Pharmacokinetics, Efficacy, and Safety of Encaleret in Pediatric Participants With Autosomal Dominant Hypocalcemia Type 1 (ADH1)

Key Inclusion Criteria:

• Provide written informed consent (if legally permitted), or have written informedconsent from a parent/legal guardian and provide assent (where required and asappropriate per local requirements)

• Have a documented pathogenic or likely pathogenic activating variant, or variant ofuncertain significance of the calcium-sensing receptor (CASR), associated withbiochemical findings of hypoparathyroidism at screening or a documented history ofhypoparathyroidism as manifested by hypocalcemia and intact parathyroid hormone (PTH) <40 picogram per milliliter (pg/mL) (4.2 picomoles per liter [pmol/L])

• Have at least 1 symptom or sign of hypoparathyroidism at screening or a documentedhistory of symptoms or signs of hypoparathyroidism

• Be on ADH1 treatment for at least 6 months before screening for cohorts 1 to 3, orfor at least 3 months before screening for cohort 4

Key Exclusion Criteria:

• History of thyroid or parathyroid surgery

• History of renal transplantation

• History of cancer (except thyroid cancer, basal cell skin cancer, or squamous cellskin cancer), skeletal malignancies, bone metastases, irradiation (radiotherapy) tothe skeleton, chemotherapy with alkylating agents, Paget disease, fibrous dysplasia,chronic osteomyelitis, bone infarcts, benign bone tumors with curettage and bonegrafts, retinoblastoma, or Li-Fraumeni syndrome within 5 years before screening

• Received any investigational medicinal product within 30 days or 5 half-lives beforeDay 1, whichever is longer, or is in follow-up for another interventional clinicalstudy during screening

• Treatment with a strong P-glycoprotein (P-gp) inhibitor within 300 days beforescreening for amiodarone or within 30 days before screening for any other strongP-gp inhibitor

• Treatment with cardiac glycosides, or is being breastfed while the participant'snursing mother is treated with cardiac glycosides, within 30 days before screening

• Presence or history of any disease or condition (eg, drug or alcohol dependence)that would affect the participant's safety, treatment compliance, or ability tocomplete the study, in the opinion of the investigator

Other protocol defined inclusion/exclusion criteria apply.