HypoparathyroidismPhase 3RECLAIM-HPNCT07805356
Efficacy, Safety, and Tolerability of Encaleret in Participants With Chronic Hypoparathyroidism
A Phase 3 study testing Encaleret in people with Hypoparathyroidism and Chronic Hypoparathyroidism, run by Calcilytix Therapeutics, Inc., a BridgeBio company at 5 sites in 2 countries.
Trial 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). Read more about this study
- Who is it for?
- Ages 16 years and older
- Conditions the study is for
- Hypoparathyroidism, Chronic Hypoparathyroidism
- What is being tested?
- Encaleret
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 160 participants
- Where
- 5 sitesin 2 countries
- Study dates
- 31 Aug 2026to Jan 2033
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 16 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- 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, genetic, 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:
- Calcitriol ≥0.5 micrograms (μg)/day or alfacalcidol ≥1.0 μg/day
- Elemental calcium ≥800 milligrams (mg)/day (for example, calcium citrate, calcium carbonate)
Show all 11Show fewer
- 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.
Who cannot join
- 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 thyroid cancer, 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/exclusion criteria apply.
Trial locations and contacts
5 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
5 sites in 2 countries
United States4 sites, 4 recruiting
- Recruiting
Calcilytix Therapeutics, Inc., a BridgeBio Company, Investigational Site
El Paso, Texas, 79935
- Recruiting
Calcilytix Therapeutics, Inc., a BridgeBio Company, Investigational Site
Greenville, North Carolina, 27834
- Recruiting
Calcilytix Therapeutics, Inc., a BridgeBio Company, Investigational Site
Morehead City, North Carolina, 28557
- Recruiting
Calcilytix Therapeutics, Inc., a BridgeBio Company, Investigational Site
Reno, Nevada, 89511
Canada1 site, 1 recruiting
- Recruiting
Calcilytix Therapeutics, Inc., a BridgeBio Company, Investigational Site
Oakville, Ontario, L6M 1M1
About this study
Official title: A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study With an Open-Label Extension Investigating Efficacy, Safety, and Tolerability of Encaleret in Participants With Chronic Hypoparathyroidism
The aim of the study is to evaluate the efficacy, safety, and tolerability of orally administered encaleret tablets in participants with chronic hypoparathyroidism (HP).
- Conditions
- Hypoparathyroidism, Chronic Hypoparathyroidism
- Being tested
- Encaleret, Placebo
- Keywords
- Chronic Hypoparathyroidism, Hypoparathyroidism, Encaleret
- Medical subject headings
- Hypoparathyroidism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EncaleretDrug
Oral tablets
PlaceboDrug
Oral tablets
| Study group | Role | What they receive |
|---|---|---|
| Encaleret | Experimental | Participants will receive encaleret during the 24-week double-blind treatment period. Participants will then have the option to enter an open-label long-term extension (LTE) period to continue receiving encaleret for up to 192 weeks. Receives: Drug: Encaleret |
| Placebo | Placebo comparator | Participants will receive placebo during the 24-week double-blind treatment period. Participants will then have the option to enter an open-label LTE period to receive encaleret for up to 192 weeks. Receives: Drug: Encaleret; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Responders who Achieve Both Albumin-Corrected Blood Calcium (cCa) and 24-hour Urine Calcium (UCa) Within the Protocol-defined Target Range
Measured: Week 24
Secondary outcomes (14)
Number of Participants With cCa Within Protocol-defined Range
Measured: Week 24
Change From Baseline to Week 24 in cCa
Measured: Baseline, Week 24
Absolute Value of cCa at Week 24
Measured: Week 24
Number of Participants With 24-hour UCa Below the Sex-specific Upper Reference Limits (Protocol-defined Range)
Measured: Week 24
Change from Baseline to Week 24 in 24-hour UCa
Measured: Baseline, Week 24
Absolute Value of 24-hour UCa at Week 24
Measured: Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Calcium Supplements Dose
Measured: 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)
Measured: Baseline, Week 24
Number of Participants With Calcium Independence
Measured: Week 20 to Week 24
Change from Baseline in Signs and Symptoms of Hypoparathyroidism, Based on Participants' Responses
Measured: Baseline, Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Active Vitamin D Dose
Measured: Week 24
Percent Change From Baseline in Daily Intake of Active Vitamin D Among the Participants Who Meet the Primary Endpoint (Biochemical Response)
Measured: Baseline, Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Has Active Vitamin D Independence
Measured: Week 24
Number of Participants Who Meet Specific Protocol-defined Criteria or Calcium and Vitamin D Analysis
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.
Measured: Week 20 to Week 24
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Sep 2026
- Study start31 Aug 2026
- Primary completionJan 2028 (estimated)
- Study completionJan 2033 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HypoparathyroidismStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 160 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Calcilytix Therapeutics, Inc., a BridgeBio company
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Calcilytix Medical Director, Study director, Calcilytix Therapeutics, Inc., a BridgeBio company
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07805356
- Sponsor's protocol ID
- CLTX-305-304
- Other IDs
- 2026-526140-13, U1111-1341-6994
- Acronym
- RECLAIM-HP
- Status last verified
- Nov 2026
- First submitted
- 1 Sep 2026
- Last updated
- 4 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 4 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study With an Open-Label Extension Investigating Efficacy, Safety, and Tolerability of Encaleret in Participants With Chronic Hypoparathyroidism
- ClinicalTrials.gov ID
- NCT07805356
- Acronym / sponsor ID
- RECLAIM-HP / CLTX-305-304
- Conditions
- Hypoparathyroidism, Chronic Hypoparathyroidism
- Keywords
- Chronic Hypoparathyroidism, Hypoparathyroidism, Encaleret
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 160 participants (estimated)
- Lead sponsor
- Calcilytix Therapeutics, Inc., a BridgeBio companyIndustry (pharma, biotech, devices)
- Study start
- 31 Aug 2026 (actual)
- Primary completion
- Jan 2028 (estimated)
- Study completion
- Jan 2033 (estimated)
- First posted
- 4 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the study is to evaluate the efficacy, safety, and tolerability of orally administered encaleret tablets in participants with chronic hypoparathyroidism (HP).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Encaleret | Experimental | Drug: EncaleretParticipants will receive encaleret during the 24-week double-blind treatment period. Participants will then have the option to enter an open-label long-term extension (LTE) period to continue receiving encaleret for up to 192 weeks. |
| Placebo | Placebo comparator | Drug: Encaleret, Drug: PlaceboParticipants will receive placebo during the 24-week double-blind treatment period. Participants will then have the option to enter an open-label LTE period to receive encaleret for up to 192 weeks. |
Who may qualify
- Ages
- 16 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (11 listed)
- 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, genetic, 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.
- Calcitriol ≥0.5 micrograms (μg)/day or alfacalcidol ≥1.0 μg/day
- Elemental calcium ≥800 milligrams (mg)/day (for example, calcium citrate, calcium carbonate)
Key exclusion criteria (6 listed)
- 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 thyroid cancer, 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| EncaleretOral tablets | Drug | Encaleret, Placebo |
| PlaceboOral tablets | Drug | Placebo |
Primary outcome
Number of Responders who Achieve Both Albumin-Corrected Blood Calcium (cCa) and 24-hour Urine Calcium (UCa) Within the Protocol-defined Target Range
Time frame: Week 24
14 secondary outcomes
Number of Participants With cCa Within Protocol-defined Range
Time frame: Week 24
Change From Baseline to Week 24 in cCa
Time frame: Baseline, Week 24
Absolute Value of cCa at Week 24
Time frame: Week 24
Number of Participants With 24-hour UCa Below the Sex-specific Upper Reference Limits (Protocol-defined Range)
Time frame: Week 24
Change from Baseline to Week 24 in 24-hour UCa
Time frame: Baseline, Week 24
Absolute Value of 24-hour UCa at Week 24
Time frame: Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Calcium Supplements Dose
Time frame: 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)
Time frame: Baseline, Week 24
Number of Participants With Calcium Independence
Time frame: Week 20 to Week 24
Change from Baseline in Signs and Symptoms of Hypoparathyroidism, Based on Participants' Responses
Time frame: Baseline, Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Have a Reduction From Baseline in Active Vitamin D Dose
Time frame: Week 24
Percent Change From Baseline in Daily Intake of Active Vitamin D Among the Participants Who Meet the Primary Endpoint (Biochemical Response)
Time frame: Baseline, Week 24
Number of Participants Who Meet the Primary Endpoint (Biochemical Response) and Has Active Vitamin D Independence
Time frame: Week 24
Number of Participants Who Meet Specific Protocol-defined Criteria or Calcium and Vitamin D Analysis
Time frame: Week 20 to Week 24
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Nov 2026.
- Individual participant dataSharing planned: No
Related trials for Hypoparathyroidism
Recruiting
NIRAF-Guided Parathyroid Identification During Thyroidectomy
Hypocalcemia, Hypoparathyroidism
RecruitingPhase 3
A Phase 3 Randomized Clinical Trial to Investigate the Safety and Efficacy of Palopegteriparatide at Doses Greater Than 30 μg/Day in Adult Participants With Hypoparathyroidism
Hypoparathyroidism, Endocrine System Diseases
RecruitingPhase 3
A Study to Investigate Canvuparatide Compared With Placebo in Adult Patients With Hypoparathyroidism
Hypoparathyroidism
RecruitingObservational study
The ADVANCE (Assay Development and Validation for Pre-Natal and Obstetric Conditions) Study is the Largest U.S.-Based Prospective Study Demonstrating a Circulating Fetal Cell (CFC) Based Approach to Non-invasive Fetal Risk Assessment
Pregnant Individuals, Aneuploidy
Active, not recruitingPhase 2
Extension Study to Evaluate the Long-Term Safety and Tolerability of MBX 2109 in Patients With Hypoparathyroidism
Hypoparathyroidism
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Calcilytix Medical Director study director
Calcilytix Therapeutics, Inc., a BridgeBio company
5 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Encaleret in people with Hypoparathyroidism and Chronic Hypoparathyroidism, run by Calcilytix Therapeutics, Inc., a BridgeBio company at 5 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 4 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 5 sites in United States, Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Medical Information (650-600-3610, MedInfo@bridgebio.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of Responders who Achieve Both Albumin-Corrected Blood Calcium (cCa) and 24-hour Urine Calcium (UCa) Within the Protocol-defined Target Range (time frame: Week 24). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Nov 2026.