Adjunction of a MEK inhibitor to Vemurafenib in the treatment of metastatic melanoma results in a 60% reduction of acute kidney injury

A combined therapy MEK inhibitor, Cobimetinib (CB) and BRAF inhibitor, Vemurafenib (VMF), results in an improvement in progression-free survival among patients with BRAF V600-mutated metastatic melanoma. VMF skin adverse effects attributed to ERK paradoxical activation are decreased by the adjunction of CB. The aim of this study was to determine if this combination also improved the renal side effects of VMF. To investigate the incidence of acute kidney injury (AKI), we conducted a retrospective observational monocentric study in Lyon Sud University Hospital in France. We included 38 patients with metastatic BRAF-mutated melanomas treated by VMF and CB between March 2015 and June 2016. According to the NCI-CTCAE classification, AKI was defined as an increase in serum creatinine exceeding the baseline concentration by 1.5-fold. Serum creatinine was measured before treatment, then on a monthly basis during treatment, and 1 month after treatment discontinuation. Patients were divided into two main groups: AKI-positive (AKI+) and AKI-negative (AKI-), and further subdivided into three groups according to AKI severity (stage 1-5). Of 38 patients, 29 (76%) were AKI-, and all 9 AKI+ patients (24%) were diagnosed within the first trimester of treatment. Three-quarters of AKI (n = 7, 77%) had stage 1 AKI and the remaining 23% stage 2 AKI. Pre-treatment renal function was significantly better in AKI+ group: 105 vs. 80 ml/min/1.73mA(2) AKI-, p = 0.009. Compared to previous results, the AKI incidence under the combined VMF-CB vs. VMF monotherapy was reduced by 60%. We reported a reduced incidence and severity of nephrotoxicity of the association inhibitors of BRAF and MEK compared to a BRAF inhibitor monotherapy.