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.
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.
Why is research into pridopidine continuing?
Pridopidine is an oral treatment taken twice a day. It works by activating a protein in the brain called the sigma-1 receptor, which is involved in mechanisms that help neurons stay healthy and function properly. Researchers believe that stimulating this receptor could help protect nerve cells affected by Huntington’s disease. This is why pridopidine remains one of the therapies still being investigated.
The design of PRECISE-HD is not starting from scratch. It builds on knowledge gained from years of research, input from the Huntington’s disease community, and ongoing dialogue with regulatory authorities. Furthermore, it takes into account the results published in Nature Medicine, where an analysis of a specific group of participants in the early stages of the disease showed that pridopidine could slow clinical progression and help preserve functions such as movement, thinking and the ability to carry out activities of daily living for longer.
As with all clinical trials, the success of PRECISE-HD will depend largely on the community’s participation. Every clinical trial is much more than a scientific study. Behind every participant is a person, a family and a decision to contribute to the future of the entire Huntington’s community.
It represents the continuation of a line of research that did not come to a halt following last year’s EMA decision, and reflects the shared commitment of researchers, healthcare professionals, pharmaceutical companies and, above all, people and families living with Huntington’s disease. the individuals and families who make it possible for research to continue to advance, helping to answer questions that benefit the entire Huntington’s community and bring us closer to effective treatments.
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Article written by Ruth Blanco