AstraZeneca said its Enhertu cancer drug has been shown to significantly help women suffering from a type of breast cancer that leaves them with poor treatment options, opening the door to a much larger potential patient group.
AstraZeneca, which is working on the drug with Japan's Daiichi Sankyo, said on Monday that Enhertu prolonged survival and slowed the progression of metastatic breast cancer with low levels of a protein known as HER2.
The improvement was "clinically meaningful" when compared with standard chemotherapy, it said, adding that detailed trial results would be presented at an as-yet undisclosed medical conference.
While the study was limited to low-HER2 patients whose tumors had spread to other parts of the body, analysts have said a positive trial read-out could portend future use at an earlier stage of the disease with potentially hundreds of thousands of new eligible patients per year.
AstraZeneca has predicted a decline in sales of its widely used COVID-19 vaccine this year.
However, brisk revenue growth from new cancer drugs has prompted analysts to rank the Anglo-Swedish company as one of the world's fastest growing major pharma groups.
Enhertu belongs to a promising class of therapies called antibody drug conjugates (ADC), which are engineered antibodies that bind to tumors cells and then release cell-killing chemicals.
AstraZeneca secured rights to the Daiichi Sankyo compound three years ago in a deal worth up to $6.9 billion, challenging the world's biggest cancer drug maker, Roche.
Enhertu has since been shown to help women with breast cancer characterized by high levels of HER2, a cell receptor that leads to uncontrolled tissue growth, when compared to Roche's ADC drug Kadcyla. This led to initial market approvals in late 2019.
Astra's drug is also being tested against gastric, lung and colorectal cancers.