A handful of large law firms are backing Finnegan, Henderson, Farabow, Garrett & Dunner in a Massachusetts case that could upset the conflict of interest rules that cover patent prosecution.

Finnegan squares off at the commonwealth's top court Sept. 8 with a former client who is suing for malpractice. Christopher Maling says Finnegan represented him before the U.S. Patent and Trademark Office for six years without disclosing it also was working with a larger competitor on a similar patent. Finnegan succeeded in obtaining patents for both clients, but Maling says his was rendered useless by the competitor's patent, and that Finnegan should have warned him before he invested “several million dollars” developing his invention.

Last week Knobbe Martens Olson & Bear, Morrison & Foerster, Pillsbury Winthrop Shaw Pittman and several other firms cautioned that a ruling for Maling “would severely disrupt the practices of patent lawyers and law firms” and create incentives that favor large corporations over individual inventors and startup companies.