Subcutaneous infliximab CT-P13 without intravenous induction in psoriatic arthritis: A case report and pharmacokinetic considerations.

The biosimilar CT-P13, the first and only subcutaneous (SC) infliximab formulation, is recommended for patients with psoriatic arthritis (PsA) and can be administered as a maintenance treatment, to be started 4 weeks after the induction treatment with 2 intravenous (IV) infliximab infusions. To evaluate treatment with SC infliximab without prior IV infusion induction to meet patient needs. After approval by the ethics review board and based on the schedule approved for rheumatoid arthritis, SC induction was performed with infliximab CT-P13 120 mg weekly for 4 weeks, followed by an injection of 120 mg every 2 weeks. After 4 months of therapy, joint symptoms were resolved, inflammation parameters were normalized (erythrocyte sedimentation rate) reduced from 42 to 16 mm/h, and C-reactive protein from 1.74 to 0.43 mg/dL), and clinical assessment parameters were improved. After 9 months of therapy, the clinical data remained stable, with no adverse events or local side effects. SC infliximab was successfully used without previous IV infusion induction. Although, to date, the induction of PsA treatment via the SC route is not foreseen, the known pharmacokinetic properties and the outcome improvements observed in our patient show that subcutaneous treatment induction, as is already done in the treatment of rheumatoid arthritis, is also possible.