A Kansas man with a rare disorder spent decades advocating for gene therapy. It may never help him
Donavon Decker became, in more ways than one, an ambassador of limb girdle muscular dystrophy type 2D, a rare degenerative disorder. But decades after he participated in patient trials and fundraised for research, drug companies are still nowhere close to a cure.
In the summer of 1999, a soft-spoken air traffic control specialist from South Dakota named Donavon Decker captured national attention when he signed on for a patient trial testing the safety of a potential breakthrough treatment for a form of muscular dystrophy.
On the Muscular Dystrophy Association telethon — hosted by comedian Jerry Lewis — in USA Today and in news outlets across the country, Decker told his story.
He was born with a degenerative disorder called limb girdle muscular dystrophy type 2D, which affects just three or four people in 1 million. It gradually weakens patients’ muscles and caused Decker to walk with a gait.
Researchers at Nationwide Children’s Hospital in Ohio, led by Dr. Jerry Mendell, aimed to treat LGMD2D by injecting patients with a virus that contained a working copy of the gene that caused their condition.
Decker had four sisters who also had the disorder, and he eagerly volunteered for the trial.
“I knew it wasn’t going to be a cure, but I thought eventually, they would come up with this to where it would be a cure,” Decker told KCUR recently. “Having my family affected the way it was, was important to me to try to help myself and my family.”
The risks of this early gene therapy research became apparent just a few weeks later, when a patient named Jesse Gelsinger died in an unrelated trial.
Decker, however, was undeterred. He became a passionate advocate for gene therapy research, speaking at conferences, urging other patients to volunteer for trials, and lobbying Congress for funding.
This kind of intense patient advocacy is common, and necessary, in the rare disease world. Big drug companies usually don’t have much financial interest in early-stage research for conditions that affect so few patients.
So it’s often up to those very patients, their families and nonprofit groups to fund researchers.
Sharon Hesterlee is the chief research officer for the Muscular Dystrophy Association. The organization has spent $125 million to develop gene therapy, often with the goal of attracting a company that could fund more expensive further steps.
For example, the Muscular Dystrophy Association spent $4 million for the safety trial that Decker participated in.
“A lot of what we do is de-risking,” Hesterlee said. “So we want to pave the way and make it easier for the next party — it’s usually a drug development company — to pick things up and move it forward.”
While drug companies foot the bill for larger trials or virus manufacturing, they may also bring their own considerations as for-profits.
“Companies have a lot of thing they have to pay attention to,” Hesterlee says. “From shareholders to timelines they have to prioritize sometimes. Some things will fall off the radar because they’ve got to prioritize a different drug. So all of that can be very frustrating.”
Now, the Muscular Dystrophy Association sometimes requires companies that purchase intellectual property it helped develop to show their progress on the research, or else that ownership will revert back to the nonprofit group.
Much of the media coverage of Decker’s 1999 trial suggested a treatment might be developed just around the corner, but that didn’t happen. In fact, Gelsinger’s death caused gene therapy research as a whole to grind to a halt, and when trials resumed, the pace of research struggled to regain momentum.
Decker’s sister, June, participated in another LGMD2D trial conducted by Children’s Nationwide a few years later.
However, it took nearly two decades after Decker's trial before a company finally took a serious interest.
In 2017, an Ohio-based company named Myonexus Therapeutics was formed to advance the gene therapy research developed at Children’s Nationwide. Then in 2019, Massachusetts-based Sarepta Therapeutics purchased Myonexus for $165 million.
To Donavon’s disappointment, Sarepta didn’t launch more advanced clinical trials for LGMD2D treatment.
Instead, the company announced it would began a natural history study, in which scientists may spend years simply monitoring how a condition like limb girdle muscular dystrophy affects patients.
Sarepta chief medical officer Louise Rodino-Klapac explains this is a prerequisite to taking additional steps for rare disease research.
“When you can’t do a large clinical trial with hundreds of patients, you really need to understand the natural history, meaning how patients progress over time so that you can design a clinical trial that can show improvement, for example, and then lead to approval of the therapy,” Rodino-Klapac said.
Rodino-Klapac previously worked on limb girdle muscular dystrophy treatment development with Mendell at Nationwide Children’s Hospital. She said she sympathizes with waiting patients like Decker.
“We completely understand the communities’ desire to move investigational treatments faster, and that’s our desire too,” Rodino-Klapac said. “It’s just important to understand that there are steps in the drug development process that just take time.”
To Decker, though, Sarepta's natural history study seemed to be a step backwards. Especially since other gene therapy treatments have already hit the market — like Zolgensma, which dramatically improves spinal muscular atrophy.
Earlier this year, Sarepta announced its own encouraging results in trials to treat Duchenne muscular dystrophy.
But gene therapy development for other muscular disorders has proven more complicated than many researchers initial expected, Hesterlee says, due to the challenge of affecting large areas of muscles and because of toxicity issues related to the treatment.
According to Dr. John Porter, gene therapy research across the board has been plagued by slow progress and setbacks, in part because many researchers had incomplete knowledge of the rare diseases they attempted to treat and the steps involved in getting treatments approved.
Porter is a former muscular dystrophy researcher, patient advocate and program director of the National Institutes of Health / National Institute of Neurological Disorders and Stroke.
He says researchers underestimated the importance of natural history trials, like the one Sarepta is conducting, which can provide essential information to help demonstrate whether a treatment is effective.
“Even in the company level, researchers didn’t fully understand just how important it was to understand how the disease progresses in informing what you measure in a clinical trial,” Porter said.
But he says researchers and companies also created unrealistic expectations about their work as they sought to attract research funds or investor dollars. News outlets’ often-breathless coverage of the research added to that problem as well.
By suggesting that breakthrough cures could be imminent, these groups have sometimes misled patients and the general public about the realities of medical research.
“It’s actually very damaging for a researcher to hype both the timeframe and the level of effect that any particular drug might achieve,” Porter says.
Today, Donavon Decker is 59 and he lives in a sunny ranch-style house near Wichita, Kansas, with his wife, Kirsten. His health has been declining more rapidly due to his condition. He now uses a motorized wheelchair and his lung capacity is diminishing, although he still enjoys time with his friends and family.
Donavon is no longer able to work, but he closely follows news about gene therapy from a computer in his living room.
After nearly 25 years of advocating for gene therapy research, Decker is disappointed that much of its potential has yet to be realized.
“I think of all the families that have been helped with gene therapy,” Decker says. “It’s good to know that I had a part to play in the ones for the muscular dystrophy and spinal muscular atrophy. But there’s still a big hole there for me because my family hasn’t been helped.”
Still, Decker encourages other patients to take part in research. He remains hopeful that someday, gene therapy will lead to a cure.