Autosomal Dominant Hypocalcemia (ADH)
Conditions
Keywords
Autosomal Dominant Hypocalcemia Type 1 (ADH1), Hypocalcemia, Musculoskeletal Diseases, Muscular Diseases, Musculoskeletal Abnormalities, Calcium Metabolism Disorders, Metabolic Diseases, Hypoparathyroidism, Hypocalcemic Seizures, Hypercalciuria, Nephrocalcinosis, Nephrolithiasis, Calcium Sensing Receptor, Encaleret, Hypopara
Brief summary
The primary purpose of the study is to understand the effectiveness, safety, and tolerability of encaleret when compared to standard of care (SoC) treatment in participants with Autosomal Dominant Hypocalcemia Type 1 (ADH1).
Interventions
DRUGEncaleret
Administered as film-coated tablet for oral use
DIETARY_SUPPLEMENTStandard of Care
Calcium supplements and/or active Vitamin D (calcitriol, alfacalcidol, falecalcitriol, etc.)
Sponsors
Calcilytix Therapeutics, Inc., a BridgeBio company
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
16 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Key Inclusion Criteria: 1. Participants must have a documented pathogenic or likely pathogenic activating variant, or variant of uncertain significance, of the calcium sensing receptor (CASR) gene associated with biochemical findings of hypoparathyroidism. 2. Participants must have a documented history of symptoms or signs of ADH1. 3. Participants 16 to \<18 years old must have closed growth plates on hand radiograph. 4. Participants treated with thiazide diuretics must discontinue thiazides for at least 14 days prior to SoC Optimization Visit 1 through Week 24 (Period 3). When the thiazide is being used as an antihypertensive, alternative therapy will be prescribed by the Investigator as needed. 5. Participants treated with phosphate binders (other than calcium salts) must discontinue the phosphate binders at least one day prior to the SoC Optimization Visit 1. 6. Participants treated with magnesium or potassium supplements must be willing to discontinue such treatment prior to the first dose of encaleret. 7. Participants treated with potassium-sparing diuretics must be willing to discontinue such treatment prior to the first dose of encaleret. 8. Participants must meet SoC Optimization criteria as defined in the protocol. Key
Exclusion criteria
1. History of hypocalcemic seizure within the past 3 months preceding Screening. 2. History of thyroid or parathyroid surgery. 3. History of renal transplantation. 4. Pregnant or nursing (lactating) women, where pregnancy is confirmed by a positive beta-human chorionic gonadotropin (β-hCG) laboratory test. 5. History of treatment with parathyroid hormone (PTH) 1-84 or 1-34 within the 2 months preceding Screening and requiring SoC doses exceeding \>1.2× their pre-PTH treatment total daily doses or bone turnover markers, Collagen cross-linked C-telopeptide (CTx )and Procollagen type 1 N-propeptide (P1NP), \> upper limit of normal for sex, age (men only) and menopausal status (women only). 6. Blood 25-OH Vitamin D level \<25 nanograms (ng)/milliliter (mL). 7. Estimated glomerular filtration rate (eGFR) \<30 mL/minute/1.73 m\^2 using chronic kidney disease-EPI creatinine equation refit without the race variable (chronic kidney disease-EPI creatinine equation refit without the race variable \[CKD-EPIcr\_R\]) (for participants \<18 years old the Bedside Schwartz equation should be used). 8. Participants with positive Hepatitis B surface antigen (HBsAg), Hepatitis A immunoglobulin M (IgM), or human immunodeficiency virus (HIV) viral serology test at the Screening Visit. Participants who are in complete remission from Hepatitis C virus (HCV) as evidenced by sensitive assay ≥12 weeks after completion of HCV therapy may participate in the study. Note: Other protocol defined Inclusion/
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Responders who Achieve Both Albumin-Corrected Blood Calcium (cCa) and 24-hour Urinary Calcium (UCa) Within the Target Range | Up to Week 24 | * cCa within 8.3-10.7 mg/dL (2.08-2.68 millimoles per liter \[mmol/L\]) * 24-hr UCa within the reference range (\< 300 mg/day for men \[7.5 mmol/day\], \< 250 mg/day for women \[6.25 mmol/day\]) |
Secondary
| Measure | Time frame |
|---|---|
| Number of Participants With Intact Parathyroid Hormone (iPTH) Within or Greater than the Reference Range | Up to Week 24 |
| Number of Participants who Achieve Blood Magnesium Within the Reference Range | Up to Week 24 |
| Number of Participants who Achieve Blood Phosphate Within the Reference Range | Up to Week 24 |
| Change From Baseline in Blood 1,25-(OH)2 Vitamin D | Baseline to Week 24 |
| Change From Baseline in cCa | Baseline to Week 24 |
| Change From Baseline in 24-hour UCa | Baseline to Week 24 |
| Change From Baseline in iPTH | Baseline to Week 24 |
| Change From Baseline in Blood Phosphate and Blood Magnesium | Baseline to Week 24 |
| Change From Baseline in Urine Magnesium, Phosphate, Sodium, and Citrate Handling | Baseline to Week 24 |
| Change From Baseline in QT Interval Corrected for Changes in the Heart Rate With Fridericia Formula (QTcF) as Assessed by Electrocardiogram (ECG) | Baseline to Week 24 |
| Change from Baseline in 36-Item Short Form Health Survey (SF-36) Physical Component Score and Mental Component Score and Each of the Sub-Domains | Baseline to Week 24 |
| Number of Participants in the Encaleret Arm Receiving Calcium and/or Vitamin D Supplements | Up to Week 24 |
| Steady State Encaleret Trough Concentration (Ctrough) | Up to Week 24 |
Countries
Australia, Canada, Czechia, Denmark, France, Italy, Japan, Netherlands, United Kingdom, United States
Contacts
STUDY_DIRECTORCalcilytix Medical Director
Calcilytix Therapeutics, Inc., a BridgeBio company
Outcome results
None listed