A Phase 1/2 interventional study of Parathyroid Allotransplant in Hypoparathyroidism, Hypoparathyroidism Postprocedural and Hypoparathyroidism Post-surgical, sponsored by Peter Stock. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-27.
Sponsored by Peter Stock · Phase 1/2, Interventional, and Treatment
This study is being done to see if transplanting parathyroid tissue into the forearm will help hypo-parathyroid patients achieve parathyroid hormone (PTH) levels that would help normalize their serum calcium and phosphorus levels. The parathyroid tissue used in this study will come from cadaveric tissues that were donated at the time of the death of the donor(s).
The company that makes the parathyroid hormone NATPARA will no longer be making the product by the end of 2024 which is one of the reasons the investigators are doing this study: to see if parathyroid transplantation is another way to treat hypoparathyroidism. This procedure is investigational and one of the first times the procedure is being done in humans. It is not approved by the FDA.
128 studies on the registry are indexed under Hypoparathyroidism; 30 are open to participants now.
This study's planned enrollment of 3 is below the median of 50 across 77 interventional studies indexed under Hypoparathyroidism.
Browse Hypoparathyroidism studies →Peter Stock is the lead sponsor of 2 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria Only subjects who meet all of the following criteria are eligible for enrollment.
Exclusion Criteria Subjects who meet any of the following criteria are not eligible for enrollment
Severe co-existing cardiac disease, characterized by any one of these conditions:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Parathyroid Allotransplant to treat hypoparathyroidism
Biological: Parathyroid Allotransplant
Parathyroid Allotransplant
Levels of intact PTH
The primary efficacy endpoint is attainment of levels of intact PTH levels that are in the normal range and at least double the baseline intact PTH level at one year following the PTG transplant from a single donor.
Time frame: From baseline to week 52 (year 1)
Incidence of Serious Adverse Events
The primary safety endpoints are the incidence of serious adverse events related to the transplant procedure or immunosuppression, incidence of post- transplant infections and malignancies, incidence of de novo sensitization.
Time frame: From baseline to Year 1
Dose of oral calcium supplements and calcitrol
in patients on conventional Ca and calcitriol supplementation, a 50% reduction in the pre-transplant oral dose of calcium supplements and calcitrol with maintenance of stable serum calcium in the normal;
Time frame: From baseline to week 52 (year 1)
Dose of subcutaneous parathyroid hormone (PTH) replacement therapy
for patients on subcutaneous PTH replacement therapy, a 50% reduction in the dose of PTH replacement therapy with maintenance of serum calcium in the normal target range.
Time frame: From baseline to week 52 (year 1)
PTH replacement therapy
Discontinuation of PTH replacement therapy while maintaining serum calcium in the normal target range while taking 1000 mg or less of elemental calcium in the form of calcium supplements.
Time frame: From baseline to week 52 (year 1)
Quality of Life measurement
An exploratory endpoint is the improvement in one or more quality of life measurements comparing baseline with one-year post-transplant using the Medical Outcomes Study Short Form 36 (SF36) survey and the Hypoparathyroidism Experience Scale (HPES).
Time frame: From baseline to Year 1
Plan to share: Yes — The study protocol, informed consent, clinical study report, and de-identified individual participant data (IPD) collected in this trial will be made available to other researchers.
Supporting information: Study protocol, Informed consent form, Clinical study report
Time frame: Upon completion of the clinical study report and publication of the trial outcomes.
Access criteria: Researchers may contact Dr. Peter Stock, MD, PhD at UCSF by contacting the primary contact listed in this CT.GOV record.
No publications or documents are linked to this record.
Started Jan 2026 (actual). Primary completion is estimated for Jan 2028, 24 months after the start.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Peter Stock