As reported in the Journal of Clinical Oncology by Bhatia et al, nivolumab/ipilimumab did not produce better outcomes vs nivolumab alone in a cohort of immune checkpoint inhibitor (ICI)-naive patients with recurrent or metastatic Merkel cell carcinoma (MCC) enrolled in the phase I/II CheckMate 358 trial.
Study Details
In the nonrandomized open-label trial, which focused on patients with virus-associated cancers, the MCC cohort included 25 patients who received nivolumab at 240 mg every 2 weeks and 43 who received nivolumab at 3 mg/kg every 2 weeks plus ipilimumab at 1 mg/kg every 6 weeks. The primary outcome of interest was objective repose rate.
Key Findings
Objective responses were observed in 15 of 25 patients in the nivolumab group (60%, 95% confidence interval [CI] = 38.7%–78.9%), including complete response in 8 (32%), vs 25 of 43 patients in the combination group (58%, 95% CI = 42.1%–73%), including complete response in 8 (19%). Median response durations were 60.6 months (95% CI = 16.7 months to not evaluable) in the nivolumab group vs 25.9 months (10.4 months to not evaluable) in the combination group.
Median progression-free survival was 21.3 months (95% CI = 9.2–62.5 months) in the nivolumab group vs 8.4 months (95% CI = 3.7–24.3 months) in the combination group. Median overall survival was 80.7 months (95% CI = 23.3 months to not evaluable) vs 29.8 months (95% CI = 8.5–48.3 months) in the combination group.
Grade 3 or 4 treatment-related adverse events occurred in 28% of patients in the nivolumab group vs 47% of the combination group.
The investigators concluded: “This nonrandomized study showed frequent and durable responses with both [nivolumab and nivolumab plus ipilimumab] in patients with ICI-naive advanced MCC. However, it did not show improvement in efficacy with the combination, thus contradicting previous study reports that had suggested clinical benefit with combination ICI. A randomized trial of [nivolumab plus ipilimumab vs nivolumab] monotherapy is warranted.”
Shailender Bhatia, MD, of the Division of Hematology-Oncology, University of Washington and Fred Hutchinson Cancer Center, Seattle, is the corresponding author of the Journal of Clinical Oncology article.
Disclosure: The study was supported by Bristol Myers Squibb. For full disclosures of the study authors, visit ascopubs.org.
