NEW YORK CITY — When data from clinical trials of JAK inhibitors in atopic dermatitis (AD), vitiligo, and other skin diseases are stratified by race, response rates appear to diverge, with both higher and lower response rates observed for Black than White populations across specific pathologies.

For many of the trials, enrollment of Black patients was relatively low, but the datasets are relatively large, and the signal of a difference in response deserves to be better understood, according to Brett King, MD, PhD, who was previously associated with Yale University and is now in private practice with Dermatology Physicians of Connecticut, Fairfield. 

Analyzing trial data for each dermatological disease for which there is an approved JAK inhibitor, King looked not only at outcomes by race but also, when available, by Fitzpatrick skin type. In this preliminary survey, which appears to be the first to evaluate response to this drug class by race, he did not apply statistical analyses but looked for numerical differences as a starting point for further research.

He presented the results on October 5 at the 2025 Skin of Color Update (SOCU).

JAK Inhibitors Are Safer in Dermatologic Diseases

Safety was also examined, but the major point made by King is that serious adverse events on JAK inhibitors are rare among patients treated for dermatological diseases, regardless of race. So far, the boxed warning in the labels of JAK inhibitors, based on findings in rheumatoid arthritis trials, have not proven relevant to skin diseases, he said.

For AD, nearly 1000 patients have participated in phase 3 trials with abrocitinib, a JAK 1 inhibitor now approved for moderate-to-severe AD for patients ages 12 and older. Of these, 83 (8.8%) patients were Black, according to the data collated by King. 

The graphs of response for an Investigator Global Assessment (IGA) score of 0/1 (clear or almost clear) are similar by race but not identical. At week 12, only 28% of Black patients, 43% of White patients, and 38% of Asian patients achieved an IGA 0/1 on the highest dose of 200 mg once daily. No major difference was seen when patients with Fitzpatrick skin types I-III (FST I-III) were compared with FST IV-VI (40% vs 45%). However, the proportion with a 4-point reduction in the Peak-Pruritus Numerical Rating Scale also differed by race. At week 12, this endpoint was met by 61% of White patients, 49% of Asian patients, and 39% of the Black patients on the 200 mg dose. 

When collating data from the AD trials of upadacitinib, a JAK inhibitor approved for moderate-to-severe AD, responses varied more substantially. King analyzed data on 2583 patients (6% were Black). For the proportion achieving 90% clearance on the Eczema Area and Severity Index — a result similar to IGA 0/1 — the response rate was nearly 20% lower on the 15 mg once daily dose among Black vs White populations (24.1% vs 43.3%, respectively).

Although still somewhat lower among Black patients (46.9% vs 55.1% among White patients), “this difference washes away when we look at the responses to the 30 mg dose,” King said. Yet, he considers the 20% gap with the lower dose concerning.

Response to Topical Ruxolitinib Lower in Black Populations

Moreover, the same gap was observed in data with 673 adults and adolescents (4.8% were Black) treated with ruxolitinib cream for mild-to-moderate AD. In these studies, IGA 0/1 was achieved by 26.6% of Black patients, 45% of White patients, and 51.3% of Asian patients, King reported.

This lower numerical benefit among Black persons was not seen in trials of ruxolitinib cream for vitiligo. Rather, the 75% reduction in the Vitiligo Area Scoring Index on the face was 60% for Black patients, 50.7% for White patients, and 46.2% for Asian patients. When FST I-III was compared to FST IV-VI, there seemed to be a greater response among those with darker skin (57.4% vs 47.4%). Topical ruxolitinib is approved for treating mild-to-moderate AD, and for nonsegmental vitiligo. 

An addendum analysis of a phase 3 alopecia areata trial of baricitinib, approved for severe alopecia areata in adults, might provide a clue about racial differences. Concern about diagnostic accuracy in the BRAVE-AA trials, which King led, triggered a reanalysis of photographs taken of Black participants. Of the photographs of 36 patients assessed by independent experts, 12 were determined to show traction alopecia or central centrifugal cicatricial alopecia rather than alopecia areata. 

“Here, we are seeing some evidence that we are doing a lousy job of diagnosing hair loss disorders in Black patients,” King said. “We really have to question data when we see something like this,” he added. 

It cannot be assumed that this explains the lower IGA 0/1 responses in AD, but King pointed out that there are studies suggesting clinicians might not be as good in assessing symptoms of this condition, such as erythema, in Black patients. Conversely, he noted that a good response to vitiligo might be easier to detect because of the stark contrast of skin involvement among patients with Black skin.

In fact, there are no conclusions to be drawn from this work, which might be better understood as a first step toward determining whether there are racial differences in response to JAK inhibitors, King suggested.

“I think the overarching message from these data is that we should be doing these kinds of studies,” said King, who is looking forward to the ongoing phase 3 data with JAK inhibitors in hidradenitis suppurativa. Expected next year, these will have a higher representation of Black patients, with better numbers to evaluate relative response rates.

An ongoing open-label trial of abrocitinib in sarcoidosis, which has also enrolled a substantial number of Black patients, will be another opportunity to explore response differences when the data are released. Ultimately, more and better data are needed to identify racial differences, if any, in relative benefit, according to King. 

“There is certainly a knowledge gap in this area,” he said, adding, “We need to do a better job in extracting data across skin types.” 

Whether or not a difference can be established in relative response to JAK inhibitors or other drug classes by race in dermatologic diseases, these analyses might also be helpful for considering whether there are racial differences in how these diseases are assessed, he added.

These data are intriguing, but Andrew Alexis, MD, professor of clinical dermatology, Weill Cornell Medicine, New York, who was at the meeting, said that they primarily represent a direction of research. He agreed with King that larger data sets are needed, particularly those with enough power to detect differences that are statistically significant.

While he agreed completely that more data about racial differences between drug classes — and between agents within a drug class — are particularly important when considering benefit for skin diseases, he indicated that data on skin types rather than race alone might provide the most useful clinical information.

King reported financial relationships with AbbVie, Almirall, AltruBio, Amgen, AnaptysBio, Apogee, Aquestive, Arena, Aslan, Bristol-Myers Squibb, Concert, Equilibrium, Horizon, Incyte, Janssen, Leo, Lilly, Merck, Otsuka/Visterra, Novartis, Pfizer, Regeneron, Sanofi/Genzyme, Soterios, Sun, Takeda, and TWi. Alexis reported financial relationships with AbbVie, Alphyn, Almirall, Apogee, Arcutis, Bausch, Beiersdorf, Boehringer-Ingelheim, Bristol-Myers Squibb, Canfield, Castle, Dermavant, Galderma, Genentech, HairDays, Incyte, Johnson & Johnson, Leo, Lilly, L’Oreal, Novartis, Ortho, Pfizer, Sanofi-Regeneron, Swiss American, Symrise, UCB, VisualDx.