From certificates to courts: litigating second medical use patents

With the lengthy period needed to receive a market authorization (MA) for a new medical product, a supplementary protection certificate (SPC) delivers much-needed assurance to the patent holder. The compensatory period of up to five or five-and-a-half years of exclusivity offsets the commercial impact arising from the delay between invention disclosure and obtaining an MA. However, the existence of SPCs within the European Economic Area (EEA) has invited a number of burning questions on their availability to second medical use patents and, followingly, the stances of national and supranational courts.

SPCs and Brexit

Chief among the ambiguities that have come before European courts lately is whether new SPCs can be obtained for second medical use patents.

In Santen (Case C-673/18), the Grand Chamber of the Court of Justice of the European Union (CJEU) ruled that Regulation (EC) 469/2009, Article 3(d) "must be interpreted as meaning that a marketing authorisation cannot be considered to be the first marketing authorisation, for the purpose of that provision, where it covers a new therapeutic application of an active ingredient, or of a combination of active ingredients, and that active ingredient or combination has already been the subject of a marketing authorisation for a different therapeutic application." 

This 2020 decision represented a departure from a previous judgment by the Fourth Chamber in Neurim (Case C-130/11). In Neurim Pharmaceuticals (1991) Ltd vs. Comptroller-General of Patents, the CJEU held that the mere existence of an earlier MA obtained for a veterinary medicinal product did not preclude the grant of an SPC for a different application of the same product, provided that the SPC application was within the limits of the protection conferred by the basic patent. In Santen, the Court instead adopted a strict construction of the term "product," concluding that, for any active pharmaceutical ingredient or combination of active ingredients, only the first use authorized by an MA may be granted an SPC. This decision effectively closed any uncertainty caused by Neurim. 

Based on the Santen judgment, the United Kingdom Intellectual Property Office (UK IPO) rejected an application for an SPC filed by Merck Serono for cladribine's treatment of highly active relapsing-remitting multiple sclerosis. The Office held that the application did not satisfy the criteria of the European Union SPC Regulation as retained in UK law since there had been two earlier MAs for medicinal products containing cladribine, both indicated for hairy cell leukemia.

One of Merck's arguments in challenging the UK IPO decision was that Santen was wrongly decided. Under the EU (Withdrawal) Act 2018 and its regulations, the UK Supreme Court, High Court of Justiciary and Court of Appeal (and equivalents) can depart from CJEU jurisprudence following Brexit. Nonetheless, upon hearing the case in December 2024, the Court of Appeal opted to maintain alignment with CJEU rulings on second medical use SPCs.

In dismissing Merck's appeal, the Court concluded that second medical use SPCs cannot be obtained in the United Kingdom, which is consistent with the EU's approach. While this may frustrate pharmaceutical companies hoping to extend the term of patents protecting new therapeutic uses of known products in the United Kingdom, it does provide some certainty for third parties seeking to launch generic versions.

Eyes on the UPC

While national courts in Europe continue to play an important role in patent litigation, the launch of the Unified Patent Court (UPC) in June 2023 has provided a new and attractive forum for litigants, with more than 633 orders and decisions having been issued at first instance by the end of 2024.

However, just 48 of the 219 infringement actions brought before the UPC by the end of November 2024 relate to International Patent Classification (IPC) class A ("human necessities") and just 10 to class C ("chemistry; metallurgy"). Comparing these tallies to the 84 cases in class H ("electricity") suggests that pharmaceutical companies are not using the Court as much as those in sectors such as telecoms and medical devices. 

This means that any decisions of the UPC in cases involving second medical uses will be particularly closely followed. In this context, a dispute between Sanofi and Accord Healthcare and other companies over Sanofi's European Patent for "Novel antitumoral use of cabazitaxel" is likely to give a strong insight into the Court's rationale. Sanofi has filed an infringement action, and Accord has filed a counterclaim for revocation, with both being heard at the Munich Local Division. Decisions can be expected this year.

A three-way legal balance: needs, incentives and protections

The issue of patents for second medical uses goes to the heart of the IP system in the pharmaceutical sector. These rights serve to incentivize research in a high-risk field wherein repurposing an existing drug or identifying a specific route of administration, dosage or formulation is not merely a different use but requires a non-obvious inventive step. 

Given the hundreds of millions of dollars required to develop, test and gain approval for new drugs, repurposing known products offers significant advantages for both patients and health systems. However, as various cases show, there are a number of legal complexities that must be navigated first.

Specifically, there is a need for clarification regarding the scope of exclusivity granted to inventions of new therapeutic uses. These should be viewed as product inventions confined to their specific field of use, even though their structure generally is the same as other inventions based on the same molecular composition. Bearing this assumption in mind, the thorny problem – unique to the medical field – remains the infringement of such purpose-limited product claim inventions. For this reason, some confusion still permeates second medical use patents today, as shown by the very different positions espoused by national and regional courts.

These dilemmas are likely to become more pressing as innovative pharmaceutical companies explore more targeted treatments, including precision / personalized medicines, and use genetic and other data to identify further uses of known compounds. Questions relating to non-infringing uses of clinical data are also likely to arise as patent and SPC protections for blockbuster drugs expire. 

The Boards of Appeal of the EPO, national courts and the CJEU have all published recent judgments addressing some or all of these questions. Although it is not yet a prolific source of case law, the UPC will also surely have a significant influence on how second medical use patents are deployed and disputed.