Ty Sperle says he felt “insane shock” after learning he’d been cured of a rare genetic disease through a clinical trial using a new gene-editing treatment.

The B.C. man says he’d started that day last year feeling hopeless, but the news he was cured filled him with indescribable happiness.

Sperle is the first person known to have received and be cured by a treatment known as “prime editing,” in a breakthrough by U.S.-based Prime Medicine reported in the peer-reviewed New England Journal of Medicine last December.

The 19-year-old, who lives in Kelowna, B.C., had been diagnosed with chronic granulomatous disease around age five, compromising his immune system.

Dr. Stuart Turvey, a pediatric immunologist who treated Sperle for more than a decade during his stays at BC Children’s Hospital in Vancouver, says the disease leaves patients susceptible to infections that can turn serious, even fatal.

“People with this disease don’t live long and healthy lives,” Turvey says.

But the sequencing of the human genome has allowed researchers to identify “spelling” mistakes in people’s DNA, he says, and “the era we’re really in now is about translating those fundamental discoveries to helping patients.”

In a statement issued by the hospital, Turvey says he “jumped” at the opportunity to register Sperle for the clinical trial, which was offered at a limited number of sites. The only one in Canada was Montreal’s Sainte-Justine university hospital, he says.

Prior to the gene-editing treatment, which Turvey calls a “miracle,” he says Sperle was taking antibiotics and antifungal medications daily to help protect him.

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“But that’s not perfect,” he says. “So every day there was a possibility sort of hanging over (Sperle) and his family that some serious infection might sneak in.”

Other patients with the same disease may undergo a combination of chemotherapy and a bone-marrow transplant to effectively wipe out their compromised immune system and build a new one using cells from a healthy donor, Turvey says.

“But not everyone has an optimal donor to give those healthy cells, and (Sperle) was in a position where there was no good donor,” he says.

Chronic granulomatous disease is rare, he says, with just a handful of diagnoses over the two decades Turvey has worked at the hospital.

The gene-editing treatment involved extracting Sperle’s own cells, fixing the “spelling mistake” and inserting the cells back into his body, where they multiplied, overriding his cells that hadn’t been working properly, Turvey says.

“What that meant was, you know, his body wasn’t going to reject those cells, those cells weren’t going to attack his body because they were his cells, just fixed up.”

Turvey says it’s a “dream come true” for his patient to be free of symptoms.

Sperle, who’s now a second-year science student at the University of B.C.’s Okanagan campus, says he’d been living with constant uncertainty.

Being cured of the disease means he no longer has to live in fear of developing a serious or life-threatening infection, Sperle says.

“I do like camping as well and you know, it was a risk before, like there’s lots of bacteria in the woods … so now I can do that without having that risk,” he says.

“I was on a regimen of pills and all those are gone, so I don’t have to take medication anymore, which is just amazing,” he adds.

Sperle says he was “extremely nervous” to be the first patient to undergo the treatment.

“When they put the transplant thing inside me, I was super stressed out, unimaginable stress,” he told The Canadian Press in an interview.

But he had confidence in his doctors, he says.

Sperle says his mother was with him at the Montreal hospital following the gene-editing treatment, but she wasn’t in the room when he first heard he was cured.

She reacted with “instant tears” of happiness when he told her, he says.

Sperle says the success of his treatment can provide hope for others with genetic diseases, especially as the technology advances in years to come.

Turvey says certain diseases may be individually rare, but considered in the aggregate, they’re common. “For us, at BC Children’s Hospital, we estimate that about one in three admitted to hospital actually has a rare disease.”

He says Sperle’s case proves the gene-editing technology can be a cure. But it’s not yet routinely available for patients.

“The next (step), and these are complex steps, is to work out how to deliver this within our various health-care systems, and that’s still an ongoing effort.”

In the statement issued by BC Children’s Hospital, the provincial health minister, Josie Osborne, says Sperle’s successful treatment is a “milestone” that shows the power of public health care, research and global collaboration.

“This gives hope to families facing rare conditions and shows how smart investment in science can lead to life-changing care.”