Efficacy and safety of combination immunotherapy for malignant solid tumors: A systematic review and meta-analysis

Background: Combination immunotherapy has become an actively growing field of clinical investigation.

Methods: We searched for clinical trials of combination immunotherapy and calculated the pooled hazard ratio (HR), odds ratio (OR) of clinical outcomes and safety by subgroups of different combination regimens.

Results: Totally 28 clinical trials were analyzed. The study showed that the pooled HRs of overall survival and progression-free survival for combination therapy were 0.77 (95% CI: 0.70-0.84, p < 0.001) and 0.72 (95% CI: 0.66-0.79, p < 0.001) while the pooled OR of high-grade adverse effects was 1.45 (p = 0.004). Subgroup analysis showed that the HR of overal survival were 0.74 (p = 0.005), 0.79 (p < 0.001), 0.70 (p = 0.003) and 0.85 (p = 0.052) for immunotherapy combined with immunotherapy, chemotherapy, targeted therapy and radiotherapy group, respectively.

Conclusions: The meta-analysis indicated that combination immunotherapy could bring more clinical benefits with increased high-grade adverse effects.