Another attempt to repurpose an existing drug into a COVID-19 treatment has failed. In a phase 3 study with 420 severely ill COVID-19 patients, adding an anti-inflammation drug called Kevzara to standard hospital care didn't produce any significant benefits. 

Kevzara from the partners Sanofi (NASDAQ:SNY) and Regeneron (NASDAQ:REGN) is an interleukin 6 (IL-6) inhibitor approved by the FDA to treat rheumatoid arthritis patients. It's almost always a bad idea to suppress an immune system when it's trying to fight COVID-19 or any infection, except in extreme cases when that immune system enters a lethal hyperinflammatory state.

A lab technician with a pipette and pink liquid.

Image source: Getty Images.

Kevzara isn't the first IL-6 that has failed to provide a mortality benefit for severe COVID-19 patients. In July, Actemra, an IL-6 drug from Roche (OTC:RHHBY), failed to improve patients' clinical status or prevent their deaths.

Fortunately, a widely available option has been proven capable where pricey IL-6 treatments have failed. Dexamethasone, a decades-old steroid has been shown to reduce the risk of death by 35% for ventilated COVID-19 patients.

Regeneron isn't pursuing Kevzara as a treatment for COVID-19 anymore, but the biotech isn't finished addressing the pandemic. At the moment, the company is running three pivotal studies with an experimental antibody cocktail tentatively named REGN-COV2.

Regeneron developed REGN-COV2 to mimic a pair of antibodies human immune systems produce in response to SARS-CoV-2, the virus that causes COVID-19. This is an approach that worked with REGN-EB3, an antibody cocktail that significantly reduced the risk of death from the Ebola virus in 2019.

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