2027P - Immune checkpoint inhibitors in the treatment of small cell lung cancer: A systematic review and meta-analysis

Background

Multiple randomized trials have evaluated immune checkpoint inhibitors (ICI) as first- and second-line treatment in extensive-stage small cell lung cancer (ES-SCLC). We sought to conduct a pooled analysis to characterize the efficacy and toxicity of ICI in ES-SCLC.

Methods

Medline (PubMed), EMBASE, and Cochrane Library databases were queried between January 2010 and March 2022 and conference proceedings between 2018 and 2022 were searched for randomized clinical trials assessing ICI (combined with chemotherapy or as single agents), compared with chemotherapy, in patients with ES-SCLC. The primary endpoints were overall survival (OS) and progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), and grade 3 or higher adverse events (AEs). Pooled hazard ratios (HR) for OS and PFS were meta-analyzed using the generic inverse variance method, and random-effect models were used to compute pooled estimates. Subgroup analyses compared survival by line of therapy, sex, age, and ECOG status.

Results

A total of 5,325 patients from 10 trials were included. Compared to chemotherapy, ICI-based treatment decreased the risk of death by 19% (HR 0.81, 95% confidence interval (CI) 0.76-0.86). The OS benefit was seen regardless of age, sex, or ECOG status, but was only seen in patients treated in the first-line setting. Similarly, ICI-based therapy decreased the risk of disease progression by 20% (HR 0.80, 95%CI 0.68-0.94) and the PFS benefit was restricted to first-line treatment with detrimental effect in the second-line setting. ORR was also improved with ICI (odds ratio (OR) 0.80, 95%CI 0.65-0.97) with an increase in grade 3 or higher diarrhea (OR 3.63, 95%CI 1.46-9.02).

Conclusions

ICI conferred efficacy benefits (OS, PFS and ORR) and an acceptable safety profile in the treatment of patients with ES-SCLC in the first-line setting and should not be used in the second-line setting as single agents. Valid biomarkers predicting long-term benefit are needed to further improve outcomes.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.