Humanigen said Thursday that the FDA declined a request for emergency-use authorisation (EUA) of lenzilumab to treat newly hospitalised COVID-19 patients, sending the company's shares down as much as 60%. Chief executive Cameron Durrant remarked "we remain committed" to the antibody, which binds to and neutralises GM-CSF.
The application was based on findings of the Phase III LIVE-AIR study, which the company announced in March had achieved its primary endpoint. Results showed that the therapy improved the chances of hospitalised adults with COVID-19 surviving without the need for invasive mechanical ventilation by 54%, compared to placebo and other treatments. At the time, the company also noted that there was a "favourable trend" in terms of overall survival, although the trial was not powered to demonstrate a difference in mortality.
According to Humanigen, the FDA determined that it was unable to conclude that the known and potential benefits of lenzilumab outweigh the known and potential risks of its use as a treatment for COVID-19. The agency called for the drugmaker to submit additional data as it becomes available.
"We believe the ongoing ACTIV-5/BET-B trial, which has been advanced to enrol up to 500 patients, may provide additional safety and efficacy data sufficient to support our efforts to obtain an EUA to treat hospitalised COVID-19 patients," noted Durrant. In July, ACTIV-5/BET-B, which is being funded by the US National Institutes of Health, advanced from a Phase II to a Phase II/III study, while the primary endpoint was modified to survival without ventilation, similar to that in LIVE-AIR.
Meanwhile, a marketing submission for lenzilumab has been accepted for accelerated review by the UK's Medicines and Healthcare Products Regulatory Agency.
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