Patent Application
20250170317
Sickle Cell Disease is an inherited red blood cell disorder that affects up to 100,000 people in the United States and 20 million people worldwide. People with this disease have atypical hemoglobin molecules often called hemoglobin S (sickle hemoglobin, often abbreviated HbS or Hb-S).
Sickle cell disease causes red blood cells that are normally disc-shaped and flexible to change shape, such as by becoming sickle-shaped or other shape and/or becoming less flexible. The sickled red blood cells can block blood flow to parts of the body which can lead to serious problems. For example, complications and symptoms from sickle cell disease can include chronic anemia, pain crises, vaso-occlusive crisis, stroke, acute chest syndrome, pulmonary hypertension, splenic and renal dysfunction. Also, due to extreme membrane damage, sickled red blood cells survive only about 20 days as opposed to the 120 day life of healthy red blood cells.
There are presently few effective treatment options for sickle cell disease. Conventional courses of treatment involve pain management, treatment with oral drug hydroxyurea, and/or red blood cell transfusion therapy. Treatment with the drug Hydroxyurea remains the most commonly used drug treatment. It was shown to induce hemoglobin F (fetal hemoglobin, often appreviated as HbF or Hb-F) production leading to development of red blood cells containing in addition to hemoglobin S, which is responsible for red blood cell sickling, also variable amounts of hemoglobin F. The more hemoglobin F is contained in such red blood cells, the less likely are such cells to sickle. The amount of hemoglobin F generated due to the treatment and its distribution among the red blood cells produced was shown to be highly variable and patient-dependent. Recently, several drugs have been introduced to help managing sickle cell disease. Adakveo (crizanlizumab) reduces red and white cell binding to blood vessel wall thus reducing the risks of development of vaso-occlusion. Endari (L-Glutamine) improves energy production in red blood cells, which supports better anti-oxidation activity resulting, it is believed, in reduced oxidative damage to red blood cell membrane. Oxbryta (voxelotor) binds to hemoglobin molecule leading to delayed red blood cell sickling. A number of other drugs with similar mechanisms of action are currently in development. Significantly, depending on multiple factors (e.g., cell age, history of previous cell sickling, cell hemoglobin concentration, cell size, etc.) cells containing hemoglobin S may have different propensity to sickle. Such variability would be further enhanced by treatments affecting internal red blood cell hemoglobin composition (e.g., introduction of hemoglobin F) or ability of hemoglobin molecules to bind to each other (polymerize) as is the case with e.g., Oxbryta treatment. Red blood cell transfusion therapy introduces to the patient previously collected and stored donor red blood cells containing hemoglobin A (normal hemoglobin, often abbreviated HbA or Hb-A) that does not sickle. Despite recent advances in drug development, this therapy remains one of most often used methods to managing sickle cell disease.
Red blood cell transfusion can be performed with pheresis. The public and individual cost of sickle cell disease is exceptionally high. The annual costs estimate for sickle cell disease treatment range from $50,000/child to $300,000/adult, with a life-time cost of care of $9M per individual. Sickle cell disease related annual cost of care in the United States exceeds $10B. Chronic red blood cell transfusion therapy, the present treatment of choice for more severe sickle cell disease patients, including about 10,000 children, has an estimated annual transfusion-associated hospital costs have been reported at $20,000-$50,000 per sickle cell disease patient, with pediatric being at the lower end of the range due to lower contribution of chelation therapy, which alone contribute ˜40% to total therapy costs. Pediatric red blood cell costs also can vary from $200 to over $1,500 for rare type units, with insurance reimbursement sometimes lower than actual hospital costs. Reported hospital transfusion-related costs also typically do not include those for treatment of post-transfusion complications ranging from minor fever/allergy to life threatening conditions such as transfusion related acute lung injury (TRALI). Accounting even for a part of these complications can double transfusion-related costs.
Red blood cell transfusion therapy is an important but less than ideal treatment option for sickle cell disease patients. It can be performed as a direct transfusion or in association with phlebotomy or pheresis with the goal of maintaining total hemoglobin and/or hemoglobin A above predefined levels. When transfusions are insufficiently or infrequently performed, i.e. “under-transfusion” complications can occur due to high hemoglobin S being present between transfusions which can lead to increased sickling. Increasing the frequency of the transfusions can also be problematic. “Over-transfusion” incurs extra costs and can expose the patient to volume and iron overload and toxic effects of cell free hemoglobin, as well as to additional risks associated with transfusions themselves. Chronic transfusions predispose individuals with sickle cell disease to iron overload, alloimmunization and autoimmunization. Iron overload, common for chronically transfused patients, and exacerbated in sickle cell disease by the shortened red blood cell lifespan, is often addressed through expensive chelation therapy. Alloimmunization results in life-threatening delayed hemolytic transfusion reactions and the autoimmune hemolytic anemia arising from hyper-hemolysis. Even with antigen match, 29% of transfused pediatric sickle cell disease patients can develop clinically significant alloantibodies, and 8% can develop autoantibodies. For adults, the respective values were 47% and 10%.
Transfusions for treating sickle cell disease can be administered as either a simple transfusion, which involves the addition of donor blood cells without the removal of any of the patient's blood, or as an exchange transfusion where a patient's blood is removed and exchanged with donor blood. Simple transfusions increase blood oxygen-carrying capacity but at a risk of elevating blood viscosity (hyper-viscosity) due to elevation of total hemoglobin levels. There is also an increased risk of transfusion associated volume overload (TACO) that can occur in patients receiving large volume of transfused blood especially over a short period of time, and pulmonary edema can develop as a result. The risks of TACO are elevated with underlying cardiovascular or renal disease. Because of these risks, simple transfusions are mostly performed in cases of acute, severe anemia that needs to be treated quickly. The risks of TACO and blood hyper-viscosity can be reduced by the use of exchange transfusion, which is the procedure most often used when the need for a transfusion is chronic, when a significant amount of blood needs to be transfused, and when the volume overload may lead to particularly elevated risks such as with some pediatric patients. The exchange transfusion has the additional benefit of increasing both blood oxygen-carrying capacity and reducing the fraction of hemoglobin S-containing cells in circulation since hemoglobin S-containing blood is removed from the patient.
With exchange transfusion, hemoglobin A levels can be safely maintained at a high level. Exchange transfusions can be performed as a manual procedure or as an automated procedure using an apheresis machine. Manual exchanges are performed using repeated alternating isovolumetric phlebotomy and blood transfusion. This can be a useful procedure, particularly in the acute situation to enable increase in hemoglobin A-containing cells and oxygen-carrying capacity with concurrent removal of hemoglobin S-containing red cells to prevent hyperviscosity. However, the process is time-consuming and needs skilled staff and constant medical supervision during the procedure. Automated red cell exchange also involves the replacement of red blood cells of a patient with sickle cell disease with donor red blood cells. The automated red cell exchange is performed by an apheresis machine and is a reasonably rapid procedure faster than the equivalent manual process, taking only 90 to 120 minutes, and can be performed in children as young as 5 years. Its other main advantage is the decreased rate of iron loading associated with this procedure, with a reduction of iron loading of ˜85% compared with simple transfusion. Automated red cell exchange is well tolerated in patients with sickle cell disease and results in good control of hemoglobin S without an increase in viscosity.
There are inherent disadvantages and problems with performing transfusions, no matter which type of transfusion is used. First is the need for and cost of securing suitable donor blood. Second, there is the risk to the patient due to transfusion-related complications, such as one or more of hemolytic transfusion reactions, non-immune hemolysis, various allergic and anaphylactic reaction, transfusion-related acute lung injury, febrile nonhemolytic transfusion reaction, post-tranfusion purpura, and infections like Hepatitis, West Nile Virus, and HIV. In addition, blood transfusions are typically associated with both immediate (up to 25 percent of transfused cells within the first 24 hours post transfusion as per FDA guidelines) and delayed (while the cells are in circulation) cell hemolysis. Such hemolysis depends on factors such as donor blood properties, manufacturing methods or blood donor processing methods, and stored blood properties over time.
There is therefore a need for an improved system and method for treating sickle cell disease. There is further a need for a system and method for treating a patient with sickle cell disease that reduces the need for donor blood. There is further a need for a system and method for treating a patient with sickle cell disease that offers benefits to the patient over receiving multiple blood transfusions.
The present invention satisfies these needs. In one aspect of the invention, an improved system and method for treating sickle cell disease is provided.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease in a manner that reduces the need for donor blood.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease in a manner that offers benefits to the patient over receiving multiple blood transfusions.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickled, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that contain Hemoglobin S, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that contain Hemoglobin S or any Hemoglobin variant that contains a single nucleotide replacement in the sixth amino acid of the Beta-Hemoglobin chain from glutamic acid to valine (Glu6Val).
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by deoxygenating hemoglobin, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by enzymatic oxygen consumption, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by photochemical modification, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by gas exchange, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by chemically-induced oxygen scrubbing, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone by using natural deoxygenation, separating out at least a portion of the sickled red blood cells, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, separating out at least a portion of the sickle-prone red blood cells, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, separating out at least a portion of the sickle-prone red blood cells by filtration, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, separating out at least a portion of the sickle-prone red blood cells by density separation, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, separating out at least a portion of the sickle-prone red blood cells by cell adhesion, and reintroducing the treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone, separating out at least a portion of the sickled red blood cells by filtration, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone, separating out at least a portion of the sickled red blood cells by density separation, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to induce sickling of red blood cells in the blood that are sickle-prone, separating out at least a portion of the sickled red blood cells by cell adhesion, and reintroducing the treated blood back into the patient with a reduced fraction of sickle-prone red blood cells.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, storing the treated blood, and reintroducing the stored treated blood back into the patient.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, and reintroducing the treated blood back into the patient along with the introduction of stored blood.
In another aspect of the invention, a system and method is provided for treating a patient with sickle cell disease by removing blood from the patient, treating the blood to decrease the fraction of red cells in the blood that are sickle-prone in that they are or may become sickled, and reintroducing the treated blood back into the patient along with the introduction of stored blood, wherein the stored blood in introduced in an amount selected in relation to the treatment of the patient's blood.
In another aspect of the invention, a method for treating sickle cell disease comprises removing blood from a patient with sickle cell disease; treating the removed blood to decrease the fraction of sickle-prone cells in the removed blood; reintroducing the treated blood back into the patient, wherein the treated blood that is reintroduced back into the patient has a reduced number of sickle-prone red blood cells when compared to the blood removed from the patient.
In another aspect of the invention, a method for treating sickle cell disease comprises removing blood from a patient with sickle cell disease; inducing sickling of at least some sickle-prone cells in the removed blood; removing at least some sickled cells from the sickling-induced blood; and reintroducing the blood with the removed sickled cells back into the patient, wherein the reintroduced blood has a reduced number of sickle-prone red blood cells when compared to the blood removed from the patient.
In another aspect of the invention, a sickle cell disease treatment system comprises a line adapted to receive blood from a patient; a blood treatment unit in communication with the line adapted to receive blood from a patient, the blood treatment unit comprising: a sickling inducement unit adapted to receive blood from the patient and induce sickling of sickle-prone cells in the blood from the patient; and a sickled cell separation unit adapted to remove sickled cells from the blood received from the sickling inducement unit; and a line adapted to reintroduce treated blood from the blood treatment unit back into the patient, wherein the reintroduced blood has a reduced number of sickle-prone red blood cells when compared to the blood removed from the patient.
These features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings which illustrate exemplary features of the invention. However, it is to be understood that each of the features can be used in the invention in general, not merely in the context of the particular drawings, and the invention includes any combination of these features, where:
The present invention relates to a system and method for treating a patient with sickle cell disease. In particular, the invention relates to a system and method for treating a patient with sickle cell disease by treating the patient's blood outside the patient's body. Although the system and method are illustrated and described in the context of being useful for treating sickle cell disease, the present invention can be useful in other instances. Accordingly, the present invention is not intended to be limited to the examples and embodiments described herein.
More specifically, the treatment 115 of the blood from the patient 105 is designed to decrease the fraction of sickle-prone cells in the blood. By sickle-prone cells it is meant red blood cells that are present in the blood of a patient with sickle cell disease that are either sickled or that have a propensity or an ability to become sickled under certain sickling conditions that might occur in a sickle cell disease patient. Sickle-prone red blood cells include Hemoglobin S, any Hemoglobin variant that contains a single nucleotide replacement in the sixth amino acid of the Beta-Hemoglobin chain from glutamic acid to valine (Glu6Val), and/or any other type of Hemoglobin or other composition that would give the red blood cell the ability to sickle under sickling conditions, including HbS-Beta thalassemia, HbS-Beta-Plus thalassemia, HBS-Beta-Zero thalassemia, HbSC, HbD-Punjab, HbO-Arab, and HbE, and the like. By sickle (and sickled, sickling, etc.) it is meant a change of shape or character of a red blood cell that results from the sickle cell disease state of the red blood cell, such as changes that occur due to polymerization of deoxygenated Hemoglobin S, or other Hemoglobin variant such as those mentioned above, inside the red blood cell. The change in shape often causes the red blood cell to take on an elongated, sickle, or crescent shape but shapes other than the norm disc shape of a non-sickled red blood cell are possible. Sickled red blood cells are more rigid, less bendable or pliable, and have decreased oxygen carrying ability when compared to normal red blood cells. It should be noted that sickle-prone red blood cells that are subjected to drug treatment might have a reduced propensity to sickle while under the treatment, but the propensity will increase over time as the drug effect lessens. As a result of the treatment step 115, the treated blood has fewer red blood cells that are prone to sickle than if the blood had not gone through the treatment step 115. The treated blood that is then reintroduced 120 back into the patient 105 so that the patient's blood has a decreased fraction of sickle-prone red blood cells. Accordingly, the patient 105 will experience improved health due to the removal of at least a portion of the sickle-prone red blood cells. The method of
The fewer red blood cells that are sickled within a patient's blood, the healthier the patient 105 will be and feel. Many of the deleterious effects of sickle cell disease are as a result of the actual sickling of the red blood cells. For example, with reduced sickling, a patient 105 with sickle cell disease is less likely to experience one or more of pain, vaso-occulsion, stroke, acute chest syndrome pulmonary hypertension, vaso-occlusive crisis, stroke, acute chest syndrome, pulmonary hypertension, splenic dysfunction, and renal dysfunction. In one version, the method of
The invention of
A particular version of the method for treating a patient with sickle cell disease 100 is shown in
Thus, in the version of
In one version, the enzyme for use in step 505 can comprise an oxidase. Oxidases are a prominent subclass of redox enzymes, which use oxygen either as oxidant or as electron acceptor. Multiple oxidase enzyme-substrate pairs can be used for removal of oxygen from the environment, as is known in the art. One such system is the combination of protocatechuate acid and protocatechuate dioxygenase (PCA/PCD). Other examples include glucose oxidase with glucose (Glu-Glu), galactose oxidase with galactose (Gal-Gal), and pyranose 2-oxidase with glucose (Pyr-Glu). Another example is a family of alcohol oxidases (AOX) that reduce primary and secondary alcohols to aldehydes and ketones, respectively. During this reaction, molecular oxygen is converted to hydrogen peroxide. Alcohol oxidases are not very specific in terms of substrates and can convert both primary and secondary alcohols to aldehydes and ketones, respectively. Such substrates include also methanol, ethanol, propanol, and butanol. Optionally, for many enzymatic oxygen scavenging systems, such as Glu-Glu, Gal-Gal, Pyr-Glu, or AOX systems, catalase can be added to the reaction medium for dismutation of hydrogen peroxide generated during the process the enzyme catalyzed oxygen removal. PCA/PCD system, does not generate reactive oxygen species, which makes it attractive for this step. The use of e.g., PCA/PCD or glucose oxidase (with catalase) may also be accompanied by pH stabilization as the reaction produces carboxylic acids. In another version, F420H2-oxidase is used in combination with reduced form of F420 (a deazaflavin derivative, which functions as electron carrier) to catalyze the four-electron reduction of O2 to 2 molecules of water. In this version. reactive oxygen species formation is prevented through a combination of difference reaction mechanisms blocking unwanted side-reaction between the catalytic intermediates and solvents.
In one version of the invention, the step 400 of deoxygenating the hemoglobin in the method of
Whole blood, red blood cells separated from the blood, or red blood cells in buffer or storage solution, or packed RBC used for transfusion contain oxygen both dissolved in the medium and attached to hemoglobin molecules. Oxygen-free, closed-to-air, and open-to-air conditions can be differentiated. By open-to-air it is meant a condition when the medium (containing or not containing red blood cell and hemoglobin) is in contact with atmosphere and by extension in contact with atmospheric oxygen. This would allow for oxygen diffusion into the medium. Closed-to-air condition describes the conditions where blood is isolated from the atmosphere, but would contain the oxygen, bound and free in medium, it had before been placed in the close-to-air condition. In this condition there is no liquid-gas interface and no oxygen diffusion into the medium is possible. Note that in the case of open-to-air condition, unless there is agitation or mixing of the medium, oxygen will be very slow to diffuse from the liquid-gas interface into the medium (e.g., at room temperature the diffusion rate is about 1×10−5 cm/s, corresponding to about 0.3 mm propagation per minute). This implies that without mixing, if oxygen consumption occurs within the medium, volume of the medium sufficiently distanced from the liquid-gas interface can be considered to be closed-to-air if viewed on an appropriate time scale. Oxygen-free or anaerobic condition refers to a condition corresponding to anoxia or deep hypoxia when there is no or minimal amount of oxygen in the medium and by extension attached to hemoglobin. When open-to-air condition is present, especially with mixing enabling more efficient oxygen diffusion into medium, photochemistry of hemoglobin is significantly impacted by hemoglobin re-oxygenation by oxygen that is being diffused into the medium. Oxygen impact is significantly reduced when no diffusion is possible as in closed-to-air condition. In one version of the invention, we can assume whole blood or isolated red blood cells is in closed-to-air conditions. Irradiation of OxyHb free in solution or inside RBC, results in dose-and wavelength-dependent formation of alternative hemoglobin forms including oxidated Hb (metHb), deoxygenated Hb (DeoxyHb), and corboxy-Hb (COHb). The quantum yields of the reactions increase with the use of more high-energy (shorter wavelength) irradiation. Some of the quantum yields measured in human blood plasma are given in the table found in U.S. Provisional Patent Application 63/535,377 filed on Aug. 30, 2023 which is incorporated herein by reference.
Additionally or alternatively, illumination, and in particular shorter wavelength UV light (less than 320 nm) representing short UV-B and UV-C, can induce both red blood cell rupture (photo-induced hemolysis) and hemoglobin photo degradation. While hemolysis can be induced by UV-C irradiation (wavelength<300 nm), irradiation with light in UV-B, UV-A and VIS ranges (wavelength>300 nm) does not result in red blood cell lysis (at least up to the doses of 3×106 J/m2). In should be noted, that when UV-C irradiation is used, in case of photo-induced lysis of RBC, Hb released in buffer solution or blood plasma is predominantly in the COHb state.
Under irradiation in both VIS and UV ranges, hemoglobin photoconversion tend to follow the transition of oxyHb to MetHb and then to DeoxyHb, with the direct transition of OxyHb to DeoxyHb also being possible. Higher doses, especially at shorter wavelengths, leads to formation of COHb. Relative efficiency of Hb photo transformations in both buffer solutions and in plasma in close-to-air conditions is presented in the table found in U.S. Provisional Patent Application 63/535,377 filed on Aug. 30, 2023 which is incorporated herein by reference. Quantum yields of the reactions decline with the increase in the wavelength of irradiating light. In comparison with buffer solutions, in blood plasma the same irradiation dose leads to efficient formation of deoxyHb through metHb and directly to deox with an increase being about 3-5 times for UV-C irradiation and close to an order of magnitude increase for irradiation in the UV-A/VIS spectral range. Additionally, in plasma, higher dose of irradiation results in a formation of a significantly smaller follow-on COHb fraction. It can be seen that by appropriate selection of wavelength and dose of irradiation it is possible to transition a significant fraction of hemoglobin from oxyHb to deoxyHb form. While shorter wavelength may offer higher efficiency of the transformation, longer wavelengths allow for better defined approach even if higher total irradiation doses would be required.
In case of red blood cell containing hemoglobin S or any other hemoglobin variants capable of polymerization, Hb photo-induced deoxygenation would result in polymerization with the follow-up red blood cell sickling. Note, that in close-to-air environment, photo-generated hemoglobin can still be reoxygenated with the final amount of sickling dependent on relative magnitudes of polymerization and polymer melting delays, and on polymer formation and polymer melting rates. In red blood cells, such would be dependent on hemoglobin concentration and its composition with e.g., the presence of HbF introducing significant delay in polymerization and cell sickling further inhibited by the oxygen availability in the medium supporting hemoglobin reoxygenation.
It is also possible to select for or against generation of COHb. Notably, COHb had been proposed as a therapeutic agent for SCD. As CO binds to Hb much tighter than oxygen, presence of COHb fraction in red blood cells would reduce the amount of hemoglobin being deoxygenated and thus capable of polymerization. This is expected to have an inhibitory effect on red blood cell sickling, an effect potentially beneficial in prevention of vaso-occlusion. Note, that this would come at the expense of reduced blood oxygen carrying capacity and oxygen delivery to the tissues. In one version, systems optimized for photo-induced generation of carboxy form of hemoglobin can be used as a therapy by themselves, as well as in combination with cell separation and reinfusion. Short-wave irradiation (e.g., below 320 nm) allows for more efficient transition between hemoglobin forms, however it also induces hemolysis with hemoglobin being released into the medium. While cell-free hemoglobin would be detrimental for a patient, such undesirable effects can be avoided when post-irradiation, red blood cells are separated from plasma, buffer, or blood cell storage solution with such separated medium being replaced with e.g., buffer solutions supplemented with albumin. It should be noted, that hemolysis would be reduced when no oxygen is coming to the sample from the environment as in e.g., any closed to air circuit. This allows for a two-step process when initial irradiation is with a longer wavelength UV-A (e.g. 365 nm of the emission peak of a mercury lamp) or light in the visible range (e.g. 405-430 nm bands on a mercury lamp) to induce initial and partial hemoglobin deoxygenation with the follow up shorter UV irradiation (e.g., 250-320 nm range) to speed up the photoinduced Hb transformations with reduced amount of hemolysis. Irradiation with the longer wavelengths (in the near UV and visible spectrum (e.g. >400 nm, 400-550 nm) will induce progressively smaller (per unit of time) changes in hemoglobin form with increasing wavelength of irradiation. However, total irradiation time can be extended, and in a flow through system, this can be achieved by increasing the length of the path for the blood flow, thus extending the residence time of the blood or red blood cells under the irradiation.
In one version of the invention, the step 400 of deoxygenating the hemoglobin in the method of
While microfluidics allows for faster oxygen exchange than open-well systems, the rates remain limited by diffusion through artificial membranes. Alternatively, diffusion rates can be increased by mixing the blood with an e.g., perfluorinated carrier oil as oxygen sink which allows for faster (0.1 to 0.5 sec) pO2 equilibration. However, achieving low oxygen concentration in blood by this method is at least problematic, if not completely impossible. There are also other gas-exchange techniques that also aim to reduce diffusion time, but they need for gas tanks, such as oxygen, nitrogen and/or argon tanks, and pressure regulators, often require control of sample dehydration, as well as retain the inherent complexity of changing deoxygenation levels and/or of controlling oxygen gradients in the target medium. Gas-exchange systems are also commercially available, albeit commonly used for blood oxygenation, not deoxygenation. Such systems implement multiple strategies for fastest and most efficient oxygenation, through gas exchange, on flow-through patient blood when such oxygenation support is required. Blood oxygenators are commonly used as part of the ECMO (Extracorporeal Membrane Oxygenation) circuits. When part of ECMO system, such units are connected to oxygen gad tanks, however if connected to e.g., nitrogen gas supply, they would allow for blood deoxygenation.
In one version of the invention, the step 400 of deoxygenating the hemoglobin in the method of
In one version of the invention, the step 400 of deoxygenating the hemoglobin in the method of
In one version, the filtration or sieving step 605 of
In one version, such as shown in 7B and 7C, the introduction of stored blood 705 can be done to account for the volume of blood that is separated 310 and discarded 325 so that the overall blood volume does not decrease or decreases less than it would without the introduction of stored blood 705. In
In the version of
It should be noted that the word “blood” is used herein with its commonly usage in the art, such as when used with a blood transfusion, even if that which is being introduced is not actually blood. Only a portion of all transfusions are performed with actual blood, typically referred to as whole blood. Many transfusions are performed with red cell concentrates (processed donor red cells in storage solution). Unlike whole blood, such concentrates do not contain blood plasma or other cells (like white cells or platelets). The concentrates also have a much higher number of cells per ml than whole blood and are often referred to as packed red blood cells. In the version of
A particular version of a system 900 for treating a patient with sickle cell disease is shown in
While the material between the sample in channels 945 and irradiation source 960 should be transparent to the wavelength or the range of wavelengths of radiation used for hemoglobin photo conversion, it can be simultaneously used to filter out the radiation with “undesirable” wavelengths. Considering the differences in quantum yields of the photo-induced reactions (Table 1 above), it is more important to filter out shorter wavelength radiation before it reaches the blood or red blood cells in solution. For example, if a mercury-based light source is used, and the band with maximum at 365 nm is used for photoconversion, bands with the longer wavelengths (>400 nm) would have relatively small effect on the process, however the bands with shorter wavelengths (e.g. 300-310 nm, or 254 nm) would, if not filtered out, drive the reactions instead of the 365 nm selected. Optimally, both shorter and longer wavelengths (relative to the spectrum range used) would be filtered out. Such filtering can be achieved using common band-bass filters or could be implementing by proper selection of the material for the enclosure 970 of channels 945 and path 940. Absorbance of high intensity irradiation, particularity of UV light, results in heating of absorbing material, necessitating the use of a cooling system. Such can be implemented e.g., through immersion of the blood (red blood cell) flow path or the whole enclosure 970 in a circulating low temperature water bath, by using cold air flow, or by any other means conventionally employed for temperature stabilization.
Regarding deoxygenation and associated cell sickling in all of the versions described above, hemoglobin polymerization is a process that depends on both the rate of deoxygenation and hemoglobin (mainly related hemoglobin S fraction) concentration within the red blood cell. If hemoglobin S fraction within the cell is low as it may be as a result of e.g., hydroxyurea or gene editing therapy, hemoglobin polymerization may still be possible, but would be, sometimes very significantly, delayed. Thus, the time the cells spent under deoxygenated conditions can be an important factor in the size of the fraction of cells that would sickle and later removed by the filtration system. Such time can be regulated e.g., by controlling the flow rate of blood or isolated red blood cell through the flow path 910, by introducing a delay between deoxygenation and sickled cell separation (e.g., through filtration) or by other means changing the time treated red blood cells remain under deoxygenated condition.
In one application, the emphasis of the procedure would be on complete removal of any cells capable of sickling regardless of hemoglobin polymerization and related red blood cell sickling delays associated with such these processes. Under such approach, re-transfusion would be predominantly with hemoglobin A cells that survived in circulation from the previous red cell exchange (RCE) or single transfusion. Assuming that at the time of red cell exchange the patient has e.g., 50% of hemoglobin A cells from previous red cell exchange and 50% of patient's own hemoglobin S cells and further assuming 100% efficiency of cell separation, the amount of red blood cells (typically packed red blood cells units from storage) to be transfused would be reduced 2-fold (assuming replacement to the same hematocrit, Hb concentration or red blood cell count), as compared to standard procedure where all collected patient blood is discarded. A smaller fraction of surviving hemoglobin A cells and lower separation efficiency would result in smaller decrease in the amount of transfused red blood cells. Higher hemoglobin A fraction with high separation efficiency would result in less red blood cells being required to achieve transfusion or red cell exchange goals e.g., in terms of either or both final blood Hb concentration and blood oxygen carrying capacity and post-RCE hemoglobin S fraction in circulation.
In another application, the emphasis of the procedure would be on the reduction of the volume of transfused blood (packed red blood cells) through the reuse of all patient cells with low risk of sickling. Such cells may contain hemoglobin S, and while they would be capable of sickling under prolonged low oxygen conditions, such may be not clinically relevant if the delay in Hb polymerization of red blood cells sickling is significantly longer than the cell transit time through microvasculature. Additional consideration could be given to physiologically anticipated severity of hypoxia (low oxygen condition with more severe hypoxia corresponding to lower oxygen environment). Such severity varies between organs of the body and could also be specific to each patient due to its dependence of multiple genetic and lifestyle factors. Polymerization and sickling would be further inhibited when cells are experiencing hypoxia less than anoxia with Hb polymerization and associated red blood cell sickling further delayed or reduced in less severe hypoxia conditions. Based on the available clinical knowledge, clinician can elect to preserve maximum amount of patient's own cells that in clinician's opinion would offer low risk of sickling for the patient thus further reducing the amount of stored packed red blood cell to be transfused. Following the previous example with patient's blood containing 50% of HbAA cells and 50% of hemoglobin S containing cells, and 100% efficiency of separation, the deoxygenation conditions could be set such that only 25% of hemoglobin S cells, presumably with the highest hemoglobin S content and thus most prone to sickling, would sickle, be removed, and discarded. The remaining 75% of patient's own cells would be returned to circulation. In this scenario, only 25% of the cells would need to be replaced assuming replacement to the same hematocrit level. That would be only a quarter of the cells that would have been transfused if all patient blood would have been discarded as is done under the current procedure.
The following are examples of infusion processes and determinations in accordance with the version of the invention shown in
Transfusion goal: maintain hemoglobin S percentage at a pre-defined level (e.g., at 30%) while maintaining patient total blood volume constant (significantly reduces the risks of volume overload). Note, post-procedure total hematocrit (percent of cell volume to total blood volume) can be either kept constant or changes as per clinician's preference. In some cases, increase in hematocrit may be advantageous to the patient (e.g. in case of severe anemia and compromised oxygen delivery), but it also can be detrimental to patient health e.g., as higher hematocrit leads to elevated blood viscosity and potentially higher risks of vaso-occlusion.
Step 1. Determine the percent hemoglobin S in patient blood.
Step 2. Calculate the amount of hemoglobin S containing cells to be removed and replaced with hemoglobin A containing cells from the transfused units to achieve predefined post-blood exchange final percent of hemoglobin S in patient blood.
Step 3. Calculate the volume of blood to be removed from the patient.
Option A. Volume is small (suitable for single-step phlebotomy that would not put the patient at risk due to blood loss).
Step A1. Remove the calculated volume of blood from the patient.
Step A2. Treat removed blood in accordance with step 115.
Step A3. Reintroduce treated blood back to the patient.
Step A4. Transfuse the patient with the calculated volume of packed hemoglobin A red blood cells.
Alternatively, step A1 can be replaced by an estimate of the percent hemoglobin S in patient blood based on the amount of red blood cells that would sickle as a result of complete (no or very little oxygen) blood deoxygenation and then separated in step 115. Such evaluation can be performed by simple measurement of total hemoglobin e.g., by using commercially available HemoQue systems, in the sample of blood removed from the patient as compared to the total hemoglobin in the sample of non-sickled red blood cells to be reintroduced to the patient corrected as may be necessary to the change of the sample volume.
Option B. Volume is large. (phlebotomy would be performed in several
incremental steps with blood both autologous and from the blood units being transfused back to the patients after each phlebotomy step).
Step B1. Remove the first volume of blood from the patient.
Step B2. Treat blood in accordance with step 115.
Step B3. Calculate the amount of hemoglobin A containing cells to be transfused—that is translated into the packed red blood cell volume to be transfused using unit hematocrit/hemoglobin concentration, measured or known average for units of a given type (e.g., based on storage solution, manufacturing method, etc.) equal to the amount of separated hemoglobin S containing red blood cells keeping patient blood volume and hematocrit (if desired) constant
Step B4. Reintroduce treated blood from the first volume back to the patient.
Step B5. Transfuse the patient with the calculated first volume of packed hemoglobin A red blood cells.
Step B6. Repeat the steps with the second and so on volumes of blood removed from the patient.
Option C. Options A and B with no calculations.
Step C1. Treat blood in accordance with step 115.
Step C2. (Optional) Transfuse the patient with packed hemoglobin A stored red blood cells e.g., in the amount of sickled patient red blood cells that were separated and not re-introduced into the patient.
Step C3. Estimate the size of Hemoglobin S fraction in terms of hemoglobin S containing red blood cells that are susceptible to sickling under the utilized deoxygenation level or other method.
Step C4. Repeat steps 1 through 3 until the estimated amount of hemoglobin S in patient blood reached the predefined level.
Method for patient-specific treatment aimed to remove hemoglobin S containing red blood cells that present maximum probability of sickling for a particular patient for e.g., patient condition, anticipate or established clinical risk, or patient lifestyle. Optionally, replacing separated (not re-introduced) sickled patient red blood cells with stored packed hemoglobin A containing red blood cells (e.g., when the volume of separated and not re-introduced red blood cells is large enough to significantly decrease patient hematocrit with the potential to create clinically undesirable anemia).
Step 1. Such level can be established based on physician's understanding of a given patient's condition, medical history, pulse oximetry measurements and other tests, based on measured changes in blood deoxygenation during exercise assessment or other approaches indication of anticipated patient-specific blood deoxygenation levels during normal activities or exercise.
Step 2. Treat blood in accordance with step 115 with maximum blood
deoxygenation corresponding to the deoxygenation level established in step 1. As a result of such limitation on the deoxygenation level, hemoglobin S containing red blood cells with lower propensity to sickling (e.g., due to elevated hemoglobin F content of with higher intracellular concentration of sickling inhibiting drug like Oxbryta) would remain un-sickled and would not be separated during the process 115 and would then be re-introduced to the patient. Only the cells with higher propensity to sickling, corresponding to the maximum blood deoxygenation level established in step 1 would sickle and then separated out and not re-introduced to the patient.
Step 3. (Optionally) Transfuse the patient with stored hemoglobin A packed red blood cells e.g., in the amount corresponding to the amount of removed sickled patient red blood cells.
Step 4. Repeat process 115 as necessary progressively removing red blood cells that sickled and optionally replacing them with stored packed hemoglobin A red blood cells.
Inducing a therapeutic effect by generation and re-introduction to the patient carboxy form on hemoglobin (CO-HB) in addition to the removal of patient red blood cells most susceptible to sickling.
Step 1. Remove a first volume of patient blood.
Step 2. Irradiate the blood with the wavelength and dose of irradiation selected to (a) induce blood deoxygenation to a desired level, (b) induce CO-Hb formation to a desired level.
Step 3. Separate sickled red blood cells and re-introduce non-sickled red blood cells to the patient.
Step 4. (Optionally) transfuse the patient with packed hemoglobin A containing red blood cells.
Step 5. (Optionally) Remove the second volume of blood and follow steps 2 through 4.
Inducing a therapeutic effect by generation and re-introduction to the patient carboxy form on hemoglobin (CO-HB) without the removal of patient red blood cells most susceptible to sickling.
Step 1. Remove a first volume of patient blood.
Step 2. Irradiate the blood with the wavelength and dose of irradiation optimized to induce maximum Co-Hb formation or alternatively, formation of desired fraction of Co-Hb.
Step 3. (Optionally) transfuse the patient with packed hemoglobin A containing red blood cells.
Step 4. (Optionally) Remove the second volume of blood and follow steps 2 through 3.
Using the steps of process 115 in combination with packed red blood cells storage to eliminate the delays in blood processing that may be associated with performing the process 115.
Step 1. Perform the steps as in process 1, except that the patient blood that would have been re-transfused to the patient is processed for storage instead.
Step 2. At the steps requiring re-introduction of treated patient blood processed according to step 115, transfuse the patient with autologous blood processed according to the step 115, collected and stored during the previous procedure. Non-sickled blood collected and processed for storage under current procedure would be stored until the time of the next treatment.
Using process 115 to create autologous packed red blood cells with reduced sickle-prone cells for future autologous transfusion (e.g., post or during surgery or other procedure or condition necessitating blood transfusion).
Step 1. Remove the first volume of blood from the patient as may be allowed by clinical blood donation guidelines.
Step 2. Use the steps of the process 115, with the separated red blood cells that would have been re-transfused to the patient being processed for storage instead.
Step 3. (Optionally) Remove the second (third, etc.) volume of blood and process it for storage.
Step 4. Transfuse the patient with autologous stored blood with low propensity for sickling as may be required.
Although the present invention has been described in considerable detail with regard to certain preferred versions thereof, other versions are possible, and alterations, permutations and equivalents of the versions shown will become apparent to those skilled in the art upon a reading of the specification and study of the drawings. For example, the cooperating components may be reversed or provided in additional or fewer number, and all directional limitations, such as up and down and the like, can be switched, reversed, or changed as long as doing so is not prohibited by the language herein with regard to a particular version of the invention. Like numerals represent like parts from figure to figure. When the same reference number has been used in multiple figures, the discussion associated with that reference number in one figure is intended to be applicable to the additional figure(s) in which it is used, so long as doing so is not prohibited by explicit language with reference to one of the figures. Also, the various features of the versions herein can be combined in various ways to provide additional versions of the present invention. Furthermore, certain terminology has been used for the purposes of descriptive clarity, and not to limit the present invention. Throughout this specification and any claims appended hereto, unless the context makes it clear otherwise, the term “comprise” and its variations such as “comprises” and “comprising” should be understood to imply the inclusion of a stated element, limitation, or step but not the exclusion of any other elements, limitations, or steps. Throughout this specification and any claims appended hereto, unless the context makes it clear otherwise, the term “consisting of” and “consisting essentially of” should be understood to imply the inclusion of a stated element, limitation, or step and the exclusion of any other elements, limitations, or steps or the exclusion of any other essential elements, limitations, or steps, respectively. Throughout the specification, any discussion of a combination of elements, limitations, or steps should be understood to include (i) each element, limitation, or step of the combination alone, (ii) each element, limitation, or step of the combination with any one or more other element, limitation, or step of the combination, (iii) an inclusion of additional elements, limitations, or steps (i.e. the combination may comprise one or more additional elements, limitations, or steps), and/or (iv) an exclusion of additional elements, limitations, or steps or an exclusion of essential additional elements, limitations, or steps (i.e. the combination may consist of or consist essentially of the disclosed combination or parts of the combination). All numerical values, unless otherwise made clear in the disclosure or prosecution, include either the exact value or approximations in the vicinity of the stated numerical values, such as for example about +/−ten percent or as would be recognized by a person or ordinary skill in the art in the disclosed context. The same is true for the use of the terms such as about, substantially, and the like. Also, for any numerical ranges given, unless otherwise made clear in the disclosure, during prosecution, or by being explicitly set forth in a claim, the ranges include either the exact range or approximations in the vicinity of the values at one or both of the ends of the range. When multiple ranges are provided, the disclosed ranges are intended to include any combinations of ends of the ranges with one another and including zero and infinity as possible ends of the ranges. Therefore, any appended or later filed claims should not be limited to the description of the preferred versions contained herein and should include all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
The present application claims the benefit of domestic priority based on U.S. Provisional Patent Application 63/535,377 filed on Aug. 30, 2023, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63535377 | Aug 2023 | US |
