In 2015, Kelly Hennings got the devastating news that her infant son had a severe form of spinal muscular atrophy (SMA), a disease that causes progressive muscle loss starting before birth. There were no treatments, and he passed away before his second birthday. Hennings and her husband were both carriers of SMA, meaning that there was a 25% chance any future biological children would also be affected. When Hennings got pregnant again years later, she learned via amniocentesis that this child, too, had SMA.
Treatment options had expanded since their first child, but Hennings wanted to give her baby the best shot at a stronger life. “I was willing to do anything we could,” she says.
There is no approved prenatal drug for SMA. But she asked Dr. Richard Finkel, an SMA expert and director of the Center for Experimental Neurotherapeutics at St. Jude Children’s Research Hospital, if there was anything they could try. He had been mulling this very idea. “It's something I've been thinking about for some time but had not actively pursued, so this kind of fell in my lap,” Finkel says.
He had a hunch that the oral SMA treatment risdiplam, made by Roche, had prenatal potential because it’s safe for kids and adults and crosses the placenta. Finkel set up a single-patient trial, got it approved by the FDA, and had Hennings take the drug for the last six weeks of her pregnancy—“a first-in-human situation,” he says.
It appears to have worked. Baby March was born in 2022 and shows no signs of SMA at nearly three years old, according to a paper published in the New England Journal of Medicine in February. She continues to take the drug every day.
Finkel, who is considering doing a full clinical trial on the prenatal use of risdiplam, credits the parents with helping to advance science. “They understood that, in effect, they were going to be pioneers, and that they were taking some added risk without any clear assurance that there would be added benefit.”