Tofacitinib-induced eosinophilia.

Area of Science:

• Gastroenterology and Hepatology
• Pharmacology and Therapeutics
• Clinical Case Reports

Background:

• Tofacitinib is an approved oral JAK inhibitor for moderate to severe ulcerative colitis (UC).
• Its efficacy and safety are established in clinical trials and real-world data.
• This report details a patient with refractory left-sided UC, previously treated with infliximab, vedolizumab, and tacrolimus.

Observation:

• An 18-year-old female patient with UC experienced severe exacerbation and was initiated on tofacitinib.
• Within days, she developed peripheral eosinophilia and acute kidney injury (AKI) grade 1 KDIGO.
• Both eosinophilia and AKI resolved upon temporary tofacitinib suspension and recurred upon re-challenge.

Findings:

• Tofacitinib was identified as the likely cause of recurrent eosinophilia, a rare adverse effect not previously reported in UC patients.
• The patient achieved clinical remission with high-dose corticosteroids, ustekinumab, and tacrolimus after tofacitinib discontinuation.
• No eosinophilia recurrence was observed at three-month follow-up post-tofacitinib suspension.

Implications:

• This case highlights a rare adverse reaction (eosinophilia) to tofacitinib in UC management, necessitating vigilance.
• It underscores the importance of monitoring for potential toxicities, even with established drug safety profiles.
• Multidisciplinary discussion is crucial for managing complex UC cases refractory to multiple therapies.