A grandpa's hope for hemophilia cure leads him to gene therapy clinical trial 

Key Points
  • James Addie, a 53-year-old with hemophilia, is in a clinical trial for a gene therapy developed by BioMarin.
  • It is an experimental treatment that uses a virus to deliver a healthy copy of a gene to make up for one that causes excessive bleeding. 
  • BioMarin's treatment is the most advanced in a race that also includes Spark Therapeutics, UniQure, Sangamo and Pfizer.
VIDEO2:0102:01
Modern Medicine: Gene therapy for hemophelia

At two months old, it's too early to say if Andrew Michael will take after his grandpa in most respects. Whether he'll have the same affinity for photography, or easy approach to life's challenges.

What Andrew does have in common with his grandpa, James Addie, is hemophilia. Addie, 53, was diagnosed early in his life with the inherited bleeding disorder; his older brother also has it, as does his nephew. Now, so does his baby grandson.

For Addie, the disease has meant years of bleeds, progressive joint damage, eventually the replacement of his left knee and both hips. Contaminated blood used for treatment decades ago left Addie with HIV, not uncommon among those his age with hemophilia.

But Addie's got a reason to be optimistic that things will be different for Andrew. In fact, Addie is the reason.

Four months ago, he traveled from his home in St Louis to the University of Michigan to get a single treatment he hoped would change his life — and that of his baby grandson. So far, it appears that it has.

Addie is in a clinical trial of a gene therapy for hemophilia developed by biotech BioMarin Pharmaceutical. It is an experimental treatment that uses a virus to deliver a healthy copy of a gene to make up for one that causes his excessive bleeding. The goal: to effectively cure the disease with just one administration, righting the genetic mistakes that afflict the families of 400 babies born in the U.S. each year.

"The hope with gene therapy is that we can get people to that place where hemophilia's not something that they wake up in the morning and think about first thing," said Dr. Catherine McGuinn, director of the hemophilia treatment center at Weill Cornell Medical Center. "I think of it as a way to protect people sort of every moment of the day."

The current treatment for hemophilia requires patients get infusions every few days with medicine that helps their blood clot, known as factor replacement therapy.

It's a dramatic improvement from treatment years ago. Addie remembers getting severe bleeds once or twice a week before he started prophylactic therapy. Once he started factor replacement every three days, he estimates he only had three bleeds per year.

Still, said McGuinn, "it is pretty onerous to think about finding a vein and doing this as part of your routine a couple of times a week."

Gene therapy would change that. And, in the four months since his treatment, it has for Addie.

James Addie with his grandson Andrew Michael. Both have hemophilia.
Source: CNBC

The severity of hemophilia is measured by how much clotting factor is in the blood. People with severe hemophilia have less than 1 percent of normal. When Addie started the trial, his level was about 0.4 percent, he said.

A month later, his level was up to 10 or 12 percent. A few weeks after that, it had shot up to 50 percent of normal. At its peak, Addie said, his clotting factor level reached 147 percent, before he took a fall and his elbow swelled up.

"It dropped down to 106," Addie recalled. "The doctor said, 'Well, that's because your body is using that factor that's there.'"

Addie said he took some of his factor replacement after the fall, because his elbow "was so swelled up that it looked like a grapefruit."

Two weeks later, he fell again.

"But I didn't take any factor," he said. "It didn't swell up as bad or anything. I'm back to whatever my normal is."

His factor levels, as of two weeks ago, were back up to 127 percent.

Addie's not the only patient in BioMarin's clinical trials that have seen a benefit. In an update in May, the company said those taking a high dose had an average factor level of 59 percent two years after their infusion. Those on a lower dose had an average level of 32 percent one year later.

The treatment Addie is helping test is the most advanced in a race that also includes Spark Therapeutics, UniQure, Sangamo and Pfizer. If successful, BioMarin's treatment could reach the market as soon as 2020, according to Cowen analyst Phil Nadeau.

The companies are not all competing directly: some are focused on hemophilia A, the most common form of the disease, some on hemophilia B, and some on both.

For the winner, the spoils are potentially enormous: Nadeau estimates the total potential revenue for treating all the existing hemophilia patients in the U.S. is $20 billion.

That's assuming, as most do, an eye-popping price tag: about $1 million per patient.

"Gene therapy's a one-time treatment; all of the cost of the therapy has to be paid upon that treatment," Nadeau said. "It's a different paradigm than what is typically seen in the pharmaceutical industry today, where the patient gets drugs over many days, weeks or years, and so the cost of the therapy is paid out over time."

Still, $1 million sounds like a lot — until one compares it with the cost of annual treatment for hemophilia with factor replacement therapy.

"These patients can be very expensive," said McGuinn. "The cost of treating a hemophilia patient can be somewhere like $100,000 all the way up to probably $1 million or $1.5 million for a patient who's much more complicated."

That's per year.

Addie sees it as a bargain. And while it's not clear yet how long the treatments will last — the goal is patients' lifetimes, but clinical trials currently have tracked patients for just a few years — he says even a few months without having to take his factor replacement felt like a major benefit.

James Addie, 53, is in a clinical trial of a gene therapy for hemophilia.
Source: CNBC

"We're just tickled pink," said Addie's wife, Sandy. "I'm happy for the both of us, because at one point we didn't think we'd get to grow old together."

Though participating in a clinical trial of an unproven therapy can be scary, Addie's decision to do it, he said, wasn't a hard one. His daughter was six months pregnant at the time, and Addie knew — because of the way hemophilia is inherited — if she had a boy, he'd have a 50/50 chance of having the disease.

"Well, he's got it," Addie said. "But then she got thinking when we were out in Michigan (for the treatment), and said, 'Well, Daddy, you might actually be the cure for your grandson, you know?'"

"So, she goes, 'That's pretty cool,'" Addie recalled. "I think it's pretty neat too."

—CNBC's Jodi Gralnick contributed to this report.

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