Efficacy and Safety of Glofitamab Plus Polatuzumab Vedotin in Relapsed/Refractory Large B-Cell Lymphoma Including High-Grade B-Cell Lymphoma: Results From a Phase Ib/II Trial

PURPOSE: An unmet need remains for more effective therapies for relapsed/refractory (R/R) large B-cell lymphoma (LBCL), especially high-grade B-cell lymphoma (HGBCL). We present the primary analysis of a phase Ib/II study (ClinicalTrials.gov identifier: NCT03533283) investigating efficacy and safety of glofitamab plus polatuzumab vedotin (Glofit-Pola) in patients with R/R LBCL, including HGBCL and those who received previous chimeric antigen receptor (CAR) T-cell therapy. METHODS: Patients received 1,000 mg obinutuzumab on Cycle (C)1 Day (D)1 (once daily). Polatuzumab vedotin (1.8 mg/kg) was given on C1D2 and D1 of C2-6 (21-day cycles; once daily). Glofitamab was given as step-up doses in C1 (D8, 2.5 mg; D15, 10 mg) followed by 30 mg on D1 of C2-12 (21-day cycles; once daily). Polatuzumab vedotin was given for six fixed-duration cycles, and glofitamab for 12. RESULTS: As of September 2, 2024, 129 patients with LBCL (HGBCL; n = 44, 34.1%), received ≥1 dose of study treatment. The median age was 67 years (range, 23-84), and 63.6% were male. Patients had received a median of 2 (range, 1-7) previous lines of treatment (previous CAR T-cell therapy, n = 28, 21.7%). The independent review committee-assessed overall response rate was 78.3% (complete response rate, 59.7%). The median progression-free survival and overall survival (OS) were 12.3 and 33.8 months, respectively (median OS follow-up time, 32.7 months). The most common adverse event (AE) was cytokine release syndrome (43.4%; grade 1-2: 41.9%; one grade 5 event). Grade 3-4 AEs occurred in 58.9% of patients; 9.3% had grade 5 AEs, and 14.7% discontinued treatment because of AEs. CONCLUSION: Glofit-Pola demonstrated high efficacy and durable responses, with manageable safety, in heavily pretreated patients with R/R LBCL, including patients with HGBCL and previous CAR T-cell therapy failure.