The regulatory pathways for Janus kinase (JAK) inhibitors represent one of the most prominent examples of safety-labeling divergence between the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). While both agencies initiated safety reviews following the landmark ORAL Surveillance trial, they reached different conclusions on how to manage these risks in clinical practice.
This divergence has significant implications for market access, physician prescribing habits, and commercial lifecycle management across the United States and Europe.
Short Answer
Following the safety signals from the ORAL Surveillance trial (which showed increased risk of major adverse cardiovascular events [MACE], thrombosis, malignancy, and death with tofacitinib relative to TNF blockers), both the FDA and EMA implemented class-wide safety measures. In the United States, the FDA applied a class-wide Boxed Warning in September 2021 to all JAK inhibitors approved for inflammatory conditions, and simultaneously limited all approved uses to patients who had an inadequate response to, or could not tolerate, one or more TNF blockers. In Europe, the EMA’s Pharmacovigilance Risk Assessment Committee (PRAC) took a structurally different approach in November 2022. Rather than a blanket TNF-prior-failure requirement, it imposed class-wide restrictions targeting specific high-risk cohorts: JAK inhibitors should only be used in patients aged 65+, active/long-time smokers, or those at increased risk of major cardiovascular events or malignancy if no suitable treatment alternatives are available. Furthermore, the two regions diverged structurally on filgotinib (Jyseleca), which is centrally approved in Europe but was rejected and abandoned in the U.S. due to FDA safety concerns.
Who This Is For
This regulatory analysis is designed for clinical development planners, safety and pharmacovigilance teams, and global market access directors navigating label negotiations and reimbursement criteria across the US and EU markets.
Janus Kinase (JAK) Inhibitor Approvals and Status
The EMA human medicines database and FDA records document the following approved JAK inhibitors and their divergent regulatory status:
| Brand Name | Active Substance | EMA Approval Status | U.S. FDA Approval Status | Notable Divergence / Key Indications |
|---|---|---|---|---|
| Xeljanz | Tofacitinib | Centrally Approved (2017) | Approved (2012) | Rheumatoid arthritis, psoriatic arthritis, ulcerative colitis |
| Olumiant | Baricitinib | Centrally Approved (2017) | Approved (2018) | Rheumatoid arthritis, atopic dermatitis, alopecia areata |
| Rinvoq | Upadacitinib | Centrally Approved (2019) | Approved (2019) | Rheumatoid arthritis, Crohn's, ulcerative colitis, atopic dermatitis |
| Cibinqo | Abrocitinib | Centrally Approved (2021) | Approved (2022) | Moderate-to-severe atopic dermatitis |
| Jyseleca | Filgotinib maleate | Centrally Approved (2020) | Not Approved (CRL in 2020) | Approved in EU for RA and UC; development abandoned in the U.S. |
Comparative Regulatory Analysis
1. The Catalyst: ORAL Surveillance
The regulatory reassessment of the JAK class was triggered by ORAL Surveillance (NCT02092467), a post-marketing safety study required by the FDA for tofacitinib (Xeljanz). The trial evaluated patients with active rheumatoid arthritis (RA) aged 50 and older with at least one cardiovascular risk factor, comparing tofacitinib (5 mg and 10 mg twice daily) against a TNF inhibitor (adalimumab or etanercept).
The study failed to demonstrate non-inferiority for its primary co-endpoints, showing statistically significant increases in:
- MACE: Hazard Ratio (HR) of 1.24 for the 5 mg dose and 1.43 for the 10 mg dose (1.33 for the combined tofacitinib doses).
- Malignancy (excluding NMSC): HR of 1.47 for 5 mg and 1.48 for 10 mg.
- Thrombosis (VTE/PE): HR of 1.66 for 5 mg and 3.52 for 10 mg.
- All-Cause Mortality: HR of 1.49 for 5 mg and 2.37 for 10 mg.
2. The US FDA Response: Boxed Warnings
In September 2021, the FDA required class-wide Boxed Warnings for the three JAK inhibitors approved for inflammatory conditions at the time: Xeljanz, Olumiant, and Rinvoq. The FDA subsequently applied the same Boxed Warning to abrocitinib (Cibinqo) and ritlecitinib (Litfulo) upon their approvals.
The FDA’s approach was characterized by two principles:
- Class Effect Assumption: The FDA applied the warnings class-wide, concluding that since baricitinib and upadacitinib share a similar mechanism of action, they could carry similar risks even without dedicated head-to-head safety data.
- Indication Restriction (TNF-Prior-Failure): The FDA paired the Boxed Warning with a label limitation, restricting all approved JAK inhibitor uses to patients who have had an inadequate response to, or cannot tolerate, one or more TNF blockers. For rheumatology and gastroenterology indications this functionally repositioned the entire class as a post-TNF option; U.S. commercial payers then encoded that label limitation directly into step-therapy criteria. (Atopic dermatitis and alopecia areata, which are not treated with TNF blockers, sit on a different sequencing ladder, but the Boxed Warning still applies.)
3. The EMA Response: Annex II Restrictions
In Europe, the EMA’s PRAC concluded its safety review of JAK inhibitors in November 2022. While the EMA agreed that the safety risks represented a class effect, its regulatory response was structurally different:
- "Alternative-Restricted" Mandate: The EMA added clinical restrictions stating that JAK inhibitors should only be used in patients aged 65+, active/long-time smokers, or those at high risk for MACE or malignancy if no suitable treatment alternatives are available. This positioned the class behind other systemic options specifically for these high-risk cohorts, rather than imposing a blanket TNF-prior-failure rule on every patient.
- Dose Minimization: The EMA recommended using the lowest effective dose, especially in patients with risk factors for thrombosis.
- Indication-Universal Scope: The referral covered every approved chronic-inflammatory indication — rheumatoid arthritis, psoriatic arthritis, juvenile idiopathic arthritis, axial spondyloarthritis, ulcerative colitis, atopic dermatitis, and alopecia areata — so the restrictions reach dermatology and AA use as well, even though the practical "no suitable alternatives" calculus differs because TNF blockers are not standard therapy for those conditions.
4. The Filgotinib (Jyseleca) Divergence Case Study
The most significant regional divergence in the JAK inhibitor class involves filgotinib (Jyseleca). Filgotinib is a highly selective JAK1 inhibitor developed by Galapagos and Gilead Sciences.
- Europe: The EMA approved Jyseleca on September 24, 2020 for moderate-to-severe active rheumatoid arthritis and later expanded the label to ulcerative colitis. In late 2023, Galapagos signed a letter of intent to transfer the European Jyseleca business to Alfasigma, with the transaction closing in early 2024.
- United States: In August 2020, the FDA issued a Complete Response Letter (CRL) for filgotinib. The FDA expressed concerns over the safety of the 200 mg dose and requested data from two ongoing trials (MANTA and MANTA-RAy) evaluating the drug's impact on sperm parameters and testicular toxicity (which had been flagged in preclinical animal models). Following the CRL, Gilead abandoned U.S. development, and filgotinib was never launched in the U.S. market.
Strategic Market Access Considerations
For global pharmaceutical manufacturers, the US and EU safety profiles create divergent market access pathways:
- In the U.S., market access is governed by payer-enforced step therapy. Payers routinely require patients to try and fail one or two TNF inhibitors (like Humira or Enbrel) before approving Rinvoq or Xeljanz, citing the FDA's class-wide safety warnings as clinical justification.
- In Europe, market access is governed by national health authority guidelines that incorporate the EMA's alternative-restricted criteria. Prescribing registries and national health insurance systems actively monitor patient age and cardiovascular risk factors to enforce compliance with the PRAC recommendations.
Sources
- EMA human medicines database, Jyseleca (EMA/H/C/005113), Rinvoq (EMA/H/C/004953), Olumiant (EMA/H/C/004085), Cibinqo (EMA/H/C/005481), and Xeljanz (EMA/H/C/004212) product information and procedure histories. https://www.ema.europa.eu/en/medicines/
- EMA, "EMA confirms recommendations on minimizing risk of serious side effects with Janus kinase inhibitors," November 11, 2022. https://www.ema.europa.eu/en/news/ema-confirms-recommendations-minimizing-risk-serious-side-effects-janus-kinase-inhibitors
- FDA Drug Safety Communication, "FDA requires warnings about increased risk of serious heart-related events, cancer, blood clots, and death for JAK inhibitors," September 1, 2021. https://www.fda.gov/drugs/drug-safety-and-availability/fda-requires-warnings-about-increased-risk-serious-heart-related-events-cancer-blood-clots-and
- Ytterberg SR, et al., "Cardiovascular and Cancer Risk with Tofacitinib in Rheumatoid Arthritis" (ORAL Surveillance primary outcomes), New England Journal of Medicine, 2022; 386(4):316-326. https://www.nejm.org/doi/full/10.1056/NEJMoa2109927
Disclaimer: This article provides independent regulatory and market access analysis for biopharma professionals and does not constitute clinical or medical advice.
