Natural Compound Timosaponin AIII Breakthrough Enhances CAR-T Efficacy and Overcomes Immunotherapy Resistance in Solid Tumors

Chinese researchers find Timosaponin AIII eliminates CAR-Tregs, enhancing the ability of CAR-T cells to kill tumors and prevent relapse in cancer models.

By: AXL Media

Published: Apr 30, 2026, 8:04 AM EDT

Source: Information for this report was sourced from EurekAlert!

Targeting Immune Suppression to Restore Therapeutic Potency

While CAR-T cell therapy has revolutionized the treatment of hematological malignancies, the emergence of resistance remains a formidable barrier to long-term patient survival. Researchers at the Hefei Institutes of Physical Science and Tongji University have identified a primary culprit in this therapeutic failure: CAR-T regulatory T cells, or CAR-Tregs. These specific cells act as internal brakes on the immune system, effectively weakening the response meant to destroy cancer cells. The team's recent discovery of a natural compound that can selectively neutralize these suppressive cells without damaging active CAR-T cells offers a potential solution to one of immunotherapy's most persistent challenges.

Identifying Timosaponin AIII Through High-Throughput Screening

The breakthrough originated from an exhaustive screening process involving more than 3,000 small molecules on a high-throughput platform. Led by Prof. LIU Qingsong, the pharmaceutical research team isolated Timosaponin AIII, or TAIII, a natural product extracted from the medicinal plant Anemarrhena asphodeloides. According to the study published in Nature Communications, TAIII serves as a highly effective regulator of T cell suppression. By specifically blocking the adenosine A2A receptor, which is a known immune checkpoint, the compound prevents the biochemical signals that typically allow tumors to evade immune detection.

Proven Efficacy in Lymphoma and Patient-Derived Models

Initial laboratory experiments demonstrated that TAIII successfully restored the killing ability of CAR-T cells, significantly enhancing their overall function. When applied to lymphoma models, the combination of TAIII and standard CAR-T therapy resulted in a notable inhibition of tumor growth and a reduction in relapse rates. These findings were further validated using patient-derived cells, where the compound extended survival times compared to traditional single-therapy approaches. This suggests that the natural molecule could be integrated into existing treatment protocols to provide more durable responses for patients with blood cancers.