This will take a little time because you have to block the annoying pages individually but if you work on it for a few days, blocking pages each time you scan your news feed, you will have a much cleaner news feed in a week or two.
To block an annoying page, wait for one of your friends to share something from it.
Click the small arrow button next to the post and scroll down until you see the Hide all from [Page Name] option. Click it and you will no longer see posts from that page no matter which friend shares it. No matter how often content from the blocked page is shared by any one of your friends, it will never appear in your news feed. If you visit a friend’s profile page though, it will still be visible there.