A topical formulation of the phosphodiesterase-4 (PDE4) inhibitor roflumilast is potentially effective in the treatment of plaque psoriasis, according to US researchers.

Results from a phase 2b randomised controlled trial involving 331 adults with plaque psoriasis found that patients assigned to treatment with roflumilast cream showed significant improvements in psoriasis signs and symptoms within two weeks.

Patients using the once-daily treatment reported clear skin as well as improvement in itch and burden of disease, according to results reported at the American Academy of Dermatology’s 2020 virtual meeting.

PDE4 inhibition regulates pro-inflammatory and anti-inflammatory cytokine production and cell proliferation and roflumilast has been licensed for the treatment of COPD for almost a decade. Another PDE-4 inhibitor apremilast is already used in the treatment of psoriasis

But according to study investigator Professor Mark Lebwohl, a dermatologist at the Icahn School of Medicine at Mount Sinai, New York, roflumilast is a more potent PDE-4 inhibitor whose effects as a topical formulation have shown promise.

In the study, adults with plaque psoriasis were randomly assigned to receive topical treatment with roflumilast cream 0.3%, 0.15%, or matching treatment applied once daily for 12 weeks.

While improvements were seen within two weeks, peak improvement in the primary outcome measure of investigator global assessment (IGA) of clear or almost clear occurred at week 8 with response maintained to week 12.

A week 8 IGA of 0 or 1 plus at least a 2-grade improvement from baseline occurred in 32.2% of the 0.3% roflumilast group, 24.5% of patients using 0.15% roflumilast and 9.8% of controls.

Similarly 31.2% of patients using roflumilast 0.3% had a PASI 75 and 16.5% had a PASI 90, compared with 12.2% and 5.5%, respectively, among those using the control (p ≤ 0.015)

In secondary outcomes, intertriginous IGA success was seen in 87.1% in the 0.3% roflumilast group, compared with 36.1% among patients using the control (p = 0.007).

Adverse events related to were primarily mild or moderate, with no clinically significant differences across groups.

Professor Lebwohl said the results from the phase 2 study were particularly encouraging for patients who need new and better options to treat this chronic skin disease, and drug is now being investigated in a phase 3 trial.

“Plaque psoriasis imposes a significant burden on patients, and is often associated with poor quality of life,” he said.

“Effectively treating psoriasis with topical therapies, which the vast majority of patients receive, is especially challenging due to side effects, tolerability, or efficacy of existing topical treatments. Roflumilast cream could really be a game changer.”

The study was sponsored by the manufacturer Arcutis.