NATPARA (parathyroid Hormone)

NATPARA (PARATHYROID HORMONE)- parathyroid hormone injection, powder, lyophilized, for solution
Takeda Pharmaceuticals America, Inc.

WARNING: POTENTIAL RISK OF OSTEOSARCOMA

  • In male and female rats, parathyroid hormone caused an increase in the incidence of osteosarcoma (a malignant bone tumor). The occurrence of osteosarcoma was dependent on parathyroid hormone dose and treatment duration. This effect was observed at parathyroid hormone exposure levels ranging from 3 to 71 times the exposure levels in humans receiving a 100 mcg dose of NATPARA. These data could not exclude a risk to humans [see Warnings and Precautions (5.1), Nonclinical Toxicology (13.1)].
  • Because of a potential risk of osteosarcoma, use NATPARA only in patients who cannot be well-controlled on calcium and active forms of vitamin D alone and for whom the potential benefits are considered to outweigh this potential risk [see Indications and Usage (1), Warnings and Precautions (5.1)].
  • Avoid use of NATPARA in patients who are at increased baseline risk for osteosarcoma, such as patients with Paget’s disease of bone or unexplained elevations of alkaline phosphatase, pediatric and young adult patients with open epiphyses, patients with hereditary disorders predisposing to osteosarcoma or patients with a prior history of external beam or implant radiation therapy involving the skeleton [see Warnings and Precautions (5.1)].
  • Because of the risk of osteosarcoma, NATPARA is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the NATPARA REMS Program [see Warnings and Precautions (5.2)].

1 INDICATIONS AND USAGE

NATPARA is a parathyroid hormone indicated as an adjunct to calcium and vitamin D to control hypocalcemia in patients with hypoparathyroidism.

Limitations of Use

  • Because of the potential risk of osteosarcoma, NATPARA is recommended only for patients who cannot be well-controlled on calcium supplements and active forms of vitamin D alone [see Warnings and Precautions (5.1)].
  • NATPARA was not studied in patients with hypoparathyroidism caused by calcium-sensing receptor mutations.
  • NATPARA was not studied in patients with acute post-surgical hypoparathyroidism.

2 DOSAGE AND ADMINISTRATION

2.1 Dosing Guidelines

The dose of NATPARA should be individualized based on total serum calcium (albumin-corrected) and 24-hour urinary calcium excretion. The recommended NATPARA dose is the minimum dose required to prevent both hypocalcemia and hypercalciuria. This dose will generally be the dose that maintains total serum calcium (albumin-corrected) within the lower half of the normal range (i.e., between 8 and 9 mg/dL) without the need for active forms of vitamin D and with calcium supplementation sufficient and individualized to meet the patient’s daily requirements.

Doses of active forms of vitamin D and calcium supplements will need to be adjusted when using NATPARA.

2.2 Before Initiating NATPARA and During Therapy with NATPARA

  • Confirm 25-hydroxyvitamin D stores are sufficient. If insufficient, replace to sufficient levels per standard of care.
  • Confirm serum calcium is above 7.5 mg/dL before starting NATPARA.
  • The goal of NATPARA treatment is to achieve serum calcium within the lower half of the normal range.

2.3 Initiating NATPARA

1.
Initiate NATPARA 50 mcg once daily as a subcutaneous injection in the thigh (alternate thigh every day).
2.
In patients using active forms of vitamin D, decrease the dose of active vitamin D by 50%, if serum calcium is above 7.5 mg/dL.
3.
In patients using calcium supplements, maintain calcium supplement dose.
4.
Measure serum calcium concentration within 3 to 7 days.
5.
Adjust dose of active vitamin D or calcium supplement or both based on serum calcium value and clinical assessment (i.e., signs and symptoms of hypocalcemia or hypercalcemia). Suggested adjustments to active vitamin D and calcium supplement based on serum calcium levels are provided below (see Table 1).
Table 1: Recommended Dosage Adjustments for NATPARA
Adjust First Adjust Second
Serum Calcium Active Vitamin D Forms Calcium Supplement
*
Discontinue in patients receiving the lowest available dose
Above the Upper Limit of Normal (10.6 mg/dL) Decrease or Discontinue * Decrease
Greater than 9 mg/dL and below the Upper Limit of Normal (10.6 mg/dL) Decrease or Discontinue * No change or decrease if active vitamin D has been discontinued
Less than or equal to 9 mg/dL and above 8 mg/dL No change No change
Lower than 8 mg/dL Increase Increase
6.
Repeat steps 4 and 5 until target serum calcium levels are within the lower half of the normal range, active vitamin D has been discontinued and calcium supplementation is sufficient to meet daily requirements.

2.4 NATPARA Dose Adjustments

The dose of NATPARA may be increased in increments of 25 mcg every four weeks up to a maximum daily dose of 100 mcg if serum calcium cannot be maintained above 8 mg/dL without an active form of vitamin D and/or oral calcium supplementation.

The dose of NATPARA may be decreased to as low as 25 mcg per day if total serum calcium is repeatedly above 9 mg/dL after the active form of vitamin D has been discontinued and calcium supplement has been decreased to a dose sufficient to meet daily requirements.

After a NATPARA dose change monitor clinical response as well as serum calcium. Adjust active vitamin D and calcium supplements per steps 4-6 above if indicated [see Dosage and Administration (2.3)].

2.5 NATPARA Maintenance Dose

The maintenance dose should be the lowest dose that achieves a total serum calcium (albumin-corrected) within the lower half of the normal total serum calcium range (i.e., approximately 8 and 9 mg/dL), without the need for active forms of vitamin D and with calcium supplementation sufficient to meet daily requirements. Monitor serum calcium and 24-hour urinary calcium per standard of care once a maintenance dose is achieved.

2.6 NATPARA Dose Interruption or Discontinuation

Abrupt interruption or discontinuation of NATPARA can result in severe hypocalcemia. Resume treatment with, or increase the dose of, an active form of vitamin D and calcium supplements if indicated in patients interrupting or discontinuing NATPARA, monitor for signs and symptoms of hypocalcemia and serum calcium levels [see Warnings and Precautions (5.4)].

In the case of a missed dose, the next NATPARA dose should be administered as soon as reasonably feasible and additional exogenous calcium should be taken in the event of hypocalcemia.

2.7 Reconstitution and Administration Instructions

  • Patients and caregivers who will administer NATPARA should receive appropriate training and instruction by a trained healthcare professional prior to first use of NATPARA.
  • Follow the Instructions for Use to reconstitute NATPARA using the mixing device for reconstitution and to administer NATPARA using the pen delivery device (i.e., Q-Cliq® pen).
  • Inspect NATPARA visually for particulate matter and discoloration prior to administration.
  • Discard the needle in a puncture-resistant container following administration.
  • Store the Q-Cliq pen containing the remaining doses of NATPARA in a refrigerator.
  • All reconstituted NATPARA medication cartridges older than 14 days must be discarded [see How Supplied/Storage and Handling (16.2)].

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