Atezolizumab Combined with Personalized Neoantigen Vaccine Shows Feasibility in Urothelial Cancer

In this phase 1 trial, 10 out of 12 enrolled urothelial cancer patients successfully received the personalized neoantigen vaccine PGV001 alongside atezolizumab, with a median vaccine production time of 20.3 weeks. Manageable grade 1 adverse events were observed, and promising immune activation occurred as all participants developed neoantigen-specific T cell responses. Notable clinical outcomes included recurrence-free status in 3 of 4 adjuvant patients and objective responses in 2 of 5 metastatic patients.

The study establishes that combining immune checkpoint inhibitors (ICI) with personalized neoantigen vaccination is both feasible and safe, supporting further trials to explore its potential to enhance antitumor immunity in urothelial cancer.