Syntara SNT-4728 Shows Motor Signal in iRBD Phase 2 Data

Syntara (ASX:SNT) released secondary endpoint results from its Phase 2 study of SNT-4728 in isolated REM Sleep Behaviour Disorder (iRBD), which it says support further clinical development of the drug as a potential disease-modifying therapy in prodromal and early Parkinson's Disease.

The randomised, double-blind, placebo-controlled study enrolled 41 participants, randomised 3:1 to SNT-4728 or placebo. Clinician-assessed motor signs measured by MDS-UPDRS Part III showed a statistically significant difference for SNT-4728 versus placebo at Week 24, 12 weeks after treatment ceased (p=0.021). Treated participants showed slightly improved motor scores after the 12 week treatment period and further improvement at week 24, while placebo participants' scores worsened. A smartphone-based motor composite score was directionally consistent, with no statistically significant difference between groups. These results add to the primary imaging endpoint reported 6 July 2026, a statistically significant reduction in brain inflammation unilaterally in the putamen (p-value 0.0145), with 20 out of 30 patients on active treatment recording a reduction from baseline. No treatment-related serious adverse events were reported.

No marked changes were observed in other MDS-UPDRS measures or in cognitive, quality-of-life and iRBD questionnaire measures. The study was small and exploratory, and further analysis of digital, clinical and biomarker data remains outstanding.