Inclusion Criteria:
1. Participants legally competent to sign and give informed consent.
2. Males and females ages 12 years of age and older.
3. Clinical diagnosis of psoriasis vulgaris of at least 6 months duration as determined by the Investigator. Stable psoriasis for the past 6 months and stable nail disease for the past 6 months.
4. Psoriasis vulgaris on the face, extremities, trunk, and/or intertriginous areas and groin (excluding the scalp, palms and soles).
5. Nail psoriasis affecting ≥3 fingernails on hands.
6. An Investigator's Global Assessment of disease severity (IGA) or (I-IGA) of at least Almost Clear ('1') at Baseline
7. Females of childbearing potential (FOCBP) must have a negative urine pregnancy test at Screening (Visit 1) and a negative urine pregnancy test at Baseline (Visit 2) (if not combined).
- In addition, sexually active FOCBP must agree to use at least one form of highly effective contraception throughout the trial.
- Highly effective forms of contraception include: oral/implant/injectable/transdermal contraceptives, intrauterine device, and partner's vasectomy.
- If barrier methods are used (e.g., condom with spermicide, diaphragm with spermicide), then 2 forms of conception are required.
- The use of abstinence as a contraceptive measure is acceptable as long as this is a consistent part of a lifestyle choice and an acceptable backup method has been identified if the subject becomes sexually active.
8. In good health as judged by the Investigator, based on medical history, physical examination.
Exclusion Criteria:
1. Subjects who cannot discontinue medication and treatments prior to the Baseline visit and during the study according to Excluded Medications and Treatments (Table 1).
2. Subjects who currently have or plan to have gel or acrylic overlays on nails during the study.
3. Subjects who cannot discontinue nail care habits that will confound efficacy and safety assessments (e.g. buffing, filing, excessive trimming). Routine simple clipping is allowed.
4. Subjects who cannot discontinue any nail topcoat products (e.g. hardeners, strengtheners, nail polish) Simple nail polish will be allowed for special events and removed the next day. Subject will note in diary days this occurs and the total days may not exceed 5 study days.
5. Planned excessive exposure of treated area(s) to either natural or artificial sunlight, tanning bed or other LED.
6. Subjects currently taking lithium or antimalarial drugs.
7. Planned initiation or changes to concomitant medication that could, in the opinion of the Investigator, affect psoriasis vulgaris (e.g. beta blockers, ACE inhibitors).
8. Current diagnosis of drug-induced psoriasis.
9. Any recent infection, presence of onychomycosis or any other confounding nail disorder as determined by investigator.
10. Subjects with any condition on the treatment area which, in the opinion of the Investigator, could confound efficacy measurements.
11. Known allergies to excipients in roflumilast cream (petrolatum, isopropyl palmitate, methylparaben, propylparaben, diethylene glycol monoethyl ether, hexylene glycol, cetylstearyl alcohol, dicetyl phosphate and ceteth-10 phosphate).
12. Females who are pregnant, wishing to become pregnant during the study, or are breast-feeding.
13. Previous treatment with any topical PDE4i. Subjects who have received oral roflumilast (Daliresp®, Daxas®) or other PDE4 inhibitors (apremilast) within the past 6 months.
14. Known or suspected:
- severe renal insufficiency or moderate to severe liver impairment (Child-Pugh B or C)
- known HIV infection
- hypersensitivity to component(s) of the study drugs
- history of severe depression, suicidal ideation
15. Subjects with a history of chronic alcohol or drug abuse within 6 months of initiation of study medication.
16. Subjects with a history of a major surgery within 4 weeks prior to Baseline (Visit 2) or has a major surgery planned during the study.
17. Subjects who are unable to communicate, read or understand the local language, or who display another condition, which in the Investigator's opinion, makes them unsuitable for clinical study participation.
18. Subjects who are family members of the clinical study site, clinical study staff / sponsor, or family members of enrolled subjects.
19. Subjects with any serious medical condition or laboratory abnormality that would prevent study participation or place the subject at significant risk, as determined by the Investigator.
20. History of and/or concurrent condition of serious hypersensitivity (anaphylactic shock or anaphylactoid reaction) to PDE-4 inhibitors.
21. Current or a history of cancer within 5 years with the exception of fully treated skin basal cell carcinoma, cutaneous squamous cell carcinoma or carcinoma in situ of the cervix.