The field of cancer immunotherapy is progressing rapidly with several new agents approved by the FDA just this year. Most exciting are so-called checkpoint inhibitors that “take the brakes off” the immune response and enable a stronger immune attack against cancer. Despite their demonstrated benefits of tumor regression and increased overall survival, these therapies are effective in only 20-40% of patients.
Focused ultrasound may play a role in improving the effectiveness of immunotherapy to fight cancer. On March 18th, the Foundation hosted “Cancer Immunotherapy – Opportunities and Barriers,” a 90-minute webinar featuring Tim Bullock, PhD, Associate Professor in the Department of Pathology at the University of Virginia. Dr. Bullock presented an introduction to cancer immunotherapy and discussed opportunities for focused ultrasound to make an impact in this burgeoning field.
Ablation or mechanical damage induced by focused ultrasound can promote the release of cellular components, which signals that something is wrong and activates the immune system. Further, the damage induced in the tumor by focused ultrasound can lead to increased release of tumor antigens. These antigens, not normally expressed by our healthy cells, let the immune system know what to target. We then make white blood cells and antibodies that selectively target the tumors.
When a tumor cell is damaged, the immune system will send white blood cells to the area. But tumors have a way of suppressing the immune response – the white blood cells go to the area but cannot remove the cancer cells. By dialing down the white blood cell response, the tumor effectively shields itself from the immune system.
Focused ultrasound could help the immune system to “see” tumors and aid in their removal in three ways:
- Augment the release of tumor antigens, giving the immune system more targets.
- Modulate or disrupt the tumor’s microenvironment. This would break the tumor’s shield and create a more favorable environment for the immune system’s work.
- Deliver or release immunotherapy and targeted therapy drugs directly into a tumor.
Dr. Bullock’s slides from this presentation are available here.