Long Term Safety of Immediate-release Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease

Inclusion Criteria: * Male and female participants ≥ 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. Participants may be enrolled with the medical monitor approval, and additional close monitoring may be required at the beginning of the trial. * eGFR ≥ 20 milliliter (mL)/minute (min)/1.73 meter squared (m\^2) within 3 months prior to the baseline visit. Participants who have an eGFR ≤ 20 mL/min/1.73 m\^2 may be enrolled with medical monitor approval. Exclusion Criteria: * Need for chronic diuretic use * Hepatic impairment based on liver function abnormalities other than that expected for ADPKD with cystic liver disease * Women of childbearing potential 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 investigational medicinal product (IMP) * Women who are breast-feeding and/or who have a positive pregnancy test result prior to receiving IMP. * Participants with contraindications to required trial assessments (contraindications to optional assessments, for example, magnetic resonance imaging \[MRI\] are not a limitation). * Participants who in the opinion of the investigator or the medical monitor, have a medical history or medical finding inconsistent with safety or trial compliance