Open-label Trial to Evaluate the Long Term Safety of Titrated Immediate-release Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease

This trial is a phase 3b to evaluate and describe the long-term safety of tolvaptan treatment
in ADPKD patients with CKD (chronic kidney disease). Eligible Subjects will enter the trial
from Trial 156-08-271 or other Tolvaptan interventional trials. Renal function will be
assessed during screening by using historical laboratory values for serum creatinine levels
to calculate the estimated glomerular filtration rate (eGFR). General safety endpoints will
be assessed and also relevant safety endpoints for the trial as Serum transaminase elevations
in frequency & Serum sodium excursions.

Inclusion Criteria:

1. Male and female subjects ≥ 18 years with confirmed diagnosis of ADPKD (during
participation in prior tolvaptan trials) who have

- Completed and transferred from the double-blind Trial 156-13-210 (12-month period
including post treatment follow-up, regardless of whether this was on-treatment
or off-treatment), or

- Completed Trial 156-08-271 or a prior tolvaptan trial, or

- Interrupted or discontinued treatment in a prior tolvaptan ADPKD trial other than
Trial 156-13-210. Subjects may be enrolled with the medical monitor approval, and
additional close monitoring may be required at the beginning of the study

2. Estimated glomerular filtration rate (eGFR) ≥ 20 mL/min/1.73m2 within 45 days of the
baseline visit. Subjects who have an eGFR between 15 and 19 mL/min/1.73m2 may be
enrolled with medical monitor approval

3. Diagnosis of ADPKD by modified Pei-Ravine criteria

Exclusion Criteria:

- Need for chronic diuretic use

- Hepatic impairment based on liver function assessments other than that expected for
ADPKD with cystic liver disease

- Women of childbearing potential (WOCBP) who do not agree to practice 2 different
methods of birth control or remain abstinent during the trial and for 30 days after
the last dose of IMP

- Women who are breast-feeding and/or who have a positive pregnancy test result prior to
receiving IMP.

- Subjects with contraindications to required trial assessments (contraindications to
optional assessments, eg, MRI are not a limitation).

- Subjects who in the opinion of the Investigator or the Medical Monitor, have a medical
history or medical finding inconsistent with safety or trial compliance