1435 GMT - AstraZeneca is opening a new treatment paradigm in breast cancer with its Etcamah drug, which just got the green light from the U.S. Food and Drug Administration, Jefferies analysts say. This is arguably one of the most important approvals in breast cancer of the recent past, the analysts say. The FDA is validating an entire new treatment paradigm based on intervention guided by testing to detect a mutation that makes tumors resistant to treatment, before observing the disease progress through X-ray scans, they add. While Etcamah's approval matters clinically, it is authorized for a subset of the overall breast-cancer patient population for now, limiting its commercial benefit, Jefferies says. Shares rise 0.5%.