Written by Gina Kolata.
A new drug, created to treat just one patient, has pushed the bounds of personalized medicine and has raised unexplored regulatory and ethical questions, scientists reported Wednesday.
The drug, described in the New England Journal of Medicine, is believed to be the first “custom” treatment for a genetic disease. It is called milasen, named after the only patient who will ever take it: Mila (mee-lah) Makovec, who lives with her mother, Julia Vitarello, in Longmont, Colorado.
Mila, 8, has a rapidly progressing neurological disorder that is fatal. Her symptoms started at age 3. Within a few years, she had gone from an agile, talkative child to one who was blind and unable to stand or hold up her head. She needed a feeding tube and experienced up to 30 seizures a day, each lasting one or two minutes.
Vitarello learned in December 2016 that Mila had Batten’s disease. But the girl’s case was puzzling, doctors said. Batten’s disease is recessive — a patient must inherit two mutated versions of a gene, MFSD8, to develop the disease.
Mila had just one mutated gene, and the other copy seemed normal. That should have been sufficient to prevent the disease.
In March 2017, Dr. Timothy Yu and his colleagues at Boston Children’s Hospital discovered that the problem with the intact gene lay in an extraneous bit of DNA that had scrambled the manufacturing of an important protein.
That gave Yu an idea: Why not make a custom piece of RNA to block the effects of the extraneous DNA? Developing such a drug would be expensive, but there were no other options.
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