The US Food and Drug Administration (FDA) has granted fast track designation (FTD) to Genprex’s lead drug candidate, Reqorsa Immunogene Therapy, plus Keytruda to treat histologically confirmed unresectable stage III or IV non-small cell lung cancer (NSCLC).

The combination treatment is intended for use in NSCLC patients whose disease advanced on receiving Keytruda treatment.

Keytruda is a checkpoint inhibitor of Merck & Co’s (MSD).

Genprex anticipates commencing a multicentre, open-label Phase I/II Acclaim-2 clinical trial of Reqorsa plus Keytruda to treat NSCLC in the first quarter of this year.

This is the second FTD granted by the FDA for Reqorsa.

The first status was granted for Reqorsa plus AstraZeneca’s Tagrisso to treat histologically confirmed unresectable stage III or IV NSCLC patients with EGFR mutations that advanced on receiving Tagrisso.

According to the preclinical data, Reqorsa plus Keytruda demonstrated to be efficient over treatment with Keytruda alone to boost survival in mice with a humanised immune system having metastatic lung tumours.

The drug’s multiple impacts on the immune system such as a rise in natural killer cells and a reduction in PD-L1 expression on cancer cells were observed in these mice studies.

This is believed to add to the synergy of Reqorsa seen with Keytruda.

Genprex president and CEO Rodney Varner said: “This Fast Track Designation is an important step in our efforts to accelerate clinical development of Reqorsa and another validation of the potential of Reqorsa to treat the unmet medical need of patients with late-stage NSCLC.

The company noted that it is positioned to progress the Acclaim-1 and Acclaim-2 trials this year with a $42m balance sheet in cash as of the third quarter ended last year and specialised trial management.

In September, Merck reported that Keytruda (pembrolizumab) met the primary goal of overall survival in the Phase III KEYNOTE-394 trial in Asian patients with advanced hepatocellular carcinoma.