FDA approves new drug for rare disease hypoparathyroidism

The FDA announced in a press release dated August 9, 2024, that it has approved Yorvipath (palopegteriparatide), a product of Ascendis Pharma, for administration by subcutaneous injection to adults with hypoparathyroidism (1).

“We are deeply grateful to patients, physicians and stakeholders for their many contributions to this important milestone,” said Jan Mikkelsen, President and CEO of Ascendis Pharma, in a press release (2).

Hypoparathyroidism, a rare endocrine disorder affecting between 70,000 and 90,000 people in the United States, is most commonly caused by damage to the parathyroid glands, either caused by an autoimmune disease or surgery (notably, the FDA press release states that Yorvipath has not been studied in adults with acute postoperative hypoparathyroidism) (1,2). Low parathyroid hormone (PTH) levels are a major feature of hypoparathyroidism and result in too low a level of calcium in the blood, which is called hypocalcemia.

Depending on the level of calcium in the blood, other symptoms may vary, including tingling or numbness in the lips, fingertips and toes, muscle cramps or spasms, and seizures.

While patients with hypoparathyroidism are typically treated with active vitamin D and (usually high doses) calcium taken several times daily to raise blood calcium levels to the low-normal range, Yorvipath complements this with once-daily administration of a prodrug of PTH (1-34), which provides continuous exposure to released PTH over a 24-hour period (1,2).

“The FDA approval of Yorvipath is such an important milestone for our community,” said Patty Keating, executive director of the HypoPARAthyroidism Association, in an Ascendis press release. “We are grateful that the severity of our condition has been recognized and our voices heard. We look forward to this new treatment option that will help us overcome the limitations and risks of conventional therapy.”

“The consequences of hypoparathyroidism on the health and quality of life of our patients can be extraordinarily debilitating,” said Lynn Kohlmeier, MD, endocrinologist at Spokane Osteoporosis & Endocrinology, chair of the HypoPARAthyroidism Association Medical Advisory Board, and investigator in the PaTHway trial that led to FDA approval (2). “The ability to treat the underlying cause of this disease is critical and will represent an important advance for our patients with hypoparathyroidism.”

Ascendis expects that a first commercial supply of Yorvipath will be available in the United States in the first quarter of 2025. In addition, the company plans to apply to the FDA for approval to commercialize the already manufactured product, which could be ready for market in the fourth quarter of 2024 (2).

The FDA granted Yorvipath priority review, aiming to decide on an application within six months instead of the usual ten, and designated the drug as an orphan drug, which allows sponsors incentives such as tax credits for qualified clinical trials, exemption from royalties, and the possibility of up to seven years of post-approval market exclusivity (3,4).

References

1. FDA. FDA approves new drug for hypoparathyroidism, a rare disease. Press release. August 9, 2024.
2. Ascendis Pharma. FDA approves YORVIPATH (palopegteriparatide) as the first and only treatment for hypoparathyroidism in adults. Press release. August 12, 2024.
3. FDA. Priority review. FDA.gov/patientsupdated on January 4, 2018 (accessed August 14, 2024).
4. FDA. Orphan Product Designation: Drugs and Biological Products. FDA.gov/Industryupdated on August 12, 2024 (accessed August 14, 2024).