Inclusion Criteria:

• Subject will sign and date an informed consent form (ICF).
• Willing and able to comply with scheduled visits, observation period, study restrictions, laboratory tests, contraceptive guidelines, and other study procedures.
• Males and females between the ages of 18 and 65 years, inclusive.
• Body mass index (BMI) of 18.0 to 36.0 kg/m^2 , inclusive,and body weight <136 kg.

The following Inclusion Criteria apply to subjects in the healthy subject cohort:

• Healthy, as defined by no clinically relevant abnormalities identified by a detailed medical history, full physical examination (PE), including blood pressure and pulse rate measurement, and clinical laboratory tests.
• eGFR ≥ 75 to <  120 mL/min/1.73 m^2 based on the Modified Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation without the race adjustment.
• Subjects will be matched during Screening to subjects in the ADPKD Cohort for age (± 5 years) and gender.

The following Inclusion Criteria apply to subjects in the ADPKD cohort:

• Diagnosis of ADPKD demonstrated by evidence of polycystic kidney disease in one or both biological parents and meeting Pei-Ravine classification noted below.
  • Cysts must be > 2.5 mm in diameter and the minimum number of cysts present for each age category are as follows:
    • Subjects < 40 years of age: ≥ 3 cysts in between both kidneys;
    • Subjects ≥ 40 years of age: ≥ 2 cysts in each kidney.

Note: If there is no family history of ADPKD, then a clinical diagnosis of ADPKD and imaging documentation of > 10 cysts per kidney can be used for enrollment.

• ADPKD subjects with Mayo imaging classification (MIC) status of class 1C through of 1E. MIC status can be determined through historical (≤5 years) or screening MRI.
• eGFR ≥ 45 to < 120 mL/min/1.73 m^2 based on the Modified CKD-EPI equation without the race adjustment.
• For subjects receiving tolvaptan therapy: must have received tolvaptan for ≥ 12 months at time of Screening with no plans to discontinue therapy before study completion.

Note: Subjects not currently receiving tolvaptan therapy should not plan to initiate tolvaptan therapy for the duration of this study.

Exclusion Criteria: 

• Subjects with metallic implants or medical conditions that are contraindicated with MRI.
• History of any illness or any clinical condition that, in the opinion of the investigator, might confound the results of the study or pose an additional risk during the trial. This may include, but is not limited to, risk of compliance, mental disease, and history of cancer, except squamous cell skin cancer, basal cell skin cancer, stage 0 cervical carcinoma in situ (all 3 diagnosed ≥ 3 years ago with no recurrence in the past 3 years).
• Females who are pregnant, nursing, or planning to become pregnant during the study.
• Use of substances, activities, or devices as indicated in Section 9.4 during the specified times.
• Subject, or close (first degree) relative of the subject, is the investigator or a subinvestigator, research assistant, pharmacist, study coordinator, or other staff directly involved with the conduct of the study at that site.
• Uncontrolled hypertension, defined as systolic blood pressure > 160 mmHg or diastolic blood pressure > 95 mmHg.
• A diagnosis of cystic fibrosis.
• Ongoing or history of dialysis.
• History of solid organ or bone marrow transplant.
• Immediate genetic relative of an enrolled subject (parent, grandparent, or child).
• Currently enrolled in an interventional trial.
• Has taken somatostatin analogues within the 12 weeks before Screening and has plans to start taking somatostatin analogues during study participation.
• Had renal cyst infection or ruptured cyst ≤ 6 months before Screening.
• Has had a renal cyst aspiration or fenestration within 12 weeks of Screening.
• Active diuretic use.

The following Exclusion Criterion applies to subjects in the healthy subject cohort:

• History of kidney disease that in the opinion of the investigator could confound study results, including but not limited to PKD, family history of PKD, congenital or acquired (cyst) anomalies of the kidney and urinary tract , previous nephrectomy, kidney stones, and recurrent urinary tract infections.

The following Exclusion Criteria apply to subjects in the ADPKD cohort:

• History of diabetes mellitus or history of kidney disease other than PKD;
• eGFR <45 mL/min/1.73 m^2 based on the modified CKD-EPI equation without the race adjustment.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 10/23/2024. Questions regarding updates should be directed to the study team contact.