Intraclass switching of interleukin-23 inhibitors in psoriasis: effectiveness, patterns and predictors of response – a retrospective multicentre study in Italy

Background Interleukin (IL)-23 inhibitors are highly effective therapies for psoriasis, but some patients may need to discontinue the treatment. Intraclass switching is a potential strategy, although data on its effectiveness remain limited. Objectives To evaluate the patterns and effectiveness of intraclass switching among IL-23 inhibitors in a real-world setting. Methods This retrospective, multicentre study included adult patients with plaque psoriasis who switched between IL-23 inhibitors. Clinical and demographic data were analysed, and univariable and multivariable analyses identified predictors of treatment response. Results We analysed 116 patients (120 switches). Switching occurred from guselkumab (45.0%), tildrakizumab (44.2%) and risankizumab (10.8%), mainly due to secondary ineffectiveness (82.5%). Risankizumab was the most common post-switch agent (70.0%), followed by guselkumab (23.3%) and tildrakizumab (6.7%). Psoriasis Area and Severity Index 90% improvement (PASI 90) rates were 28.5% at week 16, 49.5% at week 36 and 60.7% at week 52. Fifteen patients (12.5%) withdrew from treatment, mainly due to lack of efficacy (10 patients, 67%) or adverse events (4 patients, 27%). Univariate analysis showed lower PASI 90 achievement in patients with psoriatic arthritis at weeks 16 after the switch (P = 0.02) and 36 (P = 0.02) and in those with body mass index (BMI) ≥ 25 kg m–2 at week 52 (P = 0.01). Patients switching from risankizumab had lower PASI 90 rates at weeks 16 (P = 0.04) and 36 (P = 0.03), while those switching to risankizumab had higher PASI 90 rates at week 16 (P = 0.02). Multivariate analysis confirmed BMI ≥ 25 kg m–2 was associated with reduced PASI 90 at weeks 36 (P = 0.04) and 52 (P = 0.04). Conclusions Intraclass switching among IL-23 inhibitors is an effective strategy, with risankizumab emerging as the most favourable option.