Therapex, a Korean anticancer drug developer, said on Monday it initiated dosing of the first patient in the local phase 1 clinical trial of TRX-221, an antitumor drug targeting EGFR-mutated non-small cell lung cancer (NSCLC), at Samsung Medical Center in Seoul.

Under an IND approved by the U.S. FDA, Therapex is exploring the safety and efficacy of TRX-221 in 115 patients with EGFR-mutated NSCLC whose disease has progressed after receiving one or more of the existing EGFR inhibitors.

The phase 1/2 clinical trial of TRX-221 will be conducted in three phases. The phase-1a dose-escalation study will evaluate the safety and tolerability of the drug through stepwise dose escalation, while the phase-1b dose exploration will determine the maximum tolerated dose or recommended population dose (RP2D) for the phase 2 trial. Finally, the phase 2 study will evaluate TRX-221’s objective response rate (ORR) based on solid cancer endpoints and explore any adverse events caused by the drug.

"To accelerate the clinical trial, the phase 1 dose escalation will be conducted at six hospitals in Korea, including Samsung Medical Center, and from the dose exploration phase, we plan to conduct a global clinical trial, including the U.S., to expand patient recruitment," Therapex said.

TRX-221 is a fourth-generation EGFR tyrosine phosphatase inhibitor that selectively inhibits EGFR C797S, the primary mutation responsible for resistance to the EGFR-mutated NSCLC drug Tagrisso. 

As a broad-spectrum inhibitor that inhibits a single EGFR variant, as well as the T790M variant caused by first- and second-generation therapies, TRX-221 has demonstrated in preclinical trials the potential to expand AstraZeneca's Tagrisso market, which was valued at approximately 8 trillion won (about $6 billion) in annual sales last year.

"With no clinically successful fourth-generation EGFR therapies available, there is a growing unmet medical need for NSCLC therapies, and we are pleased to announce the first patient dose of TRX-221," said Lee Koo, CEO of Therapex. 

"We are committed to rapidly advancing our clinical trials to bring new treatment options to patients with advanced NSCLC as soon as possible."