A Long-term Administration Study of OPC-41061 in Patients With Autosomal Dominant Polycystic Kidney Disease (ADPKD) [Extension of Study 156-04-001]

Inclusion Criteria: * Patients who completed 5-day repeated administrations and the follow-up observation in the preceding study (156-04-001) * Patients in whom the safety of repeated administration was confirmed based on the investigator's reports from the preceding study (156-04-001) Exclusion Criteria: * Patients with serum creatinine concentration of 2.5 mg/dL or higher at the screening examination * Patients with any of the following complications * Uncontrolled hypertension * Serious cardiovascular disease (eg. heart failure) or hepatic disease (eg. cirrhosis)" * Patients with any of the following complications or history thereof * Clinically significant drug allergies (anaphylaxis) or hypersensitivity (especially, hypersensitivity to benzazepine derivatives or suspected hypersensitivity thereto) * Inability to personally give consent due to a mental disease " * Patients with SBP (in sitting position) \<90 mm Hg (at screening examination) * Patients with history of massive bleeding or bleeding tendency * Patients with a history of drug or alcohol abuse within 6 months prior to the screening examination * Pregnant women, lactating women, or women who may become or plan to become pregnant * Patients who received any investigational drug other than OPC-41061 within 30 days prior to commencement of administration of OPC-41061 * Any patient who, in the opinion of the principle investigator or attending investigators, should not participate in the study