The U.S. Patent and Trademark Office (PTO) has released a guidance to aid patent examiners in dealing with questions of obviousness in patent applications, but patent attorney Michael Borella told BioWorld that this new guidance could resurrect the law of unintended consequences. Borella, a partner in the Chicago office of McDonnell Boehnen Hulburt & Berghoff LLP, said the guidance might lead to more inappropriate rejections of patent claims for obviousness, and thus make the process of obtaining a clean patent more difficult, not less.