Chronic Hypoparathyroidism, Hypoparathyroidism
Conditions
Keywords
Chronic Hypoparathyroidism, Hypoparathyroidism, Encaleret
Brief summary
The aim of the study is to evaluate the efficacy, safety, and tolerability of orally administered encaleret tablets in participants with chronic hypoparathyroidism (HP).
Interventions
DRUGEncaleret
Oral tablets
DRUGPlacebo
Oral tablets
Sponsors
Calcilytix Therapeutics, Inc., a BridgeBio company
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Masking description
The treatment period will be double-blind. The long-term extension period will be open-label.
Eligibility
Sex/Gender
ALL
Age
16 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Key Inclusion Criteria: * Participants must have had a clinically confirmed diagnosis of chronic HP, with disease duration of at least 26 weeks prior to screening. Cause of chronic HP can be postsurgical, autoimmune or idiopathic. * For participants with nonsurgical chronic HP etiology, sufficient documentation that the participant does not harbor any variants in calcium-sensing receptor (CASR) or GNA11 that are classified as pathogenic, likely pathogenic, or of uncertain significance, with the exception of benign common polymorphisms (CASR A986S and R990G) is needed. * Participants must be on stable doses of calcium and active vitamin D supplementation at or above the following minimum thresholds for at least 6 weeks prior to screening. For participants enrolled in study sites outside Japan: 1. Calcitriol ≥0.5 micrograms (μg)/day or alfacalcidol ≥1.0 μg/day 2. Elemental calcium ≥800 milligrams (mg)/day (for example, calcium citrate, calcium carbonate) * Participants must meet the following criteria during screening: cCa within 7.8 to 9.5 mg/deciliter (dL) and 24-hour UCa ≥300 mg/day (males) or ≥250 mg/day (females). * Participants have serum 25-hydroxy (OH) vitamin D concentration of 20 to 80 nanograms (ng)/milliliter (mL) (50-200 nanomoles \[nmol\]/liter \[L\]). * Participants have serum magnesium concentration within the reference range. * Participants on thiazide or loop diuretics must be able to discontinue them during the first 24 weeks of study (treatment). * Participants must be capable of giving signed informed consent or assent, which includes compliance with the requirements and restrictions listed in the informed consent form and in this protocol. Key
Exclusion criteria
* Genetically confirmed diagnosis of autosomal dominant hypocalcemia type 1 (ADH1) or autosomal dominant hypocalcemia type 2 (ADH2) due to activating variants in CASR or GNA11, respectively. * History of hypocalcemic seizure in the 3 months prior to screening. * History of cancer (except non-melanoma skin cancer) or bone metastases in the 5 years prior to screening. * Prior skeletal irradiation, chemotherapy with alkylating agents, or diagnosis of Paget's disease, fibrous dysplasia, chronic osteomyelitis, bone infarcts, benign bone tumors with curettage and grafting, retinoblastoma, or Li-Fraumeni syndrome. * Presence or history of any disease or condition (for example, drug or alcohol dependence) that, in the view of the investigator, would affect the participant's safety or places the participant at high risk of poor treatment compliance or of not completing the study. Other protocol-defined inclusion/
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Number of Responders who Achieve Both Albumin-Corrected Blood Calcium (cCa) and 24-hour Urine Calcium (UCa) Within the Protocol-defined Target Range | Week 24 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of Participants With cCa Within Protocol-defined Range | Week 24 | — |
| Change From Baseline to Week 24 in cCa | Baseline, Week 24 | — |
| Absolute Value of cCa at Week 24 | Week 24 | — |
| Number of Participants With 24-hour UCa Below the Sex-specific Upper Reference Limits (Protocol-defined Range) | Week 24 | — |
| Change from Baseline to Week 24 in 24-hour UCa | Baseline, Week 24 | — |
| Absolute Value of 24-hour UCa at Week 24 | Week 24 | — |
| Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Calcium Supplements Dose | Baseline up to Week 24 | — |
| Percent Change From Baseline to Week 24 in Daily Intake of Calcium Supplements Among the Participants Who Meet the Primary Endpoint (Biochemical Response) | Baseline, Week 24 | — |
| Number of Participants With Calcium Independence | Week 20 to Week 24 | — |
| Change from Baseline in Signs and Symptoms of Hypoparathyroidism, Based on Participants' Responses | Baseline, Week 24 | — |
| Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Active Vitamin D Dose | Week 24 | — |
| Percent Change From Baseline in Daily Intake of Active Vitamin D Among the Participants Who Meet the Primary Endpoint (Biochemical Response) | Baseline, Week 24 | — |
| Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Has Active Vitamin D Independence | Week 24 | — |
| Number of Participants Who Meet Specific Protocol-defined Criteria or Calcium and Vitamin D Analysis | Week 20 to Week 24 | Protocol-defined criteria which include the following: cCa within protocol-defined range, 24-hour UCa below the sex-specific upper reference limits (protocol-defined range), independence from conventional therapy, no increase in the study drug dose, and no missing active vitamin D and calcium supplementation data. |
Countries
Canada, United States
Contacts
CONTACTMedical Information
STUDY_DIRECTORCalcilytix Medical Director
Calcilytix Therapeutics, Inc., a BridgeBio company
Outcome results
None listed