Breast cancer drug may help thousands more women than previously thought

Pembrolizumab is used to treat triple-negative form of disease but researchers say it could be used more widely

Thousands more women with breast cancer could benefit from a blockbuster immunotherapy drug than previously thought, research suggests.

Pembrolizumab, sold under the brand name Keytruda, targets and blocks a specific protein on the surface of certain immune cells that then seek out and destroy the cancerous cells.