Dose-finding Study of New Tolvaptan Formulation in Subjects With ADPKD

Group 1 will have 12 subjects enrolled in a 3-period, randomized, crossover to compare
multiple doses of a 90-30 mg split-dose of the tolvaptan IR formulation, a 120 mg once daily
(QD) dose of the tolvaptan MR formulation, and, in an incomplete block randomization,
multiple doses of either 20 mg QD, 60 mg QD, or 20 mg twice daily (BID) tolvaptan MR
formulation. All dose regimens will be administered for 7 days. Placebo doses will be
administered in order to mask QD vs BID treatments.

Group 2 will have 12 subjects enrolled in a 3-period, randomized, crossover to compare
multiple oral doses of the tolvaptan MR formulation administered for 7 days as 20 mg QD, 60
mg QD, and 20 mg BID. Placebo capsules will be administered in order to mask QD vs BID
treatments.

Subjects will have in-clinic assessments on 12 days to obtain 24-hour PK and PD data.
Subjects will visit the clinic from the afternoon of Day -1 through the morning of Day 1.
They will return at the end of each dosing period for a similar inpatient period (ie, from
the afternoon of Day 6 through the morning of Day 8, from the afternoon of Day 13 through the
morning of Day 15, from the afternoon of Day 20 through the morning of Day 22). Except for
the first dose of each period and the doses taken in the clinic on the last day of each
regimen and the afternoon of Days 6, 13 and 20, all other doses will be taken by the subject
as an outpatient.

Inclusion Criteria:

- Subjects (male or female) who are surgically sterile (ie, have undergone hysterectomy)
or using contraception or agree to remain abstinent

- Subjects between the ages of 18 and 50, inclusive

- Subjects with a body mass index between 19 to 35 kg/m2 (inclusive)

- Subjects with a diagnosis of ADPKD by modified Ravine criteria

- Subjects must be in good health as determined by medical history, physical
examination, ECG, serum/urine biochemistry, hematology, and serology tests

- Subjects with the ability to provide written, informed consent prior to initiation of
any trial-related procedures, and ability, in the opinion of the principle
investigator, to comply with all requirements of the trial

- Subjects who expect to be able to complete all dosing periods and assessments within
42 (+2) days after dosing on Day 1

Exclusion Criteria:

- Subjects using diuretics within 14 days prior to check in on Day -1

- Subjects with incontinence, overactive bladder, or urinary retention (eg, benign
prostatic hyperplasia)

- Subjects (male or female) with nocturia/urgency (outside of the 2 to 4 times awakening
per night expected for ADPKD patients) at screening

- Subjects with liver disease, liver function abnormalities or serology other than that
expected for ADPKD with cystic liver disease at baseline

- Subjects with clinically significant abnormality in past medical history, or at the
Screening physical examination, that in the investigator's or sponsor's opinion may
place the volunteer at risk or interfere with outcome variables including absorption,
distribution, metabolism, and excretion of drug. This includes, but is not limited to,
history of or concurrent cardiac, hepatic, renal, neurologic, endocrine,
gastrointestinal, respiratory, hematologic, and immunologic disease

- Subjects with a history of drug and/or alcohol abuse within 2 years prior to screening

- Subjects who have a history of or test positive at screening for hepatitis B surface
antigen (HBsAg), hepatitis C antibodies (anti-HCV), and/or human immunodeficiency
virus (HIV)

- Subjects who have clinically significant allergic reactions to tolvaptan or chemically
related structures such as benzazepines (eg, benzazepril, conivaptan, fenoldopam
mesylate or mirtazapine)

- Subjects who have taken an investigational drug within 30 days preceding trial entry

- Subjects with any history of significant bleeding or hemorrhagic tendencies

- Subjects with a history of difficulty in donating blood

- Subjects who have donated blood or plasma within 30 days prior to dosing

- Subjects who have consumed alcohol and/or food or beverages containing
methylxanthines, grapefruit, grapefruit juice, Seville oranges, or Seville orange
juice within 72 hours prior to Day 1 dosing

- Subjects taking CYP3A4 inhibitors, with the exception of amiodarone, taken within 30
days of dosing (eg, amprenavir, atorvastatin, aprepitant, chloramphenicol [not eye
drops], cimetidine, clarithromycin, clotrimazole [if used orally], danazol,
delavirdine, diltiazem, erythromycin, fluconazole, fluvoxamine, indinavir, isoniazid,
itraconazole, josamycin, ketoconazole, nelfinavir, nefazadone,
quinupristin/dalfopristin, ritonavir, saquinavir, troleandomycin, verapamil)

- Subjects taking CYP3A4 inducers taken within 7 days of dosing (eg, rifampin, St. Johns
Wort)

- Subjects with a history of serious mental disorders

- Subjects with previous exposure to tolvaptan