Keymed Biosciences Inc. announced that the latest data from a Phase I clinical study of CMG901 (also known as AZD0901), a claudin 18.2 (CLDN18.2) targeted antibody-drug conjugate, in the treatment of advanced gastric/gastroesophageal junction (G/GEJ) cancer has been presented by way of oral presentation at the November 2023 session of the American Society of Clinical Oncology (ASCO) Plenary Series. The KYM901 trial (NCT04805307) was designed to evaluate the safety/tolerability, pharmacokinetics, immunogenicity, and preliminary efficacy of CMG901 in patients with advanced solid tumors. As of July 24, 2023, totally 113 patients with G/GEJ cancer received CMG901 at doses of 2.2, 2.6, and 3.0 mg/kg (n=44, 50, and 19, respectively).

All patients previously received 1 line of prior therapy. The median line of prior therapy was two. 74% of patients previously received PD-1/PD-L1 therapy.

In terms of safety, drug-related grade 3 treatment-emergent adverse events (TEAEs) occurred in 54% of patients, and drug-related serious AEs were reported in 31% of patients. 8% of patients had discontinued CMG901 treatment due to TEAEs. Among 89 evaluable patients with claudin 18.2-positive G/GEJ cancer in 2.2-3.0 mg/kg cohorts, confirmed objective response rate (ORR) and confirmed disease control rate (DCR) were 33% and 70%, respectively.

Among others, CMG901 showed a 42% confirmed ORR in 2.2 mg/kg dose cohort, with median progression free survival (mPFS) of 4.8 months, and the median overall survival (mOS) was not reached yet. In this trial, CMG901 had a manageable safety and tolerability profile, and most patients were well-managed by standard treatment management while continuing CMG901 treatment. CMG901 demonstrated promising efficacy in patients with advanced claudin 18.2-positive G/GEJ cancer.

CMG901 is a potential first-in-class claudin 18.2 targeted antibody conjugated to monomethyl auristatin E (MMAE) payload via a linker, currently being evaluated in a Phase 1 clinical study in advanced solid tumors (gastric and pancreatic). Claudin 18.2 is a promising therapeutic target for advanced G/GEJ cancer. In February 2023, KYM Biosciences Inc. (a 70% non-wholly owned subsidiary of the Group) entered into a global exclusive out-license agreement with AstraZeneca for CMG901.

Under the license agreement, AstraZeneca is responsible for the research, development, manufacture and commercialization of CMG901 (also known as AZD0901) globally.