On and off-label uses of interleukin-17 inhibitors for patients with plaque-type psoriasis in Thailand: a real-world study

Off-label uses of biologics in the treatment of psoriasis are usually implemented in limited-resource settings and studies regarding their response profiles are limited. This was a retrospective study performed in moderate-to-severe plaque-type psoriasis patients who had been treated with either secukinumab, ixekizumab or brodalumab at a university hospital in Thailand between 1 January 2017 and 1 April 2021. A total of 142 patients were included in the data analysis consisting of three groups of 48 patients, 86 patients, and 8 patients treated by secukinumab, ixekizumab, and brodalumab, respectively. Patients were then classified into five groups according to the dosing pattern they received; on-label, off-label with induction, off-label with specific pattern, off-label with irregular dosing interval <8 weeks and >8 weeks. Considering both secukinumab and ixekizumab, the adjusted hazard ratios (95%CI) for complete skin clearance of the four off-label regimens were 2.2(0.9–5.2), 1.9 (0.9–3.9), 1.0 (0.4–2.2), and 1.6 (0.7–3.6), compared to on-label regimen, respectively. In each biologic drug, almost all off-label dosing regimens demonstrated higher adjusted hazard ratios compared to on-label regimen. Off-label, patient-oriented regimens could be a promising choice of IL-17 inhibitors for administration in special settings. Off-label regimens are not inferior in terms of skin clearance to an on-label regimen in the efficacy of psoriasis treatment of secukinumab and ixekizumab but do cause more flares. The decision to use off-label regimens must account for the benefits and associated risks.