Treatment with the anti-PD1 antibody, nivolumab, did not improve response rates or survival over standard chemotherapy in patients with metastatic small-cell lung cancer (SCLC) who relapsed following first-line treatment, according to findings presented at the ESMO Immuno-Oncology Congress 2018 in Geneva, Switzerland.
Martin Reck of the Lung Clinic Grosshansdorf, German Centre of Lung Research in Grosshansdorf, Germany noted that, although patients with SCLC often show high initial response rates, most patients will relapse soon after first-line treatment. These relapsing patients have few treatment options leaving them with a poor prognosis.
Professor Reck and colleagues conducted the CheckMate 331 (NCT02481830) study evaluating nivolumab, which has been approved in the USA for treatment of patients with SCLC and progression after platinum-based chemotherapy and one or more other lines of treatment.
CheckMate 331 was a global, open-label, phase III trial comparing nivolumab to chemotherapy. The trial enrolled 569 patients with limited or extensive relapsed metastatic SCLC who progressed after first-line platinum-based chemotherapy. The patients were randomly assigned 1:1, with 282 patients receiving nivolumab and 285 receiving chemotherapy with topotecan or amrubicin, according to local approval. The patients were stratified by platinum sensitivity (90 days) and the presence of CNS metastases. Both treatments were continued until progression, or clinical benefit was no longer observed with nivolumab, or until unacceptable toxicity occurred. Overall survival (OS) with nivolumab versus chemotherapy served as the primary endpoint.
The duration of response was longer with nivolumab
After a minimum follow-up of 15.8 months, 225 (79%) OS events occurred with nivolumab compared to 245 (86%) with chemotherapy.
No statistically significant improvement in OS was seen with nivolumab compared to chemotherapy; median OS was 7.5 months versus 8.4 months with nivolumab versus chemotherapy, respectively (hazard ratio [HR] 0.86; 95% confidence interval [CI], 0.72–1.04]). However, the OS curves showed delayed separation after month 12; the one-year OS rates were 37% with nivolumab versus 34% with chemotherapy.
With the respective treatments, median progression-free survival (PFS) was median 1.5 versus 3.8 months (HR 1.41; 95% CI, 1.18-1.69) and the one-year PFS rates were 11% versus 10%.
The objective response rates were 39% versus 47%, and the duration of response in responding patients was median 8.3 (95% CI 7.0-12.6) months versus 4.5 (95% CI 4.4-5.8) months with nivolumab versus chemotherapy, respectively,
In patients with platinum-resistant SCLC, the HR for OS with nivolumab versus chemotherapy was 0.71 (95% CI, 0.54–0.94).
The safety profile was improved with nivolumab compared to chemotherapy. All-grade treatment-related adverse events (TRAE) occurred in 55% versus 90% and grade 3–4 TRAE occurred in 4% versus 73% of nivolumab versus chemotherapy treated patients. Two treatment related deaths occurred with nivolumab and 3 deaths occurred that were chemotherapy related.
Conclusion
The primary overall survival endpoint for second-line nivolumab versus chemotherapy was not met in CheckMate 331.
However, according to the authors, the late separation of curves and potential activity in the platinum-refractory setting suggests possible long-term benefit for some patients. There were no new safety signals, and lower adverse event rates were reported with nivolumab.
Reference
LBA5 – Reck M, Vicente D, Ciuleanu T, et al. Efficacy and safety of nivolumab (nivo) monotherapy versus chemotherapy (chemo) in recurrent small cell lung cancer (SCLC): Results from CheckMate 331.
Funding from Bristol-Myers Squibb was reported.