Montreal teen first minor in Quebec to receive CAR-T cell therapy for cancer treatment

Sofia Pezet became the first minor in Quebec to receive a groundbreaking treatment and now she’s helping open the door for others.

A teenage girl is celebrating a milestone after a long battle with an aggressive cancer.

Sofia Pezet became the first minor in Quebec to receive CAR-T cell therapy for cancer treatment, and now she’s helping open the door for others.

There was a time when Pezet’s future felt uncertain, but today, the 15-year-old is allowing herself to think ahead.

She’s been cancer-free since March.

“And for all the things I went through, even though it was hard, I think I was pretty lucky,” she said in an interview.

Months before her diagnosis in early 2025, she struggled to breathe. She felt weak and coughed constantly.

Doctors eventually discovered a 15-centimetre mass pressing against her lungs and heart. Pezet describes the time that followed as brutal, with aggressive chemotherapy and days on end unable even to walk, all while being away from home and forced to stay in the hospital for five months.

“That time was kind of a blur for me because with all the treatment, I was not really myself,” she recalled.

Then came another blow.

Just one month after finishing chemo, the cancer returned. Doctors tried immunotherapy, but the cancer kept progressing. With options running out, Dr. Stephanie Mourad pushed for something never done before in a pediatric hospital in Quebec: CAR T-cell therapy.

The treatment takes Pezet’s own T-cells, modifies them in a lab, and trains them to attack cancer. To make it happen, her medical team built a case with experts across Canada.

“And it was unanimous in the country that people would recommend this treatment for Sofia’s case. And the beauty of this product is that it lasts in the body for months, hopefully years,” explained Mourad, a pediatric hematologist-oncologist.

Pezet’s cells had to be sent to California, where they were modified before being shipped back. For doctors at the Montreal Children’s Hospital, this isn’t just a success story — it’s a proof of concept, and they want to make the treatment more accessible in Quebec.

Pezet hopes more families will get the same chance she did. For her father, the result is still hard to put into words.

“She’s a very strong girl. That makes us very hopeful,” said Alexandre Pezet.

While follow-up appointments will continue, Pezet is focused on something she once couldn’t take for granted: a future.

“That’s what I’m thinking about every day,” she said. “I hope I can have a normal life again before the cancer, before everything.”