Tolerance Bio

Tolerance Bio, Inc. is a Philadelphia-based biotechnology company developing therapies that target the thymus, the organ that governs immune tolerance. It is building an allogeneic, off-the-shelf induced pluripotent stem cell (iPSC)-derived thymus cell therapy platform alongside pharmacological thymus therapies. The company aims to treat immune-mediated conditions including cancer, autoimmunity, transplant rejection, infection, immune deficiency and allergy, and to extend healthspan by preserving and restoring thymic function. It launched in 2024 with $17.2M in seed financing, later completed as an oversubscribed $20.2M round.

Rather than suppressing immune responses downstream, Tolerance Bio targets the thymus itself as the master regulator of immune tolerance, using implanted iPSC-derived thymic organoids that have shown in vivo positive selection of human T cells and tumor burden reduction in melanoma models.