Judge rebuffs Novartis bid to block generic Entresto

A judge in the US has denied an attempt by Novartis to stop MSN Pharmaceuticals from launching a generic version of heart failure blockbuster Entresto.

MSN Pharma was given FDA approval for its Entresto (sacubitril and valsartan) generic on 24th July, prompting a lawsuit from Novartis claiming patent infringement and seeking a preliminary injunction on the launch of the drug.

US District Judge Richard Andrews, presiding over a court in Delaware, concluded after hearing oral arguments last Friday that an injunction can only be granted in these cases if the plaintiff can demonstrate it is very likely to win the patent infringement dispute.

He concluded that Novartis had failed to do that in this case, but also introduced a temporary three-day stay on the launch of the generic to allow time for the Swiss pharma group to file an appeal.

The case revolves around Novartis' contention that MSN's generic contains small amounts of crystalline forms of the active ingredients in Entresto that would infringe a patent on the drug (No. 11,096,918) that confers protection until 8th November 2026.

On that point, Judge Andrews concluded: "Novartis bears the burden of proof, both on infringement and on showing likelihood of success. I find it has not met the burden it bears at this stage" in proving the presence of the contested forms in MSN's product.

At stake for Novartis is the protection of sales for its top-selling product, which is still growing at a phenomenal lick nearly a decade after it was first launched.

Entresto has been approved by the FDA since 2015 to reduce the risk of cardiovascular death and hospitalisation for heart failure in adult patients with chronic heart failure, with its label extended to include paediatric patients and patients with higher left ventricular ejection fraction (LVEF) measures.

In the first half of this year, sales grew by around a third to $3.8 billion, and Novartis' sales predictions for 2024 – high-single to low double-digit growth – rely on the assumption that no Entresto generics will reach the market this year.

The Delaware district court also struck down a so-called 'combination patent' (No. 8,101,659) on Entresto last year in a case that has also gone to appeal. At the time, there were no FDA-approved generics, but Novartis said that any rival that launched a copycat product while that appeal is pending would do so at risk of litigation. The patent is due to expire on 15th July 2025.

Prior to that, it won a patent infringement lawsuit brought against generic drugmaker Mylan in a West Virginia district court, which found that proposed Entresto generics infringed two other patents on the drug (Nos. 8,877,938 and 9,388,134).