NIH Study Unable to Confirm Benefit of Humanigen’s Lenzilumab in COVID-19

Courtesy of Humanigen, Inc.

Shares of New Jersey-based Humanigen are crashing Wednesday morning after the company announced that a trial assessing a combination of its experimental therapeutic lenzilumab and Gilead Sciences’ remdesivir as a potential treatment for COVID-19 failed to achieve statistical significance in its primary endpoint.

The combination therapy was being evaluated in the ACTIV-5/BET-B trial conducted by the National Institutes of Health. The combination of lenzilumab and remdesivir was being compared to remdesivir plus placebo in hospitalized COVID-19 patients. The primary endpoint of the study was defined as the number of hospitalized patients under the age of 85 with baseline CRP who remained alive and without the need for mechanical ventilation after 29 days of treatment.

Humanigen said the data from the study showed a “non-significant trend toward a reduction in mortality in the overall patient population.” There were no new safety signals attributed to lenzilumab in the ACTIV-5/BET-B study.

As could be expected, Humanigen shareholders reacted negatively to the announcement and began dumping the stock. Shares of Humanigen were down nearly 66% in premarket trading to under $1. The stock closed at $2.99 per share on Tuesday.

Cameron Durrant, chairman and CEO of Humanigen, expressed his disappointment in the trial results. He said the NIH-sponsored study was not able to confirm the positive results the company reported in its Phase III LIVE-AIR study. Data from that study, which was included in a failed attempt to secure Emergency Use Authorization from the U.S. Food and Drug Administration last year, showed that newly hospitalized COVID-19 patients treated with lenzilumab and remdesivir saw a 54% improvement in the likelihood of survival without ventilation.

Although the data was seen as positive, the FDA said it was unable to determine if the use of lenzilumab in COVID patients outweighed the known and potential safety risks. The company had hoped the NIH study would provide the necessary data the FDA requested in its rejection.

Although the NIH was unable to replicate the results seen in LIVE-AIR, Durrant suggested additional studies need to be conducted in order to “prove the therapeutic benefits” of immunomodulators.

“With the continued resurgence of COVID-19, further exploration of variant agnostic treatments to improve outcomes in hospitalized COVID-19 patients should be a priority,” he said in a statement.

Lenzilumab has been evaluated as a potential treatment for the hyper-immune response seen in some COVID-19 patients known as the cytokine storm. This phenomenon occurs when a significant amount of inflammatory cytokines are produced by the body at an exceedingly high rate. Those cytokines can ultimately attack healthy tissue and organs.

Prior to the pandemic, Humanigen had been studying lenzilumab as a treatment for cancer patients who receive CAR-T cell therapies, since the cytokine storm is one of the potential side effects of that treatment.