IL-17 inhibitors raised candidiasis risk; TNF inhibitors carried most TB and meningitis

Design

Nationwide registry cohort with doubly robust comparison

Population

18,635 adults with psoriasis on systemic treatment, 118,018 person-years (BADBIR)

Primary outcome

Tuberculosis, meningitis, candidiasis and other fungal infections

Effect

Candidiasis IRR 2.67 (95% CI 1.33 to 5.36) to 4.65 (3.46 to 6.24) for IL-17 inhibitors vs other systemics

This nationwide cohort used the British Association of Dermatologists Biologic and Immunomodulators Register from 2007 to 2024: 18,635 adults with psoriasis, 40,930 treatment episodes and 118,018 person-years of follow-up. Statistical balancing aimed to make treatment groups comparable.

Tuberculosis (22 cases, 0.19 per 1,000 person-years) and meningitis (29 cases, 0.25 per 1,000 person-years) were rare. Most were in people on TNF inhibitors, particularly adalimumab; meningitis was mostly viral and TB mostly pulmonary. Fungal infections were far more common (888 cases, 7.5 per 1,000 person-years), including 450 cases of candidiasis. IL-17 inhibitors carried a higher candidiasis risk than every other treatment group, with rate ratios from 2.67 (95% CI 1.33 to 5.36) against apremilast to 4.65 (95% CI 3.46 to 6.24) against IL-12/23 inhibitors. Individual IL-17 inhibitors did not differ, and other fungal infections did not differ between groups.

For India the TB result needs translating: background TB incidence is many times that of the UK, so the absolute risk on TNF inhibitors will be much higher here. That strengthens the case for latent TB screening before any biologic and for choosing agents with lower TB risk where infection risk is high. Patients starting an IL-17 inhibitor should know to report symptoms of thrush.

• Screen for latent TB before starting any biologic, and repeat if exposure risk changes.
• Consider an IL-23 or IL-12/23 inhibitor over a TNF inhibitor when TB risk is a major concern.
• Warn patients starting IL-17 inhibitors about oral and genital thrush and ask about it at reviews.
• Treat candidiasis on IL-17 inhibitors promptly and record it, so recurrence can inform the choice of agent.
• Keep a low threshold for investigating fever, cough or weight loss in anyone on a TNF inhibitor.

Why it matters

It gives comparable real-world infection rates across psoriasis systemics, including the newer IL-17 and IL-23 classes.

Don't overread it

TB rates come from a low-incidence country; the UK figures underestimate the absolute risk in India.

The statistics, in plain English

An incidence rate ratio of 4.65 means candidiasis was diagnosed about four to five times as often on IL-17 inhibitors as on IL-12/23 inhibitors. The intervals are clear of 1, so chance is an unlikely explanation. With only 22 TB cases in total, comparisons between drugs for TB are imprecise.

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