Supplemental material for: Concentration of Mechlorethamine Prescribing Among a Small Number of Specialists.

Data were derived from the publicly available Centers for Medicare & Medicaid Services Medicare Part D Prescriber Public Use Files for calendar years 2018 through 2023. Mechlorethamine claims were identified annually and aggregated by prescriber, prescriber specialty, and state to characterize utilization, prescriber concentration, geographic distribution, and cost.

The analytic sample comprised 3,945 claims from 96 unique prescribers. This deposit contains two supplemental items referenced in the article: a table comparing prescribing metrics between dermatologists and hematology-oncology specialists, and a map showing state-level distribution of mechlorethamine claims and prescribers. Both are provided here because the Journal of the American Academy of Dermatology no longer publishes supplemental material within articles.