Apremilast in Patients With Moderate to Severe Palmoplantar Pustulosis (PPP) (APLANTUS)

Inclusion Criteria

• Male and female patients aged 18 years or more at screening visit.
• Patients with chronic PPP (disease history of at least 6 months of diagnosis), who were eligible for treatment with systemic therapy defined as having PPP inadequately controlled by topical treatment and/or phototherapy and/or previous systemic therapy
• Patients with chronic moderate to severe PPP defined as patients with a PPPASI ≥12 with or without concomitant plaque-type psoriasis
• Negative result of a urine pregnancy test taken at screening and at baseline for all women, except those who were surgically sterile or at least 1 year postmenopausal (i.e. at least 12 consecutive months with amenorrhea without other known or suspected medical cause)
• Willingness and capability of using a highly effective contraceptive measures from Screening visit until the end of at least one menstrual cycle (but not less than 28 days) following discontinuation of apremilast as defined below:
• Female patient of childbearing potential (fertile, following menarche and until becoming post- menopausal unless permanently sterile) using a highly effective method of contraception OR female patients of non-childbearing potential (surgically sterilized [e.g. hysterectomy, bilateral salpingectomy and bilateral oophorectomy] or postmenopausal)
• Male patient, and their female partner of childbearing potential, using a highly effective method of contraception
• Adequate contraceptive method defined as:
• A method with less than 1% failure rate (e.g. permanent sterilization, hormone implants, hormone injections, some intrauterine devices, or vasectomized partner) OR
• The use of two methods of contraception (e.g. one barrier method [condom, diaphragm or cervical/vault caps] with spermicide and one hormonal contraceptive [e.g. combined oral contraceptives, patch, vaginal ring, injectables and implants])
• Patient was capable of understanding and giving written, voluntary informed consent before study screening.
• Willingness and capability of complying with all study procedure requirements, as per the Investigator's judgment (e.g. patient able to swallow the apremilast tablets, blood sampling).

Exclusion Criteria

• General:
• Pregnant or breast-feeding women
• Current or history of psychiatric disease that would interfere with the ability to comply with the study protocol or give informed consent
• Patients known to have had a substance abuse (drug or alcohol) problem within the previous 12 month
• Individuals who were involved in the organization of the study
• Patients who were in any way dependent on the investigator
• Patients who were participating in a clinical study
• Relatives, partner or staff of any clinical site personnel
• Disease-related:
• Evidence of skin conditions (e.g. eczema) other than PPP/psoriasis that would interfere with evaluations of the effect of study medication on PPP or psoriasis.
• Laboratory values from routine blood test taken within the 8 weeks prior to screening with any of the following:
• Serum creatinine >1.4 x upper limit of normal (ULN) for age and gender
• Estimated Glomerular Filtration Rate (eGFR) <30 mL/min/1.73m2 according to the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation
• Pustular psoriasis lesions on the part of body other than hands or feet
• Significant concurrent medical conditions at the time of screening, including:
• Risk factors for renal toxicity (renal inflammation)
• Severe hepatic dysfunction
• Unstable angina pectoris
• Uncompensated congestive heart failure
• Severe pulmonary disease requiring hospitalization or supplemental oxygen therapy
• Immunodeficiency disorders: primary or secondary
• Known positive human immunodeficiency virus (HIV) test result, hepatitis B surface (HBS) antigen or hepatitis C virus (HCV) test result
• Uncontrolled insulin-dependent diabetes mellitus
• Cancer or history of cancer (except for resected cutaneous basal cell or squamous cell carcino