Guselkumab as a Successful Fourth-Line Therapy

Abstract

Guselkumab is a monoclonal antibody that selectively inhibits the p19 subunit of interleukin-23, providing a targeted mechanism for controlling inflammatory pathways in psoriasis and psoriatic arthritis. It has demonstrated high efficacy and favorable safety profile in both biologic-naïve and biologic-experienced patients. We present a case of a 42-year-old male with plaque psoriasis successfully treated with guselkumab after inadequate responses to methotrexate, adalimumab, ustekinumab, and secukinumab. At guselkumab initiation, the disease was extensive (Psoriasis Area and Severity Index 22, Body Surface Area 50%, Dermatology Life Quality Index 20/30). After 14 months of therapy, the patient achieved near-complete skin clearance (Psoriasis Area and Severity Index 1.9, Body Surface Area 3%, Dermatology Life Quality Index 7/30) with no adverse events. This case highlights the robust clinical efficacy of guselkumab even in patients previously treated with multiple biologic agents. Compared to anti-tumor necrosis factor-α, anti-interleukin-12/23, and anti-interleukin-17 therapies, guselkumab demonstrates superior selectivity, durability of response, and convenient dosing. Its effectiveness as a fourth-line option reinforces interleukin-23 inhibition as a valuable therapeutic strategy in refractory psoriasis and psoriatic arthritis.