PITTSBURGH - The filed-rate doctrine precludes the antitrust claims of individual and some small-group purchasers of health insurance against insurer Highmark Inc. and health care provider University of Pittsburgh Medical Center (UPMC), but the filed-rate doctrine may not be applicable to claims of small-group purchasers that asserted a measure of damages based on unregulated rates, a federal judge in Pennsylvania ruled Aug. 21 in granting in part the purchasers' motion for leave to file a third amended complaint (Royal Mile Company, Inc., et al. v. UPMC, et al. No. 2:10-cv-01609, W.D. Pa.; 2014 U.S. Dist. LEXIS 116224).