Montreal Children's: Youngest baby in North America to be treated with gene therapy for rare disease

The Montreal Children's Hospital says its nine-day-old patient is the youngest in North America to receive a type of gene therapy for a rare progressive disease.

Better still, the gene therapy, called Zolgensma, was effective. It has so far stopped the development of any symptoms. Now four months old, Samuel is developing normally, when his health would have otherwise deteriorated.

The condition, which can start showing signs in utero, is a rare progressive genetic disease called spinal muscular atrophy (SMA) that affects the nerve cells controlling a person's muscles. It affects one in 10,000 people.

"You develop weakness in the muscles of your arms and your legs, but also the muscles that help you swallow safely and that help you breathe. So the infants lose strength over time and without treatments or care, most die by the age of one," said Dr. Maryam Oskoui, the head of pediatric neurology at the MCH.

"When we saw him doing so well after the treatment, moving along, reaching milestones as a normal baby would, it's just incredible," said his mother Audrey Bouchard, a Montreal-area resident.

Bouchard is elated that Samuel was treated for his rare disease, arresting its progression. But, she said, it also feels bittersweet.

While her middle child Jacob is not affected by SMA, her eldest child, daughter Ariane, was born with the condition nine years ago.Samuel received his gene therapy treatment, Zolgensma, at the Montreal Children's Hospital when he was nine days old. Photo: Audrey Bouchard

"We have it as a reminder every day…she did not receive the treatment as soon as him," Bouchard said, explaining that while Ariane did get the same therapy as Samuel, and was the second patient in the world to get it, she didn't benefit in the same way.

That's because, at the time, the treatment was still the subject of clinical trials. As a result, Ariane received only half the dose, and got it too late. At six months of age, she had already suffered irreversible damage.

With nothing to stop progression, and no drugs to fix the loss of motor neurons, Oskoui said there were no other options for Ariane other than supportive care. At nine years old, she can barely move and needs permanent tracheostomy ventilation and a feeding tube.

"We tried to make her live her best life despite the disease…she's still pretty happy," Bouchard said, adding "it's not a disease that will affect the intelligence or the brain."

That is a particularly "devastating" outcome for some, said Oskoui "because the children remain bright and communicative with their eyes, even as they lost skills," she said.Audrey Bouchard from the Montreal areas has two children, Ariane and Samuel who were born with a rare condition, spinal muscular atrophy. While the gene therapy was in it's early stages when Ariane was born, in 2023, Samuel has been helped by the treatment. Photo: Audrey Bouchard

SAMUEL PAVES THE WAY

Since Ariane started showing symptoms of SMA early, Oskoui knew when Bouchard was pregnant with Samuel they would need to act quickly to try and preserve his health immediately after birth.

"We knew a few weeks along, during the pregnancy, that he is going to have SMA so we contacted right away our neurologist," Bouchard said.

"The diagnosis of spinal muscular atrophy has become a neurological emergency," Oskoui said. "In our practice, we know that each day that we delay, the treatment has an impact on how well the kids develop over time."

The specialist credited the team at the MCH for putting all the pieces in place rapidly. Samuel received the gene therapy transfusion, which is a one-time treatment that costs more than $2 million and is covered by the Quebec government, Oskoui said.

"I'm looking at Sam and I'm just amazed that a few years ago, we were so close, but now, every baby born with SMA will not know the effect as before, and we are very grateful for that," said Bouchard.

Samuel will be closely monitored to make sure his body safely adapts to the gene therapy in the long-term, Oskoui explained.

INFANT SCREENING COMING SOON TO QUEBEC

Newborn screening for SMA has already being practiced around the world, including in some Canadian provinces.

In June last year, the Quebec government announced that the province would initiate its own SMA screening program and work is underway to set it up, said Oskoui.

She expects it will be added to the Programme québécois néonatal de déspitage sanguin et urinaire, likely before the end of the year.

"If we're making treatments available and we know that there's a drastic difference in outcomes if they're treated earlier," she said, adding that early detection is the key to saving lives.