Pfizer (PFE) has reached an agreement with British drugmaker AstraZeneca (AZN) to buy the latter's small-molecule antibiotics operations in a transaction that could eventually be worth $1.575 billion. The deal will allow AstraZeneca to focus on three main therapy areas and realize value "from the strong portfolio of established and late-stage small molecule antibiotics." According to the terms of the agreement, PFE will make an upfront payment of $550 million plus $175 million in January and as much as $850 million in milestones and sales-related payments.