First drug approved for perinatal, infantile, juvenile-onset hypophosphatasia

The FDA recently approved Strensiq, the first drug for the treatment of perinatal, infantile and juvenile-onset hypophosphatasia, according to an FDA press release.

“For the first time, the [hypophosphatasia] community will have access to an approved therapy for this rare disease,” Amy G. Egan, MD, MPH, deputy director of the Office of Drug Evaluation III in the FDA’s Center for Drug Evaluation and Research, said in the release. “Strensiq’s approval is an example of how the Breakthrough Therapy Designation program can bring new and needed treatments to people with rare diseases.”

Strensiq (asfotase alfa, Alexion Pharmaceuticals, Inc.) has been designated as a breakthrough therapy as the first and only treatment for the disease. The drug was also granted an orphan drug designation because of its treatment for fewer than 200,000 patients in the United States.

Asfostase alfa will be administered three to six times per week by injection. The drug works by replacing the enzyme that is responsible for forming an essential mineral in normal bone.

Safety and efficacy was determined through four prospective open-label studies on 99 patients with perinatal, infantile or juvenile-onset hypophosphatasia. Those with perinatal and infantile hypophosphatasia had improved overall survival as well as survival without the need for a ventilator. Improvements in growth and bone health were shown in patients with juvenile-onset hypophosphatasia.

The most commonly reported side effects were injection-site reactions, hypersensitivity reactions, lipodystrophy at the injection site and ectopic calcifications of the eyes and kidney.