Alphabet Inc.'s Google, Amazon.com Inc., and other companies and groups have been invited by lawmakers to a closed-door Capitol Hill meeting Dec. 12 to discuss potential legislation to rework the definition of patent eligibility.

Sens. Thom Tillis (R-N.C.) and Chris Coons (D-Del.) also invited Apple Inc., Qualcomm Inc., Ericsson Inc., pharmaceutical industry group PhRMA, and the Biotechnology Innovation Organization, among others, according to an email invitation obtained by Bloomberg Law. A Coons spokesman confirmed the meeting.

Several U.S. court decisions in recent years have left technology and pharmaceutical companies unsure of whether their inventions are patentable under federal law. Tillis and Coons want to discuss recent case law and whether there’s a need for Congress to step in, according to the invitation.

The senators’ renewed interest in the hot-button topic signals that patent eligibility issues could be high on the next Congress’ intellectual property agenda. The current Congress focused mainly on copyright legislation, leading to October’s signing of the Music Modernization Act to streamline royalty payments to artists from digital music platforms, such as Spotify.

The U.S. Supreme Court since 2012 has created tough standards for overcoming the three court-made exceptions to patent eligibility; inventions covering a law of nature, a physical phenomenon, or an abstract idea can’t be patented.

Practitioners say the terms as laid out in the Mayo, Myriad, and Alice cases are poorly defined and leave companies unable to to predict whether they can patent their inventions. Critics say such uncertainty undermines the U.S. patent system and discourages research and innovation.

The American Bar Association’s IP law section, the IP Owner’s Association, and the American IP Law Association (AIPLA) in a joint paper in July proposed ways Congress could improve Section 101 of the patent statute, which sets the benchmark for patent eligibility.

Representatives of the three legal associations have also been invited to the meeting along with Paul Michel, a retired chief judge of U.S. Court of Appeals for the Federal Circuit, the nation’s patent appeals court. The meeting could be the first of several discussions on the complex topic of patent eligibility, according to the email.

Apple, Google, Amazon, Qualcomm, Ericsson, PhrMA, BIO, and the legal associations didn’t immediately respond to a Bloomberg Law request for comment.