The safety and tolerability of combined immune checkpoint inhibitors (anti-PD-1/PD-L1 plus anti-CTLA-4): a systematic review and meta-analysis

BACKGROUND: The future of combined immunotherapy (a PD-1/PD-L1 plus a CTLA-4 antagonist) is very bright. However, besides improving efficacy, combined therapy increases treatment-related adverse events (TRAEs). Also, the clinical application is limited in some solid tumors. METHODS: This paper purports to investigate the TRAEs for the combined immunotherapy aiming for a more appropriate utilization of immune checkpoint inhibitors (ICIs) in clinical practice through a meta-analysis. RESULTS: A total of 17 eligible studies covering 2626 patients were selected for a meta-analysis based on specified inclusion and exclusion criteria. The incidence rates of any grade and grade 3 or higher TRAEs were 88% (95%CI, 84–92%) and 41% (95%CI, 35–47%), respectively. The overall incidence of any grade TRAEs leading to discontinuation of treatment was 20% (95%CI, 16–24%). The incidence rate of treatment related deaths was 4.3‰ (95%CI, 1.4‰-8.4‰). Analysis showed that NIVO1 + IPI3 cohort had higher incidences of grade 3 or higher TRAEs (RR = 1.77, 95%CI, 1.34–2.34, p < 0.0001) and any grade TRAEs leading to discontinuation of treatment (RR = 1.81, 95%CI, 1.08–3.04, P = 0.02), compared with NIVO3 + IPI1 regimen. CONCLUSIONS: The combined therapy had high TRAEs. The TRAEs, especially grade 3 or higher, led to discontinuation of the treatment. Furthermore, the incidence of treatment-related deaths was rare. Moreover, the NIVO3 + IPI1 regimen, regardless of efficacy, is more recommended because of better tolerance and lower adverse events. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12885-019-5785-z) contains supplementary material, which is available to authorized users.