06 Mar, 2026
A first-in-human Phase I clinical trial published in The Lancet has demonstrated that the use of stem cell therapy in combination with standard prenatal surgery is a safe and potentially beneficial approach for treating myelomeningocele, the most severe form of spina bifida.1 This study represents the first reported use of viable stem cells applied directly to the fetal spinal cord in utero, offering the possibility of improved neurological outcomes beyond those achieved with fetal surgery alone.
Spina bifida is a congenital neural tube defect characterized by incomplete closure of the spinal column, resulting in exposure of neural tissue to the intrauterine environment. Affected children frequently experience long-term complications, including lower-limb weakness or paralysis, impaired ambulation, and bladder and bowel dysfunction.2 Prenatal surgical closure of the spinal defect has been shown to reduce the need for ventriculoperitoneal shunting and improve motor outcomes; however, many children continue to have significant neurological impairment despite early intervention.3
In this Phase I trial, six pregnant women carrying fetuses diagnosed with myelomeningocele underwent standard open fetal surgical repair supplemented by the application of placenta-derived mesenchymal stromal cells (PMSCs) directly onto the exposed spinal cord.1 These cells possess anti-inflammatory, neuroprotective, and regenerative properties, which may enhance spinal cord preservation during development.4
All six infants, delivered between July 2021 and December 2022, demonstrated intact spinal closures without evidence of infection, abnormal tissue proliferation, or tumour formation. Postnatal magnetic resonance imaging confirmed resolution of hindbrain herniation in all cases, a key marker of improved neuroanatomical outcomes in spina bifida.1 Importantly, no serious adverse events attributable to stem cell exposure were observed during the perinatal period or early follow-up.
The children enrolled in the study will continue to undergo structured clinical, neurological, and functional assessments until six years of age to evaluate long-term safety and efficacy. Ongoing and future larger-scale trials aim to validate these findings, refine operative techniques, and determine whether this combined approach results in sustained improvements in mobility, neurological function, and quality of life.5 Collectively, these findings mark a significant advancement in fetal regenerative medicine and suggest a promising role for stem cell–augmented surgery in the management of congenital spinal disorders.
References:
1. Farmer DL, et al. Safety and feasibility of placental mesenchymal stromal cells in fetal repair of myelomeningocele: a phase 1 clinical trial. Lancet. 2024;403(10429):XXX–XXX.
2. Copp AJ, Adzick NS, Chitty LS, Fletcher JM, Holmbeck GN, Shaw GM. Spina bifida. Nat Rev Dis Primers. 2015;1:15007.
3. Adzick NS, Thom EA, Spong CY, et al. A randomized trial of prenatal versus postnatal repair of myelomeningocele. N Engl J Med. 2011;364(11):993–1004.
4. In ’t Anker PS, et al. Mesenchymal stem cells in human second-trimester bone marrow, liver, lung, and umbilical cord blood. Blood. 2003;102(4):1548–49.
5. Kabagambe SK, Jensen GW, Chen YJ, Vanover MA, Farmer DL. Fetal surgery for myelomeningocele: a systematic review and meta-analysis of outcomes in the era of the MOMS trial. J Pediatr Surg. 2018;53(4):647–53.