Aiyda Cobb urges patent owners to file a preliminary response when a third party requests an inter partes review:

The America Invents Act created a post-grant review process to challenge the validity of a patent before the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board. An Inter Partes Review (IPR), one of the proceedings introduced in 2012, provides an opportunity for the Board to review the patentability of one or more claims in a patent on a ground that could be raised under §§ 102 or 103, and only on the basis of prior art consisting of patents or printed publications.