Safety evaluation of immune checkpoint inhibitors combined with chemotherapy for the treatment of small cell lung cancer: A meta-analysis of randomized controlled trials

Background: The addition of immune checkpoint inhibitors (ICIs) to chemotherapy is the new standard of care in the first-line treatment of small cell lung cancer (SCLC). However, although the concomitant use of immunotherapy and chemotherapy can increase the antitumor efficacy, it can also increase toxicity. The present study evaluated the tolerability of immune-based combinations in the first-line treatment of SCLC.

Methods: Relevant trials were identified by searching electronic databases and conference meetings. Seven phase II and III randomized controlled trials and 3766 SCLC patients were included in the meta-analysis (immune-based combinations = 2133; chemotherapy = 1633). Outcomes of interest included treatment-related adverse events (TRAEs) and the rate of discontinuation due to TRAEs.

Results: Immune-based combination treatment was associated with a higher risk of grade 3-5 TRAEs (odds ratio [OR], 1.16; 95% confidence interval [CI]: 1.01-1.35). Immune-based combinations were associated with a higher risk of TRAEs leading to discontinuation (OR, 2.30; 95% CI: 1.17-4.54). No differences were observed in grade 5 TRAEs (OR, 1.56; 95% CI: 0.93-2.63).

Conclusion: This meta-analysis indicates that the addition of immunotherapy to chemotherapy in SCLC patients is associated with a higher risk of toxicity and probably of treatment discontinuation. Tools for identifying SCLC patients that would not benefit from immune-based therapy are urgently needed.