FDA Approves First Therapy for Rare Disease that Causes Low Phosphate Blood Levels, Bone Softening - Drug Information Update

https://www.fda.gov/news-events/press-announcements/fda-approves-first-therapy-rare-disease-causes-low-phosphate-blood-levels-bone-softening?utm_campaign=FDA%20Approves%20First%20Therapy%20for%20Rare%20Disease%20that%20Causes%20Low%20Phosphate%20Blood%20Levels%2C%20Bone%20Softening&utm_medium=email&utm_source=Eloqua

Today, the U.S. Food and Drug Administration approved Crysvita (burosumab-twza) injection to treat patients age two and older with tumor-induced osteomalacia (TIO), a rare disease that is characterized by the development of tumors that cause weakened and softened bones. The tumors associated with TIO release a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23) that lowers phosphate levels.

Hypersensitivity reactions such as rash and hives have been reported in patients who took Crysvita. If serious hypersensitivity reactions occur, patients should stop taking Crysvita and talk with their health care provider about further medical treatment. Additionally, higher than normal levels of phosphorus may be associated with an increased risk of nephrocalcinosis (a disorder that occurs when too much calcium is deposited in the kidneys).

The most common side effects reported in adults with TIO taking Crysvita were tooth abscess (infection), muscle spasms, dizziness, constipation, injection site reaction, rash and headaches.

Patients taking oral phosphate or active vitamin D, those who have serum phosphate levels within or above the normal range for their age, and patients with severe kidney impairment or end stage renal disease should not take Crysvita.