New-Onset Drug-Induced Lupus After a Switch to an Infliximab Biosimilar
Background:
Clinical trials like NOR-SWITCH have paved the way for widespread adaptation of infliximab (IFX) biosimilars. They have overwhelmingly demonstrated similar efficacy, immunogenicity and pharmacokinetics to the IFX originator (Remicade). In this case, we report a case of new onset drug-induced lupus (DIL) after switching from IFX to biosimilar, Inflectra.
Methods:
A 43-year-old female patient with a medical history of UC and psoriasis presented at an outpatient clinic for UC monitoring. The patient had previously maintained her UC on 6-mercaptopurine, which she discontinued independently due to safety concerns related to conceiving. Despite being asymptomatic, her fecal calprotectin (FC) was moderately elevated. Biologic therapy was recommended but declined by the patient. She then developed symptoms of profuse bloody diarrhea (15-20 episodes daily), with further FC elevation to 1018 ug/g. Colonoscopy revealed diffuse, Mayo 1-2 pancolitis. At this point, the patient agreed to IFX treatment. Autoimmune labs prior to IFX. She received her first infusion soon after with a marked reduction in her symptoms. She underwent regular IFX infusions every 8 weeks, achieving sustained remission.
Results:
After 12 months on IFX, the patient’s insurance mandated a non-medical switch from IFX to biosimilar, Inflectra. Two weeks after her first Inflectra infusion, the patient developed migratory arthralgias affecting the hands, fingers, elbows, and shoulders, prompting renewed autoimmune investigations. Her IFX level was < 0.8 ug/mL with a IFX antibody level of 49. The patient was diagnosed with DIL, likely attributed to Inflectra. Inflectra was discontinued, and she was started on vedolizumab and hydroxychloroquine. Her UC remained in deep remission despite the diagnosis of DIL. Her rheumatological symptoms gradually resolved over the course of eight months. As of May 2023, the U.S. The Food and Drug Administration (FDA) has approved 41 biosimilars. Extensive clinical trials have underscored the safety, efficacy, and interchangeability between IFX biosimilars and the originator. However, in this rare instance, a patient who experienced sustained remission with IFX originator (Remicade) developed DIL upon switching to Inflectra. This divergence in response underscores the intricate interplay between individual immunogenicity and biosimilar transition. While immunogenicity is addressed in the development of biosimilars and for FDA approval, not all studies include anti-drug antibodies (ADA), despite its association with nonresponse to biologics in multiple populations.
Conclusions:
In a clinical setting, evaluating adverse events post-biosimilar transition necessitates measuring ADAs and therapeutic levels. This is the first case, to our knowledge, where a switch to biosimilar elicited both ADA generation and DIL. Vigilance is essential in monitoring patients’ post-transition to biosimilars for potential adverse events, ensuring that benefits of biosimilars are upheld while acknowledging the potential for idiosyncratic responses.
