For the first time, focused ultrasound is being used in combination with a cancer immunotherapy drug.

In a clinical trial for patients with metastatic breast cancer, non-invasive focused ultrasound therapy is being used to ablate (or destroy) a portion of the primary tumor or metastatic tumors in conjunction with the cancer immunotherapy drug pembrolizumab (Keytruda®). The first patient was treated October 20.

The clinical trial is taking place at the University of Virginia Health System and is led by Patrick Dillon, MD, Associate Professor of Hematology and Oncology, and David Brenin, MD, FACS, Associate Professor of Surgery and Chief of Breast Surgery. “The immune system does not recognize most breast cancers as invading or foreign cells, so the body does not mount an immune response against it,” said Dr. Brenin. “Focused ultrasound induces a local immune response and may have the ability to change that paradigm, enabling a medication like Keytruda to make a difference.” 

Preclinical studies suggest that focused ultrasound can “unmask” breast cancer cells, making them visible to the immune system. The hypothesis is that application of focused ultrasound to the tumor creates a local immune response that draws anti-cancer immune cells to the area. Keytruda could then prevent the tumor cells from deactivating the immune cells, allowing the immune cells to continue killing cancerous cells.

The highly accurate focused ultrasound treatment is being delivered using Theraclion’s EchoPulse system, targeting up to 50% of the breast tumor. Fifteen women will be enrolled in the study; patients will be randomized to receive their first dose of Keytruda either prior to or following focused ultrasound treatment. 

Dr. Dillon said, “Currently, women with metastatic breast cancer have to endure lifelong treatments such as chemotherapy or anti-estrogen therapy that impart toxicity. We hope that this study will help advance the application of immune therapies as we aim to create more durable responses in women with breast cancer.”

Funding for the trial was provided by the Focused Ultrasound Foundation and the Commonwealth of Virginia. “Cancer immunotherapy has emerged in recent years as one of the most promising areas of medicine. One central initiative of our Foundation is dedicated to exploring how focused ultrasound can enhance its effects even further, for more patients,” said chairman Neal F. Kassell, MD. “This is the first time these therapies have been approved by the FDA to be used in combination in patients, and we are proud to support this innovative trial.” 

Keytruda is not FDA approved for the treatment of breast cancer and is considered investigational for the purposes of this study.