TY - JOUR T1 - Checkpoint inhibitor-induced polymyalgia rheumatica controlled by cobimetinib, a MEK 1/2 inhibitor JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis DO - 10.1136/annrheumdis-2018-213672 SP - annrheumdis-2018-213672 AU - Karmela Kim Chan AU - Anne R Bass Y1 - 2018/05/12 UR - http://ard.bmj.com/content/early/2018/05/13/annrheumdis-2018-213672.abstract N2 - We read with great interest the recently published paper by Kostine et al1 reporting on musculoskeletal immune-related adverse events (IRAE) related to cancer immunotherapy. We applaud the authors for being able to identify the incidence of these side effects and of their relation to tumour response.Of particular interest to us is the fact that most of the musculoskeletal IRAE were polymyalgia-like. We are eager to add to that discussion by presenting this case of checkpoint inhibitor-induced polymyalgia rheumatica (PMR) that was partially treated by targeted therapy with a MEK 1/2 inhibitor.A 70-year-old woman presented in November 2015 with rectal cancer that was locally invasive and metastatic to peritoneum and lung. She failed chemotherapy (5-fluorouracil, leucovorin and irinotecan) and in September 2016 was enrolled in a trial of atezolizumab (anti-PD-L1) every 2 weeks plus cobimetinib (a MEK 1/2 inhibitor). Cobimetinib was given daily for 3 … ER -