In utero stem cell therapy for spina bifida found safe in early trial

The use of stem cell patches to treat fetuses with spina bifida appears to be safe following a phase 1 clinical trial.

Building on the initial phase of the trial (see BioNews 1163), researchers from the University of California, Davis have reported that none of the six children born in the CuRe trial encountered any infections, spinal fluid leaks or abnormal tissue growth, which may result from stem cell use. Furthermore, the procedure resulted in the reversal of a brain condition associated with spina bifida.

'Putting stem cells into a growing fetus was a total unknown. We are excited to report great safety,' said Professor Diana Farmer, who led the trial and is chair of the UC Davis Department of Surgery. 'It paves the way for new treatment options for children with birth defects. The future is exciting for cell and gene therapy before birth.'

Spina bifida, which is found in around six babies out of every 10,000 in the UK, occurs when the spine and spinal cord fail to close properly during early pregnancy, leaving part of the spinal cord exposed. All six fetuses treated as part of the trial, which was published in The Lancet, were diagnosed with myelomeningocele or another type of 'open' spina bifida, where the spinal cord pushes out of a gap in the spine. The condition often results in brain abnormalities such as hindbrain herniation, and can cause lifelong issues in motor, urinary and bowel functions. 

Operating on fetuses between 24 and 25 weeks, surgeons worked through a small incision in the uterus. A patch made from mesenchymal stem cells sourced from donor placentas was placed over the abnormal opening in the spinal cord, which was then closed. Compared to traditional surgical repairs, which help protect the spinal cord against further damage, the team hope that the addition of mesenchymal stem cells will actively promote healing and regeneration of neural tissues.

When assessing the children after birth, the researchers found no evidence of complications typically associated with stem cell transplantations, such as abnormal tissue growth, tumour formation or infections. In addition, MRI scans performed shortly after birth showed that hindbrain herniation was reversed in all six infants.

Kate Steele, CEO of the spina bifida and hydrocephalus charity Shine, told the Guardian: 'Having seen the difference fetal surgical repair is already making to the lives of children with myelomeningocele, and knowing that adding stem cell therapy to these established surgery techniques might one day improve outcomes for babies born with spina bifida, is very encouraging and very exciting.'

The CuRe trial will now proceed to its next phase, which will involve up to 35 patients. Children born following the procedure will be followed up to the age of six, allowing the researchers to fully assess the long-term safety of the treatment, as well as its impact on movement, bladder and bowel function.