Neoadjuvant followed by adjuvant pembrolizumab in melanoma: time biases in the data analysis of the SWOG S1801 trial

Area of Science:

• Oncology
• Immunotherapy
• Melanoma Research

Background:

• Investigating perioperative pembrolizumab (anti-PD1) for stage III/IV melanoma.
• Neoadjuvant therapy offers early tumor control and response assessment but risks toxicity and surgical delays.
• Comparing neoadjuvant-adjuvant vs. adjuvant-only pembrolizumab strategies.

Purpose of the Study:

• To evaluate the efficacy of perioperative pembrolizumab in melanoma.
• To compare event-free survival (EFS) between neoadjuvant-adjuvant and adjuvant-only treatment arms.
• To critically assess potential limitations of the SWOG S1801 trial's findings.

Main Methods:

• Phase 2 clinical trial (SWOG S1801) in stage III or IV melanoma patients.
• Two arms: pembrolizumab both before and after surgery (neoadjuvant-adjuvant) vs. post-surgery only (adjuvant-only).
• Primary endpoint: event-free survival (EFS).

Main Results:

• The study met its primary endpoint.
• Event-free survival (EFS) was 72% in the neoadjuvant-adjuvant group versus 49% in the adjuvant-only group.
• Identified potential limitations: arbitrary event assignment, informative censoring, and risk of fluke results in phase 2 trials.

Conclusions:

• Perioperative pembrolizumab demonstrated a higher EFS rate compared to adjuvant-only therapy in this phase 2 trial.
• Concerns regarding event assignment, censoring, and the inherent nature of phase 2 results necessitate careful interpretation.
• Further phase 3 trials are required to validate these findings and fully assess neoadjuvant pembrolizumab's role in melanoma treatment.