US-based gene therapy company Genprex has enrolled and dosed the first subject in a Phase I/II trial to assess a combination therapy for extensive-stage small cell lung cancer (ES-SCLC).

The Acclaim-3 trial aims to determine the safety and optimal dosage of Reqorsa (quaratusugene ozeplasmid) Immunogene Therapy when given in combination with Genentech’s Tecentriq.

The open-label dose escalation and clinical response study is enrolling patients who have not experienced tumour progression following initial treatment with Tecentriq and chemotherapy.

Its first phase aims to enrol up to 12 subjects across roughly ten clinical sites in the US to identify the maximum tolerated dose.

Should the Phase I study proceed without dose-limiting toxicities, the highest dose tested will be the recommended Phase II dose.

The Phase II portion is anticipated to involve around 50 patients at up to 15 US locations.

Treatment with Reqorsa and Tecentriq will continue until disease progression or unacceptable toxicity occurs.

Genprex plans to begin the Phase II expansion study in the second half of this year.

A futility analysis is scheduled for after the 25th participant reaches an 18-week follow-up period.

Reqorsa has received orphan drug designation and fast track status from the US Food and Drug Administration (FDA) for use in combination with Tecentriq in ES-SCLC patients whose disease has not progressed after initial standard treatment.

Genprex chief medical officer Mark Berger said: “The Phase I dose escalation portion of the Acclaim-3 study is expected to determine the maximum tolerated dose for the Phase II expansion study.

“The favourable results from our Phase I Acclaim-1 study in non-small cell lung cancer enabled us to shorten the Phase I portion of Acclaim-3.

“This should allow us to complete the Phase I portion of the study during the second half of 2024 and to advance more quickly into the Phase II expansion portion of Acclaim-3 in the second half of 2024.”