On January 8, Chongqing Genrix Biopharmaceutical Co.,Ltd. announced that the conditional new drug application for its bispecific antibody drug GR1803 (velinotamig) has been accepted by the National Medical Products Administration (NMPA). The application is for the treatment of adult patients with relapsed or refractory multiple myeloma (R/R MM) who have received at least three prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.

GR1803 is a BCMA/CD3 bispecific antibody drug independently developed by Chongqing Genrix Biopharmaceutical. Its affinity for binding BCMA (10^-10 M) is two orders of magnitude higher than its affinity for binding CD3 (10^-8 M).

This asymmetric affinity design ensures that the bispecific antibody molecule recruits and activates T cells to kill tumor cells, while effectively reducing non-specific T cell activation caused by the CD3 antibody, thereby lowering the toxicity and side effects of the GR1803 injection within the body.

In November 2025, Chongqing Genrix Biopharmaceutical presented Phase I study data for GR1803 in the treatment of R/R MM at the ASH 2025 annual meeting.

As of July 1, 2025, a total of 60 patients were enrolled and received treatment, with 48 patients receiving the 180 µg/kg dose (the recommended Phase II dose, RP2D).

The results showed that among the 57 patients who had received at least one efficacy evaluation, the objective response rate (ORR) was 89.5% (51/57).

In the RP2D cohort, the ORR reached 87.5% (42/48), the rate of achieving at least a very good partial response (≥VGPR) was 70.8% (34/48), the rate of achieving at least a complete response (≥CR) was 37.5% (18/48), and the rate of achieving minimal residual disease (MRD) negativity was 54.2% (26/48).