The implementation of odronextamab, a CD20-CD3 bispecific antibody, as treatment for patients with relapsed/refractory (R/R) follicular lymphoma (FL) at grade 1 to 3a yielded high complete response (CR) rates and an appropriate safety level, according to findings from a pivotal phase 2 study. 

At the 2022 ASH Annual Meeting and Exposition in New Orleans, LA, Tai Min Kim, MD, PhD, Seoul National University Hospital, South Korea, presented the latest data.

ELM-1, a previous study, produced results that indicated patients with FL grade1 to 3a who received odronextamab (≥5mg) as treatment and had received 2 or more prior lines of therapy had a high overall response rate (ORR) of 91%, and complete response rate (CR) of 72%. In this study, Dr. Kim and colleagues aimed to analyze the efficacy and safety of odronextamab in a new study (ELM-2), stating that they incorporated “an optimized step-up regimen designed to maintain efficacy while minimizing acute toxicity including cytokine release syndrome (CRS).”

Patients with R/R FL grade 1 to 3a who have had at least 2 prior lines of therapy, including an anti-CD20 antibody or an alkylator, were eligible for the ELM-2 study. On April 20, 2022, the data collection date, 96 patients were evaluable for safety and 85 were evaluable for efficacy. The median age was 59 with a range of 22 to 84, and the gender distribution was 52% male. The median number of prior lines of therapy was 3, with 74% being resistant to their last therapy and 79% resistant to prior anti-CD20 therapy. 

As of April 20, 2022, patients had an 81% OR (n=69) and a 75% CR rate (n=64). These results were consistent across different subgroups, including older patients (≥65 years of age), those who had progression of disease within 2 years, and those who were treated with the revised regimen. The median duration of response and CR rate was 18.2 months, and the median overall survival (OS) rate had not been reached. The median progression-free survival (PFS) rate was 20.2 months (95% CI). 

The most commonly occurring treatment related adverse events (TEAEs) present in 99% of patients (n=95) were cytokine release disease (CRS) (51%), pyrexia (32%), anemia (31%), and infusion-related reactions (31%). No cases of immune-mediated adverse events were observed in patients who were given the revised regimen, compared to 3% with the original regimen. COVID-19 was reported in 14% of patients, with 5% experiencing grade 5 or higher. 

As primary endpoints of revising a step-up dosing regimen to reduce the risk of CRS without losing efficacy was reached, Dr. Kim et al concluded, “odronextamab may represent an important treatment option for R/R FL, providing a more accessible option with favorable benefit/risk compared with existing therapies including CAR- T cell therapy. Updated safety and efficacy data will be presented.”

Source: 

Kim TM. Odronextamab in Patients with Relapsed/Refractory (R/R) Follicular Lymphoma (FL) Grade 1–3a: Results from a Prespecified Analysis of the Pivotal Phase II Study ELM-2. Presented at ASH Annual Meeting and Exposition; December 10-13, 2022; New Orleans, LA. Abstract 949.