Study to Evaluate the Efficacy and Safety of P-3073 Nail Solution in the Treatment of Mild to Moderate Psoriatic Fingernail/s

Inclusion Criteria: * Written informed consent before starting any study related procedure. * Patients ages ≥ 18 and ≤ 80 years old. * Men or women. * Outpatients. * Patients with mild to moderate psoriatic fingernail/s, defined as fingernail/s with matrix psoriasis NAPSI score and/or bed psoriasis NAPSI score ≥ 1 and ≤ 3 at baseline. The sum of the scores for each nail should range between 1 and 6. * In case of skin involvement, patients with established clinical diagnosis of mild to moderate psoriasis (BSA involvement ≤ 8% or Psoriasis Area Severity Index (PASI) ≤ 10). Exclusion Criteria: * Use of any systemic treatment for psoriasis and/or nail psoriasis during the last six months before the screening visit. * Use of any topical treatment for nail psoriasis on fingernails during the last six months before the screening visit. * Use of photochemotherapy (phototherapy is allowed) or other forms of radiotherapy during the last four weeks before the screening visit. * Positive mycology findings (KOH evaluation or culture) obtained in the three months before the screening visit or positive KOH evaluated at the screening visit. * Patients using nail polish or other nail cosmetic products during last 72 hours prior to study drug application. * Systemic use of the following therapies for any reason during last three months before the screening visit: immunosuppressives, chemotherapy and corticosteroids (topical use for plaque psoriasis is allowed). * Consumption of oral Vitamin D or its analogues for any reason during the last three months before the screening visit (Calcipotriene topical use for plaque psoriasis is allowed). * Patients with a clinically significant history of cardiovascular, renal, neurologic, liver, immunologic or endocrine dysfunction. A clinically significant disease is defined as one that in the opinion of the investigator may either put the patient at risk because of participation in the study or a disease that may influence the results of the study or the patient's ability to participate in the study. * Patients with a recent history (\< 1 year) of myocardial infarction and/or (\< 3 years) of heart failure or patients with any cardiac arrhythmia requiring drug therapy. * History of hypercalcaemia or hypercalciuria. * History of previous or current malignancy in particular lymphoma, melanoma and/or basal cell carcinoma. * History of allergic reactions to Calcipotriene or P-3073 excipients. * Patients unable to understand the procedures and purposes of the study. * Patients unable or unwilling to accept and meet study requirements. * Use of an investigational drug or participation in an investigational study within 30 days, or 6 half lives whichever is longer, prior to application of study medication. * Alcohol or substance abuse. * AIDS symptoms or any other immunodeficiency. Additional exclusion criteria for females only: * Breast-feeding patients. * Positive urine pregnancy test at screening (performed for all females of child bearing potential or for those in non-surgical post-menopause for less than 1 year). * Female of childbearing potential having unprotected sexual intercourse with any non-sterile male partner (i.e., a male who has not been sterilized by vasectomy at least 6 months prior to drug application) within 14 days prior to study drug application. Acceptable methods of contraception are the following: condom, diaphragm, intrauterine contraceptive device (placed at least 4 weeks prior to study drug application), pill + condom.