Canadian family raised $3.5M to develop individualized gene therapy for son’s rare condition

The family is cautiously optimistic about the improvements they are seeing in Michael, 4, since the gene therapy three months ago

Four-year-old Michael Pirovolakis sits with his mother and father, Georgie and Terry, before his gene therapy procedure. Photo by SickKids

Doctors and researchers at The Hospital for Sick Children in Toronto have conducted one of the first individualized gene therapies as part of a single-patient clinical trial.

There is hope that this success will begin to carve a path for precision child health care and more patients will have the opportunity to receive individualized care and treatments for a wide range of conditions.

David Malkin, lead of the Precision Child Health initiative, director of the Cancer Genetics Program, and the CIBC Children’s Foundation Chair in Child Health Research at SickKids, said the idea behind precision medicine is to use the unique features of an individual to make diagnosis more precise and to predict approaches and outcomes to treatments.

“The concept is that we take all information, from the postal code to the genetic code, so it is more than medicine, its overall health and everything that encompasses,” said Malkin.

This groundbreaking individualized gene therapy procedure was years in the making.

After fundraising over $3.5 million to develop the therapy, successfully testing it in mice, and finally getting Health Canada approval, Toronto-born four-year-old Michael Pirovolakis received the procedure in March to hopefully slow the progression of his ultra-rare genetic condition, SPG50.

In April 2019, Michael was diagnosed with the progressive neurodegenerative disorder spastic paraplegia type 50 or SPG50. This condition, which is caused by variants in a gene called AP4M1, causes developmental delays, speech impairment, seizures, and progressive paralysis of the arms and legs. Over the course of a few years, children lose the ability to walk and use their hands, and eventually lose their mental capacity. It is also likely to be fatal.

Dr. Manohar Shroff, neuroradiologist at SickKids, prepares Michael for his procedure. Photo by SickKids

Michael is currently the only known patient with the condition in Canada. It is estimated that there are around 80 other children with SPG50 around the world, making it an ultra-rare disease.

Having a child with an ultra-rare disease is difficult, said Terry Pirovolakis, Michael’s father. Someone has to be watching him at all times because he doesn’t understand that climbing up on the couch or opening the fridge door could be unsafe.

“We love him more than anything, you know, but it is difficult,” he said.

Upon diagnosis, the treatment options for SPG50 were extremely limited. So, Terry and his wife Georgia started the charity CureSPG50 to raise money to develop a gene therapy that would help their son and others with SPG50.

Gene therapies are usually used to treat conditions caused by genetic mutations, said Jim Dowling, staff physician in the Division of Neurology and senior scientist in the Genetics & Genome Biology program at SickKids.

“The idea is that through some delivery mechanism, a gene is added back to an individual,” he said.

Currently, the standard way of delivery is to replace the DNA of a virus, most commonly an adeno-associated virus (AAV), with the healthy DNA of the mutated gene. An AAV is used because people do not get sick when they are exposed to it, said Dowling.

The virus is then given to the patient in a way that is specific to their condition. Sometimes this is through an IV, sometimes into the muscle, or even into the eyeball. For SPG50, gene therapy is given into the spinal fluid so it can easily access the brain.

There are risks associated with the gene therapy procedure, specifically if the patient may develop cancer.

“It was exciting that we can give Michael a better life, but scary at the same time because the last thing I ever want to do is hurt my child,” said Terry

What was especially unique about Michael’s gene therapy was that it was designed specifically for him and his condition, said Dowling, who led Michael’s clinical trial.

This type of individualized treatment is what the doctors behind the Precision Child Health initiative at SickKids have been working towards.

Toronto-born four-year-old Michael Pirovolakis received the procedure in March to hopefully slow the progression of his ultra-rare genetic condition, SPG50.Photo by SickKids

Currently, the precision child health team is gathering case studies that show the use of individualized medicine, like Michael’s gene therapy, to create a plan on how to go from the discovery of disease to medical intervention.

They hope that they will soon be able to give the same specialized treatment that Michael received to many more children with many different types of conditions.

Terry said that he and his family are cautiously optimistic about the improvements they are seeing in Michael since the gene therapy three months ago. He is doing well and there are small signs that his symptoms may be improving.

“We wouldn’t have gotten here without the amazing people helping us along the way,” said Terry. “I want to thank everybody for just truly being there for us.”

Michael will hopefully not be the only child that receives gene therapy to treat SPG50.

Currently, another batch of treatment is being made with the hope of having 10 doses to give to other kids, said Terry. If all goes to plan and the U.S. Food and Drug Administration (FDA) approves the treatment, in October there will be another clinical trial in Texas.

Terry said this plan relies on CureSPG50 raising another quarter of a million dollars per child. The money is needed to cover a five-year study and hospital costs.

“Our goal is to save as many kids as we humanly can,” said Terry. “I hope we can raise enough money to eradicate this disease.”