HHS has formally appealed a July ruling by a federal court in Washington, D.C., which blocked the department from requiring drug companies to disclose the prices of drug prices in their direct-to-consumer TV ads.

The filing of an appeal was the latest tactical move in a battle over the proposed rule that has gone on since last October when the Centers for Medicare and Medicaid proposed the rule.

Merck, Eli Lilly, Amgen, and the Association of National Advertisers sued HHS in June to block the rule, arguing that it lacks authority to create the rule.

In July, Judge Amit Pehta of the U.S. District Court for the District of Columbia agreed with the drugmakers, ruling that “HHS lacks the statutory authority under the Social Security Act … to issue a rule that compels drug manufacturers to disclose list prices,” adding that the decision should rest with the Congress.