CAR-T, or chimeric antigen receptor T-cell therapy, is an immunotherapy approach that involves genetically modifying a person’s own T cells so they can recognize and target specific proteins on cancer cell surfaces, enhancing the immune system’s capacity to seek out and destroy malignant cells. CAR-T therapies have been successful against blood cancers, such as leukemia, lymphoma, or myeloma, but have largely failed with solid tumors. Now, a new study in mice demonstrates that CAR-T is effective against ovarian cancer, nearly doubling survival time.

Researchers identified a unique carbohydrate present only on the surface of solid tumor cells, not healthy ones, and engineered CARs with a strong affinity for the carbohydrate. Then, they delivered the CAR-T therapy via intravenous injection to mice with ovarian cancer. Because ovarian cancer treatments delivered directly into the abdominal area are particularly effective, they also administered the CAR-T therapy into the animals' abdomens.

They found that the CAR-equipped T cells effectively located and eliminated the cancer cells, promoting tumor shrinkage or elimination with just one dose. The genetically engineered cells maintained their effectiveness for several months, with no evidence of toxicity or adverse effects. Intravenous injection of CAR-T cells increased survival to 145 days, but direct delivery into the animals' abdomens extended survival to 270 days.

These findings demonstrate that modified CAR-T cells show promise as a potential treatment for ovarian cancer and other solid tumors. Future studies are needed to assess the treatment’s effectiveness in humans. Learn more about genetic engineering in this episode featuring Dr. George Church.

• Read study abstract.