2103 Resolution of Infliximab-Induced Palmar Pustular Psoriasis (PPP) After Switching to Biosimilar Infliximab-DYYB

Abstract

INTRODUCTION: Biosimilars are designed to approximate the effectiveness and safety profile of the reference drugs they are based upon. A person who has a side effect to either the biosimilar or the reference drug would have a similar adverse event to the other medication. Infliximab is an anti-TNF drug used in a variety of autoimmune conditions including UC. While highly effective, it is associated with new onset psoriasis in 5-9% of patients with IBD. That is not typically an indication to abandon the medication if it is otherwise effective. We describe the case of a person with UC on infliximab with the adverse event of PPP who was changed to infliximab-dyyb for financial reasons and had resolution of their skin lesions. CASE DESCRIPTION/METHODS: A 68 year old F with history of pancolonic UC was started on Infliximab 5 mg/kg/8 weeks. After 8 months of therapy and due to unresolved inflammation and symptoms, infliximab was increased to 10 mg/kg/8 weeks resulting in clinical remission. She had no prior history of psoriasis or other skin disease but after one year on infliximab she developed a new rash, examination showed well demarcated, pruritic, tender raised erythematous plaques on bilateral palms with salmon colored papules and small pustules (Figures 1 and 2). Dermatology diagnosed her with PPP secondary to infliximab. She was treated for over a year with clobestasol ointment with only modest improvement. Due to infusion center policy, her infliximab was changed to infliximab-dyyb. On 3 month follow up it was noted that the rash had completely resolved since switching to the biosimilar (Figure 3). DISCUSSION: Biosimilars of biologic therapies have become increasingly available. They are designed to recreate the effectiveness and safety of the reference medication. While some people develop side effects or loss of response when switching to a biosimilar from a reference medication, adverse events tend to happen at the same rate, suggesting that the event is not due to the biosimilar. Psoriasis caused by anti-TNF is a known adverse reaction. This may be due to a disruption in the balance from TNFα leading to increased production of IFN gamma. In studies infliximab led to psoriasis 5-9% compared to 5-12% in infliximab-dyyb. Even though it is believed that both the reference drug and biosimilar drug have similar efficacy and adverse reaction profiles, we hypothesize that our patient may have developed an immunogenic reaction to a part of the infliximab molecule that is not present in its biosimilar product infliximab-dyyb.