AstraZeneca’s (AZN.L) hopes of topping $45 billion in revenue by 2023 have been dealt a blow by a problem with an experimental psoriasis drug that the drugmaker had viewed as a potential billion-dollar plus seller. Amgen (AMGN.O), its partner on the project, announced late on Friday it was ending a collaboration to develop brodalumab after suicidal thoughts were observed in patients taking the medicine. Shares in AstraZeneca fell 1 percent on Tuesday in the wake of the news, following a long holiday weekend in Britain.