Utilization, cost, and specialty distribution of topical ruxolitinib prescribing in Medicare Part D, 2018-2024: A cross-sectional study

A cross-sectional studyTo the Editor: Topical ruxolitinib 1.5% cream (Opzelura) is the first U.S. food and drug administration (FDA)-approved topical Janus kinase inhibitor, with indications for atopic dermatitis since September 2021 and nonsegmental vitiligo since July 2022.We used Medicare Part D data to describe national utilization, spending, and prescriber distribution for topical ruxolitinib through 2024, alongside three established nonsteroidal topical antiinflammatories used for atopic dermatitis : crisaborole (Eucrisa, FDA-approved 2016), generic tacrolimus ointment, and generic pimecrolimus cream.We used the Medicare Part D Prescribers by Provider and Drug Public Use File for 2018-2024.1 Records were identified by the brand names Opzelura, Eucrisa, Elidel, and Protopic, and by the generic names pimecrolimus and tacrolimus, with the latter restricted to dermatology and micrographic dermatologic surgery prescribers as a proxy for topical formulation, since the file does not differentiate between routes of administration.This approach is consistent with methods used by Ugwu et al for topical calcineurin inhibitors. 2 For each drug-year, we calculated the number of unique prescribers, total claims, total days of supply, total drug cost (excluding manufacturer rebates), and cost per day of therapy.Topical ruxolitinib prescribing expanded rapidly after FDA approval.Accross all specialties, medicare Part D prescribers of topical ruxolitinib grew from 5 in 2021 to 1037 in 2024 (126 to 23,713 claims; $256,075 to $49.6 million); among dermatologist, prescribing grew from 2 to 580 (Table I; Fig 1, A). Crisaborole prescribing among dermatologists peaked in 2019 (78 prescribers; 2079 claims) and declined to 40 prescribers and 695 claims by 2024.Among dermatologists, generic tacrolimus claims grew from 32,394 in 2018 to 141,342 in 2024 and generic pimecrolimus claims from 7772 to 15,671, while their cost per day fell from $11.15 to $4.29 and $18.68 to $7.69, respectively.In 2024, dermatologists wrote 54.9% of topical ruxolitinib claims, physician assistants 26.4%, nurse practitioners 12.0%, primary care physicians 2.9%, and allergy/immunology 1.3% (Fig 1, C).For