Successfully treated a fetus with a genetic disease for the first time with medication inside the womb. The baby, who received treatment late in the pregnancy, has shown no symptoms since turning two years old.
Richard S. Finkel, a professor at St. Jude Children's Research Hospital in the United States, published the results of treating fetal spinal muscular atrophy with medication in the international journal "New England Journal of Medicine (NEJM)" on the 19th.
Spinal muscular atrophy occurs when nerves are abnormally formed during the fetal development process. It adversely affects motor neurons, leading to muscle weakness and even death. It is estimated that 1 in every 10,000 newborns worldwide suffers from this disease.
As of now, three types of spinal muscular atrophy treatments have received approval from the U.S. Food and Drug Administration (FDA). Diagnosis can be made during the fetal stage, but treatment starts after birth. If appropriate treatment is not received within a few months of birth, most do not survive beyond three years, so treatment timing is crucial.
The research team began a study on treating spinal muscular atrophy during pregnancy at the suggestion of parents whose fetus was diagnosed with the condition. These parents had already experienced loss due to spinal muscular atrophy. The study began when they asked the researchers if treatment could start before delivery.
The research team had the pregnant woman, who was at 32 weeks of pregnancy, take Risdiplam, a spinal muscular atrophy treatment from Roche of Switzerland, daily for six weeks. They then collected amniotic fluid and umbilical cord blood during the delivery process to verify if the medication taken by the pregnant woman was delivered to the fetus.
The research team confirmed that Risdiplam taken by the pregnant woman was delivered to the fetus during pregnancy by examining the amniotic fluid and umbilical cord during delivery. The baby born this way showed little to no nerve damage compared to other newborns with spinal muscular atrophy. In particular, levels of the SMN protein were elevated. SMN is a protein that plays a role in maintaining the spinal cord and neurons, and if its levels fall below normal, spinal muscular atrophy develops.
The research team directly administered the medication to the newborn starting from one week after birth. No significant nerve damage or muscle loss symptoms were observed even after re-examination at 30 months of age. Professor Finkel noted, "The child's health is in a very reassuring state," adding, "However, lifelong treatment and management will be necessary going forward."
The research team stated that this study proposed a new method for the early treatment of genetic diseases. However, there is still only one case of treatment. To apply it to other fetuses, verification involving multiple patients must be conducted through clinical trials.
Professor Finkel remarked, "If the effectiveness of treating genetic diseases after birth is uncertain, then intrauterine treatment could be an alternative," expressing hope that research on intrauterine treatment will commence following this study.
References
New England Journal of Medicine (2025), DOI: https://doi.org/10.1056/NEJMc2300802