Biologic therapies have transformed the management of moderate-to-severe psoriasis but are associated with long-term treatment burden and substantial healthcare costs. Dose spacing, defined as extending dosing intervals in patients with controlled disease, has emerged as a potential optimization strategy. However, data on real-world implementation and clinician perspectives remain limited.
Methods
We conducted a national, cross-sectional survey among Portuguese dermatologists experienced in prescribing biologic therapies for psoriasis. An anonymous, web-based questionnaire assessed clinicians' perspectives and real-world practices regarding biologic dose spacing, including eligibility criteria, preferred biologic classes, implementation strategies, outcomes after loss of disease control, and limiting clinical factors.
Results
Seventy-five dermatologists completed the survey (response rate 48.4%). All respondents considered dose spacing feasible. The most frequently cited eligibility criteria were absolute Psoriasis Area and Severity Index (PASI) ≤ 1, body surface area (BSA) ≤ 1%, and a 90% improvement in PASI (PASI 90). Interleukin-23 (IL-23) inhibitors were perceived as the most suitable class for dose spacing (93.3%). In routine practice, dose spacing was applied frequently by 30.7% of respondents and occasionally by 48.0%. Most clinicians (69.3%) required more than 12 months of sustained disease control before initiating dose spacing, predominantly using progressive extension of dosing intervals (96.0%). IL-23 inhibitors were the biologics most frequently dose-spaced in current practice. Following loss of disease control, 86.7% reported successful recapture of response after reintroduction of standard dosing. The main factors limiting dose spacing were a history of difficult-to-control psoriasis (77.3%) and concomitant psoriatic arthritis (72.0%).
Conclusion
Biologic dose spacing is already integrated into clinical practice in Portugal. Further prospective studies are needed to establish standardized criteria and guide safe implementation.
