Transcenta Holding Ltd (HKG: 6628), a China-based biopharmaceutical company, has presented progression-free survival (PFS) data based on CLDN18.2 expression levels from a Phase I/II study of osemitamab (TST001) in combination with capecitabine and oxaliplatin (CAPOX) as a first-line treatment for advanced gastric/gastroesophageal junction (GC/GEJ) carcinoma at the ESMO World Congress on Gastrointestinal Cancer 2023. The positive data supports the initiation of a global Phase III pivotal trial, scheduled for the second half of 2023.
Phase I/II Study Results and Efficacy
The efficacy and safety of osemitamab (TST001) plus the chemotherapy regimen (CAPOX) as a first-line treatment for patients with advanced GC/GEJ cancer were explored in a dose escalation and expansion Phase I/II study in China (Cohort C of TranStar102, NCT04495296). Among the 49 patients who received a 6mg/kg dose during the dose extension phase, 42 had measurable lesions and underwent at least one post-treatment tumor evaluation, with 28 patients (66.7%) achieving partial response (PR). As of the April 21, 2023, cut-off date, 26 out of 64 patients had progressive disease or death, resulting in an estimated median PFS of 9.5 months. Notably, there was no clear trend between PFS and CLDN18.2 expression levels.
Osemitamab (TST001) Profile and Clinical Progress
Osemitamab (TST001) is a high-affinity humanized anti-CLDN18.2 monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC). The drug is currently under multiple clinical studies in the US and China. It has been granted Orphan Drug Designation from the US FDA for the treatment of patients with GC/GEJ and pancreatic cancer, highlighting its potential as a valuable therapy for these patient populations.-Fineline Info & Tech
