Autosomal dominant hypocalcemia Type 1 is a rare familial genetic form of hypoparathyroidism. Autosomal Dominant Hypocalcemia (ADH) Type 1 is typically passed down from affected parents to their children.~This is a Phase 2b open label, dose finding study to evaluate the safety and tolerability of CLTX-305 (encaleret) in Autosomal Dominant Hypocalcemia (ADH) Type 1 as well as the effects of CLTX-305 (encaleret) on blood calcium concentration.~The estimated duration of this study is 41 months. This study plans to evaluate multiple doses of the investigational drug CLTX-305 (encaleret), in addition to safety and efficacy. CLTX-305 is administered orally.~The study is divided into 3 Periods followed by a Long-Term Extension (LTE):~Periods 1: Up to 8 study participants will be admitted to the NIH Clinical Center for 7 days, where they will be administered different doses of CLTX-305 (encaleret) for up to 5 days.~Period 2: Participants from Period 1, and up to 10 new study participants will be admitted to the NIH Clinical Center for 7 days, where they will be administered different doses of CLTX-305 (encaleret) for up to 5 days.~Period 3: 24 weeks during which eligible study participants who completed Period 2 will take CLTX-305 (encaleret) at home.~LTE: Up to 25 months during which eligible study participants who completed Period 3 will take CLTX-305 (encaleret) at home.~Study participants may:~Participate in Period 1~Participate in Period 2~Participate in both Period 1 and Period 2~Participate in Period 3 after completing Period 2~Participate in LTE after completing Period 3
A Phase 2b open label, dose finding study to evaluate the Safety, Tolerability and Efficacy of CLTX-305 (encaleret) in Autosomal Dominant Hypocalcemia (ADH) Type 1