Pilot Efficacy and Safety Study of Oral DF2156A in Patients With Active Bullous Pemphigoid

Inclusion Criteria: * Male and female patients aged \>50 years. * Patients with newly diagnosed or relapsing bullous pemphigoid based on clinical diagnosis to be confirmed by direct immunofluorescence and indirect immunofluorescence on salt-spit skin (or BP180 and/or BP230 ELISA). Confirmation by laboratory tests will be obtained ideally before or anyway within one week after enrolment. For the purpose of this study, clinical relapses are defined as re-appearance of clinical symptoms after the patient had attained remission lasting for more than 3 months without immunosuppressive treatment. In patients with relapsing BP, clinical diagnosis will be confirmed by indirect immunofluorescence or BP180 and/or BP230 ELISA only. * Patients with mild to moderate active blistering disease (total number of blisters between 1 and 30) whether associated or not with urticarial/eczematous lesions. * Patients with modified ABSIS score ≤50 * Patients free from any systemic treatments that may affect the course of the disease with the following off-period prior to enrolment: 1. 3 weeks: steroids, dapsone, tetracyclines, nicotinamide, 2. 3 months: azathioprine, mycofenolate mofetil, cyclophosphamide, methotrexate, intravenous immunoglobulins, immunoadsorption, TNF antagonists 3. 12 months: rituximab, leflunomide * Patients free from any topical treatments other than topical antibiotics and antiseptics in the 4 days prior to enrolment. * Patients able to comply with the protocol procedures for the duration of the study, including scheduled follow-up visits and examinations. * Patients able to provide informed consent. Exclusion Criteria: * Patients with a Karnofsky rating score \<40%. * Patients with mucosal involvement. * Patients with moderate to severe renal impairment as per calculated creatinine clearance (CLcr) \< 50 mL/min according to the Cockcroft-Gault formula (Cockcroft-Gault , 1976). * Patients with hepatic dysfunction defined by increased ALT/AST \> 3 x upper limit of normal (ULN) and increased total bilirubin \> 3 mg/dL \[\>51.3 μmol/L\]. * Patients with hypoalbuminemia defined as serum albumin \< 3 g/dL. * Patients with a baseline (day 0/1, pre-dose) QTcF \> 470 msec. * Patients who had a myocardial infarction in the 6 months prior to enrolment. * Patients on treatment with phenytoin, warfarin, sulphonylurea hypoglycemics (e.g. tolbutamide, glipizide, glibenclamide/glyburide, glimepiride, nateglinide) and high dose of amitriptyline (\> 50 mg/day). * Patients with known hypersensitivity to non-steroidal antiinflammatory drugs. * Patients using any investigational agent within 12 months prior to enrolment. * Pregnant or breast feeding women. Unwillingness to use effective contraceptive measures up to 2 months after the end of study drug administration (females and males). Additional Exclusion Criteria for Germany only: * Patients with hypokalemia defined as serum potassium \< 3.5 mmol/L. * Patients with clinically relevant bradycardia (heart rate \< 50 beats/min) * Patients with a complete left bundle branch block. * Patients with a history of uncontrolled or labile hypertension * Patients with a history of congestive heart failure. * Patients with a history of cardiomyopathy. * Patients with unstable angina pectoris. * Patients with a personal or family history of congenital or documented acquired QT interval prolongation. * Patients with a significant atrial or ventricular arrhythmia or symptomatic arrhythmia in the past.