and primate models. Regardless of the cause of induction of VEGF in human diabetic retinopathy, inhibition of ocular VEGF is useful in treating the disease.
Thus, it is further contemplated that compounds targeting VEGF receptors would be useful in combination with the neuroprotective compounds disclosed herein for use in treating diabetic macular edema and/or ocular angiogenesis in order to prevent the loss of visual acuity associated with such conditions and to provide neuroprotection to retinal tissues. Acceptable anti-VEGF compounds for use in the methods of the invention include any molecule that binds directly to VEGF and prevents ligand-receptor interaction (i.e., Macugen® (pegaptanib), Lucentis® (ranibizumab), Avastin® (bevacizumab), VEGF Trap) or any agent known to down-regulate VEGF production (i.e., siRNA molecules Cand5, Sima-027), directly or indirectly. Other known anti-angiogenic agents, such as anecortave acetate, anecortave desacetate, rapamycin, may also be used in the compositions and methods of the invention.
It is contemplated that virtually any agent capable of providing neuroprotection to retinal tissues will be useful in the compositions and methods of the present invention. Neuroprotective agents act to prevent the apoptotic cell death of neurons. An apoptotic cascade can be initiated by oxidative stress, trophic deprivation, excitotoxicity/calcium influx, and mitochondrial dysfunction leading to activation of a series of caspases which are proteases whose actions drive the cell death pathway. There exist also pathways that block the apoptotic cascade. Neuroprotective agents, then, can inhibit the pathways that commit neurons to the cell death pathway or activate those that promote cell survival (Mattson, M. P. Apoptosis in Neurodegenerative Disorders. Nature Reviews/Molecular Cell Biology, 1: 120-129 (2000)).
Preferred neuroprotective agents include beta blockers, 5HT1A agonists, agents having stimulatory activity for Nrf2 protein nuclear translocation, geranylgeranyl transferase inhibitors, statins, and antioxidants.
In preferred aspects, the neuroprotective agent for use in the compositions and methods of the invention is a beta adrenergic blocker. Beta adrenergic blockers produce a decrease in aqueous humor inflow and lower IOP. A decrease of IOP in the presence of constant blood pressure results in an increase of ocular perfusion pressure. Moreover, certain beta-blockers have been shown to produce vasorelaxation unrelated to their beta adrenergic blocking action. (Yu, et al. 1996; Hester, et al. 1994; Hoste, et al. 1994; and Bessho, et al. 1991). There is experimental evidence that this is due to the ability of certain beta-blockers to act as calcium channel blockers and to reduce the entry of calcium ion into vascular smooth muscle cells where it participates in the contraction response and reduces the diameter of the lumen of the blood vessel to decrease blood flow. (Yu, et al. 1996; Hester, et al. 1994; Hoste, et al. 1994; and Bessho, et al. 1991). Moreover, in animal models, beta blockers have been shown to prevent progression of retinal neuronal damage, i.e., they demonstrate neuroprotection of the retina. It also has been published that topical ocular administration of betaxolol was associated with stabilized vision in Japanese patients with diabetic macular edema.
Preferred beta blockers for use in the compositions and methods of the present invention are represented by the following generic structure:
R1—O—CH2—CH(OH)—CH2—NR2R3 (I)
wherein: R1 is a substituted or unsubstituted cyclic or aliphatic moiety; cyclic moieties include mono- and polycyclic structures which may contain one or more heteroatoms selected from C, N, and O; R2 and R3 are independently selected from H and substituted and unsubstituted alkyl. With regard to Structure (I), above, the following references are incorporated herein by reference: Annual Reports in Medicinal Chemistry 14, 81-87 (1979); J. Med. Chem. 1983, 26, 1570-1576; ibid. 1984, 27, 503-509; ibid. 1983, 26, 7-11; ibid. 1983, 26, 1561-1569; ibid. 1983 1109-1112; ibid 1983, 26, 950-957; ibid. 1983, 26, 649657; and ibid 1983, 26, 352-357. Representative of such basic actives are: betaxolol, timolol, befunolol, labetalol, propranolol, bupranolol, metaprolol, bunalol, esmalol, pindolol, carteolol, hepunolol, metipranolol, celiprolol, azotinolol (S-596), diacetolol acebutolol, salbutamol, atenulol, isoxaprolol, and the like. The following patent publications, which are incorporated herein by reference, further representatively demonstrate the beta blockers for use in the methods and compositions of the present invention: U.S. Pat. Nos. 4,252,984; 4,311,708 and 4,342,783.
Preferred beta blockers of the present invention include betaxolol and timolol. Another preferred beta blocker is the (S)-isomer of betaxolol, namely, levobetaxolol, the more active of the enantiomers. The inventive formulations may comprise more than one beta blocker, such as levobetaxolol or betaxolol.
Preferred 5HT1A agonists for use in the compositions and methods of the present invention include: Tandospirone, Seidel (Sumitomo); AL-38042; SM-130785; Buspirone; AL-26380 (Bayer); Isapirone (Bayer); Repinotan (Bayer); Gepirone (Bristol Meyer Squibb).
Agents having stimulatory activity for Nrf2 protein nuclear translocation include, for example: Michael addition acceptors (e.g., α,β-unsaturated carbonyl compounds), such as diethyl maleate or dimethylfumarate; diphenols such as resveratrol; butylated hydroxyanisoles such as 2(3)-tert-butyl-4-hydroxyanisole; thiocarbamates such as pyrrolidinedithiocarbamate; quinones such as tert-butyl-hydroquinone; isothiocyanates such as sulforaphane, its precursor glucosinolate, glucoraphanin, or phenethyl isothiocyanate (PEITC); 1,2-dithiole-3-thiones such as oltipraz; 3,5-di-tert-butyl-4-hydroxytoluene; ethoxyquin; coumarins such as 3-hydroxycoumarin; flavonoids such as quercetin or curcumin for treatment of drusen formation; a flavonoid other than genistein, such as quercetin or curcumin, for treatment of diabetic retinopathy; diallyl sulfide; indole-3-carbinol; epigallo-3-catechin gallate; ellagic acid; combinations thereof, or pharmacologically active derivatives or analogs thereof.
Preferred geranylgeranyl transferase inhibitors include N-4-[2(R)-Amino-3-mercaptopropyl]amino-2-phenylbenzoyl-(L)-leucine methyl ester; N-4-[2(R)-Amino-3-mercaptopropyl]amino-2-phenylbenzoyl-(L)-leucine; N-4-[2(R)-Amino-3-mercaptopropyl]amino-2-naphthylbenzoyl-(L)-leucine; N-4-[2(R)-Amino-3-mercaptopropyl]amino-2-naphthylbenzoyl-(L)-Leucine methyl ester; 4-[[N-(Imidazol-4-yl)methyleneamino]-2-(1-naphthyl)benzoyl]leucine; 4-[[N-(Imidazol-4-yl)methyleneamino]-2-(1-naphthyl)benzoyl]leucine.
Preferred statins for use in the compositions and methods of the present invention include: HMG-CoA inhibitors; Cerivastatin; Lovastatin; Atorvastatin (Pfizer); Simvastatin (Schering-Plough); Mevastatin (Daiichi); Rosuvastatin; Fluvastatin; Pravastatin.
Preferred antioxidants for use in the compositions and methods of the present invention include N-acetyl cysteine, Othera-551, INO-4885, metalloporphyrins, and mitochondrial-targeted peptide antioxidants.
Betoptic® and Betoptic® S are topical ophthalmic compositions of betaxolol HCl and are available from Alcon Laboratories, Inc., Fort Worth, Tex. These compositions can be applied to the eyes 1-4 times per day according to the routine discretion of a skilled clinician either to patients with glaucoma or ocular hypertension and ARMD or to patients with only ARMD.
According to the present invention, a therapeutically effective amount of a neuroprotective compound is administered topically, locally or systemically, in combination with a RTK inhibiting compound administered topically, locally or systemically, to treat or prevent diabetic macular edema and/or ocular angiogenesis. In another embodiment, the RTK inhibiting compound and the neuroprotective compound may be present in the same composition.
The compositions for use in the methods of the invention may be administered via any viable delivery method or route, however, local administration is preferred. It is contemplated that all local routes to the eye may be used including topical, subconjunctival, periocular, retrobulbar, subtenon, intracameral, intravitreal, intraocular, subretinal, juxtascleral and suprachoroidal administration. Systemic or parenteral administration may be feasible including but not limited to intravenous, subcutaneous, and oral delivery. The most preferred method of administration will be intravitreal or subtenon injection of solutions or suspensions, or intravitreal or subtenon placement of bioerodible or non-bioerodible devices, or by topical ocular administration of solutions or suspensions, or posterior juxtascleral administration of a gel formulation. Another preferred method of delivery is intravitreal administration of a bioerodible implant administered through a device such as that described in U.S. application Ser. No. 60/710,046, filed Aug. 22, 2005.
In general, the doses of the active agents in the compositions used for the above described purposes will vary, but will be in effective amounts to inhibit or cause regression of neovascularization or angiogenesis and to provide neuroprotection to the retinal tissues. In general, the doses of the RTKi in the compositions of the invention will be in an effective amount to treat or prevent the progression of AMD, DR, sequela associated with retinal ischemia, and macular and/or retinal edema. As used herein, the term “pharmaceutically effective amount” refers to an amount of one or more RTKi which will effectively treat AMD, DR, and/or retinal edema, or inhibit or cause regression of neovascularization or angiogenesis, in a human patient. The doses used for any of the above-described purposes will generally be from about 0.01 to about 100 milligrams per kilogram of body weight (mg/kg), administered one to four times per day. When the compositions are dosed topically, they will generally be in a concentration range of from 0.001 to about 5% w/v, with 1-2 drops administered 1-4 times per day. For intravitreal, posterior juxtascleral, subTenon, or other type of local delivery, the compounds will generally be in a concentration range of from 0.001% to about 10% w/v. If administered via an implant, the compounds will generally be in a concentration range of from 0.001 to about 40% w/v. The dose of the neuroprotective agent in the compositions of the invention will be in an effective amount to inhibit degeneration of the retinal tissues resulting from AMD, DR, sequela associated with retinal ischemia, and macular and/or retinal edema. Preferred doses for topical application of the neuroprotective agent will be from about 0.001% to about 30%, administered one to four times per day. When present in the same composition with the RTKi, for administration via intravitreal injection, subTenon administration, juxtascleral administration, or other type of local delivery, the amount of neuroprotective agent in the composition will be from about 0.01% to about 20% w/v.
The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
METHODS: Pregnant Sprague-Dawley rats were received at 14 days gestation and subsequently gave birth on Day 22±1 of gestation. Immediately following parturition, pups were pooled and randomized into separate litters (n=17 pups/litter), placed into separate shoebox cages inside oxygen delivery chamber, and subjected to an oxygen-exposure profile from Day 0-14 postpartum. Litters were then placed into room air from Day 14/0 through Day 14/6 (days 14-20 postpartum). Additionally on Day 14/0, each pup was randomly assigned as an oxygen-exposed control or into various treatment groups. For those randomized into an injection treatment group: one eye received a 5 μl intravitreal injection of 0.1%, 0.3%, 0.6%, or 1% RTKi and the contralateral eye received a 5 μl intravitreal injection of vehicle. At Day 14/6 (20 days postpartum), all animals in both studies were euthanized.
Immediately following euthanasia, retinas from all rat pups were harvested, fixed in 10% neutral buffered formalin for 24 hours, subjected to ADPase staining, and fixed onto slides as whole mounts. Digital images were acquired from each retinal flat mount that was adequately prepared. Computerized image analysis was used to obtain a NV clockhour score from each readable sample. Each clockhour out of 12 total per retina was assessed for the presence or absence of preretinal NV. Statistical comparisons using median scores for NV clockhours from each treatment group were utilized in nonparametric analyses. Each noninjected pup represented one NV score by taking the average value of both eyes and was used in comparisons against each dosage group. Because the pups were randomly assigned and no difference was observed between oxygen-exposed control pups from all litters, the NV scores were combined for all treatment groups. P≦0.05 was considered statistically significant.
RESULTS: Local administration of RTKi provided potent anti-angiogenic efficacy against preretinal neovascularization, where 100% inhibition of preretinal NV was observed between 0.3%-1% suspensions. An overall statistical difference was demonstrated between treatment groups (Kruskal-Wallis one-way ANOVA test: P<0.001) (
1% RTKi
METHODS: Pregnant Sprague-Dawley rats were received at 14 days gestation and subsequently gave birth on Day 22±1 of gestation. Immediately following parturition, pups were pooled and randomized into separate litters (n=17 pups/litter), placed into separate shoebox cages inside oxygen delivery chamber, and subjected to an oxygen-exposure profile from Day 0 to Day 14 postpartum. Litters were then placed into room air from Day 14/0 through Day 14/6 (days 14-20 postpartum). Additionally on Day 14/0, each pup was randomly assigned as oxygen-exposed controls, vehicle treated, or drug-treated at 1.5, 5, 10 mg/kg, p.o., BID. At Day 14/6 (20 days postpartum), all animals in both studies were euthanized and retina whole mounts were prepared as described in Example 1 above.
RESULTS: Systemic administration of RTKi provided potent efficacy in the rat OIR model, where 20 mg/kg/day p.o. provided complete inhibition of preretinal NV. An overall statistical difference was demonstrated between treatment groups and non-treated controls (Kruskal-Wallis one-way ANOVA test: P<0.001) (
METHODS: CNV was generated by laser-induced rupture of Bruch's membrane. Briefly, 4 to 5 week old male C57BL/6J mice were anesthetized using intraperitoneal administration of ketamine hydrochloride (100 mg/kg) and xylazine (5 mg/kg) and the pupils of both eyes dilated with topical ocular instillation of 1% tropicamide and 2.5% Mydfin®. One drop of topical cellulose (Gonioscopic®) was used to lubricate the cornea. A hand-held cover slip was applied to the cornea and used as a contact lens to aid visualization of the fundus. Three to four retinal burns were placed in randomly assigned eye (right or left eye for each mouse) using the Alcon 532 nm EyeLite laser with a slit lamp delivery system. The laser burns were used to generate a rupture in Bruch's membrane, which was indicated opthalmoscopically by the formation of a bubble under the retina. Only mice with laser burns that produced three bubbles per eye were included in the study. Burns were typically placed at the 3, 6, 9 or 12 o'clock positions in the posterior pole of the retina, avoiding the branch retinal arteries and veins.
Each mouse was randomly assigned into one of the following treatment groups: noninjected controls, sham-injected controls, vehicle-injected mice, or one of three RTKi-injected groups. Control mice received laser photocoagulation in both eyes, where one eye received a sham injection, i.e. a pars plana needle puncture. For intravitreal-injected animals, one laser-treated eye received a 5 ul intravitreal injection of 0%, 0.3%, 1%, or 3% RTKI. The intravitreal injection was performed immediately after laser photocoagulation. At 14 days post-laser, all mice were anesthetized and systemically perfused with fluorescein-labeled dextran. Eyes were then harvested and prepared as choroidal flat mounts with the RPE side oriented towards the observer. All choroidal flat mounts were examined using a fluorescent microscope. Digital images of the CNV were captured, where the CNV was identified as areas of hyperfluorescence within the pigmented background. Computerized image analysis was used to delineate and measure the two dimensional area of the hyperfluorescent CNV per lesion (um2) for the outcome measurement. The median CNV area/burn per mouse per treatment group or the mean CNV area/burn per treatment group was used for statistical analysis depending on the normality of data distribution; P≦0.05 was considered significant.
RESULTS: Local administration of RTKi provided potent antiangiogenic efficacy in a mouse model of laser-induced CNV. An overall significant difference between treatment groups was established with a Kruskal-Wallis one way ANOVA (P=0.015) (
The median and mean ±s.d. CNV area/burn per mouse in control groups with no injection was 21721 um2 and 32612±23131 um2 (n=4 mice), and with sham injection was 87854 um2 and 83524±45144 um2 (n=4 mice). The median and mean ±s.d. CNV area/burn per mouse in vehicle-treated mice was 133014 um2 and 167330±143201 um2 (n=6 mice). The median/mean ±s.d. in the 0.3%, 1% and 3% RTKi treated groups were 38891 um2 and 44283±28886 um2 (n=5 mice); 21122 um2 and 21036±3100 um2 (n=5 mice); 22665 um2 and 27288±12109 um2 (n=5 mice), respectively.
METHODS: CNV was generated by laser-induced rupture of Bruch's membrane as described above in Example 3. Each mouse was randomly assigned to one of the following treatment groups: noninjected controls, sham-injected controls, vehicle-injected mice, RTKi injected groups. Control mice received laser photocoagulation in both eyes, where one eye received a sham injection, i.e. a pars plana needle puncture. For intravitreal-injected animals, one laser-treated eye received a 5 μl intravitreal injection of 0%, 1% or 3% RTKi or 2 μl 1% RTKi. All mice received laser photocagulation at day 0. For mice randomized to an injection group, a single intravitreal injection was performed at 7 days post-laser. Also at 7 days post-laser, several mice with no-injection were euthanized and their eyes used for controls. At 14 days post-laser, all remaining mice were euthanized and systemically perfused with fluorescein-labeled dextran. Eyes were then harvested and prepared as choroidal flat mounts with the RPE side oriented towards the observer. Choroidal flat mounts were analyzed as described above in Example 3.
RESULTS: Local administration of RTKi caused regression of existing laser-induced CNV in the adult mouse. An overall significant difference between treatment groups was established with a Kruskal-Wallis one way ANOVA (P=0.002) (
METHODS: CNV was generated by laser-induced rupture of Bruch's membrane as described in Example 3 above. Mice were randomly assigned as oral gavage groups receiving 0, 3, 10, and 20 mg/kg/day RTKi. The mice received an oral gavage of 0, 1.5, 5, or 10 mg/kg twice per day and for 14 days post-laser. For the regression or intervention paradigm, mice were randomly assigned to groups receiving 0, 1.5, 5, or 10 mg/kg RTKi p.o. BID, (0, 3, 10, or 20 mg/kg/day) at day 7 after laser photocoagulation. Oral gavage dosing was continued twice per day for 14 days post-laser. Several mice were euthanized at day 7 post-laser and used for controls. At 14 days post-laser, all mice were anesthetized and systemically perfused with fluorescein-labeled dextran. Eyes were then harvested and prepared as choroidal flat mounts as described in Example 3 above.
RESULTS: Systemic administration of RTKi provided potent and highly efficacious inhibition of laser-induced CNV, where mice treated 20 mg/kg/day showed complete inhibition of CNV development and significant regression of established CNV. In the prevention paradigm, an overall significant difference between treatment groups was established with a Kruskal-Wallis one way ANOVA (P<0.001) (
In the regression paradigm, an overall significant difference between treatment groups was established with a Kruskal-Wallis one-way ANOVA (P<0.001) (
METHODS: Adult Sprague-Dawley rats were anesthetized with intramuscular ketamine/xylazine and their pupils dilated with topical cycloplegics. Rats were randomly assigned to intravitreal injection groups of 0% 0.3%, 1.0%, and 3.0% RTKI and a positive control. Ten μl of each compound was intravitreally injected in each treatment eye (n=6 eyes per group). Three days following first intravitreal injection, all animals received an intravitreal injection of 10 μl 400 ng hr VEGF in both eyes. Twenty-four hours post-injection of VEGF, intravenous infusion of 3% Evans blue dye was performed in all animals, where 50 mg/kg of Evans blue dye was injected via the lateral tail vein during general anesthesia. After the dye had circulated for 90 minutes, the rats were euthanized. The rats were then systemically perfused with balanced salt solution, and then both eyes of each rat were immediately enucleated and the retinas harvested using a surgical microscope. After measurement of the retinal wet weight, the Evans blue dye was extracted by placing the retina in a 0.2 ml formamide (Sigma) and then the homogenized and ultracentrifuged. Blood samples were centrifuged and the plasma diluted 100 fold in formamide. For both retina and plasma samples, 60 μl of supernatant was used to measure the Evans blue dye absorbance (ABS) with at 620/740 nm. The blood-retinal barrier breakdown and subsequent retinal vascular permeability as measured by dye absorbance were calculated as means +/−s.e.m. of net ABS/wet weight/plasma ABS. A two-tailed Student's t-test were used for pair wise comparisons between OS and OD eyes in each group. One way ANOVA was used to determine an overall difference between treatment means, where P≦0.05 was considered significant.
RESULTS. A single intravitreal injection of RTKi provided potent and efficacious inhibition of VEGF-induced retinal vascular permeability in the rat (
The mean ABS±s.e.m. in vehicle control group was 9.93±1.82. In drug treated group of 0.3% RTKI was 4.84±0.64; in 1.0% RTKI group was 3.87±0.62; in 3.0% RTKI group was 4.75±0.40 and in the positive control group was 3.11±0.46. There was no significant difference between drug treated groups.
METHODS: Diabetes was induced in male Long-Evans rats with 65 mg/kg streptozotocin (STZ) after an overnight fast. Upon confirmation of diabetes (blood glucose >250 mg/dl), treatment was initiated by oral gavage. Non-diabetic (NDM) and diabetic (DM) rats received oral gavage of either vehicle or RTK inhibitor at 1.5 or 5 mg/kg/d BID. After 2 weeks, jugular vein catheters were implanted 1 day prior to experimentation for the infusion of indicator dye. Retinal vascular permeability, RVP, was measured using Evan's blue albumin permeation (45 mg/kg) after a 2 hour circulation period.
RESULTS: Treatment with the oral RTKi was well tolerated by both NDM and DM groups with no observed systemic or ERG side effects. Blood glucose levels and body weights were not different between DM control and DM treatment groups. Diabetes increased RVP (38.1±33.4 μl/g/hr, n=9) as compared with NDM control (7.3±2.5 μl/g/hr, n=5, p<0.001). RVP was significantly reduced in DM animals treated with RTKI at 1.5 mg/kg/d (11.4±4.1 μl/g/hr, n=6, p<0.05) and at 5 mg/kg/d (8.9±3.1 μl/g/hr, n=7, p<0.01) as compared to DM control (
All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are both chemically and structurally related may be substituted for the agents described herein to achieve similar results. All such substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.
The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.
United States Patents
Other Publications
The present application claims priority to U.S. Provisional Patent Application No. 60/871,414 filed Dec. 21, 2006.
| Number | Date | Country | |
|---|---|---|---|
| 60871414 | Dec 2006 | US |
