This is a 12-week, single-arm, open-label pilot study to assess the safety and preliminary efficacy of oral roflumilast in adults with moderate-to-severe plaque psoriasis. All participants, both male and female, will receive oral roflumilast starting at 250 mcg once daily for 10 days, followed by 500 mcg once daily for the remainder of the study. The primary outcome is the mean change in Psoriasis Area and Severity Index (PASI) score from baseline to Week 12. Secondary outcomes include change in body mass index (BMI) and safety assessments, including treatment-emergent adverse events, serious adverse events, and laboratory abnormalities. Male and female participants will be analyzed as subgroups.

This pilot study is designed to evaluate the safety and preliminary efficacy of oral roflumilast in adults with moderate-to-severe plaque psoriasis. The study was approved by the Mansoura University Faculty of Medicine Institutional Review Board (IRB), Approval Code: R.25.06.3223.R1, and participants will be enrolled only after obtaining informed consent.

Each participant will undergo a detailed history and clinical examination, including:

Personal history: name, age, sex, occupation, residence, marital status, number of children, and special habits of medical importance.

History of present illness: onset, course, duration of psoriasis, and precipitating factors.

Medication history: nature, route, dose, compliance, duration, effect, and side effects.

Family history: psoriasis or other dermatoses.

Past medical history: associated systemic, other dermatological diseases, or major surgical operations.

Menstrual and obstetric history (for female participants).

A general clinical examination will be performed to assess overall health and exclude any systemic diseases.

The study will monitor clinical response using the Psoriasis Area and Severity Index (PASI) and record body mass index (BMI) changes. Safety will be assessed through monitoring of treatment-emergent adverse events, serious adverse events, and routine laboratory tests. Participants will attend scheduled visits throughout the 12-week treatment period, and data will be analyzed overall and by sex-based subgroups.

Inclusion Criteria:

• Psoriatic patients ≥ 18 years in whom systemic therapy is indicated.
• Chronic stable plaque psoriasis.
• Patients who don't use other systemic therapy for psoriasis in the last 2 months (or naïve who didn't use any systemic therapy before).
• Safe contraception during the study.

Exclusion Criteria:

• Pregnant or lactating women, as well as women of childbearing potential not using an effective method of contraception.
• Age <18 years.
• Other concomitant psoriasis systemic treatments such as Acitretin and biologics.
• Previous systemic treatment of psoriasis in the last 2 months.
• Patients receiving inducers or inhibitors of cytochromes CYP3A4 and CYP1A.
• Other systemic diseases other than COPD, especially hepatic impairment.
• Hypersensitivity to the active substance of roflumilast or to any of its excipients
• The use of contraception with gestodene and ethinylestradiol
• Unreliable patients.

This is an open-label study: neither the participants nor the investigators are blinded. All participants receive oral roflumilast, and both participants and study staff are aware of the treatment assignment. No placebo or comparator is used.