(RTTNews) - Innovent Biologics, Inc. (1801.HK), a biopharmaceutical company, announced updated Phase 1 clinical data for IBI3003 in patients with relapsed or refractory multiple myeloma (R/R MM), presented orally at the 23rd International Myeloma Society (IMS) Annual Meeting 2026.
IBI3003 is a trispecific antibody targeting G protein-coupled receptor C5D (GPRC5D), B-cell maturation antigen (BCMA), and CD3. Based on Phase 1 dose-optimisation results, the recommended Phase 2 dose (RP2D) of IBI3003 was determined to be 360 µg/kg.
The updated data were from the Phase 1 clinical study, which enrolled eligible patients with R/R MM who had failed at least two prior lines of therapy, including at least one proteasome inhibitor (PI), one immunomodulatory drug (IMiD), and one anti-CD38-based therapy, and who had relapsed or were refractory to their last anti-myeloma regimen.
A total of 102 patients were enrolled in this phase of the study in China and Australia, with doses ranging from 0.1 µg/kg to 800 µg/kg.
The median patient age was 62 years (range, 40-88). Of the enrolled patients, 37.1% were classified as high risk under mSMART criteria, while 53.9% had at least one site of extramedullary disease (EMD). Patients had received a median of four prior lines of therapy (range, 2-12). All patients had received at least three classes of therapy, including a PI, an IMiD, and an anti-CD38 antibody.
In addition, 55.9% had received at least five classes of therapy, including at least two PIs, two IMiDs, and one anti-CD38 antibody. Prior anti-BCMA and/or anti-GPRC5D therapy was reported in 33.3% of patients, and 88.2% were refractory to their most recent treatment.
As of the June 30, 2026 data cutoff, the median follow-up was 6.65 months (range, 0.8-15.2).
A total of 26 patients received IBI3003 at 360 µg/kg, with a median follow-up duration of 7.57 months.
According to the company, the key study findings included the following:
- The overall response rate (ORR) was 84.6%, including 11 cases of stringent complete response (sCR), 4 cases of very good partial response (VGPR), and 7 cases of partial response (PR).
- The ORR was 94.7% among 19 patients who had received 2 to 4 prior lines of therapy, 87.5% among 8 patients with non-bone-related EMD, and 92.3% among 13 patients without EMD.
- The median time to first response was 0.99 months (range: 0.9-8.3 months), the median time to first response of =VGPR was 1.87 months (range: 0.9-4.6 months), and the median time to first response of =CR was 2.79 months (range: 0.9-9.2 months).
- Under the safety profile, hematologic toxicities were the most common grade 3 and higher treatment-related adverse events (TRAEs). They occurred primarily during dose escalation and were generally manageable and reversible, the company said.
- The incidences of cytokine release syndrome(CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were 52% and 3.9%, respectively.
- The incidence of infections was 42.2%, with Grade =3 infections reported in 26.5% of patients.
- Biomarker analyses showed a significant and sustained decline in serum soluble BCMA (sBCMA) levels across the IBI3003 120 µg/kg, 360 µg/kg, and 540 µg/kg dose groups.
- After three treatment cycles, the median reduction from baseline in sBCMA levels was 98.38% in the IBI3003 360 µg/kg group.
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