Results of a Second, Prespecified Analysis of the Phase 2 Study ELM-2 Confirm High Rates of Durable Complete Response with Odronextamab in Patients with Relapsed/Refractory (R/R) Follicular Lymphoma (FL) with Extended Follow-up

• Published in: Blood 2023-11, Vol.142 (Supplement 1), p.3041-3041
• Main Authors: Villasboas, Jose. C., Kim, Tae Min, Taszner, Michal, Novelli, Silvana, Cho, Seok-Goo, Merli, Michele, Jimenez Ubieto, Ana, Tessoulin, Benoit, Poon, Michelle, Walewski, Jan, Yi, Shuhua, Song, Yuqin, Chong, Geoffrey, Luminari, Stefano, Bachy, Emmanuel, Guidez, Stephanie, Alonso, Aranzazu, Jagadeesh, Deepa, Zhang, Wei, Magnano, Laura, Iskierka-Jażdżewska, Elżbieta, Tani, Monica, Cai, Jessica, Uppala, Amulya, Shariff, Saleem, Chi, Lei, Chaudhry, Aafia, Mohamed, Hesham, Ambati, Srikanth, Tucker, David
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2023-181650

Background The class of CD20×CD3 bispecific antibodies (BsAbs) has emerged as an important anti-lymphoma modality for patients (pts) with R/R B-cell non-Hodgkin lymphoma. Odronextamab, a novel, off-the-shelf, CD20×CD3 BsAb, has previously demonstrated compelling efficacy in both R/R diffuse large B-cell lymphoma and R/R FL. In pts with R/R FL, odronextamab monotherapy achieved 75% complete response (CR) rates and encouraging durability of responses, and showed generally manageable safety, in the Phase 2 ELM-2 study (NCT03888105; Kim TM, et al. ASH. 2022). Here, we report the results of a second, pre-specified interim analysis of ELM-2. Methods Intravenous odronextamab was administered weekly in 21-day cycles during Cycles (C) 1-4. Optimization of the step-up regimen to further mitigate cytokine release syndrome (CRS) was reported previously (Kim TM, et al. ASH. 2022). Odronextamab was administered with steroid prophylaxis and step-up doses of 0.7/4/20 mg during C1, followed by 80 mg on Days 1, 8, and 15 of C2-4. After C4, odronextamab maintenance treatment continued at 160 mg every 2 weeks until disease progression or unacceptable toxicity. Pts who achieved a durable CR for ≥9 months transitioned to dosing every 4 weeks. A pre-specified interim analysis was performed when 80 pts had completed ≥12 months follow-up. The primary endpoint was objective response rate (ORR), assessed by independent central review (ICR) according to the Lugano classification. Key secondary endpoints included CR rate, duration of response (DoR), progression-free survival (PFS), overall survival (OS), and changes in scores of patient-reported outcomes. Minimal residual disease (MRD) was included as an exploratory endpoint. Results At data cut off (Jan 31, 2023), the global study was fully enrolled and included 140 safety-evaluable pts with FL; 128 pts were efficacy-evaluable and 85 pts had ≥12 months follow-up. The median duration of study follow-up for efficacy was 26.6 months. In the safety-evaluable FL population, median age was 60.5 years (range 22-84), 53% were male, and pts had received a median of 3 (range 2-13) prior lines of therapy. 73% of pts were refractory to their last therapy, 41% were double refractory, and 74% were refractory to an anti-CD20 antibody. 50% of pts had progression of disease within 2 years (POD24) and 29% had a prior autologous hematopoietic stem cell transplant. ORR and CR rate by ICR were 80% (102/128) and 72% (92/128), respectively, and were consis