Introduction/Background VB10.16 is a novel therapeutic antigen-presenting cell targeting DNA vaccine developed to treat HPV16-positive cancers. We aimed to investigate whether VB10.16 is safe and efficacious when administered to patients with advanced cervical cancer in combination with atezolizumab.

Methodology In this open-label, single-arm, phase 2a trial, patients with recurrent or metastatic HPV16-positive cervical cancer were recruited at 13 hospitals across Europe. Patients received up to 11 intramuscular 3 mg VB10.16 vaccinations in combination with 3-weekly 1200 mg atezolizumab for up to 48 weeks, or until disease progression or unacceptable toxicity. Anti-tumor activity was assessed by central independent review using RECIST v1.1 criteria.

Results At the cut-off date of 14 February 2022 for this interim analysis, 39 patients had at least one or more post-baseline scan available and were included in the efficacy analysis. 69% of patients had received 2 or more prior systemic treatment lines. Overall Response Rate (ORR) was 21%, with 2 Complete Responses (CR) and 6 Partial Responses (PR). Responses were observed in both PD-L1 positive and negative patients (ORR 27% and 17%, respectively). Disease Control Rate (DCR) was 64% (77% in PD-L1 positive and 58% in PD-L1 negative patients). HPV16-specific T cell responses were observed in the majority of patients and associated with a clinical response. 50 patients had received ≥1 doses of VB10.16 and atezolizumab and were included in the interim safety analysis. 5 patients (10%) experienced treatment-related adverse events (TRAEs) of grade 3, including 1 patient (2%) who experienced a grade 3 TRAE related to VB10.16. No grade 4–5 TRAEs were reported.

Conclusion VB10.16 combined with atezolizumab had a favorable safety profile in heavily pre-treated patients. The combination treatment showed clinically relevant HPV16-specific T cell responses and promising clinical activity with a very high DCR of 64% and 8 patients achieving CR or PR.