SmithKline Beecham’s right to exclusive marketing of a popular pharmaceutical product is under assault by three makers of generic drugs, but SmithKline, which makes the widely prescribed antidepressant Paxil, isn’t letting that get it down.

Arthur Makadon, Jamie B. Bischoff and Sally A. Steffen of Philadelphia’s Ballard Spahr Andrews & Ingersoll, aided by several lawyers from Washington, D.C.’s Finnegan Henderson Farabow Garrett & Dunner, have gone to U.S. District Court in Philadelphia and Chicago to challenge the generic producers’ petitions for accelerated approval of their versions of paroxetine hydrochloride.