First-in-Human Phase I Clinical Trial of an SFV-Based RNA Replicon Cancer Vaccine against HPV-Induced Cancers.

A first-in-human phase I trial of Vvax001, an alphavirus-based therapeutic cancer vaccine against human papillomavirus (HPV)-induced cancers was performed assessing immunological activity, safety, and tolerability. Vvax001 consists of replication-incompetent Semliki Forest virus replicon particles encoding HPV16-derived antigens E6 and E7. Twelve participants with a history of cervical intraepithelial neoplasia were included. Four cohorts of three participants were treated per dose level, ranging from 5 × 105 to 2.5 × 108 infectious particles per immunization. The participants received three immunizations with a 3-week interval. For immune monitoring, blood was drawn before immunization and 1 week after the second and third immunization. Immunization with Vvax001 was safe and well tolerated, with only mild injection site reactions, and resulted in both CD4+ and CD8+ T cell responses against E6 and E7 antigens. Even the lowest dose of 5 × 105 infectious particles elicited E6/E7-specific interferon (IFN)-γ responses in all three participants in this cohort. Overall, immunization resulted in positive vaccine-induced immune responses in 12 of 12 participants in one or more assays performed. In conclusion, Vvax001 was safe and induced immune responses in all participants. These data strongly support further clinical evaluation of Vvax001 as a therapeutic vaccine in patients with HPV-related malignancies.

GMP manufacturing of Vvax001, a therapeutic anti-HPV vaccine based on recombinant viral particles.

Therapeutic vaccination is being explored as a treatment strategy for the treatment of patients with primary or metastatic tumours. We developed a vaccine targeted to Human papillomavirus (HPV)-induced tumours based on recombinant Semliki Forest virus (rSFV) encoding a fusion protein of the E6 and E7 proteins of HPV type 16. To enable a phase I clinical trial with this vaccine, Vvax001, a Good Manufacturing Practice (GMP)-compliant manufacturing process was set up and clinical material was produced. Upstream production of the clinical material resulted in viral titers from 2.4 × 107 to 1.3 × 109 infectious particles/ mL in the harvest. The total volume of 6.0 liter crude virus was purified in 13 consecutive downstream purification runs. The mean titer after purification was 4.0 × 108 infectious particles/ mL and the mean recovery was 19%. Finally, clinical material was filled at a target concentration of 1.25 × 108 infectious particles/mL. Release testing included tests for viral titer and virus identity, biological activity, sterility, bacterial endotoxins, adventitious viruses and absence of replication competent virus. The product complied with all specifications and was released for use as an investigational medicinal product. This is the first GMP production process developed for a SFV-based therapeutic vaccine. The vaccine, Vvax001 is targeted to HPV and has shown promising results in preclinical studies. The GMP-produced Vvax001 material met the quality criteria and was of sufficient quantity to enable assessment of its immunogenicity, safety and efficacy in a clinical setting.