A magistrate judge in Washington, D.C., has granted a rarely approved request for discovery in a CEO’s fight to avoid a subpoena in an FTC investigation that stems from a reverse-payment settlement between Frazer, Pa.-based Cephalon Inc. and Watson Pharmaceuticals.

Watson Chief Executive Officer Paul M. Bisaro sought discovery in the U.S. Federal Trade Commission’s court action against him in its efforts to enforce a subpoena it issued last year.