Patents generally have a fixed lifetime, but some can linger on like zombies, thanks to clever lawyering that extends their life unnaturally.

Zombies’ cost to the healthcare system can be significant. Genentech’s Cabilly patent, for instance, should have expired in 2006, but instead stands to cost buyers of antibody drugs $1 billion or more over the next decade. We have the skinny over at VentureBeat Life Sciences.