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INTRODUCTION: The rapid clearance of factor IX necessitates frequent intravenous administrations to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration has historically been limited by low bioavailability and potency. Dalcinonacog alfa was developed using a rational design approach to be a subcutaneously administered, next-generation coagulation prophylactic factor IX therapy. AIM: This study aimed to investigate the pharmacokinetic, pharmacodynamic, and safety profile of dalcinonacog alfa administered subcutaneously in hemophilia B dogs. METHODS: Two hemophilia B dogs received single-dose daily subcutaneous dalcinonacog alfa injections for six days. Factor IX antigen and activity, whole blood clotting time, and activated partial thromboplastin time were measured at various time points. Additionally, safety assessments for clinical adverse events and evaluations of laboratory test results were conducted. RESULTS: There was an increase in plasma factor IX antigen with daily subcutaneous dalcinonacog alfa. Bioavailability of subcutaneous dalcinonacog alfa was 10.3% in hemophilia B dogs. Daily subcutaneous dosing of dalcinonacog alfa demonstrated the effects of bioavailability, time to maximal concentration, and half-life by reaching a steady-state activity sufficient to correct severe hemophilia to normal, after four days. CONCLUSION: The increased potency of dalcinonacog alfa facilitated the initiation and completion of the Phase 1/2 subcutaneous dosing study in individuals with hemophilia B.
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Factor IX/administración & dosificación , Factor IX/farmacocinética , Hemofilia B/tratamiento farmacológico , Animales , Disponibilidad Biológica , Modelos Animales de Enfermedad , Perros , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Factor IX/química , Femenino , Hemofilia B/sangre , Inyecciones Subcutáneas , Masculino , Modelos Moleculares , Tiempo de Tromboplastina Parcial , Tiempo de Coagulación de la Sangre TotalRESUMEN
The kidney is an anisotropic organ, with higher elasticity along versus across nephrons. The degree of mechanical anisotropy in the kidney may be diagnostically relevant if properly exploited; however, if improperly controlled, anisotropy may confound stiffness measurements. The purpose of this study is to demonstrate the clinical feasibility of acoustic radiation force (ARF)-induced peak displacement (PD) measures for both exploiting and obviating mechanical anisotropy in the cortex of human kidney allografts, in vivo. Validation of the imaging methods is provided by preclinical studies in pig kidneys, in which ARF-induced PD values were significantly higher ( , Wilcoxon) when the transducer executing asymmetric ARF was oriented across versus along the nephrons. The ratio of these PD values obtained with the transducer oriented across versus along the nephrons strongly linearly correlated ( R2 = 0.95 ) to the ratio of shear moduli measured by shear wave elasticity imaging. On the contrary, when a symmetric ARF was implemented, no significant difference in PD was observed ( p > 0.01 ). Similar results were demonstrated in vivo in the kidney allografts of 14 patients. The symmetric ARF produced PD measures with no significant difference ( p > 0.01 ) between along versus across alignments, but the asymmetric ARF yielded PD ratios that remained constant over a six-month observation period post-transplantation, consistent with stable serum creatinine level and urine protein-to-creatinine ratio in the same patient population ( p > 0.01 ). The results of this pilot in vivo clinical study suggest the feasibility of 1) implementing symmetrical ARF to obviate mechanical anisotropy in the kidney cortex when anisotropy is a confounding factor and 2) implementing asymmetric ARF to exploit mechanical anisotropy when mechanical anisotropy is a potentially relevant biomarker.
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Aloinjertos , Diagnóstico por Imagen de Elasticidad/métodos , Corteza Renal , Trasplante de Riñón , Adulto , Anciano , Aloinjertos/diagnóstico por imagen , Aloinjertos/fisiología , Animales , Anisotropía , Módulo de Elasticidad/fisiología , Femenino , Humanos , Corteza Renal/diagnóstico por imagen , Corteza Renal/fisiología , Masculino , Persona de Mediana Edad , Insuficiencia Renal Crónica/diagnóstico por imagen , Insuficiencia Renal Crónica/cirugía , PorcinosRESUMEN
Anti-drug antibodies in hemophilia patients substantially complicate treatment. Their elimination through immune tolerance induction (ITI) protocols poses enormous costs, and ITI is often ineffective for factor IX (FIX) inhibitors. Moreover, there is no prophylactic ITI protocol to prevent anti-drug antibody (ADA) formation. Using general immune suppression is problematic. To address this urgent unmet medical need, we delivered antigen bioencapsulated in plant cells to hemophilia B dogs. Commercial-scale production of CTB-FIX fusion expressed in lettuce chloroplasts was done in a hydroponic facility. CTB-FIX (â¼1 mg/g) in lyophilized cells was stable with proper folding, disulfide bonds, and pentamer assembly after 30-month storage at ambient temperature. Robust suppression of immunoglobulin G (IgG)/inhibitor and IgE formation against intravenous FIX was observed in three of four hemophilia B dogs fed with lyophilized lettuce cells expressing CTB-FIX. No side effects were detected after feeding CTB-FIX-lyophilized plant cells for >300 days. Coagulation times were markedly shortened by intravenous FIX in orally tolerized treated dogs, in contrast to control dogs that formed high-titer antibodies to FIX. Commercial-scale production, stability, prolonged storage of lyophilized cells, and efficacy in tolerance induction in a large, non-rodent model of human disease offer a novel concept for oral tolerance and low-cost production and delivery of biopharmaceuticals.
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Alimentación Animal , Hemofilia B/inmunología , Tolerancia Inmunológica , Lactuca , Plantas Modificadas Genéticamente , Administración Oral , Animales , Anticuerpos/inmunología , Formación de Anticuerpos , Biomarcadores , Cloroplastos/genética , Perros , Factor IX/genética , Factor IX/inmunología , Expresión Génica , Hemofilia B/sangre , Hemofilia B/genética , Humanos , Lactuca/genética , FenotipoRESUMEN
Processing by the proprotein convertase furin is believed to be critical for the biological activity of multiple proteins involved in hemostasis, including coagulation factor VIII (FVIII). This belief prompted the retention of the furin recognition motif (amino acids 1645-1648) in the design of B-domain-deleted FVIII (FVIII-BDD) products in current clinical use and in the drug development pipeline, as well as in experimental FVIII gene therapy strategies. Here, we report that processing by furin is in fact deleterious to FVIII-BDD secretion and procoagulant activity. Inhibition of furin increases the secretion and decreases the intracellular retention of FVIII-BDD protein in mammalian cells. Our new variant (FVIII-ΔF), in which this recognition motif is removed, efficiently circumvents furin. FVIII-ΔF demonstrates increased recombinant protein yields, enhanced clotting activity, and higher circulating FVIII levels after adeno-associated viral vector-based liver gene therapy in a murine model of severe hemophilia A (HA) compared with FVIII-BDD. Moreover, we observed an amelioration of the bleeding phenotype in severe HA dogs with sustained therapeutic FVIII levels after FVIII-ΔF gene therapy at a lower vector dose than previously employed in this model. The immunogenicity of FVIII-ΔF did not differ from that of FVIII-BDD as a protein or a gene therapeutic. Thus, contrary to previous suppositions, FVIII variants that can avoid furin processing are likely to have enhanced translational potential for HA therapy.
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Factor VIII/uso terapéutico , Furina/metabolismo , Terapia Genética , Hemofilia A/terapia , Animales , Línea Celular , Perros , Factor VIII/genética , Hemofilia A/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Proteínas Recombinantes/uso terapéuticoRESUMEN
Animals with hemophilia are models for gene therapy, factor replacement, and inhibitor development in humans. We have actively sought dogs with severe hemophilia A that have novel factor VIII mutations unlike the previously described factor VIII intron 22 inversion. A male Old English Sheepdog with recurrent soft-tissue hemorrhage and hemarthrosis was diagnosed with severe hemophilia A (factor VIII activity less than 1% of normal). We purified genomic DNA from this dog and ruled out the common intron 22 inversion; we then sequenced all 26 exons. Comparing the results with the normal canine factor VIII sequence revealed a CâT transition in exon 12 of the factor VIII gene that created a premature stop codon at amino acid 577 in the A2 domain of the protein. In addition, 2 previously described polymorphisms that do not cause hemophilia were present at amino acids 909 and 1184. The hemophilia mutation creates a new TaqI site that facilitates rapid genotyping of affected offspring by PCR and restriction endonuclease analyses. This mutation is analogous to the previously described human factor VIII mutation at Arg583, which likewise is a CpG dinucleotide transition causing a premature stop codon in exon 12. Thus far, despite extensive treatment with factor VIII, this dog has not developed neutralizing antibodies ('inhibitors') to the protein. This novel mutation in a dog gives rise to severe hemophilia A analogous to a mutation seen in humans. This model will be useful for studies of the treatment of hemophilia.
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Enfermedades de los Perros/genética , Perros/genética , Factor VIII/genética , Hemofilia A/veterinaria , Mutación Puntual , Animales , Codón de Terminación , Perros/sangre , Hemofilia A/genética , Análisis de Secuencia de ADN/veterinariaRESUMEN
Soy phosphatidylinositol (PI)-containing lipid nanoparticles prolong plasma survival, improve hemostatic efficacy, and decrease immunogenicity of human B-domain-deleted factor VIII (BDD FVIII) in hemophilia A (HA) mice. We hypothesize that PI-associated BDD FVIII is more potent than the free protein and, using mathematical modeling, have projected that PI-associated BDD FVIII could be used for once-weekly prophylactic dosing in patients. To facilitate translation to the clinic, comparative plasma survival and ex vivo efficacy of PI-associated recombinant canine FVIII (PI-rcFVIII) were evaluated in HA dogs. Two HA dogs were administered a 50-U/kg intravenous dose of free or PI-rcFVIII. rcFVIII activity measurements and ex vivo efficacy analyses such as whole blood clotting time and thromboelastography were conducted on recovered plasma and whole blood samples. PI association decreased clearance (â¼25%) and increased plasma exposure (â¼1.4-fold) of rcFVIII. PI-rcFVIII-treated animals had prolonged improvements in whole blood clotting time and thromboelastography parameters compared to free rcFVIII-treated animals. Because rcFVIII is a BDD form of FVIII, these studies provide proof of principle that observations with human BDD FVIII in mice translate to higher animal species. In addition, PI-rcFVIII has potential applications in canine HA management and as a bypass therapy in inhibitor-positive HA patients.
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Portadores de Fármacos/química , Factor VIII/farmacocinética , Glycine max/química , Hemofilia A/tratamiento farmacológico , Hemostáticos/sangre , Nanopartículas/química , Fosfatidilinositoles/química , Animales , Perros , Composición de Medicamentos , Estabilidad de Medicamentos , Factor VIII/administración & dosificación , Factor VIII/uso terapéutico , Femenino , Hemofilia A/sangre , Hemostáticos/administración & dosificación , Hemostáticos/uso terapéutico , Inyecciones Intravenosas , Modelos Biológicos , Proteínas RecombinantesRESUMEN
Factor VII (FVII) deficiency is a rare autosomal recessive bleeding disorder treated by infusion of fresh-frozen plasma, plasma-derived FVII concentrates and low-dose recombinant activated FVII. Clinical data suggest that a mild elevation of plasma FVII levels (>10% normal) results in improved hemostasis. Research dogs with a G96E missense FVII mutation (FVII-G96E) have <1% FVII activity. By western blot, we show that they have undetectable plasmatic antigen, thus representing the most prevalent type of human FVII deficiency (low antigen/activity). In these dogs, we determine the feasibility of a gene therapy approach using liver-directed, adeno-associated viral (AAV) serotype 8 vector delivery of a canine FVII (cFVII) zymogen transgene. FVII-G96E dogs received escalating AAV doses (2E11 to 4.95E13 vector genomes [vg] per kg). Clinically therapeutic expression (15% normal) was attained with as low as 6E11 vg/kg of AAV and has been stable for >1 year (ongoing) without antibody formation to the cFVII transgene. Sustained and supraphysiological expression of 770% normal was observed using 4.95E13 vg/kg of AAV (2.6 years, ongoing). No evidence of pathological activation of coagulation or detrimental animal physiology was observed as platelet counts, d-dimer, fibrinogen levels, and serum chemistries remained normal in all dogs (cumulative 6.4 years). We observed a transient and noninhibitory immunoglobulin G class 2 response against cFVII only in the dog receiving the highest AAV dose. In conclusion, in the only large-animal model representing the majority of FVII mutation types, our data are first to demonstrate the feasibility, safety, and long-term duration of AAV-mediated correction of FVII deficiency.
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Deficiencia del Factor VII/genética , Deficiencia del Factor VII/terapia , Factor VII/genética , Terapia Genética , Vectores Genéticos/genética , Vectores Genéticos/uso terapéutico , Precursores de Proteínas/genética , Adenoviridae/genética , Animales , Perros , Deficiencia del Factor VII/sangre , Expresión Génica , Vectores Genéticos/administración & dosificación , Células HEK293 , Humanos , Mutación Puntual , TransgenesRESUMEN
Acoustic radiation force impulse (ARFI) Surveillance of Subcutaneous Hemorrhage (ASSH) has been previously demonstrated to differentiate bleeding phenotype and responses to therapy in dogs and humans, but to date, the method has lacked experimental validation. This work explores experimental validation of ASSH in a poroelastic tissue-mimic and in vivo in dogs. The experimental design exploits calibrated flow rates and infusion durations of evaporated milk in tofu or heparinized autologous blood in dogs. The validation approach enables controlled comparisons of ASSH-derived bleeding rate (BR) and time to hemostasis (TTH) metrics. In tissue-mimicking experiments, halving the calibrated flow rate yielded ASSH-derived BRs that decreased by 44% to 48%. Furthermore, for calibrated flow durations of 5.0 minutes and 7.0 minutes, average ASSH-derived TTH was 5.2 minutes and 7.0 minutes, respectively, with ASSH predicting the correct TTH in 78% of trials. In dogs undergoing calibrated autologous blood infusion, ASSH measured a 3-minute increase in TTH, corresponding to the same increase in the calibrated flow duration. For a measured 5% decrease in autologous infusion flow rate, ASSH detected a 7% decrease in BR. These tissue-mimicking and in vivo preclinical experimental validation studies suggest the ASSH BR and TTH measures reflect bleeding dynamics.
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Diagnóstico por Imagen de Elasticidad/métodos , Hemorragia/diagnóstico por imagen , Tejido Subcutáneo/diagnóstico por imagen , Animales , Calibración , Modelos Animales de Enfermedad , Perros , Modelos Biológicos , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Insulin-resistant subjects develop more severe and diffuse coronary artery atherosclerosis than insulin-sensitive controls but the mechanisms that mediate this atherosclerosis phenotype are unknown. RESEARCH OBJECTIVE: To determine the metabolic parameters that associate with the severity of coronary atherosclerosis in insulin resistant pigs fed a high fat/high NaCl diet. KEY METHODS: The primary endpoint was severity of coronary atherosclerosis in adult pigs (Sus scrofa, n = 37) fed a high fat diet that also contained high NaCl (56% above recommended levels) for 1 year. PRINCIPAL FINDINGS: Twenty pigs developed severe and diffuse distal coronary artery atherosclerosis (i.e., severe = intimal area as a percent medial area > 200% in at least 2 coronary artery cross sections and diffuse distal = intimal area as a percent medial area ≥ 150% over 3 sections separated by 2 cm in the distal half of the coronary artery). The other 17 pigs had substantially less coronary artery atherosclerosis. All 37 pigs had blood pressure in a range that would be considered hypertensive in humans and developed elevations in total and LDL and HDL cholesterol, weight gain, increased backfat, and increased insulin resistance (Bergman Si) without overt diabetes. Insulin resistance was not associated with atherosclerosis severity. Five additional pigs fed regular pig chow also developed increased insulin resistance but essentially no change in the other variables and little to no detectible coronary atherosclerosis. Most importantly, the 20 high fat/high NaCl diet-fed pigs with severe and diffuse distal coronary artery atherosclerosis had substantially greater increases (p< 0.05) in oxidized LDL (oxLDL) and fructosamine consistent with increased protein glycation. CONCLUSION: In pigs fed a high fat/high NaCl diet, glycated proteins are induced in the absence of overt diabetes and this degree of increase is associated with the development of severe and diffuse distal coronary artery atherosclerosis.
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Presión Sanguínea/efectos de los fármacos , Enfermedad de la Arteria Coronaria , Fructosamina/sangre , Resistencia a la Insulina , Lipoproteínas LDL/sangre , Cloruro de Sodio Dietético/farmacología , Animales , Enfermedad de la Arteria Coronaria/sangre , Enfermedad de la Arteria Coronaria/fisiopatología , Modelos Animales de Enfermedad , Índice de Severidad de la Enfermedad , Cloruro de Sodio Dietético/efectos adversos , Sus scrofaRESUMEN
We investigated the efficacy of liver-directed gene therapy using lentiviral vectors in a large animal model of hemophilia B and evaluated the risk of insertional mutagenesis in tumor-prone mouse models. We showed that gene therapy using lentiviral vectors targeting the expression of a canine factor IX transgene in hepatocytes was well tolerated and provided a stable long-term production of coagulation factor IX in dogs with hemophilia B. By exploiting three different mouse models designed to amplify the consequences of insertional mutagenesis, we showed that no genotoxicity was detected with these lentiviral vectors. Our findings suggest that lentiviral vectors may be an attractive candidate for gene therapy targeted to the liver and may be potentially useful for the treatment of hemophilia.
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Terapia Genética , Hemofilia B/terapia , Lentivirus/genética , Hígado/patología , Animales , Coagulación Sanguínea , Modelos Animales de Enfermedad , Perros , Femenino , Vectores Genéticos/metabolismo , Ratones Endogámicos C57BL , Mutágenos/toxicidad , Factores de Tiempo , Transducción Genética , TransgenesRESUMEN
The liver is a very complex organ with a large variety of functions, making it an attractive organ for gene replacement therapy. Many genetic disorders can be corrected by delivering gene products directly into the liver using viral vectors. In this chapter, we will describe gene delivery via portal vein administration in mice and dogs to correct the blood coagulation disorder hemophilia B. Although there are multiple delivery routes for both viral and non-viral vectors in animals, portal vein administration delivers vectors directly and efficiently into the liver. Complete correction of murine hemophilia B and multi-year near-correction of canine hemophilia B have been achieved following portal vein delivery of adeno-associated viral (AAV) vectors expressing factor IX from hepatocyte-specific promoters. Peripheral vein injection can lead to increased vector dissemination to off-target organ such as the lung and spleen. Below, we will describe portal vein injection delivery route via laparotomy.
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Dependovirus/genética , Factor IX/genética , Terapia Genética , Vectores Genéticos/genética , Hemofilia B/genética , Hemofilia B/terapia , Administración Intravenosa , Animales , Perros , Técnicas de Transferencia de Gen , Vectores Genéticos/administración & dosificación , Ratones , Vena Porta/cirugíaRESUMEN
It is essential to improve therapies for controlling excessive bleeding in patients with haemorrhagic disorders. As activated blood platelets mediate the primary response to vascular injury, we hypothesize that storage of coagulation Factor VIII within platelets may provide a locally inducible treatment to maintain haemostasis for haemophilia A. Here we show that haematopoietic stem cell gene therapy can prevent the occurrence of severe bleeding episodes in dogs with haemophilia A for at least 2.5 years after transplantation. We employ a clinically relevant strategy based on a lentiviral vector encoding the ITGA2B gene promoter, which drives platelet-specific expression of human FVIII permitting storage and release of FVIII from activated platelets. One animal receives a hybrid molecule of FVIII fused to the von Willebrand Factor propeptide-D2 domain that traffics FVIII more effectively into α-granules. The absence of inhibitory antibodies to platelet-derived FVIII indicates that this approach may have benefit in patients who reject FVIII replacement therapies. Thus, platelet FVIII may provide effective long-term control of bleeding in patients with haemophilia A.
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Plaquetas/fisiología , Enfermedades de los Perros/terapia , Factor VIII/genética , Terapia Genética/veterinaria , Hemofilia A/veterinaria , Hemostasis , Integrina alfa2/metabolismo , Animales , Enfermedades de los Perros/genética , Perros , Regulación de la Expresión Génica/fisiología , Terapia Genética/métodos , Hemofilia A/terapia , Humanos , Integrina alfa2/genéticaRESUMEN
A validated method for assessing hemostasis in vivo is critical for testing the hemostatic efficacy of therapeutic agents designed for patients with bleeding disorders such as von Willebrand disease (VWD) and hemophilia A. We hypothesize that rate of bleeding and time to hemostasis can be monitored in vivo by acoustic radiation force impulse (ARFI) ultrasound. We performed ARFI imaging following 12-gauge needle puncture of hind limb muscle encompassing an â¼2 mm vein in six normal, eight naïve hemophilia A before and after infusing canine factor VIII, three hemophilia A expressing canine factor VIIa following gene transfer, and two naïve VWD dogs. Serial data sets were processed with custom software to (1) estimate the rate of hemorrhage and (2) estimate the time of hemostasis onset. The rate of hemorrhage during the first 30 min following puncture was markedly increased in the VWD dogs relative to normal but was not significantly different between normal, naïve hemophilia A or hemophilia A expressing cFVIIa. ARFI-derived times to hemostasis were significantly longer in naïve hemophilia A dogs than in normal dogs and were shortened by canine coagulation factors VIII and VIIa. These data support our hypothesis that rate of hemorrhage and time to hemostasis in vivo in response to a standardized hemostatic challenge can be detected by ARFI ultrasound in canine models of VWD and hemophilia. These data also suggest that the ARFI-monitored hemostatic challenge is relevant for in vivo testing of the hemostatic efficacy of therapeutic clotting factor replacement products used to treat inherited bleeding disorders.
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Diagnóstico por Imagen de Elasticidad/métodos , Hemofilia A/diagnóstico por imagen , Hemorragia/diagnóstico por imagen , Hemostasis , Enfermedades de von Willebrand/diagnóstico por imagen , Enfermedades de von Willebrand/fisiopatología , Animales , Perros , Hemofilia A/complicaciones , Hemofilia A/fisiopatología , Hemorragia/etiología , Hemorragia/fisiopatología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Enfermedades de von Willebrand/complicacionesRESUMEN
Use of animal models of inherited and induced von Willebrand factor (VWF) deficiency continues to advance the knowledge of VWF-related diseases: von Willebrand disease (VWD), thrombotic thrombocytopenic purpura (TTP), and coronary artery thrombosis. First, in humans, pigs, and dogs, VWF is essential for normal hemostasis; without VWF bleeding events are severe and can be fatal. Second, the ADAMTS13 cleavage site is preserved in all three species suggesting all use this mechanism for normal VWF multimer processing and that all are susceptible to TTP when ADAMTS13 function is reduced. Third, while the role of VWF in atherogenesis is debated, arterial thrombosis complicating atherosclerosis appears to be VWF-dependent. The differences in the VWF gene and protein between humans, pigs, and dogs are relatively few but important to consider in the design of VWF-focused experiments. These homologies and differences are reviewed in detail and their implications for research projects are discussed. The current status of porcine and canine VWD are also reviewed as well as their potential role in future studies of VWF-related disorders of hemostasis and thrombosis.
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Dogs with hemophilia A, hemophilia B, von Willebrand disease (VWD), and factor VII deficiency faithfully recapitulate the severe bleeding phenotype that occurs in humans with these disorders. The first rational approach to diagnosing these bleeding disorders became possible with the development of reliable assays in the 1940s through research that used these dogs. For the next 60 years, treatment consisted of replacement of the associated missing or dysfunctional protein, first with plasma-derived products and subsequently with recombinant products. Research has consistently shown that replacement products that are safe and efficacious in these dogs prove to be safe and efficacious in humans. But these highly effective products require repeated administration and are limited in supply and expensive; in addition, plasma-derived products have transmitted bloodborne pathogens. Recombinant proteins have all but eliminated inadvertent transmission of bloodborne pathogens, but the other limitations persist. Thus, gene therapy is an attractive alternative strategy in these monogenic disorders and has been actively pursued since the early 1990s. To date, several modalities of gene transfer in canine hemophilia have proven to be safe, produced easily detectable levels of transgene products in plasma that have persisted for years in association with reduced bleeding, and correctly predicted the vector dose required in a human hemophilia B liver-based trial. Very recently, however, researchers have identified an immune response to adeno-associated viral gene transfer vector capsid proteins in a human liver-based trial that was not present in preclinical testing in rodents, dogs, or nonhuman primates. This article provides a review of the strengths and limitations of canine hemophilia, VWD, and factor VII deficiency models and of their historical and current role in the development of improved therapy for humans with these inherited bleeding disorders.
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Modelos Animales de Enfermedad , Deficiencia del Factor VII/terapia , Terapia Genética/métodos , Hemofilia A/terapia , Hemofilia B/terapia , Proteínas/administración & dosificación , Enfermedades de von Willebrand/terapia , Animales , Coagulación Sanguínea/fisiología , Perros , Deficiencia del Factor VII/genética , Vectores Genéticos , Hemofilia A/genética , Hemofilia B/genética , Trasplante de Hígado/métodos , Enfermedades de von Willebrand/genética , Factor de von Willebrand/metabolismoRESUMEN
Intravenous administration of recombinant human factor IX (rhFIX) acutely corrects the coagulopathy in hemophilia B dogs. To date, 20 of 20 dogs developed inhibitory antibodies to the xenoprotein, making it impossible to determine if new human FIX products, formulations, or methods of chronic administration can reduce bleeding frequency. Our goal was to determine whether hemophilia B dogs rendered tolerant to rhFIX would have reduced bleeding episodes while on sustained prophylactic rhFIX administered subcutaneously. Reproducible methods were developed for inducing tolerance to rhFIX in this strain of hemophilia B dogs, resulting in a significant reduction in the development of inhibitors relative to historical controls (5 of 12 versus 20 or 20, P <.001). The 7 of 12 tolerized hemophilia B dogs exhibited shortened whole blood clotting times (WBCTs), sustained detectable FIX antigen, undetectable Bethesda inhibitors, transient or no detectable antihuman FIX antibody titers by enzyme-linked immunosorbent assay (ELISA), and normal clearance of infused rhFIX. Tolerized hemophilia B dogs had 69% reduction in bleeding frequency in year 1 compared with nontolerized hemophilia B dogs (P =.0007). If proven safe in human clinical trials, subcutaneous rhFIX may provide an alternate approach to prophylactic therapy in selected patients with hemophilia B.
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Factor IX/uso terapéutico , Hemofilia B/tratamiento farmacológico , Hemorragia/prevención & control , Animales , Animales Endogámicos , Animales Recién Nacidos , Anticuerpos Heterófilos/biosíntesis , Anticuerpos Heterófilos/inmunología , Modelos Animales de Enfermedad , Perros , Factor IX/administración & dosificación , Factor IX/inmunología , Hemofilia B/complicaciones , Hemorragia/etiología , Humanos , Tolerancia Inmunológica , Inyecciones Subcutáneas , Masculino , Proyectos Piloto , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/inmunología , Proteínas Recombinantes/uso terapéutico , Reproducibilidad de los ResultadosRESUMEN
Recombinant human interleukin-11 (rhIL-11), a glycoprotein 130 (gp130)-signaling cytokine approved for treatment of thrombocytopenia, also raises von Willebrand factor (VWF) and factor VIII (FVIII) by an unknown mechanism. Desmopressin (1-deamino-8-d-arginine vasopressin [DDAVP]) releases stored VWF and FVIII and is used for treatment of VWF and FVIII deficiencies. To compare the effect of these 2 agents, heterozygous von Willebrand disease (VWD) and normal dogs were treated with either rhIL-11 (50 microg/kg/d subcutaneously x 7 days) or DDAVP (5 microg/kg/d intravenously x 7 days). The rhIL-11 produced a gradual and sustained elevation of VWF and FVIII levels in both heterozygous VWD and normal dogs while DDAVP produced a rapid and unsustained increase. Importantly, rhIL-11 treatment produced a 2.5- to 11-fold increase in VWF mRNA in normal canine heart, aorta, and spleen but not in homozygous VWD dogs, thus identifying a mechanism for elevation of plasma VWF in vivo. Moreover, dogs pretreated with rhIL-11 retain a DDAVP-releasable pool of VWF and FVIII, suggesting that rhIL-11 does not significantly alter trafficking of these proteins to or from storage pools. The half-life of infused VWF is unchanged by rhIL-11 in homozygous VWD dogs. These results show that rhIL-11 and DDAVP raise plasma VWF by different mechanisms. Treatment with rhIL-11 with or without DDAVP may provide an alternative to plasma-derived products for some VWD and hemophilia A patients if it is shown safe in clinical trials.
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Desamino Arginina Vasopresina/uso terapéutico , Interleucina-11/uso terapéutico , ARN Mensajero/biosíntesis , Cuerpos de Weibel-Palade/metabolismo , Enfermedades de von Willebrand/fisiopatología , Factor de von Willebrand/metabolismo , Animales , Aorta/efectos de los fármacos , Aorta/metabolismo , Desamino Arginina Vasopresina/farmacología , Perros , Evaluación Preclínica de Medicamentos , Factor VIII/metabolismo , Semivida , Corazón/efectos de los fármacos , Heterocigoto , Interleucina-11/farmacología , Miocardio/metabolismo , ARN Mensajero/genética , Proteínas Recombinantes/farmacología , Proteínas Recombinantes/uso terapéutico , Bazo/efectos de los fármacos , Bazo/metabolismo , Cuerpos de Weibel-Palade/efectos de los fármacos , Enfermedades de von Willebrand/tratamiento farmacológico , Enfermedades de von Willebrand/genética , Factor de von Willebrand/biosíntesis , Factor de von Willebrand/genéticaRESUMEN
Hemophilia B is a bleeding disorder resulting from factor IX (FIX) deficiency that might be treated with gene therapy. Neonatal delivery would correct the disease sooner than would transfer into adults, and could reduce immunological responses. Neonatal mice were injected intravenously with a Moloney murine leukemia virus-based retroviral vector (RV) expressing canine FIX (cFIX). They achieved 150% to 280% of normal cFIX antigen levels in plasma (100% is 5 microg/mL), which was functional in vitro and in vivo. Three newborn hemophilia B dogs that were injected intravenously with RV achieved 12% to 36% of normal cFIX antigen levels, which improved coagulation tests. Only one mild bleed has occurred during 14 total months of evaluation. This is the first demonstration of prolonged expression after neonatal gene therapy for hemophilia B in mice or dogs. Most animals failed to make antibodies to cFIX, demonstrating that neonatal gene transfer may induce tolerance. Although hepatocytes from newborns replicate, those from adults do not. Adult mice therefore received hepatocyte growth factor to induce hepatocyte replication prior to intravenous injection of RV. This resulted in expression of 35% of normal cFIX antigen levels for 11 months, although all mice produced anti-cFIX antibodies. This is the first demonstration that high levels of FIX activity can be achieved with an RV in adults without a partial hepatectomy to induce hepatocyte replication. We conclude that RV-mediated hepatic gene therapy is effective for treating hemophilia B in mice and dogs, although the immune system may complicate gene transfer in adults.