Gastrointestinal adverse events with combination of checkpoint inhibitors in advanced melanoma: a systematic review

INTRODUCTION: Immunotherapies, including checkpoint inhibitors (CIs) such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed death-1 (PD-1) inhibitors, are revolutionizing the treatment of advanced melanoma. Combining CTLA-4 and PD-1 inhibitors provides additional clinical benefit compared with single agents alone. However, combination therapy can increase the incidence of gastrointestinal adverse events (GI AEs). This systematic review assessed the epidemiological, clinical, economic, and humanistic burden of GI AEs due to combination CIs in advanced melanoma. METHODS: MEDLINE, EMBASE, and the Cochrane Library were systematically searched (December 2011 to December 2016) to identify primary studies, systematic reviews, meta-analyses, and conference proceedings (2014–2016) evaluating adults treated with ≥2 CIs for advanced melanoma. RESULTS: Of the 3391 identified articles, 14 were included. Most studies examined the ipilimumab plus nivolumab combination. Any grade and grade 3–4 GI AEs occurred in more patients receiving ipilimumab plus nivolumab versus ipilimumab or nivolumab alone. The most common grade 3–4 GI AEs were diarrhea and colitis. Grade 3–4 colitis occurred in more patients receiving ipilimumab plus nivolumab. However, grade 3–4 diarrhea occurred at the same rate as ipilimumab alone. GI AEs developed with ipilimumab plus nivolumab approximately 6.6 weeks after initiating treatment. No studies assessing the economic or humanistic burden of GI AEs were identified. CONCLUSION: GI AEs occurred at a higher rate and greater severity in patients treated with ipilimumab plus nivolumab versus ipilimumab or nivolumab monotherapy. The lack of research on economic and humanistic burden of GI AEs with combination CIs for advanced melanoma represents an unmet need in the literature and should be explored in future studies.