Oncologists are hoping a drug developed by AstraZeneca and Daiichi Sankyo will change the way doctors treat the most common type of late-stage breast cancer, after data showed it doubled progression-free survival rates. patients in relation to chemotherapy.
Research presented at the world’s largest conference on cancer research on Sunday showed that Enhertu – an antibody treatment targeting cancers linked to a protein called HER2 – also significantly improved overall survival rates for patients when the sickness has spread throughout their body.
This is the first time that such a targeted therapy has improved survival rates in patients with HER2-low metastatic breast cancer, a category that covers up to half of all cancer patients. breast at an advanced stage.
Jane Lowe Meisel, a cancer expert at the American Society of Clinical Oncology, said the results presented at the organization’s annual meeting would “redefine” the way doctors classify breast cancer and significantly expand the population of patients who may benefit from drugs targeting the HER2 protein.
The clinical trial of more than 550 patients found that those using the drug had a 49% reduced risk of cancer progression and a 36% reduced risk of death compared to those who received the standard form of treatment of chemotherapy. It recorded progression-free survival, the time the tumor was stable or shrinking, of 10.1 months with Enhertu, compared with 5.4 months for those who received chemotherapy.
The two companies told the Financial Times they would use the results of the trial – which are expected to be published in the New England Journal of Medicine – to seek approval from global regulators to target this new category of patients with breast cancer with Enhertu.
“This isn’t just a breakthrough, it’s changing practice,” said Gilles Gallant, Global Head of Oncology Development at Daiichi.
He said Daiichi was conducting studies on early-stage breast cancer patients to see if Enhertu is more effective than existing treatments and if it could cure the disease in the future.
Enhertu is the brand name for the antibody-drug conjugate trastuzumab deruxtecan, which AstraZenca and Japanese company Daiichi are developing to treat cancers that express HER2 – a protein that helps cancer cells grow. It is a targeted treatment designed to deliver a payload of chemotherapy to shrink cancer cells while limiting damage to healthy cells.
The treatment has already been approved by the US Food and Drug Administration for a small group of advanced breast cancer patients with tumors expressing high levels of the HER2 protein. But the trial found that Enhertu also worked against a much larger cohort of tumors expressing low levels of HER2.
Existing cancer drugs, such as Roche’s Herceptin, have so far only shown benefit against the minority of tumors that produce large amounts of the HER2 protein, leaving most patients with breast cancer at an advanced stage rely on chemotherapy to slow the progression of their disease.
Enhertu is already approved to treat certain types of gastric cancer in the United States and has shown promise in treating certain lung cancers.
David Fredrickson, executive vice president of oncology at AstraZeneca, said Enhertu has the potential to become a “multi-blockbuster” drug by being transformative in the treatment of different types of breast cancer, as well as types stomach, colon and lung cancers.
He said Enhertu could become an available treatment for patients with HER2-low breast cancer within months of talks with regulators.
Analysts said the trial results would likely accelerate Enhertu’s transformation into a blockbuster cancer drug, which could bring in several billion dollars a year in peak sales.
Enhertu’s global sales outside the Japanese market were $426 million in 2021, according to AstraZeneca.
Tara Hansen, consultant at Informa Pharma Custom Intelligence, said the trial results were “groundbreaking” and would position Enhertu as a competitive option in a patient population with high unmet need. She said the results would lead to an increase in the maximum projected annual sales for Enhertu, which currently stand at just under $3 billion in 2030.
Breast cancer recently overtook lung cancer to become the most commonly diagnosed cancer in the world. Each year, more than 255,000 cases of breast cancer are diagnosed in the United States.