Real‐World Safety and Efficacy of Pola‐R‐ <scp>CHP</scp> in Previously Untreated <scp>DLBCL</scp> : <scp>POLASTAR</scp> Interim Analysis of 500 Patients

POLASTAR (jRCT1071220082) is a multicenter, prospective observational study evaluating the real-world efficacy and safety of polatuzumab vedotin plus rituximab, cyclophosphamide, doxorubicin, and prednisolone (Pola-R-CHP) in Japanese patients with diffuse large B-cell lymphoma (DLBCL), addressing the limited real-world data in this setting. Patients ≥ 18 years, with previously untreated DLBCL, receiving Pola-R-CHP were enrolled. Patients excluded from POLARIX (NCT03274492), including those > 80 years, were included. Overall, 485 patients were included in the full analysis set (FAS; median age, 71 years [range 27-93]; age ≤ 80 years, 87.6%; International Prognostic Index score 2-5, 73.7%). Median relative dose intensity (RDI) for rituximab and polatuzumab vedotin was ≥ 93.0% (both FAS and patients > 80 years), and for the chemotherapy components median RDI was ≥ 87.2% in the FAS and ≥ 49.6% for patients > 80 years. Grade ≥ 3 adverse events (AEs) occurred in 47.4% of patients in the FAS and 56.7% of patients > 80 years; serious AEs occurred in 12.6% and 25.0%, respectively. The most common Grade ≥ 3 AE (FAS/> 80 years) was neutrophil count decreased (25.6%/26.7%). In the FAS, 5 (1.0%) deaths due to AEs were reported and 33 (6.8%) patients discontinued polatuzumab vedotin due to AEs. No new safety signals were observed. In the FAS, overall response rate and complete response rate (95% confidence interval [CI]) were 93.2% (90.5-95.2) and 83.3% (79.6-86.5), respectively, and were 87.3% (76.0-93.7) and 80.0% (67.6-88.4) in patients > 80 years. Safety and efficacy of Pola-R-CHP in Japanese patients, including those > 80 years, were consistent with results from POLARIX. Trial Registration: Japan Registry of Clinical Trials (jRCT1071220082).