Entresto patent dispute comes to an end after 5yrs

Supreme Court rules in favor of generic companies on all three key patent issues…Entresto dispute nears conclusion

Different legal rationale applied to polymorph, salt/hydrate form, and use patents

“Ruling reaffirms standards on written description, doctrine of equivalents, and inventive step”

The long-running patent dispute over Novartis’ heart failure drug Entresto (sacubitril/valsartan) has effectively come to an end, with Korean generic manufacturers securing decisive victories at the Supreme Court.

The Supreme Court ruled in favor of the generic companies in all three appeals related to Entresto: ▲ the polymorph patent ▲ the salt/hydrate patent ▲ and the use-of-product patent lawsuits.

The assessment is that the domestic generic companies' consecutive victories in this dispute stemmed from a strategic approach that went beyond simple ‘patent invalidation or avoidance’ arguments, instead precisely identifying and countering the structural vulnerabilities of each individual patent.

Entresto patent dispute concludes with generic companies' victory after over 5 years

According to industry sources on the 16th, the Supreme Court on the 15th dismissed Novartis’ appeal in its scope confirmation lawsuit against 10 companies, including Elyson Pharmaceutical, concerning Entresto’s polymorph patent.

On the same day, the Court also ruled in favor of generic companies in Novartis’ appeal against Hanmi Pharmaceutical regarding the Entresto salt and hydrate patent. The dispute over the validity of the salt and hydrate patents between Novartis and Daewoong Pharmaceutical/ Elyson Pharm is awaiting a ruling at the Patent Court (second instance).

Earlier, in April 2024, the Supreme Court had already dismissed Novartis’ appeal in its use-patent lawsuit against 11 companies, thereby affirming the generics’ victory.

This effectively concludes the nearly 5-year-long Entresto patent dispute, according to analysis. Although an appeal remains pending in the salt/hydrate patent dispute between Novartis and Daewoong Pharmaceutical/ Elyson Pharm, the prevailing view is that a similar ruling will be issued, given the Supreme Court's precedent on identical patent issues.

The Entresto patent dispute intensified after 2021. Generic companies filed comprehensive patent invalidation petitions targeting Entresto's crystal form patent, salt/hydrate patents, two use patents, and two formulation patents. The generics won all cases at the first instance. After losing the first instance, Novartis selected three patents for appeal: ▲the polymorph (crystal form) patent, ▲the salt/hydrate patents, and ▲the use patent. Ultimately, these three appeals became the focal point of the litigation. For each issue, the patent challengers presented different arguments.

Polymorph patent dispute: scope of rights for ‘broad claims’ without experimentation

The starting point and most critical battle in this dispute was the validity of the Entresto polymorph patent. The patent covered a specific crystalline form of the supramolecular complex formed by sacubitril and valsartan.

The core issue was whether the patent satisfied the written description and enablement requirements. Under established precedent, polymorph inventions in chemistry are considered highly unpredictable and therefore require detailed experimental disclosure and reproducibility.

While Novartis’ specification disclosed experimental data for a specific 2.5-hydrate supramolecular complex, it failed to provide manufacturing methods, reproducibility principles, or experimental support  for other solid forms of the supramolecular complex included in the claims. The patent challengers focused on this aspect.

The Supreme Court ultimately held that a patent asserting a broad claim scope without experimental support constitutes insufficient disclosure. The rulings of the Intellectual Property Trial and Appeal Board and the Patent Court were therefore upheld.

Salt/Hydrate patent dispute: doctrine of equivalents infringement

In the salt/hydrate patent case, the key issue was whether the scope of rights was infringed, particularly whether the generics’ products infringed Novartis’ patent under the doctrine of equivalents.

Novartis's patent was based on Entresto's 2.5-hydrate supramolecular complex. In contrast, the domestic pharmaceutical company's product possesses a trihydrate structure with a different number of water molecules. Novartis argued that since the two hydrates represent substantially equivalent technology, they constitute equivalent infringement.

The generics countered that the difference was not a mere numerical change, but reflected a fundamentally different problem-solving principle for achieving supramolecular complex stability.

The Supreme Court accepted this argument. It ruled that the technical core of Novartis’ invention lay in achieving a specific stoichiometric structure. A hydrate with a different number of water molecules could not be regarded as using the same technical solution.

Use patent dispute: judgment of novelty in the heart failure treatment effect

In the Entresto use patent case, the issue was whether the patent possessed novelty. The key question was whether the heart failure treatment effect from the combination of sacubitril and valsartan could be evaluated as a new medical effect compared to prior art.

The Patent Court ruled that, in light of existing pharmacological mechanisms and prior technologies, the claimed therapeutic effect could not be regarded as an unpredictable or novel medical outcome. The Supreme Court upheld this reasoning, dismissing Novartis’ appeal without a full hearing.

Attorney Dong-joo Kwon of Yoon & Yang, who represented the client in this case, commented, “This Supreme Court ruling is significant not merely as a victory in an individual dispute, but because it provides clear guidance on the boundaries of written description requirements and on how far the doctrine of equivalents can be stretched, which is central to determining the scope of rights.”

Kwon added, “Even a global pharmaceutical company’s robust patent portfolio cannot survive if it attempts to claim excessive scope without experimental backing or relies on overly broad doctrine of equivalents arguments that deviate from the technical essence.”

“This case demonstrates that rational patent challenges by domestic pharmaceutical companies can strike a balance between market competition and patient access. This ruling will serve as an important precedent for future similar patent disputes.”