Conference Coverage

JAK inhibitors for atopic dermatitis might hit JAK-pot


 

EXPERT ANALYSIS FROM THE EADV CONGRESS

The emergence of Janus kinase inhibitors as a promising novel drug class for moderate to severe atopic dermatitis (AD) was a major theme at the annual congress of the European Academy of Dermatology and Venereology, with three positive phase 2 randomized trials featuring one topical and two oral agents presented to enthusiastic audiences.

The way has already been paved for dermatologic researchers by veterinarians, who developed oclacitinib (Apoquel), a relatively selective Janus kinase 1 (JAK1) inhibitor, for canine AD. The medication was approved by the Food and Drug Administration in 2013 for treating AD and for controlling pruritus associated with allergic dermatitis in dogs.

Dr. Melinda Gooderham Bruce Jancin/Frontline Medical News

Dr. Melinda Gooderham


PF-04965842

“Get out your pencils, everyone. This is why you’re all here at 8 o’clock on a Sunday morning,” Melinda Gooderham, MD, said, standing before a packed house at the main arena of the Geneva Convention Center, as she launched into the results of a phase II randomized, double-blind, placebo-controlled, 12-week trial of a JAK inhibitor known for now as PF-04965842. This is a JAK1-selective agent with a good effect on interleukin-4 and -13, key mediators of the Th2 cytokines implicated in the pathogenesis of AD.

The dose-ranging study included 250 adults with AD and an inadequate response to or intolerance of topical therapy. Their mean baseline Eczema Area and Severity Index (EASI) score was 25 with a 60/40 ratio of moderate to severe AD. The five-arm trial randomized patients to PF-04965842 at 10 mg, 30 mg, 100 mg, or 200 mg once daily or placebo.

The primary endpoint was the proportion of patients achieving an Investigator Global Assessment (IGA) score of 0 or 1 – clear or almost clear – along with at least a 2-grade improvement from baseline at week 12. A clear dose-response effect was evident, with the 100- and 200-mg doses achieving response rates of 28% and 45%, respectively, compared with 6% in placebo-treated controls, reported Dr. Gooderham, medical director of the Skin Center for Dermatology in Peterborough, Ont., and a dermatologist at Queen’s University in Kingston, Ont.

Onset of action was speedy: patients in the 200-mg group reached their full improvement in IGA score by week 4 and maintained that response through week 12. Maximum improvement in EASI score – a mean 80% reduction – was achieved by week 6 and sustained thereafter. The proportion of patients in the 200-mg group achieving at least a 4-point improvement on the Pruritus Numeric Rating Scale significantly exceeded that in the placebo group as early as day 2 of the trial. At week 12, 64% of patients in the 200-mg group had achieved this level of improvement in itch, compared with 26% of controls.

A dose-dependent drop in platelet count occurred in the study, reaching a 30% decline at the 4-week nadir in the 200-mg group, followed by gradual on-treatment recovery. Both LDL and HDL cholesterol rose on active therapy – a class effect of JAK inhibitors – but the ratio between the two lipid levels remained unchanged. The two serious adverse events deemed treatment related were a case of eczema herpeticum in a patient on the 100-mg dose and pneumonia in a patient on the 200-mg dose.

Baricitinib

This once-daily oral JAK1/2 inhibitor is approved for treatment of rheumatoid arthritis in Europe and Japan. Emma Guttman-Yassky, MD, PhD, presented a phase 2 study of baricitinib in 124 adults with moderate to severe AD. Notably, prior to enrollment, all participants had to have failed to respond to a 4-week run-in period of supervised treatment with 0.1% triamcinolone cream, a midpotency topical steroid. They were then randomized to 2 mg or 4 mg of once-daily baricitinib or placebo, in all cases supplemented as needed with the topical steroid. Their median baseline EASI score was 21.

The primary endpoint was the proportion of patients achieving at least a 50% improvement in EASI score, or EASI 50 response, by week 16 from baseline in a nonresponder imputation analysis. This was achieved in 65% of patients on the 4-mg dose of baricitinib, 64% on the 2-mg dose, and 46% of controls on placebo plus the topical steroid. A statistically significant difference in EASI 50 response between the baricitinib groups and controls was seen at 1 week, with nearly the maximum effect achieved at week 4. Patients with a baseline EASI score above the median had a much more impressive treatment response because the placebo effect was smaller in participants with more severe AD.

“I think this drug can be an exciting new addition to the field,” declared Dr. Guttman-Yassky, professor and vice chair of the department of dermatology at the Icahn School of Medicine at Mount Sinai, New York.

From a baseline total SCORAD (Scoring Atopic Dermatitis) score of 55, major improvements were seen in the JAK inhibitor–treated patients by week 4. At week 16, the average reduction from baseline was 47% in the 4-mg group, 41% in the 2-mg group, and 21% in the placebo group. Both the SCORAD pruritus and sleep loss subscores showed significantly more robust improvement in the baricitinib groups than in controls. Indeed, a significant drop in pruritus scores was noted within the first week.

The 4-mg dose was associated with greater improvement and faster onset of action than the 2-mg dose on some but not all disease measures.

Dr. Guttman-Yassky described baricitinib as having “an overall acceptable safety profile,” with no serious treatment-related adverse events noted. Headache, nasopharyngitis, and asymptomatic increases in serum creatinine phosphokinase were more common in baricitinib-treated patients than with placebo.

JTE-052

Hidemi Nakagawa, MD, presented a phase 2 study of topical JTE-052 ointment in 327 Japanese adults with moderate to severe AD. The drug inhibits JAK1/2/3 as well as the tyrosine kinase pathway. It also promotes keratinocyte production of filaggrin in the skin barrier. Participants were randomized to twice-daily application of JTE-052 ointment (at 0.25%, 0.5%, 1%, or 3%), vehicle ointment, or 0.1% tacrolimus ointment twice a day for 4 weeks. The primary outcome was the change from baseline in modified EASI score in the active treatment groups compared with placebo. All doses of JTE-052 proved significantly more effective than vehicle. A dose-response effect was noted, with a 42% reduction from baseline in modified EASI score in the 0.25% JTE-052 group, a 57% reduction with 0.5%, a 55% reduction with 1% ointment, and a 73% reduction with 3%, compared with a 12% reduction decrease in patients who received vehicle. The topical tacrolimus group showed a 62% reduction from baseline, reported Dr. Nakagawa, professor and head of the division of dermatology at Jikei University, Tokyo.

All doses of JTE-052 were also significantly more effective than placebo on all secondary endpoints, which included IGA, percent body surface area affected, and Pruritus Numeric Rating Scale score.

At all but the weakest concentration, JTE-052 resulted in significant reduction in pruritus starting with the second dose on day 1 of the trial, he added.

Mild nasopharyngitis occurred in 3.4% of JTE-052–treated patients. There were no serious adverse events and no changes in laboratory parameters in the study. One patient discontinued JTE-052 because of application-site contact dermatitis, another because of application-site irritation. The results of this study were recently published in the British Journal of Dermatology (Br J Dermatol. 2017 Sep 28. doi: 10.1111/bjd.16014).

Dr. Nakagawa reported receiving research grants from and serving as a consultant to Japan Tobacco, which is developing JTE-052. Dr. Guttman-Yassky reported having financial relationships with Eli Lilly and Incyte, which sponsored the baricitinib study, as well as most other pharmaceutical companies developing therapies for AD. Dr. Gooderham reported receiving research funding from and serving as a consultant to Pfizer, which sponsored the PF-04965842 study, as well as numerous other pharmaceutical companies.

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