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Federal regulators approved Pfizer‘s new Xeljanz treatment for rheumatoid arthritis Tuesday. The potentially lucrative drug is now poised to enter a market that already features Humira, Abbott Laboratories‘ top-selling rheumatoid arthritis treatment.

The Food and Drug Administration approved Xeljanz for patients with moderate to severe rheumatoid arthritis who did not benefit from the oral treatment methotrexate. Xeljanz can be used with methotrexate and certain other treatments. Industry analysts have predicted the new drug, also known as tofacitinib, could grow to sales of $3 billion annually.

Xeljanz is taken in 5-milligram pills twice daily. Abbott’s $8 billion-a-year Humira requires an injection every two weeks. The FDA said it requires more safety data on a 10-milligram, twice-daily dose of Xeljanz that  Pfizer also submitted.

About 1.3 million people in the United States suffer from rheumatoid arthritis, which can cause problems in wounds healing.