ELM-2 Trial: Odronextamab Achieves High Responses in Patients With Third-Line Follicular Lymphoma

Odronextamab achieved high complete response (CR) and overall response rates (ORR) in patients with relapsed or refractory third line (3L) follicular lymphoma (FL), according to results from the ELM-2 study presented at the 66^th American Society of Hematology Annual Meeting & Exposition.

“Patients with relapsed [or] refractory [FL] experience progressively worse outcomes with each successive line of therapy,” the researchers wrote. “CR rates are 44% with 3L, 27% with 4L, and 22% with 5L+ therapies.”

In the ongoing, open-label, multicenter, phase II ELM-2 trial, patients with relapsed or refractory non-Hodgkin lymphoma received intravenous odronextamab in step-up doses with steroid prophylaxis during cycle 1, then 80 mg on days 1, 8, and 15 of cycles two to four. After cycle 4, dosing continued at 160 mg once every two weeks (Q2W), but patients switched to Q4W dosing if they achieved a durable CR for nine months or more.

The FL cohort included 128 patients who received odronextamab for a median of 13.8 months. At a median follow-up of 20.1 months, odronextamab achieved an ORR of 80.5% (95% CI, 72.5–86.9) and a CR rate of 73.4% (95% CI, 64.9–80.9). The median duration of CR was 25.1 months (95% CI 20.5–NE), and median time to CR was 2.7 months (2.3–7.9).

Baseline characteristics were similar between patients who achieved CR (n=94) and the overall population. Eighty-five patients (90.4%) with CR had high-risk features such as progression of disease within 24 months or a FL International Prognostic Index score of 3–5, but the median duration and time to CR in these patients were comparable to the overall cohort (23.7 months [95% CI, 18.2–NE] vs 2.7 months [2.3–7.9], respectively).

Sixty-six (70.2%) patients discontinued treatment, mainly due to disease progression (n=17), treatment-emergent adverse events (TEAS; n=16), physician decision (n=12), withdrawal by subject (n=11), or death resulting from TEAS (n=8). Forty-four patients with CR (46.8%) had switched to Q4W dosing at the time of the current analysis, with a median duration of exposure of 17.7 months (13.1–45.0). Of those, 22 discontinued treatment.

“These data show the sustainability of CR in [patients] with FL treated with 3L+ odronextamab, including in those with high-risk features,” the researchers wrote. “The safety profile of odronextamab was generally manageable in the overall population, including in [patients] with CR, despite their prolonged drug exposure.”

Reference

Luminari S, Villasboas Bisneto JC, Chong G, et al. “Dynamics of complete responses in patients with relapsed or refractory follicular lymphoma treated with odronextamab in the ELM-2 study.” Abstract #1628. Presented at the 66th American Society of Hematology Annual Meeting & Exposition; December 7-10, 2024; San Diego, California.