Methotrexate as rescue therapy for hidradenitis suppurativa patients with antibodies against infliximab

Summary: Abstract Body: This study investigates the use of methotrexate (MTX) as rescue therapy for patients with Hidradenitis Suppurativa (HS) who have developed antibodies (Abs) against intravenous (IV) infliximab (IFX) therapy. We conducted a single-center, retrospective chart review of patients with HS who were prescribed IFX for HS and initiated on MTX after developing Abs. Patient demographics, comorbid medical conditions, medication regimens, markers of disease severity, and relevant laboratory markers were reviewed. Of the four patients that met the inclusion criteria, 75% were female, 50% identified as Hispanic/Latino, and all were between the ages of 22 and 53. They were managed with varying combinations of infliximab infusions and topical antimicrobials, oral/IV antibiotics, intralesional triamcinolone (ILTAC) injections, or anti-hormonal therapies. Time from infliximab initiation to Ab development ranged from 5 months to 4.5 years. Three patients were started on MTX at the first visit following Ab detection, while one started over two years later. Each patient received a different MTX dose, including 2.5, 7.5, 10 and 15 mg/week. All four patients demonstrated IFX levels ≥1 ug/mL and undetectable Ab levels at the first blood draw following MTX initiation, with time to rescue averaging 53 days. These findings suggest that MTX can be utilized as a rescue therapy for patients with IFX Abs as an alternative to switching therapy altogether. Our findings align with previous literature regarding other inflammatory diseases, in which MTX was shown to be an effective rescue therapy for neutralizing Abs and restoring therapeutic IFX levels. Moreover, the eradication of Abs even at lower doses of MTX or after years of persistent Abs indicates that patients may not always require a high dose of immunosuppression or immediate treatment to achieve a successful response. Due to the retrospective nature and small sample size of our study, further studies of MTX to rescue IFX-refractory HS are needed. Zahidul Islam^{1, 2}, Richard Rookwood², Nicole Schiraldi², Sarah Romanelli², Lana Salloum², David Ciocon² 1. School of Medicine, New York Medical College, Valhalla, NY, United States. 2. Dermatology, Montefiore Medical Center, New York, NY, United States. Clinical Research: Interventional Research