MADISON, Wis. – For many teens, getting a driver’s license is a rite of passage, but some encounter barriers that most teens don’t even consider that might make that milestone seem impossible.
Easton King, 19, of Boscobel, dreamed of earning his driver’s license as he entered young adulthood. Unlike most of his peers, King did so while navigating the use of an adapted vehicle that supports his mobility.
Diagnosed at 13 months, Easton was born with a rare genetic condition called spinal muscular atrophy, or SMA, which causes widespread loss of lower motor neurons early in life. Easton has used an electric wheelchair since age 2.
He’s always been very goal-oriented, according to his mom Laurie King.
“When he was 14, he said, ‘Mom, I want to have my driver’s license at 16,’” she said. “His whole senior year, he got to drive to school.”
Lower motor neurons are cells in the spinal cord and brainstem responsible for skeletal muscle control throughout the body. There is no cure for SMA, but in 2016, the Food and Drug Administration approved a treatment to preserve the neurons that control muscle function. The therapy, called nusinersen, which is marketed under the brand name Spinraza, is administered intrathecally. After an initial loading dose regimen of three doses administered every 14 days, followed by a fourth 30 days after the third dose, it must be given three times a year at a medical facility. In addition, a daily oral liquid medication called risdiplam, also known as Evrysdi, was approved in 2020 for individuals older than 2 to help preserve lower motor neuron function.
Easton was given nusinersen at age 11, starting in 2017, when the therapy first became available, according to Dr. Jennifer Kwon, pediatric neurologist, UW Health Kids, and professor of neurology, University of Wisconsin School of Medicine and Public Health.
“For older patients like Easton, there were no other options beyond Spinraza until Evrysdi came along,” she said. “Both these treatments are chronic, for the lifetime of a patient.”
For Easton, this meant traveling two hours each way to American Family Children’s Hospital in Madison for treatment three times a year for three years, until he was prescribed risdiplam during the COVID-19 pandemic in 2020.
While the treatment plan no longer required Easton’s family to travel throughout the year, they faced concerns over whether the therapy would be delivered to their home on time, whether it would be damaged in shipping or whether insurance would cover it, Laurie said.
In 2023, a new therapy possibility emerged. Clinical trial leaders at the University of Wisconsin collaborated with pharmaceutical company Novartis on a Phase 3 clinical trial of a gene therapy for adults called onasemnogene abeparvovec, or Zolgensma, to replace a non-working form of the SMN1 gene. The root cause of lower motor neuron dysfunction in SMA is nonfunctional SMN protein encoded by the SMN1 gene. The therapy had been available only for infants, because the gene therapy relies on a type of viral delivery that posed safety considerations at the dosages needed for an adult.
Nusinersen and risdiplam work by boosting the survival motor neuron, or SMN, protein production to allow muscle function, but don’t fix the nonfunctional gene. Those treatments need to be taken for life, whereas a gene therapy like onasemnogene abeparvovec only needs to be administered once.
Kwon, who began seeing Easton in 2019, identified him as a prime candidate for the trial, and at age 17, they enrolled him in the study, Laurie said.
“He was in the second group of the kids who got it at UW, but only one of eight kids in the world in his age range,” she said. “We are grateful for UW Health being on top of the latest treatments.”
Easton and his family drove to American Family Children’s Hospital to participate in the trial. Kwon was the trial site’s lead researcher and administered the therapy via lumbar puncture, or spinal tap. Easton stayed at the hospital for a few days for observation, but there were no adverse side effects, he said.
“I wanted to see if it worked for me, and I wanted to show others that it was safe and help advance care for other people with SMA in the future,” he said.
Two years later, Easton says he hasn’t lost any muscle function and has not reported any side effects. He initially returned to Madison every few weeks for follow-up observations, but as time went on, the visits became less frequent. He is now a college student at University of Wisconsin-La Crosse and can return for his sophomore year without the need for ongoing treatments to maintain his muscle function, he said.
Easton’s future goals include getting a degree in sports management with a minor in business administration and becoming a sports agent after college. To keep his sports acumen sharp, he currently manages the men’s basketball team.
August is SMA Awareness Month, and Easton and Laurie are hopeful that sharing their story will help others learn more about this condition, as well as understand that living with SMA doesn’t have to limit opportunities.
“I didn’t let it affect how I want to live my life; I’m going to college, and I have high goals in life with a career,” he said. “I never thought it would be possible because of my disease.”
Easton and Laurie also want to give back to the community that meant so much to them as they navigated this medical journey, Laurie said. Easton plans to attend or perhaps speak at SMA conferences in the future.
“To parents who have a child with SMA or any condition, finding the community of people is so vital,” she said. “To be able to talk to people has been so helpful.”
