Switching from Intravenous to Subcutaneous Infliximab in Psoriasis: A Case Series on Efficacy and Treatment Satisfaction.

Background/Objectives: Plaque psoriasis is a chronic immune-mediated inflammatory disease affecting approximately 3% of the global population and resulting in a significant deterioration in quality of life. Systemic therapy with monoclonal antibodies (mAbs) targeting TNF-α, IL-23, and IL-17 improves clinical outcomes and patients' quality of life. Treatment strategies commonly include different mAbs and different sequencing approaches between agents, which are well-established in clinical practice. In contrast, evidence supporting the switch from intravenous to subcutaneous administration of the same mAb remains limited. Herein, we report data from a retrospective case series of patients with plaque psoriasis treated with intravenous infliximab (IV-IFX; Anti TNF-α) and transitioned to subcutaneous infliximab (SC-IFX) to compare clinical and patient-reported outcomes across routes. Methods: A total of 11 plaque psoriasis patients were retrospectively analyzed. The scores of the Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI), and Physician Global Assessment (PGA) were assessed during IV-IFX and after switching to SC-IFX. To evaluate patients' satisfaction, the Score of Treatment Satisfaction Questionnaire Medication-9 (TSQM-9) was evaluated. Both Student's t-test and ANOVA were used to assess statistically significant differences between the two routes of administration (p < 0.05). Results: Scores for PASI, DLQI, and PGA were lower with SC-IFX compared with IV-IFX, indicating improved disease control and quality of life after the switch. PASI and DLQI improved in 81% and 100% of patients treated with SC-IFX, respectively. TSQM-9 total scores increased significantly by 24% (p < 0.001). In particular, the questions addressing the "convenience" of treatment revealed a marked advantage for the SC-IFX formulation (p < 0.001). No treatment-emergent adverse events were registered. Conclusions: In this retrospective case series, switching from IV-IFX to SC-IFX appeared to be safe and to maintain or improve clinical response and enhanced treatment satisfaction. These findings highlight the potential of SC-IFX as a viable maintenance option for patients with plaque psoriasis previously treated with IV-IFX.