Body mass index may predict the response to ipilimumab in metastatic melanoma: An observational multi-centre study.

INTRODUCTION: Immunotherapy is a well-established treatment option in patients with metastatic melanoma. However, biomarkers that can be used to predict a response in these patients have not yet been found, putting patients at risk of severe side effects. METHODS: In this retrospective analysis, we investigated the association between the body mass index and ipilimumab treatment response in patients with metastatic melanoma. Patients with metastatic melanoma who received a monotherapy of up to 4 doses of ipilimumab (3 mg/kg) every 3 weeks from 2011 to 2014 in three major hospitals in Austria were included. Patients were classified into two groups: normal group (BMI<25) and overweight group (BMI≥25). RESULTS: 40 patients had a normal BMI, and 36 had a BMI above normal. Patients with a BMI that was above normal showed significantly higher response rates (p = 0.024, χ2), and lower likelihood of brain metastases (p = 0.012, χ2). No differences were found between both groups with respect to gender (p = 0.324, χ2), T-stage (p = 0.197, χ2), or the occurrence of side effects (p = 0.646, χ2). Patients with a BMI above normal showed a trend towards longer overall survival (p = 0.056, Log-Rank), but no difference was found regarding progression-free survival (p = 0.924, Log-Rank). CONCLUSIONS: The BMI correlated with the response to ipilimumab treatment in a cohort of metastatic melanoma patients.