CAMDEN, N.J. — A federal judge on October 18 refused to dismiss claims that Actelion Pharmaceuticals Ltd. violated antitrust laws by refusing to share samples of its drugs Tracleer and Zavesca with its generic rivals.

Apotex Inc., Actavis Elizabeth LLC, Roxane Laboratories Inc. and other generic-drug companies alleged that Actelion is withholding the samples to block them from bringing low-cost versions to market. The plaintiffs argue that they need the samples to ensure — under federal laws — that generic versions of drug are identical to the brand-name version.