Pfizer’s investigational oral Janus kinase 1 (JAK1) inhibitor abrocitinib has scored positive top-line results in a phase III atopic dermatitis trial.

The 52-week phase III JADE REGIMEN study investigated abrocitinib in patients aged 12 and older with moderate to severe atopic dermatitis (AD) following response to initial open label induction with abrocitinib 200mg.

Both doses of abrocitinib tested in the study (200mg or 100mg) met the primary endpoint, resulting in significantly fewer patients experiencing a loss of response requiring rescue treatment compared to placebo.

Abrocitinib also met the key secondary endpoint of a larger percentage of patients maintain an Investigator’s Global Assessment (IGA) response of clear or almost clear compared to placebo.

Of the 1,233 participants enrolled in the study, 798 (64.7%) responded during the initial 12-week induction period with abrocitinib monotherapy.

Responder criteria was defined as achieving and IGA score of clear or almost clear, a reduction from IGA baseline of at least two points and reaching an Eczema Area and Severity Index-75 (EASI-75) response compared to baseline.

“Atopic dermatitis brings a lot of uncertainty and disruption to daily life, and the unpredictability of flares can make treating and managing the disease complex and frustrating,” said Michael Corbo, chief development officer, inflammation & immunology, Pfizer Global Product Development.

“These latest results from our phase III clinical trial programme shed light on the potential abrocitinib, if approved, could have to prevent troublesome flares in patients,” he added.

The JADE REGIMEN study is the fifth trial in Pfizer’s global development programme for abrocitinib. Pfizer previously announced complete results from the second trial in the programme, JADE MONO-2, as well as top-line results from the JADE TEEN and JADE COMPARE studies earlier this year.

In addition, complete results from JADE MONO-1 were published in The Lancet in July 2020.

Pfizer has already been granted a priority review from the US Food and Drug Administration (FDA) for its New Drug Appication (NDA) for abrocitinib 100mg and 200mg for the treatment of moderate to severe AD in patients aged 12 years and older.

The European Medicines Agency (EMA) has also accepted a Marketing Authorisation Application (MAA) for abrocitinib in the same patient population, with a decision expected in the second half of 2021.