ROCKVILLE, Md. — August 11, 2025 — Leads & Copy — I-Mab (NASDAQ: IMAB), a U.S.-based, global biotech company focused on precision immuno-oncology agents for cancer treatment, announced the completion of enrollment for the planned Phase 1b dose expansion cohorts. These cohorts are evaluating givastomig, a bispecific Claudin 18.2 x 4-1BB antibody, combined with nivolumab and mFOLFOX6, ahead of schedule.
The Phase 1b study (NCT04900818) assesses the safety, efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of givastomig, a potential best-in-class Claudin 18.2 (CLDN18.2) x 4-1BB bispecific antibody, with nivolumab and mFOLFOX6 as first-line therapy in patients with CLDN18.2-positive gastric cancers (≥1+ intensity in ≥1% of cells). The primary endpoint is safety, with the study enrolling only patients in the U.S. The dose expansion cohorts enrolled 40 patients across two doses (8 mg/kg and 12 mg/kg).
Phillip Dennis, MD, PhD, Chief Medical Officer of I-Mab, expressed optimism about givastomig, citing the accelerated enrollment pace and investigator enthusiasm, highlighting the unmet need for improved gastric cancer therapy and growing interest in Claudin 18.2-directed therapies. He thanked patients, families, investigators, and study sites for their support.
Data from the dose escalation cohorts, presented at the European Society for Medical Oncology Gastrointestinal Cancers Congress (ESMO GI) 2025 in Barcelona, Spain, on July 2, 2025, showed an 83% objective response rate (ORR) with givastomig in combination with immunochemotherapy at the selected doses (8 mg/kg and 12 mg/kg). Response onset was rapid and durable, with favorable overall safety. I-Mab hosted a virtual investor event on July 8, 2025, to review the Phase 1b dose escalation data.
Givastomig (TJ033721 / ABL111) is a bispecific antibody targeting Claudin 18.2 (CLDN18.2)-positive tumor cells, conditionally activating T cells through the 4-1BB signaling pathway in the tumor microenvironment. It is being developed for first-line metastatic gastric cancers, with potential in other solid tumors. An ongoing Phase 1b study evaluates givastomig for gastric cancer treatment in combination with nivolumab and chemotherapy in dose escalation (n=17) and dose expansion (n=40) cohorts. Givastomig is being jointly developed with ABL Bio, with I-Mab as the lead party, sharing worldwide rights (excluding Greater China and South Korea) equally with ABL Bio.
Topline results are expected in Q1 2026.
Phillip Dennis, MD, PhD, is the Chief Medical Officer of I-Mab.
PJ Kelleher, LifeSci Advisors, +1-617-430-7579, pkelleher@lifesciadvisors.com
IR@imabbio.com
