Samchundang Pharmaceuticals takes legal action to invalidate hidden patents.
In a strategic legal move, a South Korean pharmaceutical company, Samchundang Pharmaceuticals, has initiated a lawsuit challenging an unregistered patent related to "K-CAB Generic." The patent in question, titled "Use of Benzimidazole Derivatives for Nocturnal Acid Secretion," pertains to the use of benzimidazole derivatives in the treatment of gastroesophageal reflux disease with "K-CAB Tablet (active ingredient: Tegoprazan)." This legal battle comes amid the backdrop of South Korea's optional patent registration system, where pharmaceutical companies can choose not to disclose their patents.
According to industry sources on the 4th, Samchundang Pharmaceuticals has recently submitted a petition to the Patent Trial and Appeal Board (PTAB) seeking to invalidate the mentioned patent. This particular patent is set to expire on June 8, 2036. Notably, Samchundang Pharmaceuticals has previously taken steps to launch their generic version of K-CAB by initiating proceedings on both the substance patent set to expire on August 25, 2031, and the formulation patent set to expire on March 12, 2036.
The complexity of this patent dispute arises from the fact that it involves an unregistered patent, a type often referred to as a "hidden patent." In South Korea, pharmaceutical companies are not obliged to disclose their patents under the Pharmacy Law, which merely states that they "may apply" for patents. While the law does require registration for four types of patents (substances, formulations, compositions, and uses), it does not compel pharmaceutical companies to register their original drug patents.
① Those who have obtained marketing or change approval for a product under Article 31, Paragraphs 2 and 3, or Article 9, Paragraph 9 (referred to as "marketing or change approval") can apply to the head of the Ministry of Food and Drug Safety (MFDS) to register pharmaceutical patent rights (referred to as "pharmaceutical patent rights") for the approved pharmaceuticals in the MFDS-managed pharmaceutical patent list (referred to as the "patent list").
② Those wishing to register pharmaceutical patent rights as per paragraph 1 must submit an application, including the required information and a copy of the patent registration document as stipulated by the Prime Minister's decree. This submission should occur within 30 days from either the date of obtaining marketing approval or change approval for the relevant pharmaceutical product or from the date of patent rights registration under Article 87 of the Patent Act. This application should be sent to the head of the Ministry of Food and Drug Safety (MFDS), accompanied by the consent document from the patent holder or exclusive licensee as per the Patent Act (referred to as "patent holder or licensee" when applicable).
This situation mirrors a similar case involving Boehringer Ingelheim's 'Trajenta (active ingredient Linagliptin).' While five patents related to Trajenta are listed in the MFDS's patent registry, recent unregistered patents have emerged, prompting companies to engage in new patent disputes. In the case of K-CAB, industry insiders suspect the existence of several unregistered patents, though the exact number remains undisclosed.
From the perspective of companies holding original products, the need to protect potential patents from registration is paramount, as registered patents can become targets for legal disputes. Recent examples, such as the patent dispute surrounding "Maxigesic (active ingredients Paracetamol + Ibuprofen)" just a year and a half after its launch and the challenge faced by "Levotics CR (active ingredient Levodropropizine)" by Korea United Pharm Inc., launched in 2020 after an 8-year development process, illustrate this vulnerability.
Conversely, for companies aiming to introduce generic versions, the challenge extends beyond dealing with registered patents. They must meticulously search for potential hidden patents, addressing any issues through patent challenges or litigation. This added complexity intensifies the hurdles associated with launching generic versions of new products. As patent disputes involving unregistered patents become more prevalent, the battle surrounding K-CAB generic continues to escalate, leaving industry observers eagerly awaiting its outcome.