For the first time, research on spina bifida and stem cells has reached the operating room before birth. The CuRe trial, published in The Lancet in February 2026, added a patch of placental mesenchymal stem cells to fetal surgery for myelomeningocele. Phase 1 results indicate that the procedure is safe and feasible. Efficacy, however, remains to be demonstrated.
What spina bifida is and why myelomeningocele is the most severe form
Spina bifida is a neural tube defect: in the first weeks of pregnancy, the fetal spine does not close completely. There are several forms, from spina bifida occulta, often without symptoms, to myelomeningocele, the most severe.
In this form, the spinal cord remains exposed to the intrauterine environment. The resulting damage is twofold:
- primary damage, linked to the failure of anatomical closure;
- secondary damage, caused by the mechanical and chemical trauma of prolonged exposure to amniotic fluid during gestation.
It is the secondary component that makes intervening before birth worthwhile: less exposure time means, at least in theory, less damage to nerve tissue.
Fetal surgery for spina bifida: the starting point
Fetal surgery closes the lesion in utero, reducing the spinal cord’s exposure. The reference study is MOMS (Management of Myelomeningocele Study), published in the New England Journal of Medicine in 2011. Compared with surgery after birth, prenatal repair reduced the need for a shunt to treat hydrocephalus and improved motor outcomes, at the cost of a higher risk of preterm birth and uterine complications for the mother.
Today fetal surgery is a clinical standard in selected centres. Even so, a significant proportion of children are still born with residual motor disability. Hence the question behind the CuRe trial: can more be done during the same operation?
Spina bifida and stem cells: the CuRe trial hypothesis
Researchers at the University of California, Davis started from an observation: if part of the damage is inflammatory and degenerative, adding a neuroprotective element to surgical closure might improve the result.
In this study, the link between spina bifida and stem cells is therefore not about rebuilding the spinal cord, but about protecting it at its most vulnerable moment.
Why placental stem cells
The researchers chose PMSCs, mesenchymal stem cells of placental origin from donors. Preclinical studies have documented three characteristics that are useful in this setting:
- neuroprotective capacity;
- anti-inflammatory action;
- secretion of growth factors that support nerve tissue integrity.
The regenerative “patch” placed on the spinal cord
The most interesting technical aspect is the delivery method. The cells were not infused but seeded onto an extracellular matrix: a biological scaffold already used in neurosurgery as a dura mater graft. The result is an actual cellular patch.
The patch was applied directly onto the exposed spinal cord during surgery, performed at around 25 weeks of gestation. The cells therefore stay where their paracrine effect, meaning the action of the molecules they release, can act on nerve tissue.
CuRe trial: phase 1 results
The study, registered on ClinicalTrials.gov, involved six pregnant patients. Like every phase 1 study, its primary objective was safety and feasibility, not efficacy. Key points:
- No adverse effects attributable to the stem cells, in either mothers or newborns.
- Healing of surgical sites. At birth, the repair sites were intact, with no infection, cerebrospinal fluid leak or abnormal tissue growth: not a trivial finding when implanting cells with proliferative capacity.
- Neurological finding. In all newborns, postnatal MRI showed resolution of hindbrain herniation, the downward displacement of the cerebellum and brainstem typical of the Chiari II malformation associated with spina bifida.
- No newborn needed a shunt for hydrocephalus before discharge.
The last two findings should be read with caution. The study had no control group, and resolution of hindbrain herniation is also seen after fetal surgery alone: for now, it cannot be attributed to the cells.
What to expect from phase 1/2a
Based on the results of the first six cases, the data safety monitoring board and the FDA authorised the study to continue as a phase 1/2a trial with 35 new patients. As announced by UC Davis Health, the children will be followed up to the age of 6 to assess long-term safety and early signals on motor, bladder and bowel function.
This is the phase in which it will become clear whether the cells actually improve functional outcomes compared with surgery alone. Current data do not yet show this, and it would be incorrect to present them as if they did. What they show is that the procedure is feasible and safe: the necessary precondition for the efficacy question to be asked at all.
Important note. The applications described belong to clinical research and are not approved therapies in current practice. None of the information provided constitutes medical advice.
Why SSCB follows research on placental stem cells
This study concerns the placenta, the third source of perinatal stem cells alongside cord blood and cord tissue. It is the least known to the general public and, by number of active studies, the most recent: roughly 24 clinical studies under way according to ClinicalTrials.gov records, against 217 on cord blood and 313 on cord tissue.
SSCB all three. The reason is simple, and research confirms it year after year: different sources contain different cell populations, with application profiles that do not overlap.
Want to know the differences between cord blood, cord tissue and placenta? Read our dedicated article.
Frequently asked questions about spina bifida and stem cells
What is the CuRe trial?
It is the first clinical study in humans to add placental mesenchymal stem cells to fetal surgery for myelomeningocele, the most severe form of spina bifida. It is led by the University of California, Davis, and its phase 1 results were published in The Lancet in 2026.
Are stem cells already a treatment for spina bifida?
No. The use of stem cells in spina bifida is currently the subject of clinical research and is not an approved therapy. Phase 1 of CuRe assessed safety and feasibility; efficacy will be studied in the next phases.
When is fetal surgery for spina bifida performed?
In utero, usually before 26 weeks of gestation, in specialised centres and after checking that mother and fetus meet the eligibility criteria. In CuRe, surgery was performed at around 25 weeks.
Why use stem cells from the placenta?
In preclinical studies, placental mesenchymal stem cells have shown neuroprotective and anti-inflammatory properties and the ability to secrete growth factors useful to nerve tissue. That is why they were chosen to protect the exposed spinal cord during surgery.
What does it mean for a study to be phase 1?
It is the first phase of clinical testing in humans. It involves few patients and aims to check that a treatment is safe and practicable, not to prove its efficacy, which is assessed in later phases.
Sources
Farmer DL, Kumar P, Reynolds E, et al. Feasibility and safety of cellular therapy for in-utero repair of myelomeningocele (CuRe Trial): a first-in-human, phase 1, single-arm study. Lancet. 2026;407:867-75.
