Global Pharma Patent Battles : HIV integrase inhibitors “Raltegravir”


A Darts-ip user, Japanese Patent Attorney Ms. Yasuko Tanaka from S-Cube Corporation, introduces a recent remarkable Japanese patent decision in pharma sector.


Shionogi (Appellant, Plaintiff) has filed a PCT patent application for HIV integrase inhibitors named “Anti-Virus Agent” (PCT/JP2002/208108, WO2003/016275) and obtained patents in several countries, including Japan and Europe.  The claimed invention of JP5207392 and EP1422218 includes the compound Raltegravir as a part of the Markush formula, however, no pharmacological experimentation data of the compound was included in the description. MSD (Merck Sharp & Dohme; Appellee, Defendant) markets ISENTRESS® tablets containing Potassium Raltegravir, an HIV therapy agent.

IP High Court of Japan Decisions

Case No. 平成29(行ケ)10172 on September 4, 2018; Suit for cancelling a patent invalidation trial decision (darts-585-838-F-ja)

Case No. 平成29(ネ)10105 on September 4, 2018; Patent infringement litigation (darts-585-833-F-ja)

On September 4, 2018, the IP High Court of Japan upheld the patent invalidation trial decision in the JPO (Case No. 2015-800226 on August 8, 2017; JPO (darts-179-713-E-ja)) over the Shionogi patent (JP 5207392), and the lower court decision (Case No. 平成27(ワ)23087 on December 6, 2017; Tokyo District Court (darts-603-148-E-ja)) in favour of the defendant, MSD) selling the HIV integrase inhibitor Raltegravir (ISENTRESS®).

In both cases, the patent was found to be invalid on the grounds that the description was missing the required pharmacological data of the Raltegravir inhibitory effects on the HIV integrases.

Disputes in other jurisdictions

Table 1 (See Below)  shows the chronological order of the disputes in the EPO and the UK and German courts, as well as in Japan.

After EP1422218 was maintained in amended form at the EPO on March 31, 2015 (darts-717-083-D-en), Shionogi filed a patent infringement suit against MSD, who was marketing ISENTRESS®, in Japan and Germany on August 17, 2015.  MSD then countered by filing a patent invalidation trial in the UK and Japan.  At that point, Shionogi seemed likely to win based on the early EPO decision to maintain the patent.

However, the tables turned against Shionogi when the German patent was ruled invalid in Dusseldorf District Court on November 7, 2016 (darts-001-061-E-de-2), followed by the UK Patents Court (darts-658-894-D-en). The UK court found that ISENTRESS infringed Shionogi patent, but the patent was invalid.

In the next year, the JPO determined that the patent was invalid (darts-179-713-E-ja). Shionogi appealed this decision, but in December that same year, the Tokyo District Court also ruled the patent was invalid (darts-603-148-E-ja) after the EPO appeal board overturned the first decision and found the patent was invalid (darts-195-216-F-en). These are the circumstances that led to the IP high court decisions in September 2018.


Patents covering pharmaceutical products that are marketed globally are filed and granted in many countries. Patents are independent, with rules varying country by country, resulting in different outcomes in patent disputes.

In this Shionogi case, despite the EPO initially ruling the patent valid, subsequent outcomes aligned against Shionogi. And while each jurisdiction determined the patent invalid, there were still slight differences in their conclusions on the written description requirements relating to lack of required pharmacological data.

Patent disputes are inevitable in the pharmaceutical industry. Having access to a global database that enables you to check the status of multiple cases will give you insights into the thinking of courts around the world, which will better inform your patent and litigation strategies.


Table 1

PAT. # JP5207392 EP1422218 DE60242459.3 UK60242459.3
21/12/2012 MSD

Filed an opposition

31/3/2015 Patent maintained


17/8/2015 Shionogi

Filed a suit


Filed a suit

5/8/2015 MSD

Filed an invalidation trial

16/5/2016 Shionogi


4/10/2016 MSD

Filed an invalidation trial

7/11/2016 Patent invalid


25/11/2016 Infringed but patent invalid


8/8/2017 Patent invalid


8/9/2017 Shionogi


11/10/2017 Patent invalid


6/12/2017 Patent invalid


19/12/2017 Shionogi


4/9/2018 Patent invalid


Patent invalid