Gilead shares slide after FDA knocks back rheumatoid arthritis drug

(Reuters) – Shares of Gilead Sciences fell 3% after the U.S. Food and Drug Administration declined to approve its experimental rheumatoid arthritis treatment, a major setback for one of the drugmaker’s important products.

Gilead’s antiviral medicine remdesivir has put the company at the forefront of the fight against the COVID-19 pandemic, sending its shares soaring, but analysts said the FDA move could cost it millions in delayed sales while it fights to get the drug approved.

Last year, Gilead invested $5.1 billion in a major expansion of its partnership with Belgo-Dutch biotech Galapagos NV , banking on the potential of filgotinib and other drugs in development. Shares of Gilead were down 3% at $66.83 in Wednesday morning trade, while U.S. shares of Galapagos were down 27%.

In its complete response letter, the FDA expressed concerns regarding the overall benefit/risk profile of the 200 mg dose of the treatment and asked for additional data from ongoing studies before completing its review, according to Gilead.

J.P. Morgan analyst Cory Kasimov, who had forecast $2 billion in annual peak sales for the drug, said the request for data could delay any potential approval by at least a year, while “the potential lack of dosing flexibility” could hurt the drug’s competitive profile.

“There is no simple fix to these complex issues, putting the entire filgotinib program (rheumatoid arthritis and beyond) at risk,” Credit Suisse analyst Evan Seigerman said in a note.

Filgotinib belongs to a class of oral drugs called JAK inhibitors which target a range of autoimmune diseases and include AbbVie’s Rinvoq and Eli Lilly’s Olumiant as well as Pfizer’s experimental drug abrocitinib.

The oral JAK inhibitor class of molecules has produced robust efficacy results in immune and inflammatory disorders but risk/benefit profiles of these molecules have been a constant overhang due to safety and tolerability concerns, Guggenheim analysts said in a note.

(Reporting by Trisha Roy and Ankur Banerjee in Bengaluru; editing by Lewis Krauskopf and Maju Samuel)