Introduction <p>Pemphigus diseases are a family of chronic, autoimmune, blistering skin conditions. Despite advances in treatment approaches, more effective and safer therapies for pemphigus are urgently needed. Trials investigating novel therapeutics must be designed to yield evidence that can be compared to existing data, necessitating a comprehensive understanding of the clinical trial landscape. We aimed to perform a mapping review to assess the comparability of randomized controlled trials (RCTs) evaluating existing treatments for pemphigus vulgaris (PV) and pemphigus foliaceous (PF).</p> Methods <p>Embase, MEDLINE, and Cochrane Library were systematically searched from inception to July 2023, supplemented with conference abstracts, clinical trial registries, and grey literature searches, for RCTs evaluating pharmacotherapies in adults with moderate-to-severe PV or PF. Comparability of study populations (demographic and clinical characteristics), interventions and comparators (dose, administration route, regimen), and outcomes (definition, time point, measure) across trials was assessed.</p> Results <p>Fifteen RCTs were eligible for inclusion. Substantial heterogeneity was observed in participant age, sex, and disease duration at baseline, and none of the studies used the same criteria to assess illness severity. Doses and regimens differed across trials assessing the same interventions. Across 16 outcome measures extracted, clinical remission outcomes had limited comparability across studies and were often not defined according to published guidelines. Cumulative corticosteroid dose during the study period had the highest comparability. Health-related quality of life data and serious adverse events were infrequently reported.</p> Conclusions <p>The lack of comparability across studies has major implications for developers of new treatments for PV and PF and for decision-makers who must evaluate the efficacy, safety, and cost-effectiveness of these treatments relative to existing therapeutics.</p>