An exciting treatment for some patients with metastatic breast cancer

The results of the DESTINY-04 trial presented at ASCO 2022 were received with a standing ovation.

The DESTINY 04 clinical trial looked whether the drug called trastuzumab deruxtecan (Enhertu or T-DXd) helps people with metastatic breast cancer. Enhertu is a type of targeted therapy that was developed to treat HER2-positive breast cancer. HER2 is a protein found on all breast cells. It controls how the cells grow and divide. When breast cells have too much HER2, cells can multiply too quickly. Growth may then become uncontrolled and lead to cancer.Previous results showed that Enhertu can benefit people with HER2-positive breast cancer. But what about HER2-negative breast cancer? Conventional thinking might suggest that an anti-HER2 drug would not work for cancers that are HER2-negative.

Surprisingly however, people whose cancer was previously labeled as HER2-negative – but who actually had very low levels of HER2– had better outcomes when they took Enhertu than those who received standard chemotherapy. These results challenge prior thinking that cancers are either HER2-positive or HER2-negative. Instead, some cancers may be reclassified to a third possible category called HER2-low. This may affect some people whose cancer was previously call triple-negative breast cancer (TNBC), a type of cancer that is often more aggressive and can have worse outcomes than other types. This offers a new treatment option for many people with hard-to-treat metastatic breast cancers and is likely to be a practice-changing information.

Read more about this new metastatic breast cancer treatment in FORCE’s review.