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, chi(2)), and lower likelihood of brain metastases (p = 0.012, chi(2)). No differences were found between both groups with respect to gender (p = 0.324, chi(2)), T-stage (p = 0.197, chi(2)), or the occurrence of side effects (p= 0.646, chi(2)). 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.