Winnipeg hosts first-ever Canadian conference on hypophosphatasia

Winnipeg hosts first-ever Canadian conference on hypophosphatasia

Amy and Leanne Tinsley.
Amy Tinsley, at age 6.5, with her mother Leanne. Amy, now age 8, was one of the first infants to undergo a clinical trial of a drug to treat hypophosphatasia.
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BY SUSIE STRACHAN
Winnipeg Regional Health Authority
Published Friday, July 22, 2016

The first national conference on hypophosphatasia – a potentially fatal disease that attacks the bones – will be held in Winnipeg this weekend.

The conference, which will draw experts from Canada and the United States, is designed to highlight the progress being made in treating children born with the rare metabolic disorder as well as adults.

Just over a decade ago, hypophosphatasia (HPP) was considered to almost always be fatal.

But the prognosis for patients started to change about eight years ago with the development of a new drug called asfotase alfa, which targets the missing enzyme to bone.

Health Sciences Centre (HSC) Winnipeg and Children’s Hospital HSC, working with the University of Manitoba and the Children’s Hospital Research Institute of Manitoba, Winnipeg became the first in the world to enroll both adults and infants into clinical trials of the drug .

Led by Dr. Cheryl Rockman-Greenberg, a medical geneticist at Health Sciences Centre Winnipeg, the clinical trials started in 2008 and involved 11 infants and children, including some who came to Winnipeg from across Canada and as far away as Europe, the Middle East, Central America and the United States.

The very first infant to be treated in the trial was Amy Tinsley, who arrived in Winnipeg from Northern Ireland after having been diagnosed with severe life-threatening infantile HPP. Today, Amy is eight years old and living a happy, normal life

Over time, a total of 37 young children worldwide have participated in the drug trial.

“In our local population, we had 100 per cent mortality among babies born in Manitoba with the severest form of this condition,” says Rockman-Greenberg. “Worldwide including Manitoba babies, the clinical trials have shown that, with medication, the survival rate in treated patients with life-threatening infantile HPP has risen significantly to 93 per cent. Similar improvements have been seen in lung function and other measures.”

Rockman-Greenberg says the conference is attracting basic and clinical researchers, health professionals working in the medical, nursing and dental fields plus patients and their families.

Dr. Jose Luis Milan, a professor in the Human Genetics program at Sandford Burnham Presbyterian Medical Discovery Institute in La Jolla, California, will speak about his part in the research into the causes of the disease.

“He was instrumental in creating the mouse model which determined that a lack of an enzyme called alkaline phosphatase was the root cause of the disease and how replacing the enzyme in the affected mice cured their HPP,” says Rockman-Greenberg.

The second speaker, Dr. Marc McGee, is a professor in the Faculties of Dentistry and Medicine at McGill University in Montreal. He was also involved in the early research on and instrumental in showing how HPP affects the development of teeth in children.

“Dentistry is critical for the care for a patient with HPP. The new drug may not improve  tooth problems, so kids need frequent dental monitoring,” she says.
One component of the conference expected to have high attendance is the multi-disciplinary panel which features a pain specialist, a dentist, a dietitian and a genetic counselor.

“It will address how children deal with bone pain, how to prevent tooth problems, how to ensure children eat well and gain weight,” says Rockman-Greenberg. “The genetic counselor will address the genetic causes for HPP and probabilities of passing on the condition to future children. Parents and patients are showing a lot of interest in this panel.”

Winnipeg has long been a treatment centre for patients who have HPP, partly because the disorder is more prevalent among Manitoba’s Mennonite population than other groups.

World-wide, severe forms of hypophosphatasia affect an estimated one in 100,000 newborns. Yet in Manitoba, one in 2,500 infants is born with the most severe features of the condition, according to Rockman-Greenberg.

Asfotase Alfa was produced by Montreal-based Enobia Pharma and was ultimately acquired by Alexion Pharmaceuticals. Clinical trials have been recently been completed. The drug has been approved for use by Health Canada in pediatric-onset HPP patients under 18 years of age, according to Rockman-Greenberg.

“This approval is extremely encouraging but the process to ultimately have the drug covered by the different Drug Benefit programs in this country is complicated. Based on the current data on children with respect to effectiveness and safety, I am very confident the drug will be listed in the future under our Drug Benefits program in Manitoba for infants and children. More research will be pursued on adult HPP.”

The Winnipeg conference is organized by Soft Bones Canada, a non-profit lay organization dedicated to the education and support of Canadians affected by HPP. The co-organizer is the Department of Continuing Professional Development in the Max Rady College of Medicine at the University of Manitoba.

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