Study Confirms Benefit of Cobimetinib Plus Vemurafenib in Advanced BRAF V600–Mutant Melanoma


Key Points

  • Median progression-free survival was 12.3 vs 7.2 months for cobimetinib/vemurafenib vs vemurafenib in patients with BRAF V600–mutant unresectable stage IIIC or IV melanoma.
  • Median overall survival was 22.3 vs 17.4 months.

As reported by Ascierto et al in The Lancet Oncology, longer-term follow-up in the pivotal phase III coBRIM trial confirmed the benefit of adding cobimetinib to vemurafenib (Zelboraf) in first-line treatment of BRAF V600–mutant unresectable stage IIIC or IV melanoma.

Study Details

In the double-blind trial, 495 patients were randomized to receive cobimetinib (n = 247; 60 mg once daily for 21 days followed by 7 days off in each 28-day cycle) or placebo (n = 248) in combination with vemurafenib (960 mg twice daily). Progression-free and overall survival rates were the primary and secondary endpoints.

Survival Benefit

Median follow-up in the updated analysis was 14.2 months. Median investigator-assessed progression-free survival was 12.3 months in the combination group vs 7.2 months in the vemurafenib group (hazard ratio [HR] = 0.58, P < .0001). The final analysis for overall survival occurred when 52% of patients had died (August 2015). Median overall survival was 22.3 months vs 17.4 months (HR = 0.70, P = .005).

Adverse Events

No new safety signals for the combination were observed over longer follow-up. The most common grade 3 or 4 adverse events occurring more frequently in the combination group were increased γ-glutamyl transferase (15% vs 10%), increased creatine phosphokinase (12% vs < 1%), and increased alanine transaminase (11% vs 6%). Serious adverse events occurred in 37% vs 28%, with pyrexia (2%) and dehydration (2%) being the most common in the cobimetinib/vemurafenib group.

The investigators concluded: “These data confirm the clinical benefit of cobimetinib combined with vemurafenib and support the use of the combination as a standard first-line approach to improve survival in patients with advanced BRAF V600–mutant melanoma.”

The study was funded by F. Hoffmann-La Roche–Genentech.

Grant A. McArthur, FRACP, of the University of Melbourne, is the corresponding author of The Lancet Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.