Guselkumab Every 4 Weeks as a Real-World Therapeutic Option for Psoriatic Arthritis Patients at High Risk of Joint Damage

Background: Guselkumab, a monoclonal antibody selectively targeting the p19 subunit of interleukin-23, is typically administered with an induction phase at weeks 0 and 4 followed by maintenance dosing every 8 weeks for the treatment of psoriatic arthritis (PsA). In Europe, a four-week regimen (Q4W) has recently been approved for patients at high risk of joint damage progression; however, real-world evidence on this intensified schedule remains limited. This study aimed to evaluate the effectiveness and safety of guselkumab Q4W in routine clinical practice. Methods: This retrospective observational study included 18 PsA patients at high risk of structural damage treated with guselkumab Q4W at two psoriasis referral centers in the Lazio region of Italy. Baseline and 24-week clinical data were collected from medical records. Outcome measures included Disease Activity Index for Psoriatic Arthritis (DAPSA), Minimal Disease Activity (MDA), pain Visual Analog Scale (VAS), Dermatology Life Quality Index (DLQI), and Psoriasis Area and Severity Index (PASI). Results: After 24 weeks, mean DAPSA decreased from 34.3 ± 7.6 to 3.7 ± 3.0; 55.6% of patients achieved DAPSA remission and 77.8% achieved MDA. Significant improvements were observed in pain VAS, DLQI, and PASI scores. All patients achieved PASI 75, while 83.3% achieved PASI 90 and PASI 100. Treatment was generally well tolerated, with no adverse events or new safety signals documented during follow-up. Conclusions: In our study, guselkumab Q4W showed marked multidomain effectiveness and a favorable safety profile, supporting its use in PsA patients at high risk of joint damage progression.