Protein-Engineered Coagulation Factors for Hemophilia Gene Therapy
2018; Cell Press; Volume: 12; Linguagem: Inglês
10.1016/j.omtm.2018.12.007
ISSN2329-0501
AutoresBenjamin J. Samelson‐Jones, Valder R. Arruda,
Tópico(s)Blood Coagulation and Thrombosis Mechanisms
ResumoHemophilia A (HA) and hemophilia B (HB) are X-linked bleeding disorders due to inheritable deficiencies in either coagulation factor VIII (FVIII) or factor IX (FIX), respectively. Recently, gene therapy clinical trials with adeno-associated virus (AAV) vectors and protein-engineered transgenes, B-domain deleted (BDD) FVIII and FIX-Padua, have reported near-phenotypic cures in subjects with HA and HB, respectively. Here, we review the biology and the clinical development of FVIII-BDD and FIX-Padua as transgenes. We also examine alternative bioengineering strategies for FVIII and FIX, as well as the immunological challenges of these approaches. Other engineered proteins and their potential use in gene therapy for hemophilia with inhibitors are also discussed. Continued advancement of gene therapy for HA and HB using protein-engineered transgenes has the potential to alleviate the substantial medical and psychosocial burdens of the disease. Hemophilia A (HA) and hemophilia B (HB) are X-linked bleeding disorders due to inheritable deficiencies in either coagulation factor VIII (FVIII) or factor IX (FIX), respectively. Recently, gene therapy clinical trials with adeno-associated virus (AAV) vectors and protein-engineered transgenes, B-domain deleted (BDD) FVIII and FIX-Padua, have reported near-phenotypic cures in subjects with HA and HB, respectively. Here, we review the biology and the clinical development of FVIII-BDD and FIX-Padua as transgenes. We also examine alternative bioengineering strategies for FVIII and FIX, as well as the immunological challenges of these approaches. Other engineered proteins and their potential use in gene therapy for hemophilia with inhibitors are also discussed. Continued advancement of gene therapy for HA and HB using protein-engineered transgenes has the potential to alleviate the substantial medical and psychosocial burdens of the disease. Hemophilia A (HA) and hemophilia B (HB) are X-linked bleeding disorders due to inheritable deficiencies in either coagulation factor VIII (FVIII) or factor IX (FIX), respectively.1Peyvandi F. Garagiola I. Young G. The past and future of haemophilia: diagnosis, treatments, and its complications.Lancet. 2016; 388: 187-197Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 2Konkle B.A. Huston H. Nakaya Fletcher S. Hemophilia A.in: Adam M.P. Ardinger H.H. Pagon R.A. Wallace S.E. Bean L.J.H. Stephens K. Amemiya A. GeneReviews®. University of Washington, 1993Google Scholar The bleeding phenotype is generally related to the residual factor activity: people with severe disease (factor activity <1% normal) have frequent spontaneous bleeds; people with moderate disease (factor activity 1%–5% normal) rarely have spontaneous bleeds, but bleed with minor trauma; and people with mild disease (factor activity 5%–40% normal) bleed during invasive procedures or trauma. Given this well-defined relationship between factor activity and bleeding phenotype, HA and HB are attractive targets for gene therapy as small increases in factor levels are expected to have a meaningful clinical impact. Although a variety of strategies have been investigated over several decades (reviewed in Hough and Lillicrap,3Hough C. Lillicrap D. Gene therapy for hemophilia: an imperative to succeed.J. Thromb. Haemost. 2005; 3: 1195-1205Crossref PubMed Scopus (0) Google Scholar Lheriteau et al.,4Lheriteau E. Davidoff A.M. Nathwani A.C. Haemophilia gene therapy: progress and challenges.Blood Rev. 2015; 29: 321-328Abstract Full Text Full Text PDF PubMed Google Scholar Rogers and Herzog,5Rogers G.L. Herzog R.W. Gene therapy for hemophilia.Front. Biosci. 2015; 20: 556-603Crossref PubMed Scopus (0) Google Scholar Arruda and Samelson-Jones,6Arruda V.R. Samelson-Jones B.J. Obstacles and future of gene therapy for hemophilia.Expert Opin. Orphan Drugs. 2015; 3: 997-1010Crossref PubMed Scopus (10) Google Scholar and High7High K.A. The gene therapy journey for hemophilia: are we there yet? Hematology Am.Soc. Hematol. Educ. Program 2012. 2012; : 375-381Google Scholar), the field has coalesced around the use of adeno-associated virus (AAV) vectors8Zinn E. Vandenberghe L.H. Adeno-associated virus: fit to serve.Curr. Opin. Virol. 2014; 8: 90-97Crossref PubMed Scopus (33) Google Scholar, 9Mingozzi F. High K.A. Therapeutic in vivo gene transfer for genetic disease using AAV: progress and challenges.Nat. Rev. Genet. 2011; 12: 341-355Crossref PubMed Scopus (490) Google Scholar, 10Colella P. Ronzitti G. Mingozzi F. Emerging issues in AAV-mediated in vivo gene therapy.Mol. Ther. Methods Clin. Dev. 2017; 8: 87-104Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar delivering transgenes of engineered FVIII or FIX variants with therapeutically advantageous properties not present in the wild-type (WT) protein. Herein, we review the protein engineering strategies that have allowed gene therapy for hemophilia to come to fruition with phase 3 studies announced for both HA and HB. We also review alternative protein engineering approaches being undertaken for FVIII and FIX, as well as other engineered blood proteins that may have potential as transgenes for hemophilia gene therapy. We defer genomic engineering strategies to other reviews.4Lheriteau E. Davidoff A.M. Nathwani A.C. Haemophilia gene therapy: progress and challenges.Blood Rev. 2015; 29: 321-328Abstract Full Text Full Text PDF PubMed Google Scholar The armamentarium to treat HA and HB has recently expanded.11Mannucci P.M. Half-life extension technologies for haemostatic agents.Thromb. Haemost. 2015; 113: 165-176Crossref PubMed Scopus (5) Google Scholar, 12Arruda V.R. Doshi B.S. Samelson-Jones B.J. Emerging therapies for hemophilia: controversies and unanswered questions.F1000Res. 2018; 7: 489Crossref Scopus (1) Google Scholar, 13Callaghan M.U. Sidonio R. Pipe S.W. Novel therapeutics for hemophilia and other bleeding disorders.Blood. 2018; 132: 23-30Crossref PubMed Scopus (3) Google Scholar, 14Arruda V.R. Doshi B.S. Samelson-Jones B.J. Novel approaches to hemophilia therapy: successes and challenges.Blood. 2017; 130: 2251-2256Crossref PubMed Scopus (13) Google Scholar Until a few years ago, the management of HA and HB mostly comprised restoring the FVIII or FIX activity through intravenous infusions of the missing factor protein. Factor replacement was used either "on-demand" to treat acute bleeding or prophylactically to prevent bleeding, which required regular scheduled infusions of factor typically two to four times per week. There are, however, several limitations of factor protein therapy. First, it is estimated that only 20% of people with hemophilia worldwide have regular access to factor replacement because of economic reasons. Second, despite the proven benefits of factor prophylaxis for patients with severe disease,15Manco-Johnson M.J. Abshire T.C. Shapiro A.D. Riske B. Hacker M.R. Kilcoyne R. Ingram J.D. Manco-Johnson M.L. Funk S. Jacobson L. et al.Prophylaxis versus episodic treatment to prevent joint disease in boys with severe hemophilia.N. Engl. J. Med. 2007; 357: 535-544Crossref PubMed Scopus (1029) Google Scholar, 16Nilsson I.M. Berntorp E. Löfqvist T. Pettersson H. Twenty-five years' experience of prophylactic treatment in severe haemophilia A and B.J. Intern. Med. 1992; 232: 25-32Crossref PubMed Google Scholar ∼40% of adult patients with access to factor do not routinely receive prophylaxis.17Manco-Johnson M.J. Soucie J.M. Gill J.C. Joint Outcomes Committee of the Universal Data Collection, US Hemophilia Treatment Center NetworkProphylaxis usage, bleeding rates, and joint outcomes of hemophilia, 1999 to 2010: a surveillance project.Blood. 2017; 129: 2368-2374Crossref PubMed Scopus (0) Google Scholar, 18O'Mahony B. Noone D. Giangrande P.L. Prihodova L. Haemophilia care in Europe—a survey of 35 countries.Haemophilia. 2013; 19: e239-e247Crossref PubMed Scopus (48) Google Scholar The recent advent of extended half-life (EHL) factor products have allowed for prophylactic regimens with decreased infusion frequency (reviewed in Mannucci et al.,11Mannucci P.M. Half-life extension technologies for haemostatic agents.Thromb. Haemost. 2015; 113: 165-176Crossref PubMed Scopus (5) Google Scholar Arruda et al.,12Arruda V.R. Doshi B.S. Samelson-Jones B.J. Emerging therapies for hemophilia: controversies and unanswered questions.F1000Res. 2018; 7: 489Crossref Scopus (1) Google Scholar, 14Arruda V.R. Doshi B.S. Samelson-Jones B.J. Novel approaches to hemophilia therapy: successes and challenges.Blood. 2017; 130: 2251-2256Crossref PubMed Scopus (13) Google Scholar and Callaghan et al.13Callaghan M.U. Sidonio R. Pipe S.W. Novel therapeutics for hemophilia and other bleeding disorders.Blood. 2018; 132: 23-30Crossref PubMed Scopus (3) Google Scholar). These EHL products are altering the standard of care of hemophilia treatment in the developed world and consequently changing the risk-to-benefit discussion of novel approaches such as gene therapy.19Giangrande P. The future of hemophilia treatment: longer-acting factor concentrates versus gene therapy.Semin. Thromb. Hemost. 2016; 42: 513-517Crossref PubMed Scopus (12) Google Scholar The relative safety of recombinant factor protein compared with plasma-derived factor protein was recently questioned in the Survey of Inhibitors in Plasma-Product Exposed Toddlers (SIPPET) clinical trial. In this prospective randomized clinical trial, standard half-life recombinant FVIII products were observed to have increased risk of inhibitor development compared with plasma-derived FVIII products (hazard ratio, 1.87; 95% confidence interval, 1.17–2.96).20Peyvandi F. Mannucci P.M. Garagiola I. El-Beshlawy A. Elalfy M. Ramanan V. Eshghi P. Hanagavadi S. Varadarajan R. Karimi M. et al.A randomized trial of factor VIII and neutralizing antibodies in hemophilia A.N. Engl. J. Med. 2016; 374: 2054-2064Crossref PubMed Scopus (158) Google Scholar However, additional independent studies are need to confirm these data. Inhibitors are anti-FVIII or anti-FIX neutralizing alloantibodies that obstruct the hemostatic activity of FVIII or FIX. At high titers, inhibitors render replacement factor ineffective to treat bleeds. Inhibitors are the most substantial complication of factor replacement, and their development is associated with a substantial increase in morbidity and mortality.21Walsh C.E. Soucie J.M. Miller C.H. United States Hemophilia Treatment Center NetworkImpact of inhibitors on hemophilia A mortality in the United States.Am. J. Hematol. 2015; 90: 400-405Crossref PubMed Scopus (40) Google Scholar, 22Eckhardt C.L. Loomans J.I. van Velzen A.S. Peters M. Mauser-Bunschoten E.P. Schwaab R. Mazzucconi M.G. Tagliaferri A. Siegmund B. Reitter-Pfoertner S.E. et al.INSIGHT Study GroupInhibitor development and mortality in non-severe hemophilia A.J. Thromb. Haemost. 2015; 13: 1217-1225Crossref PubMed Scopus (0) Google Scholar, 23Darby S.C. Keeling D.M. Spooner R.J. Wan Kan S. Giangrande P.L. Collins P.W. Hill F.G. Hay C.R. UK Haemophilia Centre Doctors' OrganisationThe incidence of factor VIII and factor IX inhibitors in the hemophilia population of the UK and their effect on subsequent mortality, 1977-99.J. Thromb. Haemost. 2004; 2: 1047-1054Crossref PubMed Scopus (188) Google Scholar, 24Donfield S.M. Lynn H.S. Lail A.E. Hoots W.K. Berntorp E. Gomperts E.D. Hemophilia Growth and Development Study GroupDelays in maturation among adolescents with hemophilia and a history of inhibitors.Blood. 2007; 110: 3656-3661Crossref PubMed Scopus (0) Google Scholar, 25Witmer C. Presley R. Kulkarni R. Soucie J.M. Manno C.S. Raffini L. Associations between intracranial haemorrhage and prescribed prophylaxis in a large cohort of haemophilia patients in the United States.Br. J. Haematol. 2011; 152: 211-216Crossref PubMed Scopus (0) Google Scholar, 26Hoots W.K. Arthropathy in inhibitor patients: differences in the joint status.Semin. Hematol. 2008; 45: S42-S49Crossref PubMed Scopus (7) Google Scholar, 27Guh S. Grosse S.D. McAlister S. Kessler C.M. Soucie J.M. Healthcare expenditures for males with haemophilia and employer-sponsored insurance in the United States, 2008.Haemophilia. 2012; 18: 268-275Crossref PubMed Scopus (39) Google Scholar, 28Lindvall K. von Mackensen S. Elmståhl S. Khair K. Stain A.M. Ljung R. Berntorp E. Increased burden on caregivers of having a child with haemophilia complicated by inhibitors.Pediatr. Blood Cancer. 2014; 61: 706-711Crossref PubMed Scopus (18) Google Scholar Bleeding in high-titer inhibitor patients is managed with bypassing agents, which circumvent the inhibitor to provide hemostasis. Until recently, the only available bypassing agents were recombinant activated factor VII (FVIIa) and activated prothrombin complex concentrate (aPCC). Both recombinant FVIIa and aPCC require intravenous infusions and are dosed for acute bleeds every 2 and 8 h, respectively. Prophylactic regimens with less frequent injections are also established.29Leissinger C. Gringeri A. Antmen B. Berntorp E. Biasoli C. Carpenter S. Cortesi P. Jo H. Kavakli K. Lassila R. et al.Anti-inhibitor coagulant complex prophylaxis in hemophilia with inhibitors.N. Engl. J. Med. 2011; 365: 1684-1692Crossref PubMed Scopus (131) Google Scholar, 30Konkle B.A. Ebbesen L.S. Erhardtsen E. Bianco R.P. Lissitchkov T. Rusen L. Serban M.A. Randomized, prospective clinical trial of recombinant factor VIIa for secondary prophylaxis in hemophilia patients with inhibitors.J. Thromb. Haemost. 2007; 5: 1904-1913Crossref PubMed Scopus (242) Google Scholar The first non-factor prophylactic bypassing agent was recently approved for HA patients with and without inhibitors: emicizumab (Hemlibra) is a bispecific antibody that acts as a FVIIIa-mimetic with procoagulant activity.31Oldenburg J. Mahlangu J.N. Kim B. Schmitt C. Callaghan M.U. Young G. Santagostino E. Kruse-Jarres R. Negrier C. Kessler C. et al.Emicizumab prophylaxis in hemophilia A with inhibitors.N. Engl. J. Med. 2017; 377: 809-818Crossref PubMed Scopus (110) Google Scholar, 32Uchida N. Sambe T. Yoneyama K. Fukazawa N. Kawanishi T. Kobayashi S. Shima M. A first-in-human phase 1 study of ACE910, a novel factor VIII-mimetic bispecific antibody, in healthy subjects.Blood. 2016; 127: 1633-1641Crossref PubMed Scopus (69) Google Scholar, 33Shima M. Hanabusa H. Taki M. Matsushita T. Sato T. Fukutake K. Fukazawa N. Yoneyama K. Yoshida H. Nogami K. Factor VIII-mimetic function of humanized bispecific antibody in hemophilia A.N. Engl. J. Med. 2016; 374: 2044-2053Crossref PubMed Scopus (107) Google Scholar, 34Kitazawa T. Igawa T. Sampei Z. Muto A. Kojima T. Soeda T. Yoshihashi K. Okuyama-Nishida Y. Saito H. Tsunoda H. et al.A bispecific antibody to factors IXa and X restores factor VIII hemostatic activity in a hemophilia A model.Nat. Med. 2012; 18: 1570-1574Crossref PubMed Scopus (128) Google Scholar Additional non-factor therapies with bypassing activity are also in various stages of clinical development (reviewed in Arruda et al.12Arruda V.R. Doshi B.S. Samelson-Jones B.J. Emerging therapies for hemophilia: controversies and unanswered questions.F1000Res. 2018; 7: 489Crossref Scopus (1) Google Scholar, 14Arruda V.R. Doshi B.S. Samelson-Jones B.J. Novel approaches to hemophilia therapy: successes and challenges.Blood. 2017; 130: 2251-2256Crossref PubMed Scopus (13) Google Scholar and Callaghan et al.13Callaghan M.U. Sidonio R. Pipe S.W. Novel therapeutics for hemophilia and other bleeding disorders.Blood. 2018; 132: 23-30Crossref PubMed Scopus (3) Google Scholar). There is substantial excitement about these non-factor therapies because they can be administered subcutaneously with weekly to monthly dosing. However, questions remain about their safety, especially their thrombotic risk, and how best to integrate them into clinical practice.12Arruda V.R. Doshi B.S. Samelson-Jones B.J. Emerging therapies for hemophilia: controversies and unanswered questions.F1000Res. 2018; 7: 489Crossref Scopus (1) Google Scholar, 35Le Quellec S. Negrier C. Emicizumab should be prescribed independent of immune tolerance induction.Blood Adv. 2018; 2: 2783-2786Crossref PubMed Scopus (0) Google Scholar, 36Young G. Implementing emicizumab in hemophilia inhibitor management: emicizumab should be prescribed after tolerance.Blood Adv. 2018; 2: 2780-2782Crossref PubMed Scopus (0) Google Scholar Currently, the only effective therapy for inhibitor eradication is the immune tolerance induction (ITI) protocols, which involve the uninterrupted exposure to factor through regular, typically daily, intravenous administrations for months to years.37DiMichele D. Inhibitor development in haemophilia B: an orphan disease in need of attention.Br. J. Haematol. 2007; 138: 305-315Crossref PubMed Scopus (145) Google Scholar, 38DiMichele D.M. Immune tolerance in haemophilia: the long journey to the fork in the road.Br. J. Haematol. 2012; 159: 123-134Crossref PubMed Scopus (47) Google Scholar, 39Hay C.R. DiMichele D.M. International Immune Tolerance StudyThe principal results of the International Immune Tolerance Study: a randomized dose comparison.Blood. 2012; 119: 1335-1344Crossref PubMed Scopus (0) Google Scholar, 40Brackmann H.H. Gormsen J. Massive factor-VIII infusion in haemophiliac with factor-VIII inhibitor, high responder.Lancet. 1977; 2: 933Abstract PubMed Google Scholar Because of the infusion burden, immune tolerance induction for pediatric patients typically requires central venous catheters, which are associated with thrombotic and infectious complications in ∼25% of patients.39Hay C.R. DiMichele D.M. International Immune Tolerance StudyThe principal results of the International Immune Tolerance Study: a randomized dose comparison.Blood. 2012; 119: 1335-1344Crossref PubMed Scopus (0) Google Scholar, 41Van Dijk K. Van Der Bom J.G. Bax K.N. Van Der Zee D.C. Van Den Berg M.H. Use of implantable venous access devices in children with severe hemophilia: benefits and burden.Haematologica. 2004; 89: 189-194PubMed Google Scholar It is also a very challenging therapy for patients, with almost 20% of randomized subjects withdrawing from clinical trials because of compliance issues.39Hay C.R. DiMichele D.M. International Immune Tolerance StudyThe principal results of the International Immune Tolerance Study: a randomized dose comparison.Blood. 2012; 119: 1335-1344Crossref PubMed Scopus (0) Google Scholar Nonetheless, immune tolerance induction has historically been found to be cost-effective compared with a lifetime of bypassing therapy,42Rocino A. Cortesi P.A. Scalone L. Mantovani L.G. Crea R. Gringeri A. European Haemophilia Therapy Strategy Board (EHTSB)European Haemophilia Therapy Strategy Board EHTSBImmune tolerance induction in patients with haemophilia a and inhibitors: effectiveness and cost analysis in an European Cohort (The ITER Study).Haemophilia. 2016; 22: 96-102Crossref PubMed Scopus (19) Google Scholar although the emergence of non-factor therapies requires these assessments to be updated. Prior to the advent of factor-based treatments, the majority of people with severe hemophilia died before 15 years of age, mostly from spontaneous bleeding or trivial injuries.43Biggs R. Thirty years of haemophilia treatment in Oxford.Br. J. Haematol. 1967; 13: 452-463Crossref PubMed Google Scholar Viral contamination by hepatitis C virus (HCV) and HIV of plasma-based factor products had a devastating impact on the hemophilia community in the 1980s.44Evatt B.L. The tragic history of AIDS in the hemophilia population, 1982-1984.J. Thromb. Haemost. 2006; 4: 2295-2301Crossref PubMed Scopus (0) Google Scholar New iatrogenic infections are currently exceedingly rare, due to a combination of highly effective virucidal techniques and recombinant factor products. Despite these gains from current therapies, there remains a substantial medical and psychosocial burden from the disease.45Buckner T.W. Witkop M. Guelcher C. Sidonio R. Kessler C.M. Clark D.B. Owens W. Frick N. Iyer N.N. Cooper D.L. Impact of hemophilia B on quality of life in affected men, women, and caregivers—assessment of patient-reported outcomes in the B-HERO-S study.Eur. J. Haematol. 2018; 100: 592-602Crossref PubMed Scopus (1) Google Scholar, 46Cutter S. Molter D. Dunn S. Hunter S. Peltier S. Haugstad K. Frick N. Holot N. Cooper D.L. Impact of mild to severe hemophilia on education and work by US men, women, and caregivers of children with hemophilia B: The Bridging Hemophilia B Experiences, Results and Opportunities into Solutions (B-HERO-S) study.Eur. J. Haematol. 2017; 98: 18-24Crossref PubMed Scopus (6) Google Scholar, 47Darby S.C. Kan S.W. Spooner R.J. Giangrande P.L. Hill F.G. Hay C.R. Lee C.A. Ludlam C.A. Williams M. Mortality rates, life expectancy, and causes of death in people with hemophilia A or B in the United Kingdom who were not infected with HIV.Blood. 2007; 110: 815-825Crossref PubMed Scopus (279) Google Scholar, 48Mazepa M.A. Monahan P.E. Baker J.R. Riske B.K. Soucie J.M. US Hemophilia Treatment Center NetworkMen with severe hemophilia in the United States: birth cohort analysis of a large national database.Blood. 2016; 127: 3073-3081Crossref PubMed Scopus (22) Google Scholar, 49Buckner T.W. Batt K. Quon D. Witkop M. Recht M. Kessler C. Baumann K. Hernandez G. Wang M. Cooper D.L. Kempton C.L. Assessments of pain, functional impairment, anxiety, and depression in US adults with hemophilia across patient-reported outcome instruments in the Pain, Functional Impairment, and Quality of Life (P-FiQ) study.Eur. J. Haematol. 2018; 100: 5-13Crossref PubMed Scopus (0) Google Scholar The promise of gene therapy for hemophilia is to alleviate these burdens by providing lifelong hemostatic coverage after a single infusion of vector. Recent successful early-phase clinical trials using liver-directed AAV-based gene therapy with bioengineered factor transgene for men with severe HB50George L.A. Sullivan S.K. Giermasz A. Rasko J.E.J. Samelson-Jones B.J. Ducore J. Cuker A. Sullivan L.M. Majumdar S. Teitel J. et al.Hemophilia B gene therapy with a high-specific-activity factor IX variant.N. Engl. J. Med. 2017; 377: 2215-2227Crossref PubMed Scopus (80) Google Scholar and HA51Rangarajan S. Walsh L. Lester W. Perry D. Madan B. Laffan M. Yu H. Vettermann C. Pierce G.F. Wong W.Y. Pasi K.J. AAV5-factor VIII gene transfer in severe hemophilia A.N. Engl. J. Med. 2017; 377: 2519-2530Crossref PubMed Scopus (80) Google Scholar have reported phenotypic cures and normal or nearly normal factor levels in most subjects. These results, however, are built on several decades of earlier work developing the necessary technologies and protocols to achieve this goal, as detailed in several reviews;3Hough C. Lillicrap D. Gene therapy for hemophilia: an imperative to succeed.J. Thromb. Haemost. 2005; 3: 1195-1205Crossref PubMed Scopus (0) Google Scholar, 4Lheriteau E. Davidoff A.M. Nathwani A.C. Haemophilia gene therapy: progress and challenges.Blood Rev. 2015; 29: 321-328Abstract Full Text Full Text PDF PubMed Google Scholar, 5Rogers G.L. Herzog R.W. Gene therapy for hemophilia.Front. Biosci. 2015; 20: 556-603Crossref PubMed Scopus (0) Google Scholar, 6Arruda V.R. Samelson-Jones B.J. Obstacles and future of gene therapy for hemophilia.Expert Opin. Orphan Drugs. 2015; 3: 997-1010Crossref PubMed Scopus (10) Google Scholar, 7High K.A. The gene therapy journey for hemophilia: are we there yet? Hematology Am.Soc. Hematol. Educ. Program 2012. 2012; : 375-381Google Scholar here, we focus on contextualizing the challenges overcome by engineered FVIII or FIX transgenes. Because full-length FVIII cDNA (7 kb) exceeds the packing capacity of AAV vectors (∼4.7 kb), most early gene therapy studies focused on HB, because FIX cDNA is ∼1.6 kb52Choo K.H. Gould K.G. Rees D.J. Brownlee G.G. Molecular cloning of the gene for human anti-haemophilic factor IX.Nature. 1982; 299: 178-180Crossref PubMed Google Scholar despite the fact that HB accounts for only 20% of all hemophilia cases. As discussed below in detail, the removal of most of the B-domain of FVIII decreased the cDNA to ∼4.4 kb (Figure 1A), and three AAV-based clinical trials for HA have recently reported promising results using this approach (A.C. Nathwani et al., 2018, Am. Soc. Hematology, abstract; K.A. High et al., 2018, Am. Soc. Hematology, abstract).51Rangarajan S. Walsh L. Lester W. Perry D. Madan B. Laffan M. Yu H. Vettermann C. Pierce G.F. Wong W.Y. Pasi K.J. AAV5-factor VIII gene transfer in severe hemophilia A.N. Engl. J. Med. 2017; 377: 2519-2530Crossref PubMed Scopus (80) Google Scholar Notably, the first in-human use of liver-directed AAV gene therapy was in HB subjects.53Manno C.S. Pierce G.F. Arruda V.R. Glader B. Ragni M. Rasko J.J. Ozelo M.C. Hoots K. Blatt P. Konkle B. et al.Successful transduction of liver in hemophilia by AAV-Factor IX and limitations imposed by the host immune response.Nat. Med. 2006; 12: 342-347Crossref PubMed Scopus (1127) Google Scholar This study suggested a critical AAV vector dose-dependent hepatotoxicity that was hypothesized to be due to the destruction of transduced hepatocytes by cellular immunity targeting protein antigens from the AAV capsid; the loss of transduced cells resulted in a loss of circulating FIX protein.53Manno C.S. Pierce G.F. Arruda V.R. Glader B. Ragni M. Rasko J.J. Ozelo M.C. Hoots K. Blatt P. Konkle B. et al.Successful transduction of liver in hemophilia by AAV-Factor IX and limitations imposed by the host immune response.Nat. Med. 2006; 12: 342-347Crossref PubMed Scopus (1127) Google Scholar, 54Ertl H.C.J. High K.A. Impact of AAV capsid-specific T-cell responses on design and outcome of clinical gene transfer trials with recombinant adeno-associated viral vectors: an evolving controversy.Hum. Gene Ther. 2017; 28: 328-337Crossref PubMed Scopus (0) Google Scholar The subsequent trial confirmed the AAV vector dose-dependence of this hepatotoxicity and limited the loss of transgene expression by the swift initiation of oral steroids for immunosuppression.55Nathwani A.C. Tuddenham E.G. Rangarajan S. Rosales C. McIntosh J. Linch D.C. Chowdary P. Riddell A. Pie A.J. Harrington C. et al.Adenovirus-associated virus vector-mediated gene transfer in hemophilia B.N. Engl. J. Med. 2011; 365: 2357-2365Crossref PubMed Scopus (912) Google Scholar, 56Nathwani A.C. Reiss U.M. Tuddenham E.G. Rosales C. Chowdary P. McIntosh J. Della Peruta M. Lheriteau E. Patel N. Raj D. et al.Long-term safety and efficacy of factor IX gene therapy in hemophilia B.N. Engl. J. Med. 2014; 371: 1994-2004Crossref PubMed Scopus (414) Google Scholar Although the dose-dependence seems to vary between AAV serotypes (AAV2, AAV5, and AAV8), all AAV gene transfer trials for HA or HB have reported hepatotoxicity in some subjects.6Arruda V.R. Samelson-Jones B.J. Obstacles and future of gene therapy for hemophilia.Expert Opin. Orphan Drugs. 2015; 3: 997-1010Crossref PubMed Scopus (10) Google Scholar, 51Rangarajan S. Walsh L. Lester W. Perry D. Madan B. Laffan M. Yu H. Vettermann C. Pierce G.F. Wong W.Y. Pasi K.J. AAV5-factor VIII gene transfer in severe hemophilia A.N. Engl. J. Med. 2017; 377: 2519-2530Crossref PubMed Scopus (80) Google Scholar, 53Manno C.S. Pierce G.F. Arruda V.R. Glader B. Ragni M. Rasko J.J. Ozelo M.C. Hoots K. Blatt P. Konkle B. et al.Successful transduction of liver in hemophilia by AAV-Factor IX and limitations imposed by the host immune response.Nat. Med. 2006; 12: 342-347Crossref PubMed Scopus (1127) Google Scholar, 55Nathwani A.C. Tuddenham E.G. Rangarajan S. Rosales C. McIntosh J. Linch D.C. Chowdary P. Riddell A. Pie A.J. Harrington C. et al.Adenovirus-associated virus vector-mediated gene transfer in hemophilia B.N. Engl. J. Med. 2011; 365: 2357-2365Crossref PubMed Scopus (912) Google Scholar, 56Nathwani A.C. Reiss U.M. Tuddenham E.G. Rosales C. Chowdary P. McIntosh J. Della Peruta M. Lheriteau E. Patel N. Raj D. et al.Long-term safety and efficacy of factor IX gene therapy in hemophilia B.N. Engl. J. Med. 2014; 371: 1994-2004Crossref PubMed Scopus (414) Google Scholar, 57Miesbach W. Meijer K. Coppens M. Kampmann P. Klamroth R. Schutgens R. Tangelder M. Castaman G. Schwäble J. Bonig H. et al.Gene therapy with adeno-associated virus vector 5-human factor IX in adults with hemophilia B.Blood. 2018; 131: 1022-1031Crossref PubMed Scopus (16) Google Scholar However, the elapsed time from vector infusion to hepatotoxicity, as well as the lack of identifiable AAV-capsid immune cells in some studies, suggests that distinct biological mechanisms may contribute to the observed hepatotoxicity in different trials.58Doshi B.S. Arruda V.R. Gene therapy for hemophilia: what does the future hold?.Ther. Adv. Hematol. 2018; 9: 273-293Crossref PubMed Google Scholar Furthermore, although immunosuppression has reduced the loss of transgene expression in most trials, it has not succeeded in stopping clinically significant declines of FVIII and FIX levels in others (NCT01687608, NCT01620801, NCT02618915, and NCT03003533) (P.E. Monahan et al., 2015, Congr. Int. Soc. Thromb. Haemost., congress; K.A. High et al., 2018, Am. Soc. Hematology, abstract; R. Calcedo et al., 2017, Am. Soc. Hematology, abstract; S. Pipe et al., 2017, Am. Soc. Hematology, abstract),12Arruda V.R. Doshi B.S. Samelson-Jones B.J. Emerging therapies for hemophilia: controversies and unanswered questions.F1000Res. 2018; 7: 489Crossref Scopus (1) Google Scholar, 54Ertl H.C.J. High K.A. Impact of AAV capsid-specific T-cell responses on design and outcome of clinical gene transfer trials with recombinant adeno-associated viral vectors: an evolving controversy.Hum. Gene Ther. 2017; 28: 328-337Crossref PubMed Scopus (0) Google Scholar although the details of these latter studies have not yet been fully published. The prophylactic use of immune suppression with oral steroids has also been insufficient to prevent hepatotoxicity in at least one study.
Referência(s)