By PNAS.org –
In December 2025, the US Food and Drug Administration’s (FDA’s) Center for Biologics Evaluation and Review (CBER) approved a gene-based stem cell therapy for Wiskott–Aldrich syndrome, a rare and life-threatening genetic disease. This decision was appropriately based on data from two clinical studies that demonstrated a clinical benefit. Unfortunately, this standard of evidence, and FDA approval itself, are not the norm for many stem cell therapies. Instead, hundreds, if not thousands, of clinics have made unproven and unapproved stem cell treatments widely available to treat everything from common sports injuries to neurological diseases.
