Humanigen, a clinical-stage biopharmaceutical company, announced on Thursday, Sept. 9, that the U.S. Food and Drug Administration (FDA) had rejected its request for emergency use authorization of its COVID-19 drug named Lenzilumab to treat newly hospitalized patients. 

The California-based company, focusing on preventing and treating an immune hyper-response called “cytokine storm,” had requested the FDA to hand out the Emergency Use Authorization (EUA) for Lenzilumab, which it believes could help treat newly hospitalized COVID-19 patients.

However, the FDA denied the request, asking Humanigen to “submit additional data as it becomes available,” Fierce Biotech reported.

“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 FDA told Humanigen in a letter.

Humanigen said it remains committed to completing regulatory processes underway, seeking Marketing Authorization for Lenzilumab to treat hospitalized COVID-19 patients in the U.K. and other territories.

“We remain committed to bringing Lenzilumab to patients hospitalized with COVID-19,” said Humanigen Chief Executive Officer Cameron Durrant.

“We believe the ongoing ACTIV-5/BET-B trial, which has been advanced to enroll up to 500 patients, may provide additional safety and efficacy data sufficient to support our efforts to obtain an EUA to treat hospitalized COVID-19 patients,” he added.

Lenzilumab targets GM-CSF, a cytokine associated with adverse outcomes in COVID-19 patients. By neutralizing the cytokine, drug developers including Humanigen and GlaxoSmithKline have predicted that they may be able to counter life-threatening complications that arise when the immune system reacts particularly strongly to the virus, according to Fierce Biotech.

Recent data from phase 3 has shown Lenzilumab in hospitalized COVID-19 patients met its primary endpoint.

Analysts at Jefferies have previously anticipated that Humanigen, formerly KaloBios and once run by the imprisoned “Pharma Bro” Martin Shkreli, would likely win an Emergency Use Authorization.