Major U.S. companies including Ford, Apple and Pfizer have formed a lobbying group aimed at pushing back at some changes to the patent system members of Congress have proposed, saying these measures would hinder protection of valuable inventions. Called the Partnership for American Innovation, the group warned that steps to stop the PAEs could also hurt truly innovative companies. Companies signing on to the effort so far are Apple Inc., DuPont, Ford Motor Co., General Electric, IBM Corp, Microsoft Corp and Pfizer Inc. Theres a feeling that the negative rhetoric is leading to a very anti-patent environment, said David Kappos, director of the U.S. Patent and Trademark Office from 2009 to 2013, who advises the group. Google, Cisco and other supporters of efforts to curb frivolous patent litigation from PAEs, often termed patent trolls, supported a bill that easily passed the U.S. House of Representatives in December.