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Parathyroid hormone

Natpara · Recombinant human PTH (1-84)

Parathyroid hormone, or PTH, helps regulate calcium and phosphate. Natpara was a prescription form containing the full 84-amino-acid human hormone. Its U.S. label described use with calcium and vitamin D for hypoparathyroidism.

FDA

Full-length PTH (1-84) was studied as an adjunct to calcium and vitamin D in hypoparathyroidism. Natpara's U.S. product history and supply are separate from the evidence about the hormone; stopping treatment abruptly can cause dangerously low calcium.

PMID 24622413FDA

By the Peptides Media Editorial TeamEditorial policy4 min read

Product discussedNatpara, PTH (1-84)
FDA
Historical useHypoparathyroidism
FDA
U.S. supplySpecial-use program closed
FDA
Key riskCalcium after interruption
FDA

Overview

Quick answer

Natpara's U.S. special-use program has closed. The manufacturer announced that shipments would stop when the program ended. Its historical prescribing label should not be read as proof that Natpara remains available for routine use.

FDA: Natpara U.S. special-use program closure noticeFDA: Natpara prescribing information

What was Natpara prescribed for?

Its U.S. label described Natpara as an adjunct to calcium and vitamin D to control low blood calcium in hypoparathyroidism, limited to patients not adequately controlled with calcium and active vitamin D alone.

FDA

Is the U.S. special-use program still open?

No. An FDA-hosted manufacturer notice announced closure of the program and the end of U.S. shipments. A historical approval or a label in an archive does not establish current supply.

FDA

What did the REPLACE study measure?

The 24-week study tested whether participants could reduce both calcium and active vitamin D by at least half while keeping blood calcium within the study's limits. The combined endpoint was met by 48 of 90 participants assigned PTH (1-84) and one of 44 assigned placebo.

PMID 24622413

Evidence

Evidence snapshot

Historical U.S. labelAdjunct for hypoparathyroidism

Natpara was labeled with calcium and vitamin D for patients not adequately controlled on conventional treatment alone.

FDA
REPLACE trialSupplement-reduction endpoint

More participants assigned PTH (1-84) met the combined supplement and calcium endpoint than placebo at 24 weeks.

PMID 24622413
U.S. supplyProgram closed

The manufacturer announced closure of the special-use program and an end to U.S. shipments.

FDA

Claims

Common claims vs evidence

ClaimHuman evidenceVerdict
PTH (1-84) reduced supplement requirements in a clinical trial.In REPLACE, 48 of 90 participants receiving PTH (1-84) and one of 44 receiving placebo met the combined 24-week endpoint. It required at least a 50% reduction in both oral calcium and active vitamin D while maintaining calcium within the study's specified range. The study supports a combined outcome in a defined adult population, not a claim that every participant could stop all supplements.
PMID 24622413
Natpara can be obtained through its U.S. special-use program.A manufacturer notice hosted by FDA announced the program's closure and said no further shipments would be sent after it closed. Historical access under the special-use program should not be described as ongoing availability.
FDA
Any parathyroid hormone product can be substituted at the same dose.Natpara's historical label describes full-length PTH (1-84). Yorvipath's current label describes a PTH (1-34) prodrug with a different dose scheme. A change of product requires individual clinical assessment and calcium monitoring.
FDA: Natpara prescribing informationComparator prescribing labelFDA: Natpara U.S. special-use program closure notice

Bottom line

Main takeaway

What PTH does

PTH helps regulate calcium. When the body makes too little of it, treatment aims to control blood calcium and related symptoms.

FDA

Identity

What it is

Human PTH contains 84 amino acids. Natpara contained recombinant human PTH (1-84).

FDA

The historical label limited use to patients whose hypocalcemia could not be well controlled with calcium and active vitamin D alone.

FDA

Use context

Routes, doses, and cycle patterns

Natpara's archived U.S. label and the REPLACE trial describe historical administration and monitored dose adjustment.

FDAPMID 24622413

Human studies and product labels

Historical Natpara U.S. label

Purpose
Hypocalcemia in hypoparathyroidism, as an adjunct to calcium and vitamin D
Context
Archived prescription label
Route
Subcutaneous injection in the thigh
Amount
Starting dose 50 mcg
Frequency
Once daily

The label described individualized adjustments using blood and urine calcium. It included a boxed warning and a restricted risk-management program. The later U.S. special-use program closure affects current product access.

FDA: Natpara prescribing informationFDA: Natpara U.S. special-use program closure notice

REPLACE trial

Purpose
Calcium control with reduced oral calcium and active vitamin D
Context
Published study regimen
Route
Subcutaneous
Amount
Initially 50 mcg, with titration to 75 or 100 mcg in the study
Frequency
Once daily
Duration
24-week blinded period

Conventional calcium and active vitamin D were adjusted while PTH or placebo was administered.

PMID 24622413

What varies

  • Abrupt interruption can cause severe hypocalcemia. The closure notice emphasizes a clinician-guided transition and close calcium monitoring.
    FDA
  • Natpara and Yorvipath differ in the hormone form and product-specific dose; the doses are not interchangeable by number.
    FDAComparator prescribing label

Research

Research evidence

REPLACE evaluated PTH (1-84) in adults with chronic hypoparathyroidism using a combined calcium and supplement-reduction endpoint.

PMID 24622413
Study / evidence areaPopulationDesignProduct contextMain outcomeLimitationsWeight
REPLACE
PMID 24622413Trial publication correction
134 adults with hypoparathyroidism for at least 18 monthsRandomized, double-blind, placebo-controlledDaily subcutaneous PTH (1-84), initially 50 mcg with trial titrationComposite met by 48 of 90 PTH recipients versus one of 44 placebo recipients at 24 weeksThe endpoint required at least 50% reductions in both supplements, not complete independence. The journal corrected an active-vitamin-D figure label and adverse-event timing after publication.Controlled biochemical and supplement outcome
U.S. product status
FDA: Natpara prescribing informationFDA: Natpara U.S. special-use program closure notice
Patients and clinicians considering Natpara in the United StatesArchived label and FDA-hosted closure noticePreviously marketed PTH (1-84) injection and later special-use programThe manufacturer announced closure of the program and an end to U.S. shipmentsThe historical label does not establish continuing product availabilityRegulatory and supply context, not a clinical trial

Cautions

Safety and unknowns

  • The archived label contraindicated Natpara in people with known hypersensitivity to any component of the product. Serious allergic reactions were reported.
    FDA
  • The archived Natpara label has a boxed warning about potential osteosarcoma risk after tumors occurred in rat studies. It identified groups at increased baseline risk in whom use should be avoided.
    FDA
  • Both high and low blood calcium can occur. Sudden interruption can cause severe hypocalcemia, so transition plans require close monitoring.
    FDA: Natpara prescribing informationFDA: Natpara U.S. special-use program closure notice
  • The REPLACE trial reported hypocalcemia, muscle spasms, tingling, headache, and nausea among common adverse events.
    PMID 24622413

Product quality

Product identity and quality

Natpara was a defined PTH (1-84) product. A vial marketed as PTH is not established as equivalent in identity, sterility, strength, or delivery.

FDA

Supply status

Historical access and present availability are separate questions.

FDA

Transition monitoring

Changes in treatment can affect blood-calcium levels.

FDA

Mechanism

How it is proposed to work

PTH acts on the kidneys and bones to help regulate blood calcium and phosphate.

FDA
01

Recombinant PTH (1-84) has the sequence of the full human hormone; Yorvipath is a different product that releases the PTH (1-34) fragment.

FDAComparator prescribing label

FAQ

Common questions

Details

Technical details

Parathyroid hormone technical details
Hormone discussed
Human PTH (1-84)
FDA
Historical U.S. product
Natpara
FDA
Historical route
Subcutaneous
FDA
U.S. supply context
Special-use program closed
FDA

Sources

References

  1. 1.

    FDA. Natpara prescribing information

    Archived U.S. Natpara label, used to distinguish the products.

  2. 2.

    PubMed. Efficacy and safety of recombinant human parathyroid hormone (1-84) in hypoparathyroidism: a randomized phase 3 study

    doi:10.1016/S2213-8587(13)70106-2 PMID:24622413 NCT00732615

    REPLACE trial of recombinant human PTH (1-84) with calcium and active vitamin D.

  3. 3.

    The Lancet Diabetes & Endocrinology. Correction to the REPLACE trial report

    doi:10.1016/S2213-8587(13)70206-7

    Corrects an active-vitamin-D figure label and the timing of adverse-event counts.

  4. 4.

    FDA. Natpara U.S. special-use program closure notice

    FDA-hosted manufacturer notice describing the end of U.S. special-use shipments and transition safety.

  5. 5.

    DailyMed. Yorvipath prescribing information

    U.S. adult indication, dose and calcium monitoring, product handling, and safety.