Polatuzumab Vedotin Plus R-CHOP Improved PFS Among Patients With DLBCL

Results from the Phase 3 POLARIX Trial 

According to findings of the Asian population-focused phase 3 POLARIX trial recently published in Blood, polatuzumab vedotin combined with rituximab plus cyclophosphamide, doxorubicin, and prednisone (Pola-R-CHP) improved progression-free survival (PFS) among patients with previously untreated diffuse large b-cell lymphoma (DLBCL), compared to the results of rituximab plus cyclophosphamide, doxorubicin, and prednisone alone (R-CHOP). 

Dr Yuqin Song, MD, Peking University Cancer Hospital & Institute, Beijing, China, and coauthors stated, “[DLBCL] is the most common form of aggressive non‐Hodgkin lymphoma worldwide, and in Asia accounts for 40.8%, 36.0%, and 48.4% of all cases in China, Japan and Korea, respectively,” as the reasoning behind the population for this study. They added, “although R-CHOP is an effective therapy in producing clinical response, 30–40% of patients subsequently relapse or become refractory to treatment.”

In an attempt to reduce this high relapse rate, Dr Song et al aimed to assess a primary endpoint of PFS (from the time of randomization until the first instance of disease progression, relapse, or death from any cause) and secondary endpoints including event-free survival (EFS), complete response (CR), overall survival (OS), and disease-free survival (DFS) in patients who achieved a CR. They also aimed to compare the results of this Asia population study to the POLARIX global study. 

281 patients from Asia with DLBCL were enrolled in this study, with 160 in the intent-to-treat (ITT) cohort, and 121 in a China extension of the ITT cohort. All patients had been previously untreated for DLBCL. Patients were randomized 1:1 to either receive 6 21-day cycles of R-CHOP (n=140) treatment (rituximab at 375 mg/m2, cyclophosphamide at 750 mg/m², and doxorubicin at 50 mg/m² on day 1, as well as oral prednisone at 100 mg once daily on days 1–5) or Pola-R-CHP treatment (n=141), which consisted of the same dosages previously mentioned plus polatuzumab vedotin at 1.8 mg/kg on day 1. Rituximab at 375 mg/m² was given as monotherapy in 2 additional cycles. 3 patients discontinued treatment before 1 dose, leaving a total of 279 patients (140 patients in the Pola‐R‐CHP arm and 139 patients in the R‐CHOP arm) in this study.

At a median follow-up of 24.2 months, results indicate that PFS was significantly higher in the Pola-R-CHP arm versus the R-CHOP arm (74.2% vs 66.5%). EFS was consistent with PFS, with the 2-year EFS being 74.2% in the Pola-R-CHP arm and 65.6% in the R-CHOP arm. Cr rates were 82.3% in the Pola-R-CHP arm and 77.9% in the R-CHOP arm. OS was unable to be measured at the time of follow-up. There was a 99.3% incidence of adverse events in both arms, with the most common adverse events being anemia, alopecia, and neutrophil count decrease. 

As both primary and secondary endpoints were met, Dr Song et al concluded that compared to R-CHOP treatment, there is a “benefit of Pola‐R‐CHP with regard to EFS, CR rate at treatment completion, and DFS.” They added, “the results of the Asia subpopulation PFS analysis met the criteria for consistency with the primary findings of the POLARIX global study population.”

Source: 

Song Y, Tilly H, Rai S, et al. Polatuzumab vedotin in previously untreated DLBCL: an Asia subpopulation analysis from the Phase 3 POLARIX trial. Blood. Published online January 10, 2023. doi:https://doi.org/10.1182/blood.2022017734