JAK Inhibitors Efficacious for Atopic Dermatitis in Asian Patients, Study Finds

Sandy Ong

July 07, 2023

Dr Yik Weng Yew

SINGAPORE — Three oral Janus kinase (JAK) inhibitors — abrocitinib, baricitinib, and upadacitinib — have demonstrated a good treatment response in Asian patients with atopic dermatitis (AD), a small retrospective study conducted in Singapore has found.

"Abrocitinib and upadacitinib surprisingly appeared to have better treatment efficacy compared to baricitinib," said study lead Yik Weng Yew, MD, PhD, MPH, deputy head of research at Singapore's National Skin Centre (NSC), who presented the results at the 25th World Congress of Dermatology. "But overall, as a group, I think they show a very good treatment response, as well as a good effect on itch response."

JAK inhibitors are used to treat a variety of inflammatory diseases including alopecia areata, rheumatoid arthritis, and inflammatory bowel disease. Although treatment for severe eczema was previously limited to topical steroids and oral immunosuppressants, there are now two oral JAK inhibitors — abrocitinib and upadacitinib — approved in 2022 by the US Food and Drug Administration for treating AD, which affects up to 2.4% of the global population. (A topical formulation of ruxolitinib, a JAK inhibitor, was approved for AD in 2021.)

The Singapore study is one of the few that have examined the safety and efficacy of JAK inhibitors for treatment of AD in a non-White population.

Chinese Population

For the 12-week trial, conducted last year, Yew and his team recruited 35 patients from the NSC. More than half of participants (64%) were men and most (96%) were of Chinese ethnicity. Four of every five patients had previously received systemic agents: 17% had been treated with one systemic agent, 18.9% with two, 15.1% with three, 22.6% with four, and 3.8% with five. The most commonly used agents were cyclosporine (62.3%), methotrexate (47.2%), azathioprine (39.6%), and dupilumab (35.8%).  

"The switch in therapy could have been a result of inadequate efficacy or cost reasons because in Singapore patients pay out of pocket for AD treatments," said Yew.

Additionally, he offered a caveat on the profile of participants: "Perhaps they were more difficult atopic eczema patients, and therefore, the efficacy [of JAK inhibitors] might be a bit different."

Clearer Skin, Less Itch

Patients received one of the three study drugs: baricitinib (66%), abrocitinib (21%), and upadacitinib (13%). The distribution was "affected by reimbursement patterns and availability of the drug," explained Yew.

They were assessed at weeks 4 and 12. By study end, the proportion of patients who self-reported an improvement in their condition was 100% for upadacitinib, 90% for abrocitinib, and 69% for baricitinib. 

Scores on the Investigator Global Assessment (IGA) also improved with treatment. Patients in the baricitinib group saw their mean score fall from 4.0 to 3.0 by week 4, then to 2.0 by week 12. With upadacitinib and abrocitinib, "you can see that there is a nice decrease in IGA responses," said Yew, referring to the larger improvement in scores experienced by patients on those two treatments. For patients on upadacitinib, IGA decreased from 3.5 to 2 at 4 weeks, then to 0.5 at 12 weeks, while those taking abrocitinib had their scores drop from 4.0 to 2.0 at 4 weeks, then to 1.0 at 12 weeks.

When it came to itch reduction, the abrocitinib group experienced the biggest reduction, with a median reduction of 5.5 points in itch score. Median reduction in itch score was 4 points for the other two groups. "Oral JAK inhibitors appear to have a good effect on itch response," said Yew.

However, the researchers observed no significant reduction in percentage of body surface area affected, the last outcome assessed.

The most commonly reported adverse events were increased creatine kinase levels (11.3% of patients), increased low-density lipoprotein cholesterol levels (9.4%), and herpes zoster (9.4%). Those in the abrocitinib reported a higher number of these adverse events compared with the other two treatment groups. (There were no herpes zoster cases among those taking baricitinib.)

For herpes zoster, Yew said "the common recommendation" is to give the inactivated shingles vaccine. "But the problem is that, number one, these patients would have probably failed multiple agents so they probably can't wait for you to vaccinate before you initiate treatment."

In addition, people in Singapore have to pay out-of-pocket for the two vaccine doses, "which is probably a month's worth of medication," he noted. "So we have a lot of resistance from patients."

Additionally, Yew noted that contrary to what has previously been reported in the literature, there were few complaints of acne as a side effect in the Singaporean study population.

Towards Greater Representation

Yew pointed out that the study was limited by a few factors: neither the Eczema Area and Severity Index (EASI) or Scoring of Atopic Dermatitis (SCORAD) index data was used, and the study population was small and not representative of the real world.

Still, the new findings contribute to the overall safety and efficacy profile of JAK inhibitors in AD, which has so far been scarce in non-White populations.

"In Western studies, unfortunately, the representation of the population of skin of color or different ethnicities is underrepresented," said Yousef Binamer, MD, chair of the dermatology department at King Faisal Specialist Hospital, Riyadh, Saudi Arabia, when approached for an independent comment on the results.

"This is now why researchers are looking into specific groups to study them," which he pointed out, is crucial because "the immunophenotyping of AD is different for each background."

The incidence and severity of AD tend to be higher in Asian and Middle Eastern populations, for instance, he noted. "It's very common in Asia, and not so common in very white skin. I did my training in Canada so I see the difference," said Binamer. "Asian people tend to be more itchy and have a tendency to scar on pigmentation." Whereas White people "usually do not have this issue." 

"So I think real-world evidence of JAK inhibitors in the other populations is important," he said. Studies such as the one conducted in Singapore, as well as the recently reported QUARTZ3 study, which examined the use of the JAK inhibitor ivarmacitinib in 256 Chinese patients with AD, are helping to pave the way.

The study was independently supported. Yew and Binamer have reported no relevant financial relationships.

25th World Congress of Dermatology (WCD). Presented July 7, 2023.

Sandy Ong is a freelance health and science journalist based in Singapore, @sandyong_yx

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