Paradoxical reaction after switching between adalimumab biosimilars in a patient with psoriatic arthritis

Abstract

We present the case of a 56-year-old female patient with a history of cutaneous psoriasis. She presented with several months of progressive swelling and pain in proximal interphalangeal (PIP)joints of the right hand, accompanied by morning stiffness. Laboratory evaluations revealed: ESR 19 mm/h, CRP 0.5 mg/dL, anti-cyclic citrullinated peptide antibodies: 7 U/mL. A doppler ultrasound ofthe right hand showed significant increased vascularity in PIP joint. Treatment with methotrexate was initiated and titrated to 25 mg subcutaneously per week without achieving clinicalimprovement.Adalimumab (Hyrimoz®) was then started, resulting in a highly favorable response. However, three months after initiating Hyrimoz®, the patient’s health insurance replaced it with anotheradalimumab biosimilar, Amgevita®. Two months later, she developed new psoriasiform lesions on her hands and feet, along with recurrence of joint swelling and pain (Fig. 1A and B).Given the appearance of new and severe skin lesions and worsening joint symptoms, two clinical questions emerged: Was this a paradoxical reaction to the anti-TNF agent, suggesting a need toswitch therapeutic class? Or could reintroduction of the previously effective biosimilar be considered? Treatment with Hyrimoz® was assumed,leading to marked and sustained improvement after three months.