A phase 1/2 study of favezelimab in combination with pembrolizumab for heavily pretreated anti–PD-1–refractory classical Hodgkin lymphoma (cHL): An updated analysis.

Abstract

7056 Background: PD-1 inhibitors are standard of care for relapsed or refractory (R/R) cHL, but patients (pts) often progress after anti–PD-1 therapy. The immune checkpoint receptor lymphocyte-activation gene 3 (LAG-3) is proposed to contribute to anti–PD-1 resistance. In a phase 1/2 study (NCT03598608) evaluating favezelimab (anti–LAG-3) plus pembrolizumab (anti–PD-1) for R/R hematologic malignancies, the combination provided antitumor activity and manageable safety in pts with heavily pretreated anti–PD-1–refractory cHL (cohort 2). Updated results after additional follow-up are presented. Methods: Eligible pts were aged ≥18 years with R/R cHL; prior treatment with or ineligibility for autologous stem cell transplantation or no response to salvage chemotherapy; an ECOG performance status of 0 or 1; and disease progression after ≥2 doses of anti–PD-1–based therapy and within 12 weeks of the last dose of anti–PD-1 therapy. The study comprised a safety lead-in (pembrolizumab 200 mg IV Q3W + favezelimab 200-mg starting dose, then dose escalation to 800 mg IV Q3W per a modified toxicity probability interval design) and a dose expansion phase (pembrolizumab + favezelimab at the established recommended phase 2 dose of 800 mg Q3W for ≤35 cycles). Primary end point was safety. ORR per IWG 2007 criteria by investigator review was a secondary end point. DOR and PFS per IWG 2007 criteria by investigator review and OS were exploratory. Results: Cohort 2 enrolled 34 pts. Median time from first dose to data cutoff (August 15, 2023) was 40.7 months (range, 20.4-54.8). Treatment-related AEs occurred in 28 pts (82%); the most common (≥15%) were hypothyroidism (18%), nausea (18%), and fatigue (15%). Grade 3 or 4 treatment-related AEs occurred in 6 pts (18%). Discontinuation due to treatment-related AEs occurred in 6 pts (18%). No deaths due to treatment-related AEs were reported. AEs of clinical interest occurred in 17 pts (50%); 2 pts (6%) had grade 3 events (encephalitis, hepatitis) and 1 pt (3%) had a grade 4 event (type 1 diabetes mellitus). ORR was 29% (10/34; 95% CI, 15-48), with 3 (9%) complete responses and 7 (21%) partial responses. ORR was 35% (6/17; 95% CI, 14-62) in pts with anti–PD-1 and 24% (4/17; 95% CI, 7-50) in pts with non–anti–PD-1 as most recent therapy. Median DOR was 21.9 months (range, 0.0+ to 26.1+) and an estimated 17% of responders remained in response at 24 months. Median PFS was 9.7 months (95% CI, 5.1-14.7); 24-month PFS rate was 21%. Median OS was 39.0 months (95% CI, 25.7-not reached); 24-month OS rate was 73%. Conclusions: After additional follow-up, favezelimab + pembrolizumab continued to demonstrate manageable safety and antitumor activity in pts with heavily pretreated anti–PD-1–refractory cHL. The phase 3 KEYFORM-008 study (NCT05508867) will evaluate a coformulation of favezelimab and pembrolizumab in pts with anti–PD-1–refractory cHL. Clinical trial information: NCT03598608 .