Inclusion Criteria:

- Subjects judged as having cancer by biopsy or cytology

- Subjects with carcinomatous ascites

- Male or female subjects between the ages of 20 and 80, inclusive (at time of informed
consent)

- Subjects with survival expectancy of at least 3 months and an Eastern Cooperative
Oncology Group (ECOG) Performance Status score (PS score) of 0 to 2

- Subjects who are inpatients or who can be admitted to the trial site for the duration
of the trial

- Subjects who, together with their partner, are able to practice one of the specified
contraceptive methods until 4 weeks after final trial drug administration

- Subjects capable of giving informed consent to participate in the trial of their own
free will prior to start of the trial.

Exclusion Criteria:

- Subjects with any of the following complications or symptoms:

- Deep vein thrombosis

- Intestinal obstruction or intestinal edema with symptoms similar to intestinal
obstruction

- Hepatic cirrhosis

- Anuria

- Urination impaired due to urinary tract stricture, urinary calculus, tumor in
urinary tract, or other cause

- Continuing symptoms of diarrhea or vomiting

- Infection requiring systemic treatment

- Subjects with any of the following medical histories:

- History of cerebrovascular disorder or coronary disease within 4 weeks prior to
start of the pre-observation period

- History of hypersensitivity or idiosyncratic reaction to benzazepine derivatives
such as mozavaptan hydrochloride or benazepril hydrochloride

- History of gastrectomy or enterectomy to an extent affecting absorption of oral
medication

- Subjects with any of the following abnormal laboratory values:

Platelet count of < 75,000/mm3, hemoglobin of < 8.0 g/dL, neutrophil count of < 1,000/mm3,
total bilirubin of > 4.0 g/dL, serum creatinine of > 3.0 mg/dL, serum sodium of > 147
mEq/L, or serum potassium of > 5.5 mEq/L

- Subjects who have used albumin products (agents for treating hypoalbuminemia) or
blood products containing albumins within 1 week prior to start of the
pre-observation period, or after start of the pre-observation period

- Subjects who have received any investigational drug within 4 weeks prior to start of
the pre-observation period

- Subjects who have previously received OPC-41061

- Subjects who have received surgical treatment or radiation therapy for cancer within
4 weeks prior to start of the pre-observation period

- Subjects for whom the investigator or subinvestigator judges that it would be
difficult to evaluate the efficacy and safety of OPC-41061 due to the effects of
ongoing chemotherapy or other therapies for cancer (eg, improvement of carcinomatous
ascites or development of edema due to adverse events related to therapeutic
interventions other than OPC-41061)

- Subjects who are unable to sense thirst or who have difficulty with fluid or food
intake

- Subjects who are unable to take oral medication

- Female subjects who are pregnant, possibly pregnant, or nursing, or who plan to
become pregnant during the trial period Subjects otherwise judged by the investigator
or subinvestigator to be inappropriate for inclusion in the trial