mCRPC: PROSTVAC fails to meet OS endpoint in phase 3 study

  • Gulley JL & al.
  • J Clin Oncol
  • 28 Feb 2019

  • curated by Deepa Koli
  • Univadis Clinical Summaries
Access to the full content of this site is available only to registered healthcare professionals. Access to the full content of this site is available only to registered healthcare professionals.

Takeaway

  • Viral vector-based immunotherapy, PROSTVAC with or without granulocyte-macrophage-colony-stimulating factor (GM-CSF), was safe and well tolerated in patients with asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC), but it has no OS or event-free survival benefit.
  • The trial was terminated because of futility.

Why this matters

  • The PSA-targeted immunotherapy extended OS in phase 2 study, and it is being explored in combination therapy in clinical trials.

Study design

  • Phase 3, double-blind, randomized study of 1297 patients with asymptomatic or minimally symptomatic mCRPC.
  • Patients were randomly assigned 1:1:1 to PROSTVAC (n=432), PROSTVAC+GM-CSF (n=432), or placebo (n=433).
  • Primary endpoint: OS
  • Funding: Bavarian Nordic; the Institute of Cancer Research.

Key results

  • Compared with placebo, median OS was not significantly different with PROSTVAC (34.3 vs 34.4 months; HR, 1.01; P=.47) or PROSTVAC+GM-CSF (34.3 vs 33.2 months; HR, 1.02; P=.59).
  • 6-month event-free survival was not significantly different with PROSTVAC (OR, 0.96; 95% CI, 0.71-1.29) and PROSTVAC+GM-CSF (OR, 0.89; 95% CI, 0.66-1.20) vs placebo.  
  • Overall, 91% of patients experienced adverse events; most common were injection site reactions (62%-72%) and fatigue (21%-24%).
  • Grade ≥3 adverse events occurred in 21%-23% of patients.

Limitations

  • Early termination because of futility.

Please confirm your acceptance

To gain full access to GPnotebook please confirm:

By submitting here you confirm that you have accepted Terms of Use and Privacy Policy of GPnotebook.

Submit