Research Focuses On Drug Therapy for Hypophosphatasia

June 18, 2009, St.Louis,Mo.

A new experimental targeted enzyme replacement therapy strengthens the bones of infants with a severe, sometimes deadly, genetic bone disorder known as hypophosphatasia (HPP), according to early clinical data presented by Michael P. Whyte, M.D., medical/scientific director of the center for metabolic bone disease and molecular research at Shriners Hospitals for Children — St. Louis.

Dr. Whyte presented the results of a Phase I safety trial of the experimental treatment – currently known as ENB-0040 –- in adults, and early safety and efficacy findings from an ongoing study in severely affected infants at The Endocrine Society's 91st annual meeting on June 11 in Washington, D.C.

The studies which led to this finding were done in collaboration with and funding by Enobia Pharma of Montreal. Dr. Whyte’s abstract on the research was chosen as one of the 20 most promising scientific advances in endocrinology for the coming year. In addition to the presentation earlier this month, it is scheduled to be featured in a special booklet that is being prepared by The Endocrine Society.

"There is an urgent need for an effective treatment for these infants whose bones are so brittle that their rib cages often break just from breathing; about half of the babies with the severe infantile form of hypophosphatasia will die before their first birthday," Dr. Whyte said. "Without any approved treatments, we currently can only try to manage symptoms of hypophosphatasia without addressing the underlying problem - a profound lack of bone mineralization. This is the first time we've seen a drug therapy positively impact bone formation in these severely sick infant patients."

Patients with HPP lack an enzyme called tissue non-specific alkaline phosphatase (TNSALP) that plays a key role in bone formation. ENB-0040 is an enzyme replacement therapy designed to specifically target TNSALP to the bones, with the goal of "normalizing" bone mineralization.

Additional Phase II clinical trials are planned for children and adults with HPP during 2009.

In addition to his position at Shriners Hospitals for Children, Dr. Whyte is a professor of medicine, pediatrics and genetics in the division of bone and mineral diseases at Washington University School of Medicine in St. Louis. He received a Bachelor of Arts in Chemistry from New York University and a medical degree from Downstate College of Medicine, State University of New York.