Sanofi said the rheumatoid arthritis medicine Kevzara failed to work against the new coronavirus, joining a growing list of treatments that were tried and discarded in the pandemic.

The drug, which stoked hope against COVID-19 because it works on inflammation, didn’t significantly shorten patients’ hospital stays in a study involving 420 people, Sanofi said in a statement Tuesday. Patients were about as likely to develop severe infections such as pneumonia and die on Kevzara as they were on a placebo.

Doctors and drugmakers are scouring labs for existing treatments -- from antiviral drugs to plasma from recovered patients -- that can help people survive the new coronavirus and subjecting them to stringent clinical tests. Among those that have failed are the malaria medicines chloroquine and hydroxychloroquine and Roche Holding AG’s Actemra.

Sanofi Chief Executive Officer Paul Hudson had said Kevzara was a “long shot” for COVID-19. The shares traded 0.6% higher early Tuesday in Paris.

The existing-treatment approach has unearthed some promising data. Gilead Sciences Inc.’s antiviral remdesivir and dexamethasone, a cheap corticosteroid used for rheumatism and asthma, both helped patients in tests. Doctors are also routinely administering heparin and other anticoagulants to prevent dangerous blood clots from forming in the veins of the critically ill.

Regeneron Pharmaceuticals Inc., Sanofi’s partner on Kevzara, is testing an antibody drug cocktail it’s developed specifically for COVID-19.