Delgocitinib shows promise for AD
The novel Janus kinase (JAK) inhibitor delgocitinib exhibited favourable efficacy and safety for moderate-to-severe atopic dermatitis (AD), according to a phase III study presented at AAD 2019.
In the adult cohort, 158 Japanese individuals (mean age 31.7 years, 62 percent male) were randomized 2:1 to receive delgocitinib 0.5 percent or a matching vehicle ointment twice daily for 4 weeks. [AAD 2019, abstract 8214]
A substantial reduction in modified Eczema Area Severity Index (mEASI) score was observed in the delgocitinib vs vehicle arm at treatment end (least squares [LS] mean change, -44.29 percent vs 1.74 percent; p<0.0001).
A greater fraction of delgocitinib recipients achieved ≥50 and ≥75 percent improvement in mEASI score vs the vehicle arm (51.9 percent vs 11.5 percent and 26.4 percent vs 5.8 percent for ≥50 and ≥75 percent, respectively). The proportion of patients achieving an Investigator’s Global Assessment (IGA) score of 0/1 and a face/neck IGA score of 0/1 with ≥2-point improvement was also higher in the delgocitinib vs the vehicle arm (10.4 percent vs 3.8 percent and 22.8 percent vs 4.0 percent, respectively).
Another notable finding is the greater reduction in the pruritus daytime and night-time numeric rating scale (NRS) score in the delgocitinib vs the vehicle arm (-1.55 vs 0.04 and -1.39 vs 0.26, respectively).
Adverse events (AEs) were observed in about 22 percent of delgocitinib recipients, the most common being nasopharyngitis (5.7 percent). Although the AE rate was almost double compared with the vehicle arm (11.5 percent), majority of the AEs were mild in severity with no serious AEs reported.
The paediatric cohort (n=103; mean age 8.5 years, 56.3 percent male) exhibited similar results, with a significantly reduced mEASI score with delgocitinib vs the vehicle ointment (LS mean change, -61.84 percent vs -4.81 percent; p<0.001). [AAD 2019, abstract 8216]
The ≥50- and ≥75-percent improvement in mEASI score was achieved by more delgocitinib recipients at treatment end compared with those who used the vehicle ointment (58.8 percent vs 31.4 percent and 50.0 percent vs 8.6 percent, respectively). The proportion of patients achieving an IGA score of 0/1 with and without ≥2-point improvement was also higher in the delgocitinib vs the vehicle arm (20.6 percent vs 0.0 percent and 41.2 percent vs 2.9 percent, respectively).
Similarly, there was a greater reduction in the pruritus daytime and night-time NRS score in the delgocitinib vs the vehicle arm (-0.64 vs 0.04 and -0.36 vs 0.15, respectively).
AEs (38.2 percent [delgocitinib] vs 48.6 percent [vehicle]) were also mild in severity with no serious AEs reported. Nasopharyngitis was also the most common AE among paediatric delgocitinib recipients (19.1 percent).
“[Taken together,] delgocitinib markedly and rapidly improved clinical signs and symptoms … and showed a favourable safety profile, [suggesting] that topical delgocitinib can be a promising therapeutic option in [both adult and paediatric] patients with AD,” said the researchers.
A similarly positive response was observed in a proof-of-concept study evaluating 91 individuals with chronic hand eczema (CHE), with a high treatment success rate achieved by delgocitinib vs vehicle ointment recipients as per the Physician’s Global Assessment of Disease Severity (45.7 percent vs 14.9 percent, odds ratio [OR], 4.89, 95 percent confidence interval [CI], 1.49–16.09; p=0.009). [AAD 2019, abstract 8467]
“The proportion of patients achieving treatment success continuously increased over time in the delgocitinib group without reaching a plateau,” said the researchers of this study. “As a plateau in efficacy was not observed, a longer treatment period may lead to increased efficacy.”
While the molecular mechanisms underlying CHE are relatively unclear, cytokines and the JAK/STAT** signalling pathway have been implicated in its pathophysiology, noted the researchers. [J Allergy Clin Immunol 2017;139:S65-S76] “Topical delgocitinib … blocks several cytokine-mediated signalling cascades, thereby inhibiting inflammation.”
Moreover, given the potential side effects of emollients and topical and oral corticosteroids, [J Dtsch Dermatol Ges 2015;13:e1-e22] delgocitinib could be a suitable therapeutic alternative for CHE, said the researchers. While the findings established clinical proof-of-concept on the role of delgocitinib in CHE, more studies are warranted to further validate its efficacy and safety, they added.