Amgen Inc. is throwing a wrench in the gears advancing Sanofi SA's and Regeneron Pharmaceuticals Inc.'s high cholesterol drug alirocumab, seeking an injunction to block the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor's manufacture and sale over alleged infringement on patents protecting Amgen's own anti-PCSK9 therapy, evolocumab, now under regulatory review.