Expression of MCT1 determines PFS and OS in patients receiving IMiD-based maintenance therapy. (A) MCT1 gene expression in plasma cell disorders (n = 1486) and normal bone marrow plasma cells (BMPC, n = 19). MGUS, monoclonal gammopathy of unknown significance; AMM, asymptomatic MM; MM, previously untreated, therapy-requiring MM; MMR, relapsed/refractory MM; and HMCL, human myeloma cell line. Numbers in blue (red) indicate the number of patients expressing (not expressing) MCT1. (B-E) Landmark analysis of patients with MM who underwent maintenance treatment after autologous stem cell transplantation. Expression of MCT1 was assessed by gene expression profiling in CD138-purified myeloma cell samples and correlated with PFS and OS data. P-values are log-rank. (B) PFS of 455 patients who underwent lenalidomide maintenance therapy in the GMMG-MM5-trial (31.9 months vs 48.2 months; MCT1^high vs MCT1^low). (C) OS of 455 patients who underwent lenalidomide maintenance therapy in the GMMG-MM5-trial (75.9 months vs not reached months; MCT1^high vs MCT1^low). (D) PFS of 62 patients who underwent bortezomib maintenance therapy in the GMMG-MM4-trial (39.8 months vs 32.6 months; MCT1^high vs MCT1^low). (E) OS of 101 patients who underwent bortezomib maintenance therapy in the GMMG-MM4-trial, 125.8 months vs 129.8 months; MCT1^high vs MCT1^low).