Work

Recurrent hypofibrinogenemia after reduced-dose tocilizumab rechallenge in rheumatoid arthritis: a case report

Year: 2026

Type: article

Abstract: Tocilizumab (TCZ), a monoclonal antibody targeting the interleukin-6 receptor, is widely used for the treatment of rheumatoid arthritis (RA) and other inflammatory diseases. Reductions in fibrinogen levels have been reported during TCZ treatment, and some patients develop hypofibrinogenemia. Clinical experience with TCZ re-exposure after such an event, particularly at a reduced dose, remains limited. We report a 76-year-old woman with RA whose disease remained inadequately controlled despite multiple antirheumatic therapies. On 24 April 2026, intravenous TCZ was reinitiated at 400 mg, with a pretreatment fibrinogen level of 3.29 g/L. Approximately 1 month later, fibrinogen had fallen to 0.85 g/L without clinically apparent bleeding. Further TCZ treatment was withheld, and 20 units of cryoprecipitate were administered. Fibrinogen initially increased to 1.99 g/L and subsequently returned to 2.07 g/L during the period without further TCZ exposure. Her RA subsequently became highly active again and remained inadequately controlled despite ongoing conventional antirheumatic treatment. After discussion of the previous adverse event and the potential risks of re-exposure, TCZ was restarted on 19 July 2026, at a reduced intravenous dose of 240 mg; the most recent fibrinogen level before re-exposure was 2.07 g/L. Her joint symptoms and inflammatory markers improved, but 17 days later fibrinogen again decreased to 1.05 g/L, without clinically evident bleeding. The temporal association with TCZ reinitiation in 2026, subsequent recovery during TCZ withdrawal, and recurrence after reduced-dose rechallenge support a probable association between TCZ and hypofibrinogenemia in this patient. This case shows that hypofibrinogenemia can recur despite substantial TCZ dose reduction in a patient with a previous TCZ-associated episode. If TCZ re-exposure is considered clinically necessary, closer monitoring of fibrinogen may be warranted.

Source: Frontiers in Pharmacology

DOI: 10.3389/fphar.2026.1981054

Authors: Yanbiao Li, Yuhe Yan, Hua Zhou, Eyan Fu, Mengyi Zheng

Institution: Shanxi Medical University

Language: English

Topic: Rheumatoid Arthritis Research and Therapies

Subfield: Rheumatology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,801