In Agile, you are supposed to ship product on a regular cadence. All features are added to a product backlog, divided into small projects that fit within a sprint, and then prioritized. The backlog is just a way to keep track of all of the ideas people have, requests from customers, major bugs and other things.
The first patent for Pristiq is set to expire in February 2022. This is the earliest predictable date that a generic version of the drug could become available. However, other circumstances could come up to extend or shorten the exclusivity period.
Patents with 1380+ answers. Most utility patents expire 20 years after the earliest filing date, assuming the owner pays maintenance fees. Design patent expire in 14 years after they are issued. Depending on how slow is the US patent office, some US patents may get term extensions; however, no matter what, all patents do eventually expire. For more details, read: 2701-.