The world’s first in-utero treatment combining fetal surgery with stem cells has been deemed safe, according to a clinical trial led by researchers at UC Davis Health. The trial, focused on infants with spina bifida, involved applying placenta-derived stem cells directly to the exposed spinal cords of six fetuses between 24 and 25 weeks of gestation.
Spina bifida, or myelomeningocele, occurs when spinal tissue fails to properly close during early pregnancy. The condition can lead to a range of lifelong disabilities, including cognitive impairment, mobility issues, and problems with bladder and bowel control. It affects fewer than 1 in 1,000 births globally, but rates are higher in low-income countries.
During the procedure, surgeons made a small opening in the uterus and carefully lifted the fetus to access the spinal defect. A patch containing living stem cells, derived from donated placentas, was then placed over the exposed spinal cord before the layers of the back were closed to allow for tissue regeneration. Researchers reported no complications during the surgeries themselves, and all newborns were delivered around 34 weeks gestation without signs of infection, cerebrospinal fluid leakage, or tumor growth.
“Putting stem cells into a growing fetus was a total unknown,” said Diana Farmer, principal investigator of the CuRE trial and chair of the UC Davis Department of Surgery. “We are excited to report great safety. It paves the way for new treatment options for children with birth defects. The future is exciting for cell and gene therapy before birth.”
The trial also revealed that signs of hindbrain herniation – a complication of spina bifida where the back of the brain descends into the neck, potentially blocking cerebrospinal fluid circulation – had been reversed in all of the newborns. This suggests a potential benefit beyond safety, though researchers emphasize this is a Phase 1 trial focused primarily on feasibility and safety.
The study, titled “Feasibility and Safety of Cellular Therapy for In-Utero Repair of Myelomeningocele (CuRe Trial): a First-In-Human, Phase 1, Single-Arm Study,” was published in The Lancet and funded by a $9 million grant from the California Institute for Regenerative Medicine (CIRM). The research team is continuing to monitor the children born in the trial to assess long-term outcomes.
Researchers acknowledge concerns about the potential for the stem cells to become cancerous, but initial results have not indicated any such development. The team is proceeding cautiously, with further trials planned to evaluate the efficacy of the treatment and determine optimal stem cell dosage and delivery methods.
