A new targeted treatment for breast cancer could reshape the way they classify and treat the disease, providing another option for those whose tumors have spread or cannot be removed through surgery. could.
On Friday, the Food and Drug Administration approved Enhartu, a drug developed by AstraZeneca and Japanese drugmaker Daiichi Sankyo, for patients with advanced breast cancer who have low levels of a protein called HER2. It is the first targeted drug approved for this patient group.
For more than two decades, HER2 status has shaped breast cancer treatment. Named for the gene that encodes it, the presence of the protein in higher levels is linked to more aggressive tumors that grow and spread faster. But the approval of a HER2-targeting drug called Herceptin in 1998 gave doctors an effective treatment to fight breast cancer positive for the protein. Since then, several other anti-HER2 drugs have entered the market alongside Herceptin.
Until now, HER2 status has been black or white—either positive or negative. However, the study showed that Enhartu is dramatically effective in treating tumors with very low levels of HER2, which would normally be considered negative.
Approval of the drug thus creates a new classification for doctors to respond to. The FDA estimates that approximately 60% of breast cancer patients previously classified as HER2-negative tumors may now be counted as HER2-low and potentially receive Enhertu. HER2-negative cancers are estimated to be by far the most common, occurring in between 80% and 85% of the more than 250,000 people diagnosed with breast cancer each year in the United States.
“The priority is to ensure access to safe and innovative treatments that are specifically tailored for each patient’s cancer subtype,” said Richard Pazdur, FDA office chief, in a statement.
FDA approval authorizes Enhertu for use in patients with HER2-low metastatic breast cancer who have previously received chemotherapy or whose tumors are being treated with surgery or have returned within six months of completing chemotherapy.
Before Enhertu was approved, these patients would otherwise have received hormone therapy or chemotherapy.
The FDA reviewed Enhartu exceptionally quickly, completing its review just 11 days after accepting regulatory submissions from AstraZeneca and Daiichi Sankyo. However, the agency has evaluated the drug under a program that allows for “real-time” review of clinical trial data as it arises, allowing for faster regulatory decisions.
This real-time review was first used in 2019 but has become more common over the past year with reviews of nine new cancer drugs.
AstraZeneca and Daiichi Sankyo tested Enhertu against chemotherapy in a study of nearly 600 adults with metastatic or unresectable HER2-low breast cancer. The results, published in June and published in the New England Journal of Medicine, showed that treatment with Enhartu halved the risk of disease progression and reduced the risk of death by a third compared with chemotherapy. Gave.
“It’s going to really change our standard of care,” Nancy Lin, a medical oncologist at the Dana-Farber Cancer Institute, said in an interview with Biopharma Dive. “In general, anyone who has metastases needs to know their HER2 status” and whether it is defined as “positive, low, or null.”
The drug can have serious side effects and has been linked to a type of lung scarring that resulted in the deaths of three patients in the study. However, serious side effects were more common in patients receiving chemotherapy.