Innovent Biologics has reported updated Phase 1 clinical data for IBI3003, a trispecific antibody targeting GPRC5D, BCMA and CD3, in patients with relapsed or refractory multiple myeloma. The results were presented in an oral session at the 23rd International Myeloma Society Annual Meeting 2026, the company said.
From an integrated analysis of efficacy, safety and pharmacokinetic and pharmacodynamic data from dose optimization cohorts at 120, 360 and 540 μg/kg, Innovent determined the recommended Phase 2 dose to be 360 μg/kg. Twenty-six patients received that dose, with a median follow-up of 7.57 months and median progression-free survival not yet reached. The overall response rate was 84.6%, comprising 11 stringent complete responses, four very good partial responses and seven partial responses. The rate was 94.7% among 19 patients who had received two to four prior lines of therapy, 87.5% among eight patients with non-bone-related extramedullary disease and 92.3% among 13 patients without extramedullary disease.
Median time to first response was 0.99 months, to a very good partial response or better 1.87 months, and to a complete response or better 2.79 months. Among patients who reached a complete response or better as assessed by central laboratory next-generation sequencing, the minimal residual disease negativity rate was 100% in eight patients, with three reaching MRD negativity after a single treatment cycle. After three treatment cycles, the median reduction from baseline in serum soluble BCMA was 98.38% in the 360 μg/kg group.
The trial enrolled 102 patients in China and Australia at doses from 0.1 to 800 μg/kg. Median age was 62, 37.1% were classified as high risk by mSMART criteria, 53.9% had at least one site of extramedullary disease, and the median number of prior lines of therapy was four. Cytokine release syndrome occurred in 52% of patients and immune effector cell-associated neurotoxicity syndrome in 3.9%, all Grade 1 or 2 and resolved with treatment. Infections occurred in 42.2%, with Grade 3 or higher events in 26.5%. No Grade 3 or higher oral adverse events were observed, and two patients had a Grade 3 rash.
Innovent said a Phase 3 study, TriadicMM-1, is under way in China for patients who have received one to four prior lines of therapy, and that a Phase 2 study combining IBI3003 with a CD38 monoclonal antibody in frontline multiple myeloma is also ongoing. Peng Liu of Zhongshan Hospital Affiliated to Fudan University said patients with relapsed or refractory multiple myeloma have a poor prognosis after failing proteasome inhibitors, immunomodulatory drugs and anti-CD38 therapies, and described the safety profile at 360 μg/kg as manageable alongside the responses seen at that dose.
