For years, hundreds of people and families have been closely following the development of pridopidine, taking part in clinical trials and hoping that it could become a new treatment for Huntington’s disease.
Following the European Medicines Agency’s (EMA) decision not to approve pridopidine last year, Prilenia and Ferrer have announced the launch of PRECISE-HD, a new international clinical trial that will seek to confirm the most promising results obtained to date.
Many of us remember the EMA’s decision in September 2025. Although this was difficult news for the community, it is important to understand what happened. The EMA’s decision was not related to safety concerns. Rather, it considered that the available data from the PROOF-HD trial did not yet demonstrate with sufficient clarity that the treatment offered a benefit to all participants in the trial.
Upon analysing the results in greater detail, the researchers observed that a specific group of participants – people in the early stages of the disease who were not taking certain medicines – did appear to benefit from pridopidine. This raised a key question:
Prilenia and Ferrer, the companies jointly developing pridopidine, continued to work with the regulatory authorities to answer that question.
That commitment has now resulted in the launch of PRECISE-HD, an international clinical trial specifically designed to confirm whether pridopidine can help slow the progression of the disease in people who showed the most promising results in previous studies.
The design of PRECISE-HD builds on what has been learned from PROOF-HD, together with input from the Huntington's disease community and discussions with regulatory authorities.
PRECISE-HD is a phase III clinical trial; in other words, this is the final major stage of research before a medicine can be re-evaluated by the regulatory authorities. Many people take part in this type of study, as it is necessary to confirm with the greatest possible certainty whether the treatment actually works and whether it remains safe.
This new trial will include 400 people with early- or mid-stage Huntington’s disease. During the first year, participants will be randomly assigned to receive pridopidine or a placebo. Neither the participants nor the research team will know which treatment each person is receiving during this period; this design allows the results to be compared as objectively as possible. Afterwards, those who are eligible will be able to take part in a two-year open-label extension phase, during which everyone will receive pridopidine. In total, some participants may remain in the study for up to three years.
The study will be conducted at up to 75 research centres in the United States, Europe, the United Kingdom and Canada.
