Boryung(003850)·JEIL PHARMACEUTICAL(271980)·Daewon Pharmaceutical(003220)·Ildong Pharmaceutical(249420) and 16 other Korean drugmakers won a judgment that some patents related to "linagliptin," a diabetes treatment ingredient from C. H. Boehringer Sohn AG & Co. KG (Boehringer), one of the big pharma companies, are invalid. Linagliptin inhibits enzymes involved in blood sugar control and is used for type 2 diabetes. With the substance patent protecting the linagliptin ingredient itself expiring, Korean pharmaceutical companies launched generics and fixed-dose combinations, but the dispute intensified when Boehringer claimed patent infringement.
According to the pharmaceutical industry and legal circles on the 2nd, the Intellectual Property High Court on the 13th of last month upheld the Intellectual Property Trial and Appeal Board's decision that part of Boehringer's patent on "vasculoprotective and cardioprotective antidiabetic therapy" is invalid. The patent in question is a use patent that protects the method of using linagliptin for type 2 diabetes patients at high risk of cardiovascular disease. A use patent may be granted for a new method of using an existing drug for a specific disease or patient population even if it is not a new ingredient.
The crux is administering linagliptin alone or in combination with other therapies to type 2 diabetes patients at high risk of cardiovascular disease. The applicable patients are those with a history of myocardial infarction, coronary artery disease, stroke, or heart failure, or those with risk factors such as organ damage, advanced age, hypertension, smoking, or obesity.
◇ As the patent expired, Korean drugmakers rolled out generics… Boehringer hit the brakes
With Boehringer's linagliptin substance patent expiring in Jun. 2024, Korean pharmaceutical companies including Boryung, JEIL PHARMACEUTICAL, Daewon Pharmaceutical, and Ildong Pharmaceutical successively launched linagliptin generics and fixed-dose combinations. When it could no longer rely on the substance patent, Boehringer moved to block them, claiming infringement of the use patent.
Korean pharmaceutical companies filed for invalidation with the Intellectual Property Trial and Appeal Board, arguing that Boehringer's use patent lacks validity because it does not differ substantially from known treatment methods. They said it was already known that linagliptin is used to treat type 2 diabetes and can be administered to patients at risk of cardiovascular disease.
The Intellectual Property Trial and Appeal Board partly accepted the Korean companies' claims last year. Boehringer filed a lawsuit challenging that decision. In patent disputes, the board serves as the court of first instance, and the final decision is confirmed by the Supreme Court after review by the Intellectual Property High Court. In the lawsuit, Boehringer argued, "Diabetes patients at high risk of cardiovascular disease differ from general diabetes patients, and the cardiovascular protective effect and safety observed when linagliptin is administered to them are therapeutic effects that are difficult to predict based on existing data."
However, the Intellectual Property High Court found that "from the prior inventions, a person of ordinary skill could readily predict linagliptin administration and its therapeutic effect even in patient groups at high risk of cardiovascular disease." It added, "The confirmed therapeutic effect is also not a remarkable effect that could not have been predicted from the prior inventions," and upheld the board's decision.
Having lost the suit, Boehringer is said to be reviewing whether to appeal to the Supreme Court. The deadline to appeal is through the 4th.
◇ Despite partial invalidation of the use patent… follow-on disputes over formulations continue
The industry views this ruling as a major win for Korean drugmakers in the patent disputes surrounding the linagliptin generic business. Some also say Boehringer's continued legal battles are underpinned by a market defense strategy through patent disputes.
An official at one participating Korean drugmaker said, "To maintain the market monopoly of an original drug ahead of patent expiration, securing additional patents or filing lawsuits based on existing patents is a strategy big pharma has used," adding, "This Boehringer lawsuit is a classic stalling tactic."
Room for conflict remains. Boehringer and Korean drugmakers are also fighting over multiple patents beyond the use patent, including formulation, manufacturing methods, and compositions. In particular, in three formulation patents that protect the structure and blending technology that implement the active ingredient into an actual drug, some Korean companies lost.
Another official at a Korean pharmaceutical company said, "Drugmakers need to consider measures such as changing product formulations or adjusting sales strategies depending on the outcomes of the patent lawsuits," adding, "The linagliptin generic market is expanding, but how much of the remaining patents can be cleared will be key to future sales growth."