NEW YORK – Chinese biotherapeutics company Transcenta said on Monday it dosed the first patient in a Phase I study of its TST001 with chemotherapy to treat gastric cancer that expresses the Claudin18.2 protein.
The trial is evaluating TST001 with the chemo combination capecitabine and oxaliplatin (CAPOX) as a first-line treatment for locally advanced unresectable or metastatic gastric cancer. TST001 targets cancer cells that overexpress the protein Claudin18.2, which is encoded by the CLDN18 gene. About 70 percent of gastric cancer patients express Claudin18.2, according to Transcenta Head of Global R&D and CMO Michael Shi.
The Phase I study will enroll up to 114 participants and consist of two parts. In the first part, participants will be split into two cohorts to determine dosage. In the second part, researchers will divide the participants into three cohorts of about 20 patients: participants with gastric and gastroesophageal junction cancers who are dosed every two weeks, participants with solid tumors except gastric and gastroesophageal cancers who will be dosed every two weeks, and participants with any solid tumors dosed every three weeks.
TST001 was developed using Transcenta's Immune Tolerance Breaking Technology drug discovery platform. The drug uses mechanisms like complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity to kill tumor cells.
"Preclinical studies have found that TST001 can not only efficiently kill gastric cancer cells with high expression of Claudin18.2, but also [can] be very effective against gastric cancer cells with moderate to high expression of Claudin18.2," Shi said in a statement, adding, "We hope to explore the safe tolerance and anti-tumor activity of TST001 combined with CAPOX in first-line gastric cancer patients through this study, so as to provide a basis for later registrational clinical studies."
In a preclinical study of TST001, it demonstrated more potent activity in mice compared to Astellas's zolbetuximab, another drug targeting Claudin18.2. Zolbetuximab is also being studied in gastric cancers in a Phase III trial.