Salud por Derecho, together with four other organisations, has submitted third-party observations to the European Patent Office, calling for a patent application filed by Merck Sharp & Dohme (MSD) relating to alimatravir to be rejected. The observations were jointly filed by 100% Life (Ukraine); Initiativa Pozitivă/Positive Initiative (Moldova); the International Treatment Preparedness Coalition – Middle East and North Africa (ITPC MENA); ATL MST-SIDA (Tunisia); and Salud por Derecho.
Alimatravir, also known as MK-8527, is an investigational medicine for HIV pre-exposure prophylaxis, or PrEP. It is currently in Phase 3 clinical trials. If proven safe and effective, it could become a once-monthly oral pill for HIV prevention.
The European patent application, filed on 26 January 2024, does not claim alimatravir itself — an already known and publicly disclosed compound — but certain prodrug forms of it, meaning substances that are converted inside the body to release the active ingredient. The organisations submitting the observations argue that these changes lack inventive step over the prior art and that the application also fails to describe the claimed invention with the clarity and detail required under European patent law. In our view, this is a secondary patent intended to artificially extend exclusivity over the medicine, a strategy known as evergreening.
Article 115 of the European Patent Convention allows any third party to present observations concerning the patentability of an invention following the publication of a patent application. This procedure provides an opportunity to submit technical arguments before the European Patent Office decides whether to grant or refuse the patent application.
This intervention is particularly important because Merck requested that the potential effects of the patent be extended to Moldova, Morocco and Tunisia through validation agreements. According to ITPC MENA, Morocco does not conduct a new technical examination of patents validated by the European Patent Office, and organisations in the country have no administrative procedures through which to challenge them before or after grant. Submitting observations to the European Patent Office therefore represents their main opportunity to intervene during the examination process.
If the patent is granted and validated, it could delay generic market entry and restrict access to affordable alimatravir. The voluntary licences announced by Merck in July 2026 do not fully address this problem. These agreements, signed with seven generic manufacturers and covering 129 low- and middle-income countries, exclude countries with significant needs, including Moldova.
The published terms also allow Merck to terminate a licence if a manufacturer challenges the validity of any of its patents and prohibit sales outside the agreed territory. As Vanessa López, Executive Director of Salud por Derecho, states: “Voluntary licences that the company can withdraw the moment its patents are challenged by a generic manufacturer-licensee cannot substitute for ensuring that patents lacking genuine inventive merit are not granted in the first place.”
Merck has not yet disclosed the final market price. A study published in the scientific journal AIDS estimates that a generic version of alimatravir could be produced at scale for US$4.49 per person per year. The estimate includes the active pharmaceutical ingredient, formulation, production losses, packaging, transport, tariffs, taxes and a profit margin. According to the authors, intellectual property and licensing conditions will be decisive in ensuring equitable access if the medicine proves effective.
The decision taken by the European Patent Office will determine whether Merck obtains new exclusive rights over these forms of alimatravir. The organisations submitting the observations are calling for monopolies without a genuine inventive contribution not to be granted and for the generic competition needed to ensure that, if the medicine proves safe and effective, it can be made available at an affordable price.
