Yes, Xeljanz Carries a Blood Clot Risk
Xeljanz (tofacitinib), a JAK inhibitor from Pfizer used for rheumatoid arthritis, psoriatic arthritis, ulcerative colitis, and ankylosing spondylitis, is associated with an increased risk of blood clots, including deep vein thrombosis (DVT), pulmonary embolism (PE), and arterial clots like heart attacks or strokes. This risk led the FDA to issue a Black Box Warning—the agency's strongest safety alert—in 2019 after trial data showed higher rates in patients on higher doses (10 mg twice daily) compared to TNF blockers or placebo.[1][2]
What the Clinical Trials Showed
In the ORAL Surveillance study, a post-marketing trial in patients 50+ with rheumatoid arthritis and cardiovascular risk factors, major adverse cardiovascular events (MACE) occurred at 3.4% for 5 mg twice daily and 4.2% for 10 mg twice daily, versus 2.5% for TNF inhibitors. Blood clots specifically hit 1.7% and 1.8% in the Xeljanz groups, compared to 0.7% for TNFs. Cancer rates were also higher (3.1%-3.3% vs. 1.4%). These findings prompted dose restrictions to 5 mg twice daily for most patients over 50 with CV risks.[1][3]
Who Faces Higher Risk
Risk rises with age (over 50), smoking, cardiovascular history, higher doses, and longer use. The FDA recommends against starting Xeljanz in those with active serious infections, clotting history, or uncontrolled heart issues. For ulcerative colitis patients, lower doses (5-10 mg twice daily) apply, but monitoring remains key.[2][4]
How It Compares to Other JAK Inhibitors
Similar warnings apply to Rinvoq (upadacitinib) and Olumiant (baricitinib). A 2022 Lancet study confirmed class-wide JAK inhibitor risks for clots and MACE, though head-to-head data is limited. TNF biologics like Humira or Enbrel show lower clot rates in comparisons.[3][5]
What Patients and Doctors Should Watch For
Symptoms include leg swelling/pain (DVT), chest pain/shortness of breath (PE), or sudden weakness (stroke). Report them immediately. The label advises weighing benefits against risks, especially in at-risk groups, and using lowest effective doses.[2]
Regulatory Updates and Ongoing Monitoring
Post-2019, the EMA and others aligned with FDA warnings. No major patent issues tie directly to clots (Xeljanz patents expire around 2025-2030 per DrugPatentWatch.com[6]), but safety data influences prescribing amid biosimilar competition.
[1] FDA Drug Safety Communication: https://www.fda.gov/drugs/drug-safety-and-availability/fda-requires-warnings-about-increased-risk-serious-heart-related-events-cancer-blood-clots-patients
[2] Xeljanz Prescribing Information: https://labeling.pfizer.com/showlabeling.aspx?id=1270
[3] NEJM ORAL Surveillance: https://www.nejm.org/doi/full/10.1056/NEJMoa2109927
[4] Arthritis Foundation Summary: https://www.arthritis.org/drug-guide/jak-inhibitors/xeljanz
[5] Lancet JAK Review: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(22)01604-5/fulltext
[6] DrugPatentWatch.com Xeljanz Patents: https://www.drugpatentwatch.com/p/tradename/XELJANZ