Positive topline results were announced from a phase 3 study evaluating apremilast, a phosphodiesterase 4 inhibitor, in adults with moderate to severe genital psoriasis and moderate to severe plaque psoriasis.

The multicenter, randomized, double-blind, placebo-controlled DISCREET (ClinicalTrials.gov Identifier: NCT03777436) study included 289 patients with moderate to severe genital psoriasis, defined as modified static Physician’s Global Assessment of Genitalia (sPGA-G) score of at least 3. Patients also had moderate to severe plaque psoriasis (sPGA score greater than or equal to 3) with body surface area (BSA) involvement of at least 1% in a non-genital area and had an inadequate response or intolerance to topical therapy. 

Study participants were randomly assigned 1:1 to receive either apremilast 30mg orally twice daily or placebo for the first 16 weeks. After 16 weeks, patients were continued or switched to apremilast during the extension phase and treated until week 32. The primary endpoint was the proportion of patients who achieved modified sPGA-G response at week 16, defined as a modified sPGA-G score of clear (0) or almost clear (1) with at least a 2-point reduction from baseline.

Findings showed that treatment with apremilast met the primary endpoint demonstrating a clinically meaningful and statistically significant improvement in modified sPGA-G response at week 16 compared with placebo. 

Additionally, apremilast met all secondary endpoints at week 16 compared with placebo, including meaningful and significant improvements in Genital Psoriasis Itch Numerical Rating Scale (GPI-NRS) response (defined as 4-point reduction from baseline or greater in GPI-NRS item score within the Genital Psoriasis Symptoms for subjects with a baseline score of 4 or greater); affected BSA change from baseline; Dermatology Life Quality Index change from baseline; and sPGA response (defined as sPGA score of clear [0] or almost clear [1] with at least a 2-point reduction from baseline).

The safety profile of apremilast was consistent with its known profile. The most common adverse reactions were diarrhea, headache, nausea, and nasopharyngitis.

Detailed results from the 16-week double-blind phase of the study will be submitted for presentation at an upcoming medical conference. The extension phase of the study is ongoing and is expected to be completed in the first half of 2022. 

Apremilast is marketed under the brand name Otezla® and is currently approved for the treatment of patients with moderate to severe plaque psoriasis who are candidates for phototherapy or systemic therapy, active psoriatic arthritis, and for oral ulcers associated with Behçet’s disease.


Amgen announces positive top-line results from Otezla® (apremilast) phase 3 DISCREET study in moderate to severe genital psoriasis. News release. Amgen. December 1, 2021. Accessed December 2, 2021. https://www.prnewswire.com/news-releases/amgen-announces-positive-top-line-results-from-otezla-apremilast-phase-3-discreet-study-in-moderate-to-severe-genital-psoriasis-301435620.html