Two decades of using the combination of tetracycline derivatives and niacinamide as steroid-sparing agents in the management of pemphigus: defining a niche for these low toxicity agents.

Abstract

The twin goals of long-term disease control and minimizing toxicities related to immunosuppression necessitate efforts to find effective steroid-sparing agents in the management of patients with autoimmune bullous diseases. Pemphigus especially requires a long view, because the disease can persist throughout a patient's lifetime, yet few clinical trial reports exist to guide the practitioner. We review the response of pemphigus patients to tetracycline, doxycycline, or minocycline plus niacinamide (TCN/NAM) as steroid-sparing therapy and to determine the effects of TCN/NAM on autoantibody levels during the long-term treatment of pemphigus. This was a retrospective chart review in a private medical dermatology practice setting of all pemphigus patients treated between 1993 and 2013. Clinical responses to TCN/NAM therapy after initial high-dose steroid induction therapy and pemphigus antibody levels were recorded over the course of disease flares and treatment cycles along with any related side effects. Anti-desmoglein 1 and 3 titers were compared in a subset of patients over time, and a statistical analysis was performed to correlate the clinical response with antibody levels. Fifty-one pemphigus patients (43 with pemphigus vulgaris, 7 with pemphigus foliaceous, and 1 with pemphigus erythematosus) received at least 3 months of TCN/NAM, and 16 patients with pemphigus vulgaris had 1 set of pemphigus antibody titers correlating to a baseline/flare and clinical remission. TCN/NAM was associated with disease control in 43 of 51 patients, with a duration of response ranging from 1 to 13 years (mean, 3.14 ± 2.97 years). Thirteen of 51 patients needed no additional treatment for complete disease control, while 33 of 51 needed intermittent topical clobetasol or short courses of oral steroids for long-term management. There were 5 nonresponders. Antidesmoglein titers trended lower in TCN/NAM responders, but only desmoglein 3 approached statistical significance (anti-desmoglein 1, P = .21; anti-desmoglein 3, P = .02). This is a retrospective analysis from a single practice. A lack of serial autoantibody titers limited statistical analyses. TCN/NAM may be useful as a steroid-sparing therapy for pemphigus.