Immunotherapy Combination Shows Promise in Breast Cancer Treatment

Antibody-drug conjugates and immunotherapy harness immune system to target breast cancer tumors.

A combination of antibody-drug conjugates (ADCs) and immunotherapy was able to activate the immune system to help attack tumor cells in patients with breast cancer, a recent study found.

ADCs consist of an antibody that selectively binds to the tumor cell receptor and interrupts the signal to spread. ADCs also act as a transport vehicle for a chemical substance that enters the cancer cells with the antibody and triggers cell death.

In a study published in the journal Science Translational Medicine, researchers found that using specific cytotoxic substances can have a positive effect on the immune system.

Many breast cancer patients have more than the average amount of HER2 receptors located on tumor cell surface. The HER2 receptors are responsible for sending growth factor signals to the cells. The large amount of receptors causes the cancer cells to divide rapidly, allowing for tumors to grow quickly.

A pre-clinical trial performed by researchers from the University of Basel used a combination of ADC (trastuzumab emtansine) with another immunotherapy to jump start the immune system into attacking the tumors.

The study was performed on mouse breast cancer models using a complementary antibody that was able to block the function of 2 immunoregulatory checkpoints, allowing different endogenous T-cells to activate.

Immunoregulatory checkpoints are receptors on immune cells that regulate the immune system. If health cells were about to be damaged, the effector T-cells would hold back their activation.

"Our results clearly demonstrate that antibody-drug conjugates are suitable for use in a combination therapy, opening new perspectives for the treatment of breast cancer," said lead author Philipp Müller.

Although the immune response did not have an immediate effect on the breast tumors, it proved to be effective in mice when combined with ADC. This resulted in the majority of mice who had combination therapy to be completely cured.

Furthermore, researchers found that T-cells play a host protective role in the therapy setting. The removal caused an excessive amount of inflammation and damaged tissue.