Improvements in health-related quality of life (HRQoL) in the SUNMO study: Subcutaneous (SC) mosunetuzumab plus polatuzumab vedotin (Mosun-Pola) vs rituximab, gemcitabine and oxaliplatin (R-GemOx) in patients with relapsed/refractory (R/R) large B-ce

Abstract Background: HRQoL is often impaired in pts with R/R LBCL (Abramson et al. ASH 2021). SUNMO (NCT05171647), a randomized Phase III study, compared Mosun-Pola vs R-GemOx in pts with R/R LBCL. Mosun-Pola significantly improved overall response rate and progression-free survival compared with R-GemOx, with a safety profile notable for reduced chemotherapy toxicity and the lowest cytokine release syndrome incidence across T-cell engaging therapies in a Phase III setting (Westin et al. ICML 2025). We report patient-reported outcomes (PROs) from SUNMO to assess the impact of treatment on HRQoL. Methods: Pts with autologous stem cell transplant-ineligible R/R LBCL were randomly assigned (2:1) to receive Mosun-Pola or R-GemOx. HRQoL was measured using European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) for global health status, functioning, and core symptom scales; Functional Assessment of Cancer Treatment-Lymphoma (FACT-Lym) for lymphoma symptoms; and FACT Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-NTX) for peripheral neuropathy (PN). Pts completed questionnaires on Day 1 of Cycles [C]1–3, 5 and 7, at end of treatment (EOT), and at 3, 6, and 12 months post-EOT. Questionnaire completion rates, time to deterioration (TTD), change from baseline (CfB) and summary statistics were estimated at each assessment. Minimal clinically important difference (MCID) was defined as a 10-point change for EORTC QLQ-C30 and 3-point change for FACT-Lym and FACT/GOG-NTX, based on validated thresholds. Higher scores in EORTC QLQ-C30 functioning and global health scales, and FACT-Lym and FACT/GOG-NTX scales, indicate improvement; higher EORTC QLQ-C30 symptom scores indicate worsening. Results: Overall, 208 pts were randomized (Mosun-Pola, n=138; R-GemOx, n=70). Median age was 62 years (≥65 years, 41.3%), 91 (43.8%) pts received one prior therapy. Ann Arbor stage was III–IV in 160 (76.9%) pts; 121 (58.2%) had primary refractory disease; 145 (69.7%) were refractory to their last therapy. PRO questionnaire completion rates were >95% in both arms. At baseline, pts in both arms reported low-to-mild symptom severity, moderate global health status/QoL, moderate-to-high functioning, mild-to-moderate lymphoma symptoms, and low rates of PN. For Mosun-Pola, median TTD in physical functioning was delayed by >1 year compared with R-GemOx (17.4 [95% CI 5.3– not estimable (NE)] vs 5.3 [1.9–NE] months), and by >2 months for lymphoma symptoms (7.2 [95% CI 4.6–18.3] vs 4.6 [1.9–NE] months) and PN (4.4 [95% CI 3.0–6.0] vs 2.0 [1.0–6.4] months), suggesting greater durability in maintaining baseline scores. Stratified hazard ratios (HR [95% CI]) favored Mosun-Pola vs R-GemOx, with reduction in risk of deterioration by 30% for physical functioning (HR 0.7 [0.4–1.1]), 29% for PN (HR 0.7 [0.5–1.1]), 21% for fatigue (HR 0.8 [0.5–1.2]), and 18% for lymphoma symptoms (HR 0.8 [0.5–1.3]). Although mean baseline fatigue scores were higher in the Mosun-Pola arm (34.0 vs 25.6), fatigue improved with Mosun-Pola, while remaining stable in the R-GemOx arm. Improvements in lymphoma symptoms were similar in responding pts from both arms; pts with Mosun-Pola had clinically meaningful improvements in mean scores two cycles earlier for pain (CfB by EORTC QLQ-C30: Mosun-Pola: C5, -10.5; C7, -12.1; R-GemOx: C5, -6.0; C7, -13.7) and two cycles later for lymphoma symptoms (CfB by FACT-Lym: Mosun-Pola: C3, +2.5; C5, +4.8; C7, +4.8; R-GemOx: C3, +3.4; C5, +4.1; C7, +4.9) compared with R-GemOx. Pts with Mosun-Pola had clinically meaningful improvements in mean scores by EORTC QLQ-C30 for financial difficulties (C5, -10.4), emotional functioning (C5, +10.4) and constipation (C7, -10.2), while mean scores remained at baseline levels for pts in the R-GemOx arm. Conclusions: In SUNMO, Mosun-Pola provided benefits across multiple aspects of HRQoL compared with R-GemOx, particularly in maintaining/improving physical functioning, fatigue, lymphoma symptoms, and PN. Pts treated with Mosun-Pola achieved clinically meaningful improvements in PROs, with scores exceeding the MCID in several domains and exhibiting a delay in deterioration of >1 year for physical functioning, and >2 months for PN and lymphoma symptoms. Improved PROs with Mosun-Pola vs R-GemOx suggest benefits in HRQoL with chemotherapy-free bispecific antibody combinations. These findings are noteworthy given the high disease burden and refractory status of the pts at baseline.