Evelyn's older sister Josephine had spinal muscular atrophy type 1 (SMA1), a genetic disease that gradually paralyzes babies. She died at 15 months. Evelyn was an unexpected pregnancy, but her parents decided to have the baby despite one-in-four odds of a second tragedy.
Soon after Evelyn was born in December 2014, they were devastated to learn from genetic testing that she, too, had SMA1. "We knew what we were dealing with: We'll love her for as long as we can," says her father, Milan Villarreal. But that same night, frantically searching the internet, they learned about a clinical trial in Ohio and sent an email. At 8 weeks old, Evelyn received a gene therapy treatment that gave her body a crucial missing protein.
And now here she is, not so different from any healthy toddler. Although she has weak thighs and can't run normally or jump, she can walk quickly, dance, trace letters, toss foam blocks, carry a small chair, and climb onto her mother Elena's lap. After the heartbreak of losing their first baby, the Villarreals have watched in amazement as Evelyn has crawled, walked, and talked. "It was just a miracle. Every milestone was like a celebration. We opened a bottle of wine for every little thing she did," Milan says.
The results of the trial Evelyn participated in have blown away gene therapy researchers, too, marking one of the once-troubled field's most dramatic successes yet. All 15 babies treated for SMA1, expected to die by age 2, are alive at 20 months or older, and most can sit up, according to a report this week in The New England Journal of Medicine (NEJM). Like Evelyn, one boy is walking. Although a drug recently approved for SMA1 has achieved similar effects, it must be injected into the spine every 4 months. The gene therapy is intended as a one-time treatment, and it is simply infused into a vein. "I've never seen an effect [of gene therapy] that good in a lethal disease," says neurologist Jerry Mendell of Nationwide Children's Hospital in Columbus, who led the recent trial.
Spinal muscular atrophy [wikipedia.org].
Single-Dose Gene-Replacement Therapy for Spinal Muscular Atrophy [nejm.org] (DOI: 10.1056/NEJMoa1706198) (DX [doi.org])