Metformin in Combination with Standard Therapy in Patients with Diffuse Large B-Cell Lymphoma: A Randomized Phase II Clinical Trial

Background: Metformin has been shown to have antitumor activity in different tumor types. In DLBCL (Diffuse large B cell lymphoma), using metformin with front-line chemotherapy & immunotherapy resulted in improved clinical outcomes. Objectives: To assess the effectiveness of incorporating metformin into the standard initial treatment regimen of R-CHOP for patients with DLBCL. The evaluation metrics included response rate, toxicity, progression-free survival (PFS), and overall survival (OS). Patients and Methods: This prospective phase 2 trial included 100 adult patients with histopathological evidence of DLBCL, eligible for first-line treatment with R-CHOP, life expectancy of at least 6 months, and performance status (PS) ≤ 2. Patients were randomized to receive either metformin plus R-CHOP or R-CHOP alone. Results: Each group included 50 patients. The metformin arm had more females than the standard arm (p=0.016). Nausea was significantly higher in the test arm than the standard arm (p=0.008). Metformin group had higher rates of complete remission (CR) at the end of treatment (92% vs 74%; p=0.017), lower rates of relapse/progression (10% vs 36%; p=0.002), and lower rates of overall mortality (4% vs 20%; p=0.014). The mean disease-free survival (DFS) was 24.5 months in the metformin group versus 20.2 months in the control arm (p=0.023). Likewise, the mean progression-free survival (PFS) was 25.91 versus 19.81 months and the mean overall survival (OS) was 27.39 versus 23.8 months (p-values= 0.002, and 0.013 respectively). By multivariate analysis of response and relapse, the use of metformin was an independent prognostic factor of CR and relapse. Conclusions: The addition of metformin to standard R-CHOP could improve clinical outcomes in patients with DLBCL with a tolerable safety profile.