On Sept. 16, new methods of challenging patents before the Patent and Trademark Office (PTO) went into effect, thanks to the America Invents Act. Three of the four methods available to businesses now are brand-new, and similar to litigation. The last, ex parte re-examination, has been around for a while, but is pricier in this incarnation.
Ex parte re-examination
Inter partes review
The transitional program for covered business method patents