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The FDA rejected Humanigen’s application for an emergency use authorization, but the race is on to develop an effective therapy for the cytokine storms that affect patients with COVID-19.
In patients with severe COVID-19 infection, a phenomenon called a cytokine storm is often the underlying reason for complications such as pneumonia and lung failure. Cytokine storms occur when a person’s body releases too many cytokines — a broad group of small proteins integral to the immune system — too quickly. The result is a hyperinflammatory response that may injure tissues in many parts of the body. As reports of the syndrome emerged at the beginning of the pandemic, drugmakers began combing through their drug portfolios, looking for possible treatments.
Physicians are treating hospitalized patients with COVID-19 with dexamethasone, a powerful steroid that quells inflammation, and remdesivir (the Gilead drug sold under the brand name Veklury). However, there’s a need for more effective treatment that could result in fewer patients needing mechanical ventilation and improve outcomes of severe cases of COVID-19. NRx Pharmaceuticals, which is based in Wilmington, Delaware, has an application pending for an EUA of its treatment that targets the cytokine IL-6. In July, the company shared more promising data about the treatment, Zyesami (aviptadil), that suggest it may prevent cytokine storm in patients with COVID-19.
Throughout the phase 2b/3 trial, patients receiving Zyesami did not have a large rise in cytokine level, whereas patients receiving placebo experienced a significant increase. The data showed the treatment yielded a survival benefit for patients, with a sizable drop in 60-day mortality from COVID-19.
Humanigen is a biotech company in Burlingame, California, that is focused on cytokine storm treatment. The company was dealt a setback in September when the FDA rejected its application for an emergency use authorization (EUA) for its leading product, lenzilumab. In a prepared statement, Cameron Durant, M.D., the company’s CEO, said it was committed to the drug. Before the FDA rejection, some analysts were projecting $1 billion in annual sales for lenzilumab.
Humanigen had shared data suggesting that the drug may be especially effective in Black patients, a group with a threefold increased risk of hospitalization and twofold increased risk of death from COVID-19. The company said that results from the phase 3 LIVE-AIR study showed that lenzilumab resulted in a ninefold increase of survival, without the need for ventilation, among Black patients with C-reactive protein levels less than 150 milligrams per/L. C-reactive protein is found in blood plasma and increases in response to inflammation. Across all patients in the study, lenzilumab yielded a more than twofold increased chance of survival without the need for ventilation, which was the basis for the company’s application for an EUA.
Meanwhile, researchers at I-Mab Biopharma, a biotech company based in China, announced positive results for plonmarlimab, which targets the same cytokines as lenzilumab. Results from a phase 2/3 study showed that plonmarlimab reduced the number of patients needing mechanical ventilation compared with placebo and also lowered death rates (4.9% versus 13.3%).
Jaime Rosenberg is a freelance writer based in Jersey City, New Jersey.