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. 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. 10 stocks we like better than SanofiWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Sanofi wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of August 1, 2020 Cory Renauer has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source