FDA Approves New Drug for Rare Disorder Hypoparathyroidism

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FDA announced in a press release on Aug. 9, 2024 that itapproved Yorvipath (palopegteriparatide), an Ascendis Pharma product, for administration by subcutaneous injection to adults with hypoparathyroidism (1).

“We are deeply grateful to patients, clinicians, and advocates for their many contributions to this important milestone,” Jan Mikkelsen, Ascendis Pharma president and chief executive officer, said in a press release (2).

Hypoparathyroidism, which is a rare endocrine disease affecting anywhere from 70,000 to 90,000 people in the United States, is most often caused by damage to parathyroid glands either from autoimmune disease or surgery (notably, the FDA press release said that Yorvipath has not been studied in adults with acute post-surgical hypoparathyroidism) (1,2). A low level of parathyroid hormone (PTH) is a chief characteristic of hypoparathyroidism, and leads to blood calcium levels being too low, which is known as hypocalcemia.

Depending on those blood calcium levels, other symptoms can vary, but include tingling or numbness in lips, fingertips, and toes; muscle cramps or spasms; and seizures.

While patients with hypoparathyroidism are typically treated with active vitamin D and (usually large doses) of calcium, taken multiple times a day, to increase blood calcium into the low-normal range, Yorvipath supplements that with a once-daily administration of a prodrug of PTH (1-34), which provides continuous exposure to released PTH over a 24-hour period (1,2).

“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 thankful that the seriousness of our condition has been understood and our voices heard. We look forward to having this new treatment option to help us move beyond the limits 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 Medical Advisory Board of the HypoPARAthyroidism Association, and an investigator in the PaTHway trial that led to the FDA approval (2). “The ability to address the underlying cause of this disease is crucial and will be an important advancement for our patients with hypoparathyroidism.”

Ascendis said it anticipates an initial commercial supply of Yorvipath will be available in the US in the first quarter of 2025, and furthermore, is planning to request FDA approval to commercialize existing manufactured product, which could be ready for market by the fourth quarter of 2024 (2).

FDA granted Priority Review to Yorvipath, with the goal of taking action on an application within six months as opposed to the standard 10, and designated it as an orphan drug, which qualifies sponsors for incentives including tax credits for qualified clinical trials, exemption from user fees, and the potential of up to seven years of market exclusivity following approval (3,4).

References

1. FDA. FDA Approves New Drug for Hypoparathyroidism, A Rare Disorder. Press Release. Aug. 9, 2024.
2. Ascendis Pharma. FDA Approves YORVIPATH (Palopegteriparatide) as the First and Only Treatment for Hypoparathyroidism in Adults. Press Release. Aug. 12, 2024.
3. FDA. Priority Review. FDA.gov/patients, updated Jan. 4, 2018 (accessed Aug. 14, 2024).
4. FDA. Designating an Orphan Product: Drugs and Biological Products. FDA.gov/industry, updated Aug. 12, 2024 (accessed Aug. 14, 2024).