On 4th May, the UPC revoked the ‘remdesivir’ anti-viral drug unitary patent owned by Chinese research institute AMMS and rejected all limitations proposed by the patentee (case ID UPC_CFI_552/2025).
Granted on 18 June 2025, the patent EP 3854403 claimed the use of remdesivir for the treatment of COVID-19, threatening the commercial operations of Gilead Sciences – the original developers of remdesivir. Gilead brought revocation action on the day of grant on the grounds that the claimed second medical use of remdesivir for treating COVID-19 was not inventive and lacked sufficiency.
The background
Remdesivir is a prodrug that is metabolised within cells after it is administered. Once within cells, it is processed into a nucleotide analogue that mimics adenosine (an RNA building block). This nucleotide analogue halts viral replication of RNA viruses by disabling a key viral enzyme, the RNA polymerase, which is required for copying the viral RNA genome. Prior to 2020, remdesivir had not been clinically proven to treat any viral infections, but preclinical research had shown that the drug appeared to be promising for treating infections by coronaviruses SARS and MERS.
Gilead has patents for the compound and for the use of the compound for treating coronavirus infections, the latter of which was filed in 2016, years before SARS-CoV-2 (SARS2) was identified. However, AMMS managed to file an application for the second-medical use of treating viral infections by the newly identified SARS2 before the pandemic was even declared by WIPO and shortly before clinical trials began in China in early 2020.
Narrow second medical use claims are routinely accepted by the EPO, even if an identical treatment for the broader class of a disease (the “first medical use”) has been disclosed before the priority date of the second medical use patent application. However, the requirement for an inventive step still applies and this can be undermined if the skilled person has been provided with some reasonable expectation of success.
The decision
In the case of EP 3854403, the Court dismissed the claimant’s sufficient objection but revoked the patent on the grounds that the second medical use lacked an inventive step. The decision issued by the Central Milan Court states that the treatment of COVID-19 with remdesivir was an obvious choice for the skilled person at the application date because the viral genome had been made publicly available before the priority date and it was therefore known to the skilled person that SARS2 was highly similar to SARS1.
The Court further noted that experts had speculated publicly that remdesivir would be a good candidate anti-viral treatment due to the positive results from pre-clinical experiments on SARS1 and MERS. The decision highlights how the UPC applies a strict approach to assessing the inventive step of second medical use and indicates that patentees must be wary of any ‘hints’ to the treatment’s effectiveness published prior to the applications priority date.
Gilead is also pursuing an Opposition against the patent at the EPO. The UPC and EPO are distinct entities so the outcome of the opposition could differ from the UPC’s recent decision, but it seems likely that the EPO will take a similar approach since parallel decisions to date have remained broadly uniform. While the reasoning for decisions occasionally differs, the Enlarged Board of Appeal decision G1/24 regarding claim interpretation demonstrated an intent to bring EPO case law in line with UPC rulings.
Battles for pandemic innovation IP
While the commercial significance for these technologies is huge, several pharmaceutical companies publicly pledged not to enforce their patent rights to allow mass production of life saving drugs and vaccines at a time of global crisis. These allowances were short-lived, ceasing in May 2023 when the pandemic was officially declared to be over, and contentious proceedings are ongoing for a number of critical patents.
The disputes have largely been centred around patents for the widely distributed COVID-19 mRNA vaccine filed early in the pandemic. The most high-profile cases revolve around ongoing infringement and invalidity proceedings between Moderna and BioNTech/Pfizer.
In the wake of the pandemic, applications of thousands of patent families directed to Covid-19 related technologies were filed in the space of a few short years. While many patents filed in 2020 following the characterisation and subsequent proliferation of SARS-COV-2 have been granted, many divisional applications and later developments are still pending prosecution, and may yet be the subject of new infringement and revocation proceedings.
The impact of these patent disputes extends further than the ownership of the IP itself; as the decisions handed down by the UPC and European Boards of Appeal shape the case law on inventive step, plausibility and medical use claims.
