Interindividual variability in transgene mRNA and protein production following adeno-associated virus gene therapy for hemophilia A.

Factor VIII gene transfer with a single intravenous infusion of valoctocogene roxaparvovec (AAV5-hFVIII-SQ) has demonstrated clinical benefits lasting 5 years to date in people with severe hemophilia A. Molecular mechanisms underlying sustained AAV5-hFVIII-SQ-derived FVIII expression have not been studied in humans. In a substudy of the phase 1/2 clinical trial ( NCT02576795 ), liver biopsy samples were collected 2.6-4.1 years after gene transfer from five participants. Primary objectives were to examine effects on liver histopathology, determine the transduction pattern and percentage of hepatocytes transduced with AAV5-hFVIII-SQ genomes, characterize and quantify episomal forms of vector DNA and quantify transgene expression (hFVIII-SQ RNA and hFVIII-SQ protein). Histopathology revealed no dysplasia, architectural distortion, fibrosis or chronic inflammation, and no endoplasmic reticulum stress was detected in hepatocytes expressing hFVIII-SQ protein. Hepatocytes stained positive for vector genomes, showing a trend for more cells transduced with higher doses. Molecular analysis demonstrated the presence of full-length, inverted terminal repeat-fused, circular episomal genomes, which are associated with long-term expression. Interindividual differences in transgene expression were noted despite similar successful transduction, possibly influenced by host-mediated post-transduction mechanisms of vector transcription, hFVIII-SQ protein translation and secretion. Overall, these results demonstrate persistent episomal vector structures following AAV5-hFVIII-SQ administration and begin to elucidate potential mechanisms mediating interindividual variability.

Valoctocogene Roxaparvovec Gene Therapy for Hemophilia A.

BACKGROUND: Valoctocogene roxaparvovec (AAV5-hFVIII-SQ) is an adeno-associated virus 5 (AAV5)-based gene-therapy vector containing a coagulation factor VIII complementary DNA driven by a liver-selective promoter. The efficacy and safety of the therapy were previously evaluated in men with severe hemophilia A in a phase 1-2 dose-escalation study. METHODS: We conducted an open-label, single-group, multicenter, phase 3 study to evaluate the efficacy and safety of valoctocogene roxaparvovec in men with severe hemophilia A, defined as a factor VIII level of 1 IU per deciliter or lower. Participants who were at least 18 years of age and did not have preexisting anti-AAV5 antibodies or a history of development of factor VIII inhibitors and who had been receiving prophylaxis with factor VIII concentrate received a single infusion of 6×1013 vector genomes of valoctocogene roxaparvovec per kilogram of body weight. The primary end point was the change from baseline in factor VIII activity (measured with a chromogenic substrate assay) during weeks 49 through 52 after infusion. Secondary end points included the change in annualized factor VIII concentrate use and bleeding rates. Safety was assessed as adverse events and laboratory test results. RESULTS: Overall, 134 participants received an infusion and completed more than 51 weeks of follow-up. Among the 132 human immunodeficiency virus-negative participants, the mean factor VIII activity level at weeks 49 through 52 had increased by 41.9 IU per deciliter (95% confidence interval [CI], 34.1 to 49.7; P<0.001; median change, 22.9 IU per deciliter; interquartile range, 10.9 to 61.3). Among the 112 participants enrolled from a prospective noninterventional study, the mean annualized rates of factor VIII concentrate use and treated bleeding after week 4 had decreased after infusion by 98.6% and 83.8%, respectively (P<0.001 for both comparisons). All the participants had at least one adverse event; 22 of 134 (16.4%) reported serious adverse events. Elevations in alanine aminotransferase levels occurred in 115 of 134 participants (85.8%) and were managed with immune suppressants. The other most common adverse events were headache (38.1%), nausea (37.3%), and elevations in aspartate aminotransferase levels (35.1%). No development of factor VIII inhibitors or thrombosis occurred in any of the participants. CONCLUSIONS: In patients with severe hemophilia A, valoctocogene roxaparvovec treatment provided endogenous factor VIII production and significantly reduced bleeding and factor VIII concentrate use relative to factor VIII prophylaxis. (Funded by BioMarin Pharmaceutical; GENEr8-1 ClinicalTrials.gov number, NCT03370913.).

Burden of mild haemophilia A: Systematic literature review.

INTRODUCTION: Although the clinical manifestations of severe haemophilia A (HA) are well studied, the challenges, if any, of living with mild HA are not clearly delineated to date. AIM: To assess available evidence of clinical risks and societal/economic impacts of disease in adult patients with mild HA using a systematic literature review. METHODS: Prespecified study selection criteria were applied in a comprehensive literature search. Included studies varied in design and reported outcomes of interest for adults (≥13 years of age) with mild HA. RESULTS: Seventeen studies with a total of 3213 patients met eligibility criteria (published or presented in English, 1966-2017). Most studies were observational, and the outcomes reported were too sparse and dissimilar to support a formal meta-analysis. Mean annual bleeding rates ranged from 0.44 to 4.5 episodes per patient per year. Quality of life (QoL; SF-36 General Health) was impacted compared to healthy controls. Health care costs and productivity were seldom assessed and no robust comparisons to healthy controls were available. CONCLUSION: Quantifying outcomes for adult patients with mild HA remains challenging, with estimates of key QoL and cost data often based on small data sets and without comparison to population norms. Therefore, the clinical impact of mild haemophilia may be under-represented and unmet needs may remain unaddressed. As paradigm-changing therapies for HA emerge, stronger knowledge of mild HA can guide the development of care options that minimize burden and enhance the QoL for this segment of the haemophilia community, and for the haemophilia community in totality.

Examination of noninferiority, safety, and tolerability of lopinavir/ritonavir and raltegravir compared with lopinavir/ritonavir and tenofovir/ emtricitabine in antiretroviral-naïve subjects: the progress study, 48-week results.

PURPOSE: Current antiretroviral regimens recommended for treatment-naïve patients include 2 nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs). The purpose of this study is to evaluate whether a new NRTI-sparing regimen may provide an alternative for persons for whom traditional regimens may not be the best option. METHODS: PROGRESS is a 96-week, randomized, open-label, multicenter trial comparing the efficacy and safety of a boosted protease inhibitor (PI) and an integrase inhibitor (lopi-navir/ritonavir [LPV/r] + raltegravir [RAL]) to a boosted PI and 2 NRTIs (LPV/r + tenofovir/ emtricitabine [TDF/FTC]) in antiretroviral (ARV)-naïve HIV-1-infected adults. RESULTS: A total of 206 subjects were randomized to receive LPV/r + RAL (n=101) or LPV/r + TDF/FTC (n=105) and analyzed for ARV efficacy using the US Food and Drug Administration time to loss of virologic response (FDA-TLOVR) algorithm. The percentage of subjects with plasma HIV-1 RNA <40 copies/mL at week 48 was 83.2% in the LPV/r + RAL group and 84.8% in the LPV/r + TDF/FTC group (P = .850; difference -1.6%; exact 95% CI, -12.0% to 8.8%). As the lower limit of the exact 95% CI for the difference between regimens was at or above the protocol-defined threshold of -20% (as well as the more stringent threshold of -12%), LPV/r + RAL was noninferior to LPV/r + TDF/FTC. The occurrence of treatment-related, moderate/severe adverse events was similar between treatment groups through 48 weeks of treatment. CONCLUSIONS: The HIV treatment regimen of LPV/r + RAL resulted in noninferior efficacy and comparable safety and tolerability compared with a traditional NRTI-containing regimen through 48 weeks of treatment. These results support further evaluation of the LPV/r + RAL regimen.