Pfizer's arthritis drug Xeljanz shows lifesaving benefits in hospitalized COVID-19 patients

Nurse and patient
Pfizer's rheumatoid arthritis drug Xeljanz showed it could reduce the risk of death or respiratory failure among hospitalized COVID-19 patients who didn't require ventilation. (Getty/FG Trade)

Pfizer’s BioNTech-partnered COVID-19 vaccine Comirnaty may be getting all the attention these days, but the pharma giant’s anti-inflammatory drug Xeljanz just chalked up a win in treating patients hospitalized with the disease.

Xeljanz reduced the risk of death or respiratory failure among hospitalized patients with COVID-19 pneumonia who didn’t require ventilation, according to data published in The New England Journal of Medicine.

 The company is now analyzing the full dataset and will assess the next steps, Tamas Koncz, M.D., Ph.D., chief medical officer of Pfizer Inflammation & Immunology, said in a statement Wednesday.

The data come from the STOP-COVID study, which enrolled 289 hospitalized patients across 15 sites in Brazil. After 28 days of treatment, death or respiratory failure had occurred in 18.1% of patients on Xeljanz, compared with 29% for those who received placebo. All patients also received other standard-of-care treatments, including corticosteroids, which were given to nearly 90% of patients in both trial arms.

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Xeljanz, a JAK inhibitor, is currently approved in the U.S. for inflammatory diseases including rheumatoid arthritis, psoriatic arthritis and ulcerative colitis. The idea behind STOP-COVID is that JAK inhibition could reduce the release of cytokines, which can cause serious inflammation-driven lung injury or even death in hospitalized COVID-19 patients.

Before Xeljanz’s win, Incyte and Novartis’ JAK inhibitor Jakafi narrowly failed to significantly reduce the risk of death among patients on mechanical ventilation through 29 days of treatment in a separate trial. In U.S. patients, who made up 91% of that study, Jakafi demonstrated what Incyte called a “clinically and statistically significant” improvement in death.

In the Xeljanz study, 2.8% of patients who got the Pfizer drug had died through day 28, compared with 5.5% for the placebo.

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Meanwhile, Pfizer’s Xeljanz faces safety questions after a postmarketing study flagged heart risks. The FDA, under the impression that it’s a class-wide problem, has recently delayed decisions on multiple JAK drugs in various indications.

Because of that safety concern, the STOP-COVID trial excluded patients with a known history of blood clots. All told, investigators recorded four specific heart-related side effects of interest in the Xeljanz group. Hemorrhagic stroke and cardiogenic shock happened in one patient each in the placebo group.