In‑Utero Placenta‑Derived MSCs Added to Fetal Spina Bifida Repair: Early Safety Report

In a Phase I, single-arm experience, placenta-derived mesenchymal stem cells (PMSCs) seeded on an extracellular matrix graft (PMSC-ECM) were applied topically to the exposed fetal spinal cord during standard fetal surgery for myelomeningocele, with early safety observations reported in six pregnancies.

The intervention added intraoperative placement of the PMSC-ECM product to an otherwise standard prenatal closure of the defect. The report frames its initial readouts around whether the delivery step could be performed as intended and whether any early safety signals appeared during the birth hospitalization and immediate postnatal period. It also notes early postnatal imaging observations and reiterates the planned follow-up timeline as part of the preliminary account.

In the operating room, surgeons performed standard fetal myelomeningocele repair following the MOMS protocol and added an extra step in which PMSCs seeded on an extracellular matrix (Cook Biodesign Dural Graft) were placed directly onto the neural placode, with the cells in contact with the exposed fetal spinal cord, before completing dural or duraplasty closure and skin closure. The description emphasizes the practical question of delivering a living cellular product at the surgical site during an established fetal procedure, presenting this as a feasibility focus for the Phase I experience. Overall, the procedural narrative is presented as an implementation-focused account of intraoperative PMSC-ECM placement alongside customary fetal repair.

Early peri-birth observations in the report focus on repair integrity and short-term safety signals after the combined approach. The article reports that all six infants had intact spinal repairs at birth with no evidence of cerebrospinal fluid leak, infection, skin separation, or abnormal tissue growth on physical examination. Postnatal MRI performed within the early newborn period showed no evidence of abnormal tissue proliferation or tumor formation. The report states that no cell-mediated adverse events occurred. Taken together, the birth-hospitalization and early imaging findings characterize the immediate postsurgical course as uncomplicated with respect to the specific safety concerns highlighted in the study.

The report also describes post-birth MRI findings, including reversal of hindbrain herniation in all six cases, and notes that longer-term monitoring is planned, with follow-up assessments scheduled through age six years as part of the ongoing phase 1/2a study.

Key Takeaways:

• The report describes intraoperative application of placenta-derived mesenchymal stem cells seeded on an extracellular matrix graft (PMSC-ECM) directly onto the exposed fetal spinal cord as an adjunct to standard fetal surgery for myelomeningocele, with early safety observations reported.
• All six newborns had intact repairs at birth, and the article reports no cerebrospinal fluid leak, infection, abnormal tissue growth, tumour formation, or cell-mediated adverse events during the birth hospitalization and early postnatal imaging period described.
• It reports hindbrain herniation reversal on postnatal MRI in every case and outlines planned longitudinal follow-up through age six within an ongoing phase 1/2a trial conducted under regulatory oversight.