Researchers behind an Australian-led trial of an experimental drug to prevent Parkinson's disease announced Friday they would seek international sites for a larger confirmatory study. The announcement followed publication of results showing delayed disease onset in at-risk patients—the first such findings in the field.

The lead investigators, based at institutions including the Florey Institute of Neuroscience and Mental Health in Melbourne, detailed the findings as momentum built after early reports described the data as promising.

Parkinson's disease affects more than 10 million people worldwide, according to the World Health Organization, and no existing therapy has been proven to slow or prevent its progression. The trial targeted individuals carrying genetic markers or early biological signs of neurodegeneration, aiming to intervene before motor symptoms emerge. Researchers said the approach represented a shift from treating symptoms toward disrupting the underlying disease process.

The investigators cautioned that the initial cohort was small and that larger, longer studies would be required before regulatory approval could be sought. Discussions were under way with research centres in Europe and North America to recruit participants for an expanded Phase 3 programme. Funding partners and the drug's developer were expected to be named in follow-up announcements.

Parkinson's advocacy organisations, including Parkinson's Australia, welcomed the findings while urging caution about timelines. Neurologists not involved in the study said independent replication would be essential, noting that previous candidate therapies had failed in later-stage trials despite promising early signals.

"If these results hold up in a larger population, this would be a genuine turning point for a disease we have only ever been able to manage, never prevent," said one of the trial's senior investigators.