Keymed Biosciences Inc. announced that the latest data from the Phase Ia dose-escalation trial of CMG901 for advanced solid tumors will be presented as a poster at the 2023. Gastrointestinal Cancers Symposium of the American Society of Clinical Oncology. Poster Title A Phase 1a dose-escalation, multicenter trial of anti-claudin 18.2 antibody drug conjugate CMG901 in patients with resistant/refractory solid tumors Abstract # 352 Poster Bd # E13 Abstract Presenter Rui-hua Xu, Department of Medical Oncology, Sun Yat-sen University Cancer Center This Phase Ia trial was designed to evaluate the safety, tolerability, pharmacokinetics, immunogenicity, and preliminary anti-tumor activity of CMG901 in patients with advanced solid tumors.

During the dose-escalation phase, Claudin 18.2 expression was retrospectively tested by the central lab. As of August 4, 2022, totally 27 patients were enrolled in the Phase Ia clinical study of CMG901. The results showed that CMG901 was well- tolerated with a favorable safety profile.

Drug-related grade >=3 adverse events occurred in 3/27 patients. No drug-related grade >=4 AEs were reported. Patients received CMG901 at dose levels up to 3.4 mg/kg, and maximum tolerated dose was not reached.

One patient in the 2.2 mg/kg cohort developed a dose-limiting toxicity. Preliminary efficacy results demonstrated that in the 8 Claudin 18.2-positive gastric/GEJ cancer patients receiving CMG901, objective response rate and disease control rate were 75.0% and 100%, respectively, with ORR of 100% in the 2.6, 3.0, and 3.4 mg/kg cohorts. Median progression free survival and median overall survival were not reached yet.

Proporortion with complete response+ partial response oportion with CR+PR+stable disisease and mPFS and mOS were not reached. CMG901 showed a favorable safety and tolerability profile in this trial. CMG901 at doses of >=1.8 mg/kg yielded encouraging anti-tumor activity in patients with Claudin 18.2-positive gastric/GEJ cancer.