Efficacy, Safety, QOL Improvements by Mosun-Pola in R/R LBCL

Primary analysis data from the phase 3 SUNMO study (NCT05171647) evaluating the combination of mosunetuzumab (Lunsumio) and polatuzumab vedotin (Polivy) (Mosun-Pola) in second-line large B-cell lymphoma (LBCL) were recently published in the Journal of Clinical Oncology, demonstrating favorable efficacy, safety, and patient-reported outcomes over rituximab (Rituxan) plus gemcitabine and oxaliplatin (R-GemOx) and setting the stage for a potential chemotherapy-free treatment option.¹

At a median follow-up of 23.2 months, the arm receiving Mosun-Pola saw significantly prolonged survival without progression, with a median progression-free survival (PFS) of 11.5 months (95% CI, 5.6–18) vs 3.8 months (95% CI, 2.9–4.1) in the R-GemOx arm (HR, 0.41; 95% CI, 0.3–0.6; P <.0001). A significantly improved overall response rate (ORR) was also observed in the Mosun-Pola group compared with R-GemOx (70% vs 40%; P <.0001).

In terms of safety, the incidence of adverse events in the Mosun-Pola group was comparable with the R-GemOx group, with treatment duration advantages observed in the Mosun-Pola Group. Cytokine release syndrome (CRS) occurred in 26% of the Mosun-Pola group, with 5 patients experiencing a grade 2 event and 1 patient experiencing a grade 3 event.

These pivotal data were previously presented at the 18th International Conference on Malignant Lymphoma.

What Is the Benefit for Patients?

Beyond efficacy and safety, the results show marked improvements in patient quality of life (QOL) with Mosun-Pola vs R-GemOx. Treatment with Mosun-Pola delayed worsening of physical functioning and lymphoma-specific symptoms and achieved notably greater improvements in fatigue and lymphoma symptoms from baseline compared with R-GemOx.

“In the second-line, transplant-ineligible setting, patients may still meet eligibility criteria for CAR T-cell therapy; however[,] access limitations, disease status, CAR T-cell manufacturing challenges, and other healthcare system factors frequently preclude its delivery,” wrote the investigators, Budde et al, in the manuscript.¹ “Mosun-Pola represents a practical alternative to expand access to this population.”

In addition to the positive trends in patient-reported outcomes, Mosun-Pola’s fixed-duration administration and potential for outpatient delivery make the regimen a convenient, accessible, chemotherapy-free option for patients limited by disease characteristics and healthcare system requirements.

“Mosun-Pola enables broader patient access across practices and clinical settings and offers a practical alternative for patients who are unable to receive intensive therapies,” the authors added.

What Is the SUNMO Study?

The phase 3 SUNMO study is a randomized, open-label, multicenter, global trial assessing the efficacy and safety of mosunetuzumab, a T-cell -engaging bispecific antibody, plus polatuzumab vedotin, an antibody-drug conjugate (ADC), in patients with autologous stem cell transplant-ineligible, relapsed or refractory (R/R) DLBCL.² Mosun-Pola was evaluated against R-GemOx, a commonly used regimen in this patient population.

A total of 208 patients were randomized 2:1 to receive either Mosun-Pola (n = 138) or R-GemOx (n = 70). Patients in the Mosun-Pola arm received doses of subcutaneous mosunetuzumab for 8 21-day cycles (5 mg on day 1, 45 mg on days 8 and 15 of cycle 1, and 45 mg on day 1 of cycles 2 to 8), as well as 1.8 mg/kg of intravenous polatuzumab vedotin on day 1 of cycles 1 to 6. The R-GemOx group received 375 mg/m² rituximab, 1000 mg/m² gemcitabine, and 100 mg/m² oxaliplatin intravenously on day 1 of 8 14-day cycles.

The dual primary end points of the study were ORR and PFS. A key secondary end point was overall survival; other secondary end points assessed include investigator-assessed ORR and PFS, complete response (CR) rate, duration of response, and duration of CR.

REFERENCES:

1. Budde L E, Zhang H, Kim W-S, et al: Mosunetuzumab plus polatuzumab vedotin in transplant-ineligible refractory/relapsed large B-cell lymphoma: primary results of the phase 3 SUNMO trial. J Clin Oncol 10.1200/JCO-25-01957. Epub 2025 October 2.

2. A Study Evaluating Efficacy and Safety of Mosunetuzumab in Combination With Polatuzumab Vedotin Compared to Rituximab in Combination With Gemcitabine Plus Oxaliplatin in Participants With Relapsed or Refractory Aggressive B-Cell Non-Hodgkin's Lymphoma (SUNMO). ClinicalTrials.gov. Updated August 13, 2025. Accessed October 7, 2025. https://clinicaltrials.gov/study/NCT03083873