In a phase I study with 10 patients suffering from non-Hodgkin lymphoma, 100% overall response and 80% complete response was observed for REGN1979.

Regeneron is developing three bispecific antibodies for the treatment of different cancers: REGN1979 for relapsed or refractory (R/R) B cell non-Hodgkin lymphoma (B-NHL), REGN4018 (MUC16×CD3 bispecific antibody) for ovarian cancer and REGN5458 (BCMA×CD3 bispecific antibody) for multiple myeloma. 

REGN1979 is being investigated alone and in combination with Libtayo (cemiplimab-rwlc), Regeneron’s checkpoint inhibitor for the treatment of skin cancer. Based on encouraging results from a phase I proof-of-concept study involving 10 patients with R/R B-NHL, and particularly for patients with the two most common types of NHL ─ follicular lymphoma (FL) and diffuse large B cell lymphoma (DLBCL), the company is planning a potentially registrational phase II trial in 2019 investigating REGN1979 in R/R FL.

REGN1979 is a bispecific antibody designed to bind to CD3 on immune system T cells and CD20 on B cell malignancies and thus trigger tumor killing. It was developed using Regeneron’s proprietary VelocImmune^® technology for optimized fully human antibodies and its proprietary Veloci-Bi™ bispecific platform for the production of full-length bispecific antibodies similar to native antibodies that are amenable to production via standard antibody manufacturing techniques.

In the phase I study, which was intended to assess the safety, tolerability and efficacy of REGN1979 monotherapy, in addition to demonstrating an acceptable safety and tolerability profile with no observed dose-limiting toxicities (DLTs) or clinically-significant neurotoxicities, a 100% overall response rate (ORR) (eight complete responses [CR] and two partial responses [PR]) were observed for REGN1979 when given in doses of 5–40 mg to heavily pretreated patients (who received a median of three prior therapies) with R/R FL grades 1 to 3a.

Dose-dependent clinical activity was also observed for REGN1979 in heavily pretreated patients with R/R DLBCL, with the ORR increasing from 18% to 60% when the dose was raised from 5–12 mg to 18–40 mg.