Novartis has defeated a proposed class action accusing the pharmaceutical company of improperly listing a patent to delay generic competition for its blockbuster heart-failure drug Entresto.
US District Judge Lewis Liman dismissed the lawsuit brought by the Iron Workers Local 580 Insurance Fund on behalf of Entresto purchasers who alleged they paid inflated prices because of the disputed patent listing.
The case centred on the US Food and Drug Administration’s Orange Book, which identifies approved medicines and patents that manufacturers say cover those products. Patent listings can affect when generic manufacturers are able to enter the market and can therefore become the basis of competition-law disputes.
The purchasers alleged that Novartis improperly characterised one of its patents as covering Entresto even though, in their view, the patent covered the drug’s component ingredients rather than the particular form in which those ingredients are combined.
According to the lawsuit, the listing delayed generic competition by at least six months. The purchasers alleged that Novartis generated more than $2 billion in US Entresto sales during that period and that buyers consequently paid higher prices than they would have faced with earlier generic entry.
Judge Liman rejected that central argument.
He agreed with Novartis that the disputed patent was properly listed in the Orange Book, defeating the insurance fund’s claim that the listing had been improper. The ruling therefore removed the basis for the purchasers’ generic-delay theory as pleaded in the case.
The decision is significant because Orange Book disputes can extend beyond conventional patent litigation between branded pharmaceutical companies and generic manufacturers. Purchasers may also pursue Sandoz $450M Antitrust Settlement — La wyer Monthly where they allege that an improper listing delayed competition and caused them to overpay for medicines.
Those claims depend heavily on the underlying patent-listing question. If a patent was entitled to be listed, a purchaser cannot simply treat the resulting period of exclusivity as unlawful anticompetitive conduct.
The ruling does not amount to a broader finding that every element of Novartis’s Entresto patent strategy was lawful. It addresses the specific purchaser claim before Liman and his conclusion that the patent challenged in that lawsuit was properly included in the Orange Book.
Entresto, a combination of sacubitril and valsartan used to treat heart failure, has been Novartis’s best-selling medicine. The commercial significance of generic competition is already evident.
Novartis reported that Entresto sales fell 42% to $1.31 billion in the first quarter of 2026 after US patents expired and generic versions entered the market. The medicine accounted for 14% of the company’s sales in the previous year.
For Gilead Duty-to-Innovate Ruling — Lawyer Monthly and their legal advisers, the case demonstrates how patent-listing decisions can create potential exposure beyond intellectual-property litigation. A disputed Orange Book entry can become the foundation for purchaser claims seeking damages for alleged overcharges.
For purchasers, however, establishing that generic competition was delayed is not enough on its own. A viable competition claim also requires a legally sustainable basis for treating the conduct that caused the alleged delay as improper.
The Novartis ruling therefore highlights the close relationship between pharmaceutical patent law and antitrust litigation. Where a generic-delay claim depends on an allegedly improper Orange Book listing, the interpretation and scope of the patent itself can determine whether the wider competition case survives.
The case is Iron Workers Local 580 Insurance Fund v. Novartis Pharmaceuticals Corporation in the US District Court for the Southern District of New York.