A Phase I Trial of Evorpacept, Lenalidomide, and Rituximab for Patients with B-Cell Non-Hodgkin Lymphoma

Purpose: SIRPα+ macrophages can mediate resistance to lenalidomide and rituximab in patients with B-cell non-Hodgkin lymphoma (B-NHL). Evorpacept (ALX148) is a novel CD47 blocker that abrogates interactions between lymphoma cells and SIRPα+ macrophages. Patients and methods: Adult patients with B-NHL who had received at least two prior lines of systemic therapy were included in this single-arm phase I study (NCT05025800). Evorpacept was administered intravenously, in a 28-day cycle, until progression at two dose levels (DL): 30 mg/Kg on day (D) 1 and D15 (DL1) or 60 mg/Kg on day 1 (DL2); rituximab 375 mg/m2 i.v. was given weekly during cycle 1 and on D1 during cycles 2 to 6; and lenalidomide 20 mg was given orally from D1 to D21 during cycles 1 to 6. Single-cell RNA sequencing was performed on tumor biopsies collected before treatment and during cycle 1. Results: Twenty patients were included in this study. The median age was 61 (27-85) years, and 18 patients (90%) had indolent B-NHL. Three patients were treated at DL1, 17 at DL2, and no dose-limiting toxicity was observed. The most common grade 3 to 4 adverse events included neutropenia (60%), infections (30%), and alanine transferase increase (15%). Sixteen (80%) patients achieved complete response, and after a median follow-up of 28 months, 2-year progression-free survival rate was 69%. During treatment, a significant increase in T cells and macrophages was observed, and macrophage pathways associated with anti-tumoral activity were upregulated. Conclusions: Evorpacept plus lenalidomide and rituximab has a safe toxicity profile and promising anti-tumoral activity, and induces favorable biological effects on the tumoral immune microenvironment.