In a scope confirmation action involving a patent directed to a crystalline complex of sacubitril and valsartan, the Korean Supreme Court determined based on the finding that a pharmaceutical composition comprising a trihydrate compound with a different number of water molecules does not share the same principle for solving the problem as the patented invention, the disputed composition falls outside the scope of the patent (Supreme Court Case No. 2024 Hu 11590 rendered on January 15, 2026).

▶Background of the Case 

The subject patent relates to a crystalline trisodium sacubitril-valsartan 2.5-hydrate compound—a supramolecular complex comprising valsartan (an angiotensin receptor blocker), sacubitril (an endopeptidase inhibitor), sodium cations and water molecules in a stoichiometric ratio of 1:1:3:2.5.  In this complex, the two active ingredients associate with sodium cations and water molecules through non-covalent interactions, causing the complex to behave as a single compound in vitro, while dissolving into its individual components upon ingestion and absorption, to exert pharmacological effects.

Local generic companies filed a negative patent scope confirmation trial, contesting that their product--a pharmaceutical composition whose active ingredient is a crystalline trihydrate compound in which valsartan, sacubitril, sodium ions, and water molecules are combined in a ratio of 1:1:3:3--did not fall within the scope of the patent.

The Trial Board determined that the accused product did not fall within the scope of the patent, on the ground that the contested compound differed from the patented invention in the number of water molecules, crystal structure and X-ray diffraction pattern of its components.  Such differences reflected a different principle for solving the problem, thereby precluding a finding of equivalence.  The Board further noted that the patentee had narrowed the claims to the crystalline 2.5-hydrate form during prosecution and filed a divisional application directed to other solid forms, indicating that those other forms had been intentionally excluded from the claim scope of the subject patent.  The patentee appealed to the IP High Court.

▶IP High Court Decision

On appeal, the patentee argued that the accused product should be regarded as equivalent, pointing out that water molecules are merely optional components rather than an essential feature, and that pharmaceutical products differing only in their hydration level are being treated as the same drug by regulatory authorities.  

However, the IP High Court rejected these arguments, finding that the technical feature of the subject patent lies in providing a new crystalline form in which valsartan, sacubitril, sodium ions and water molecules associate in a specific stoichiometric ratio, exceeding the level of a mere combination of two known active ingredients.  On that basis, the court determined that, since the contested product had a different stoichiometric ratio, leading to differences in crystal structure and physicochemical properties, it did not share the same principle for solving the problem or the same effects as the patented invention.  Thus, the accused product was determined to fall outside the scope of equivalents of the subject patent.

The court also stated that, in light of the prosecution history, including amendments limiting the claims to a specific crystalline hydrate form and a divisional application excluding the patented invention, the accused product should be considered to have been intentionally excluded from the scope of the subject patent.

▶Supreme Court Decision

The Supreme Court affirmed the IP High Court decision and dismissed the appeal.

The Court reiterated its established precedent that, in assessing whether a contested product and a patented invention share a same principle for solving a problem, the technical idea underlying the patented invention for solving the problem should be carefully considered in view of the specification and the state of the art at the time of filing.  The Court further noted that the breadth of the principle for solving the problem should be commensurate with the patented invention's contribution to technological advancement over the prior art.

Applying this framework, the Court found that the specification does not describe the mechanism by which valsartan and sacubitril form a supramolecular complex and the only identified solid form is the 2.5-hydrate.  The Court also noted that, as of the priority date, the crystal structure, molecular arrangement or physicochemical properties of co-crystals or supramolecular complexes were not readily predictable.  In light of these circumstances, the Court held that the technical contribution of the subject patent resides in providing, as a unique problem-solving means, a supramolecular complex in which valsartan and sacubitril associate with sodium ions and water molecules in a stoichiometric ratio of 1:1:3:2.5 so as to behave as a single compound, and that the invention cannot be regarded as contributing to technological advancement to an extent of encompassing compounds having different numbers of water molecules.  

Accordingly, the Court concluded that the accused product, which differs in the principle for solving the problem, does not fall within the scope of equivalents of the subject patent.