Canada's Valeant Pharmaceuticals International Inc. has struck a deal with AstraZeneca PLC for the rights to sell psoriasis treatment brodalumab after Amgen Inc. dropped its own collaboration with the U.K.-based drug maker over concerns about the drug's side effects. Valeant said on Tuesday that it will pay AstraZeneca $100 million upfront, with another $170 million in prelaunch milestones and up to $175 million following launch.