Giroctocogene fitelparvovec gene therapy for severe hemophilia A: 104-week analysis of the phase 1/2 Alta study.

ABSTRACT: Patients with hemophilia A require exogenous factor VIII (FVIII) or nonfactor hemostatic agents to prevent spontaneous bleeding events. Adeno-associated virus (AAV) vector-based gene therapy is under clinical investigation to enable endogenous FVIII production. Giroctocogene fitelparvovec is a recombinant AAV serotype 6 vector containing the coding sequence for the B-domain-deleted human F8 gene. In the ongoing phase 1/2, dose-ranging Alta study, 4 sequential cohorts of male participants with severe hemophilia A received a single IV dose of giroctocogene fitelparvovec. The primary end points are safety and changes in circulating FVIII activity. Interim results up to 214 weeks after treatment for all participants are presented. Eleven participants were dosed. Increases in alanine and aspartate aminotransferases were the most common treatment-related adverse events (AEs), which resolved with corticosteroid administration. Two treatment-related serious AEs (hypotension and pyrexia) were reported in 1 participant within 6 hours of infusion and resolved within 24 hours after infusion. At the highest dose level (3 × 1013 vg/kg; n = 5), the mean circulating FVIII activity level at week 52 was 42.6% (range, 7.8%-122.3%), and at week 104 it was 25.4% (range, 0.9%-71.6%) based on a chromogenic assay. No liver masses, thrombotic events, or confirmed inhibitors were detected in any participant. These interim 104-week data suggest that giroctocogene fitelparvovec is generally well tolerated with appropriate clinical management and has the potential to provide clinically meaningful FVIII activity levels, as indicated by the low rate of bleeding events in the highest dose cohort. This trial was registered at www.clinicaltrials.gov as #NCT03061201.

Efficacy of immunotherapy with TG4040, peg-interferon, and ribavirin in a Phase 2 study of patients with chronic HCV infection.

BACKGROUND & AIMS: TG4040 is a modified vaccinia Ankara (MVA) virus that expresses the hepatitis C virus (HCV) proteins NS3, NS4, and NS5B. We performed a phase II open-label study to determine the efficacy, safety, and immunotherapeutic properties of TG4040 in combination with pegylated interferon α-2a and ribavirin (PEG-IFNα/RBV) in patients with chronic HCV infection. METHODS: Treatment-naive patients with HCV genotype 1 infection were assigned randomly to 1 of the following groups: PEG-IFNα/RBV for 48 weeks (group A, n = 31), PEG-IFNα/RBV for 4 weeks followed by PEG-IFNα/RBV for 44 weeks with 6 injections of TG4040 (group B, n = 63), or TG4040 for 12 weeks (7 injections) followed by PEG-IFNα/RBV for 48 weeks with 6 injections of TG4040 (group C, n = 59). The primary end point was complete early virologic response (cEVR), defined as HCV-RNA level less than 10 IU/mL after 12 weeks of PEG-IFNα/RBV treatment. RESULTS: In group C, 64.2% of evaluable patients achieved cEVR, compared with 30.0% in group A and 45.9% in group B (P = .0003 for group C vs A). A higher percentage of patients achieved a sustained virologic response 24 weeks after therapy ended in group C (58.2%) than in groups A (48.4%) or B (50.8%). HCV- and MVA-specific T-cell responses were observed predominantly in group C. As expected, most patients given injections of TG4040 developed anti-MVA antibodies. The combination of TG4040 and PEG-IFNα/RBV was reasonably well tolerated. However, PEG-IFNα-associated thrombocytopenia developed in 3 patients who carried the class II HLA allele DRB01*04. CONCLUSIONS: A higher percentage of patients with chronic HCV infection who received immunotherapy with TG4040 followed by TG4040 and PEG-IFNα/RBV achieved a cEVR compared with patients who received only PEG-IFNα/RBV therapy. These findings show that immunotherapies that activate T cells are effective in patients with chronic HCV infection. ClinicalTrials.gov number, NCT01055821.

PHOCUS: A Phase 3, Randomized, Open-Label Study of Sequential Treatment with Pexa-Vec (JX-594) and Sorafenib in Patients with Advanced Hepatocellular Carcinoma.

Introduction: Intratumoral administration of pexa-vec (pexastimogene devacirepvec), an oncolytic and immunotherapeutic vaccinia virus, given to patients with hepatocellular carcinoma (HCC), is associated with both local and distant tumor responses. We hypothesized subsequent treatment with sorafenib could demonstrate superior efficacy. Methods: This random phase III open-label study evaluated the sequential treatment with pexa-vec followed by sorafenib compared to sorafenib in patients with advanced HCC and no prior systemic treatment. The primary endpoint is overall survival (OS). Key secondary endpoints included time to progression (TTP), progression-free survival, overall response rate (ORR), and disease control rate (DCR). Safety was assessed in all patients who received ≥1 dose of study treatment. Results: The study was conducted at 142 sites in 16 countries. From December 30, 2015, to the interim analysis on August 2, 2019, 459 patients were randomly assigned (pexa-vec plus sorafenib: 234, sorafenib: 225). At the interim analysis, the median OS was 12.7 months (95% CI: 9.89, 14.95) in the pexa-vec plus sorafenib arm and 14.0 months (95% CI: 11.01, 18.00) in the sorafenib arm. This led to the early termination of the study. The median TTP was 2.0 months (95% CI: 1.77, 2.96) and 4.2 months (95% CI: 2.92, 4.63); ORR was 19.2% (45 patients) and 20.9% (47 patients); and DCR was 50.0% (117 patients) and 57.3% (129 patients) in the pexa-vec plus sorafenib and sorafenib arms, respectively. Serious adverse events were reported in 117 (53.7%) patients in the pexa-vec plus sorafenib and 77 (35.5%) patients in the sorafenib arm. Liver failure was the most frequently reported in both groups. Conclusion: Sequential pexa-vec plus sorafenib treatment did not demonstrate increased clinical benefit in advanced HCC and fared worse compared to sorafenib alone. The advent of the added value of checkpoint inhibitors should direct any further development of oncolytic virus therapy strategies.

A poxvirus vaccine is safe, induces T-cell responses, and decreases viral load in patients with chronic hepatitis C.

BACKGROUND & AIMS: Therapy for chronic hepatitis C (CHC) has limited efficacy, adverse effects, and high costs. Cohort and vaccine-based preclinical studies have indicated the importance of T-cell-based immunity in controlling viral infection. TG4040 is a recombinant poxvirus vaccine that expresses the hepatitis C virus (HCV) proteins NS3, NS4, and NS5B. We performed a phase I clinical trial to assess the safety, immunogenicity, and early antiviral efficacy of TG4040 in patients with CHC. METHODS: In an open-label, dose-escalating study, patients with mild CHC (genotype 1) were assigned to 3 groups of 3 patients each; they received subcutaneous injections of 106, 107, or 108 plaque-forming units of TG4040 on study days 1, 8, and 15. Six additional patients were given the highest dose of vaccine (108 plaque-forming units). Patients were followed for 6 months after the last injection. T-cell-based and antibody responses and levels of HCV RNA were measured. RESULTS: All 3 doses of TG4040 were well tolerated, without serious adverse events. Vaccine-induced HCV-specific cellular immune responses were observed in 5 of the 15 patients (33%). A transient decrease in circulating levels of HCV RNA, from -0.52 log10 to -1.24 log10, was observed in 8 patients; in 5 patients, the lowest level of HCV RNA was observed on day 37, after the first injection. The most pronounced decrease in viral load occurred in 2 patients, who also had marked vaccine-induced T-cell responses. CONCLUSIONS: In patients with CHC, the viral-vector-based vaccine TG4040 had a good safety profile, induced HCV-specific cellular immune responses, and reduced viral load. This vaccine should be investigated in further clinical studies, in combination with standard of care.