Safety and efficacy of odronextamab in patients with relapsed or refractory follicular lymphoma

The follicular lymphoma cohort of the phase 2 ELM-2 study of odronextamab, a CD20 by CD3 bispecific antibody, in patients with relapsed or refractory disease after two or more lines of systemic therapy. Odronextamab was given intravenously in 21-day cycles with step-up dosing in cycle 1 to mitigate cytokine release syndrome, until disease progression or unacceptable toxicity. The primary endpoint was objective response rate by independent central review.

128 patients were evaluated, of whom 95 per cent completed cycle 1 and 85 per cent four or more cycles. At 20.1 months of efficacy follow-up, the objective response rate was 80.0 per cent and the complete response rate 73.4 per cent. Median duration of complete response was 25.1 months, median progression-free survival 20.7 months, and median overall survival was not reached. Discontinuation for adverse events occurred in 16 per cent. The commonest treatment-emergent adverse events were cytokine release syndrome in 56 per cent, with grade 3 or above in 1.7 per cent (one of 60 patients) using the 0.7, 4 and 20 milligram step-up, neutropenia in 39 per cent and pyrexia in 38 per cent.