Odronextamab monotherapy in patients with relapsed/refractory diffuse large B cell lymphoma: primary efficacy and safety analysis in phase 2 ELM-2 trial

The phase 2, multicohort, ongoing ELM-2 study evaluates odronextamab, a CD20×CD3 bispecific antibody, in patients with relapsed/refractory (R/R) B cell non-Hodgkin lymphoma after ≥2 lines of therapy. Here primary analysis of the diffuse large B cell lymphoma (DLBCL) cohort is reported. Patients received intravenous odronextamab in 21-day cycles until progression or unacceptable toxicity, with cycle 1 step-up dosing to mitigate cytokine release syndrome (CRS) risk. The primary endpoint was objective response rate (ORR). Secondary endpoints included complete response (CR) rate, duration of response, progression-free survival (PFS) and overall survival. A total of 127 patients were enrolled. At the 29.9-month efficacy follow-up, the ORR was 52.0% and CR rate was 31.5%. Median durations of response and CR were 10.2 and 17.9 months, respectively. Undetectable minimal residual disease at cycle 4 day 15 was associated with PFS benefit. With a step-up of 0.7 to 4 to 20 mg (n = 60), CRS was the most common treatment-emergent adverse event (53.3% (grade ≥3, 1.7%)). No immune effector cell-associated neurotoxicity syndrome was reported. Infections were reported in 82/127 (64.6%) patients (grade ≥3, 38.6%; coronavirus disease 2019, 18.1% (grade ≥3, 12.6%)). In conclusion, odronextamab showed encouraging efficacy in heavily pretreated R/R DLBCL and generally manageable safety with supportive care. Clinical trial registration: NCT03888105.