AstraZeneca shares rose 2.7% on Friday after the British drugmaker won earlier-than-expected U.S. regulatory approval for a leukaemia drug, in a challenge to rival AbbVie. AstraZeneca said late on Thursday that the U.S. Food and Drug Administration (FDA) had given its go ahead for the company's Calquence drug to treat chronic lymphocytic leukemia (CLL), one of the most common types of leukaemia in adults. The drug was approved under a new speedy review programme in collaboration with drug watchdogs in Canada and Australia, and was also approved to treat small lymphocytic lymphoma, a similar disease. That will pit the AstraZeneca drug against AbbVie and Johnson & Johnson's established CLL treatment Imbruvica. The FDA's green light, which analysts at brokerage Bryan Garnier said came at record speed, adds momentum to Astra's growing cancer drug business with brands including Tagrisso and Imfinzi. "Physicians are used to Imbruvica and we do not expect a rapid and massive shift towards Calquence but we do see it progressively taking market share from the leader," Bryan Garnier analysts said, adding that FDA tests had showed Calquence performed well in terms of side effects. Astra shares were up 2.1% at 1415 GMT, outperforming a 0.7% gain in the STOXX Europe 600 Health Care index.