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# FDA Orders New Warning on JAK Inhibitors
- URL: https://www.fdaweb.com/fda-orders-new-warning-on-jak-inhibitors/
- Published: 2021-09-01T12:00:00.000Z
- Updated: 2026-09-14T17:12:44.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5150056

FDA has [ordered](https://www.fda.gov/drugs/drug-safety-and-availability/fda-requires-warnings-about-increased-risk-serious-heart-related-events-cancer-blood-clots-and-death?utm%5Fmedium=email&utm%5Fsource=govdelivery) a drug class warning for Janus kinase (JAK) inhibitors after reviewing a recent clinical trial that showed an increased risk of serious heart-related events such as heart attack or stroke, cancer, blood clots, and death with Pfizer’s arthritis and ulcerative colitis medicines Xeljanz and Xeljanz XR (tofacitinib). The safety trial compared Xeljanz with tumor necrosis factor (TNF) blockers in patients with rheumatoid arthritis. The latest warning is part of FDA’s ongoing safety review of JAK inhibitors which caused review extensions for Eli Lilly/Incyte and Pfizer submissions ([see earlier story](https://www.fdaweb.com/jak-inhibitor-concerns-delay-lilly-pfizer-submissions/)).  

The class concerns arose from an FDA-required safety study when Xeljanz was approved in 2012 for rheumatoid arthritis. In [2/2019](https://www.fda.gov/drugs/drug-safety-and-availability/safety-trial-finds-risk-blood-clots-lungs-and-death-higher-dose-tofacitinib-xeljanz-xeljanz-xr?ref=fdaweb.com) and [7/2019](https://www.fda.gov/drugs/drug-safety-and-availability/fda-approves-boxed-warning-about-increased-risk-blood-clots-and-death-higher-dose-arthritis-and?ref=fdaweb.com), FDA warned that interim trial results showed an increased risk of blood clots and death with the 10 mg twice daily dosage, and as a result, it approved a *Boxed Warning.*   

FDA says it is also requiring new and updated warnings for two other arthritis medicines in the same class — Eli Lilly’s Olumiant (baricitinib) and AbbVie’s Rinvoq (upadacitinib). “Olumiant and Rinvoq have not been studied in trials similar to the large safety clinical trial with Xeljanz, so the risks have not been adequately evaluated,” the FDA safety notice says. “However, since they share mechanisms of action with Xeljanz, FDA considers that these medicines may have similar risks as seen in the Xeljanz safety trial.”