Clinical-stage gene therapy company Genprex Inc (NASDAQ: GNPX) announced on Thursday that the first patient has been enrolled and dosed in the Phase 2 expansion portion of its Acclaim-3 clinical study of Reqorsa Gene Therapy (quaratusugene ozeplasmid) in combination with Tecentriq (atezolizumab) as maintenance therapy for patients with extensive stage small cell lung cancer (ES-SCLC).

The Phase 2 expansion will enrol 50 patients at approximately 10 to 15 US sites. Participants will be treated with REQORSA and Tecentriq until disease progression or unacceptable toxicity is experienced. The primary endpoint is to determine the 18-week progression-free survival rate from the time of the start of maintenance therapy with REQORSA and Tecentriq in patients with ES-SCLC. Patients will also be followed for survival.

A Phase 2 interim analysis will be performed after the 25th patient enrolled and treated reaches 18 weeks of follow up. The company expects to complete enrolment of the first 25 patients in the second half of 2025 for interim analysis.

The combination of REQORSA and Tecentriq previously received US Food and Drug Administration's (FDA) Fast Track Designation for treatment of the Acclaim-3 patient population, and the FDA has also granted Orphan Drug Designation to REQORSA for the treatment of SCLC.