Alexion's HPP Drug Improves Overall Survival In Phase 2 Trial

Alexion Pharmaceuticals reported positive new data from the Phase II studies of its investigational asfotase alfa in pediatric patients with hypophosphatasia (HPP). The company presented the results at the American Society for Bone and Mineral Research (ASBMR) 2014 Annual Meeting in Houston.

Asfotase alfa is a first-in-class targeted enzyme replacement therapy being investigated for hypophosphatasia. The drug restores the genetically defective metabolic process in HPP instead of just addressing symptoms. Through its mechanism of action, asfotase alfa prevents or reverses the potentially serious complications of lifelong dysregulated mineral metabolism characteristic of the disease. The U.S. Food and Drug Administration (FDA) designated asfotase alfa a Breakthrough Therapy in 2013. In July, the European Medicines Agency (EMA) accepted asfotase alfa’s Marketing Authorization Application (MAA) for accelerated assessment.

Analysis from two open label, Phase II studies showed that HPP patients who were treated with asfotase alfa for up to five years achieved greater overall survival (89 percent) compared to untreated (27 percent) historical control patients. Those in the asfotase alfa arm also had enhanced ventilator-free survival versus historical control patients. Findings also show that asfotase alfa improved physical function in the company’s infant and juvenile Phase II extension studies.

Dr. Martin Mackay, EVP and Global Head of R&D at Alexion, said, “Pediatric patients with severe HPP face a high risk of death, as well as significant challenges related to respiratory function, growth, development and physical function. Survival was significantly improved among severely affected infants and children with HPP treated with asfotase alfa compared with a historical control of untreated patients, which is an important finding for the HPP community who currently has no approved treatment options.”

Hypophosphatasia is an ultra-rare genetic, chronic, and progressive metabolic disease characterized by defective bone mineralization that can result in deformity and destruction of bones, severe muscle weakness, respiratory failure, seizures, and premature death.

Earlier this month Alexion reported that the Japan's Ministry of Health, Labor, and Welfare (MHLW) has granted orphan drug designation (ODD) to asfotase alfa as treatment for patients with hypophosphatasia in the country.