AstraZeneca ($AZN), working to catch up with Merck ($MRK) and Bristol-Myers Squibb ($BMY) in the growing field of immuno-oncology, said its treatment is unlikely to win speedy FDA approval in lung cancer due to the presence of more advanced agents. The therapy, durvalumab, blocks the protein PD-L1 to spur an immune attack on cancer, and AstraZeneca is planning to wrap a late-stage lung cancer trial on the treatment this year. Results from that study could support an accelerated approval in the first half of next year, but AstraZeneca is cautioning investors not to bank on a quick FDA OK, Reuters reports, as the recent approvals of Merck's and Bristol-Myers' therapies in lung cancer could remove some immediacy from the agency's proceedings. More