I-Mab Completes Enrollment in Planned Phase 1b Dose Expansion Study for Givastomig in Combination with Immunochemotherapy in Patients with 1L Gastric Cancers

Core Viewpoint - I-Mab has successfully completed enrollment in the Phase 1b dose expansion cohorts for givastomig, a bispecific antibody targeting Claudin 18.2, ahead of expectations, indicating strong interest and unmet needs in gastric cancer therapy [1][3]. Group 1: Study Details - The Phase 1b study (NCT04900818) is focused on evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of givastomig in combination with nivolumab and mFOLFOX6 for CLDN18.2-positive gastric cancers [2]. - A total of 40 patients were enrolled in the dose expansion cohorts, with two doses being tested: 8 mg/kg and 12 mg/kg [2]. - The primary endpoint of the study is safety, and it exclusively enrolled patients in the U.S. [2]. Group 2: Clinical Data and Results - Data presented at the ESMO GI 2025 indicated an 83% objective response rate (ORR) for givastomig in combination with immunochemotherapy at the selected doses [3][8]. - The response onset was reported to be rapid, durable, and deepened over time, with favorable overall safety [3]. Group 3: Product Overview - Givastomig is a bispecific antibody designed to target Claudin 18.2-positive tumor cells and conditionally activate T cells through the 4-1BB signaling pathway [4][7]. - The drug is being developed for first-line metastatic gastric cancers, with potential applications in other solid tumors [4][7]. Group 4: Development Partnership - Givastomig is being developed through a global partnership with ABL Bio, where I-Mab is the lead party and shares worldwide rights, excluding Greater China and South Korea, equally with ABL Bio [6]. Group 5: Future Expectations - The company expects to release topline results from the Phase 1b study in Q1 2026, following the positive data from the dose escalation phase [8].