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May 22 (Reuters) - The U.S. Food and Drug Administration approved Regeneron Pharmaceuticals Inc and Sanofi SA's biotech drug for adults with moderate to severe rheumatoid arthritis, the two companies said on Monday.
The drug, sarilumab, which will be sold under the brand name Kevzara, will carry a list price of $39,000 per year for the 200 milligram and 150 mg doses, which the companies said was about 30 percent lower than the list price for the two most widely used rival medicines in the highly competitive space.
U.S. approval of the drug, seen as a key medicine for both companies looking to diversify their product portfolios, had been delayed by problems at a Sanofi manufacturing plant in France that have since been resolved.
Analysts on average expect Kevzara to reach annual sales of $1 billion by 2023, according to Thomson Reuters data.
The approval marks a second major regulatory victory for the two companies in recent weeks after their potential blockbuster treatment for severe atopic dermatitis, Dupixent, won U.S. approval in late March.
Regeneron is looking to reduce its reliance on the macular degeneration drug Eylea, while Sanofi is under pressure to diversify in order to offset declining sales of diabetes blockbuster Lantus.
About 1.3 million people in the United States alone suffer from rheumatoid arthritis. The disease category is able to support several multibillion-dollar drugs, led by AbbVie's Humira, the world's top selling prescription medicine.
Regeneron shares closed up 2.4 percent on Monday ahead of the FDA's approval. They rose another 0.8 percent to $462.22 in extended trading after the news become official.
Sarilumab, already approved in Canada, is expected to obtain European approval in the coming months.
It works by blocking a protein associated with inflammation called IL-6.
Rheumatoid arthritis is a chronic inflammatory autoimmune disease in which the immune system attacks the tissues of the joints, causing inflammation, pain, joint damage and disability. (Reporting by Matthais Blamont in Paris and Bill Berkrot in New York; Editing by Andrew Hay and Tom Brown)