The last few years have seen numerous challenges from local generic companies essentially arguing that patents covering approved drug products should be interpreted to cover only the specific form of the approved drug product during the patent term extension (PTE) period. This is based on Article 95 of the Korean Patent Act, which states that during the PTE period, the scope of the patent is limited to acts of practicing the patent as it relates to the product that was approved by the Ministry of Food and Drug Safety (MFDS).
The Supreme Court ruled in the Vesicare® case earlier last year that the patent for the active ingredient of the approved product still covered different salt forms of the active ingredient during the PTE period, a huge win for patentees. Subsequently, the Patent Court followed and extended this ruling, by holding that the PTE for a compound patent that was approved based on the active ingredient salt, still covers free base (non-salt) forms of the compound (in relation to Boehringer Ingelheim's Pradaxa® product). After the Pradaxa® ruling, it had been expected that generic challenges to the scope of the PTE in Korea would substantially decrease.
However, generics continue to raise new challenges to PTE scope, now arguing that Article 95 limits the PTE scope to approved uses. Specifically, one set of generics is arguing that the PTE scope should be limited to indications that were originally approved for the product (excluding indications that were subsequently added to the approval). In these cases, the original product was originally approved for the treatment of disease A in combination with other agents, while treatment of disease A in monotherapy was added later. The generic products were intended for monotherapy treatment of disease A.
While it is unclear at this stage how courts will ultimately rule on this new generic argument, it should be noted that the previous PTE court decisions mentioned above indicated that the scope of PTE under Article 95 is not dependent on the definition of "product" under the pharmaceutical regulatory laws. Accordingly, it would seem that "use" under Article 95 should not be limited to "original approved indications" as the generic proposes. In fact, the MFDS, which regulates drug approvals and patent listings on the Green Book (similar to Orange Book listing in the US), also seems not to agree with the generics' position, in that it has allowed a patent listed for one drug approval to be listed for a subsequent approval of the same drug for a different use (indicating that the MFDS believes the patent still covers the later approval). However, innovator drug companies would be well-advised to monitor developments in these new PTE cases.
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