By Blake Brittain

WASHINGTON - A Washington, D.C. federal judge on Wednesday refused Novartis' eleventh-hour bid to block drugmaker MSN Pharmaceuticals from launching a generic version of Novartis' blockbuster heart-failure drug Entresto.

The decision by U.S. District Judge Dabney Friedrich clears a hurdle for MSN to introduce the first U.S. generic version of Switzerland-based Novartis' best-selling drug, which brought the company more than $6 billion in revenue in 2023.

An attorney for MSN declined to comment on the decision. An attorney and spokespeople for Novartis did not immediately respond to a request for comment.

MSN's version of Entresto was approved by the U.S. Food and Drug Administration last year.

Novartis sued MSN and others seeking to launch Entresto generics for patent infringement. The U.S. Court of Appeals for the Federal Circuit last week reversed a 2023 decision by a Delaware judge that invalidated one of the patents.

Novartis argued in a court filing that the appeals court ruling maintained the company's exclusive rights to sell Entresto until July. The company said MSN was preparing to launch its generic on Thursday, when Novartis' patent expires and MSN said that the ban would end.

MSN told the appeals court that the ban would expire on Thursday regardless of the decision.

The Federal Circuit on Tuesday rejected Novartis' request for a mandate that would immediately block the generic.

Novartis separately sued the U.S. Food and Drug Administration in Washington federal court on Monday to block the launch. The FDA responded on Wednesday that only the courts hearing the patent case could halt it.

Friedrich agreed with the FDA and said she would reject Novartis' request during a hearing late Wednesday.

A separate Novartis emergency request to pause the launch is still pending in the U.S. Court of Appeals for the District of Columbia Circuit.

(Reporting by Blake Brittain in Washington; Editing by David Bario and Stephen Coates)