New approach to immunotherapy leads to complete response in breast cancer patient unresponsive to other treatments

Researchers reported Monday that a novel approach to immunotherapy has resulted in the complete regression of breast cancer in a woman who did not respond to other treatments. The experimental treatment, a modified form of adoptive cell transfer, was reported in <i>Nature Medicine</i>.

Researchers reported Monday that a novel approach to immunotherapy has resulted in the complete regression of breast cancer in a woman who did not respond to other treatments. The experimental treatment, a modified form of adoptive cell transfer, was reported in <i>Nature Medicine</i>. "We've developed a high-throughput method to identify mutations present in a cancer that are recognized by the immune system," said Steven A. Rosenberg, MD, PhD, chief of the Surgery Branch at the National Cancer Institute's (NCI) Center for Cancer Research. To treat the patient, who had metastatic breast cancer, the researchers sequenced DNA and RNA from one of her tumors and identified more than 60 mutations in her tumor cells. They then tested various tumor-infiltrating lymphocytes (TILs), which were found to recognize 4 of the mutant proteins. The TILs were expanded and reinfused into the patient, who also received pembrolizumab to prevent the possible inactivation of the infused T cells by factors in the tumor microenvironment. Following treatment, the woman's cancer disappeared, and it has not returned after more than 22 months. "This is an illustrative case report that highlights, once again, the power of immunotherapy," said Tom Misteli, PhD, director of CCR at NCI. "If confirmed in a larger study, it promises to further extend the reach of this T-cell therapy to a broader spectrum of cancers."