Bone Disease and Enzyme-Replacement Therapy

Enzyme replacement therapy effective in healing rickets and improving lung function

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) A rare life-threatening bone disease that impairs breathing may soon be treatable. In a recent study, enzyme-replacement therapy was effective in improving lung function and motor skills.

Hypophosphatasia is a rare metabolic bone disease that can lead to rickets. Bones do not harden and grow properly and this affects how the ribcage is developed causing impaired lung function.

Using an enzyme-replacement therapy, ENB-0040, a recombinant issue-nonspecific isozyme of alkaline phosphatase (TNSALP), improved bone development leading to improved lung function.

"Talk to your doctor about signs and symptoms of childhood diseases."

The study was led by Michael P. Whyte, M.D., from the Center for Metabolic Bone Disease and Molecular Research at Shriners Hospital for Children in St. Louis. For the study, 11 children with life-threatening or crippling hypophosphatasia were chosen to receive the enzyme-replacement treatment. Rickets was healed after nine months for nine children and researchers noticed skeletal healing and improved lung function.

The enzyme-replacement treatment was shown to be effective in mice in previous studies. The treatment works by preventing hypophosphatasia from developing which leads to the skeleton and bones to heal and develop properly.

For the study, safety, motor skills, cognitive development and lung function were all evaluated to determine if the enzyme-replacement treatment could be effective in treating hypophosphatasia. Researchers used the curing of rickets as a sign that the treatment was effective.

Out of the 11 patients, 10 children completed 6 months of enzyme-replacement therapy and nine children completed one year of treatment. Rickets, due to hypophosphatasia, was healed in nine patients by the end of nine months which lead to developmental improvements as well as lung function improvement.

The enzyme-replacement treatment was effective in treating hypophosphatasia and was also safe to use. There were no adverse side effects reported with the treatment.

Life-threatening hypophosphatasia may no long be that threatening due to the enzyme-replacement therapy. Future studies can expand on the number of participants and the length of the trial to better understand how effective enzyme-replacement therapy is for this rare bone disease.

Funding for the study was provided by Enobia Pharma and Shriners Hospitals for Children.

This study was published in the March edition of the New England Journal of Medicine

Reviewed by: 
Review Date: 
March 9, 2012
Last Updated:
March 10, 2012