Syntara’s Parkinson’s Drug Shows Motor Improvement After Treatment Stops

SNT-4728 Produces a Motor Signal After Treatment Ends

The most consequential development in Syntara Limited’s (ASX:SNT) September quarter was not a cash figure but a signal from its small Parkinson’s-related study: participants given SNT-4728 showed statistically significant improvement in clinician-assessed motor signs 12 weeks after treatment had stopped.

The randomised, double-blind Phase 2 study enrolled 41 people with isolated REM Sleep Behaviour Disorder, a condition associated with a high risk of progression to Parkinson’s disease and related disorders. The treatment group received a once-daily 15 mg dose for 12 weeks. On the MDS-UPDRS Part III measure, which assesses features including tremor, rigidity, gait and postural stability, the difference between treatment and placebo was statistically significant at Week 24, with a p-value of 0.021.

The result adds to preliminary imaging data reported earlier, which showed a statistically significant unilateral reduction in inflammation in the putamen, a brain region involved in Parkinson’s motor symptoms. That earlier SNT-4728 inflammation data had shown 20 of 30 treated participants reducing inflammation from baseline.

The evidence remains preliminary. The study was exploratory, included only 41 participants and treated them for 12 weeks. The motor composite derived from smartphone tasks was directionally consistent but not statistically significant, while other measures covering cognition, quality of life and iRBD symptoms showed no marked changes. Further biomarker, imaging and digital-endpoint analyses are still outstanding, and Syntara said additional studies are needed to establish clinical benefit or any effect on disease progression.

Amsulostat Reaches Final AZALOX Dose Cohort

Amsulostat also moved through an important safety checkpoint in the AZALOX study for high-risk myelodysplastic neoplasms and chronic myelomonocytic leukaemia. The first Phase 1b cohort tested 150 mg twice daily alongside 5-Azacitidine, with no dose-limiting toxicities and no new adverse events attributed to amsulostat reported. An independent Drug Safety Monitoring Board approved escalation to the final cohort at 200 mg twice daily.

The Phase 1b work is designed to establish a recommended Phase 2 dose. Subject to the final safety review, the study is expected to move into a Phase 2 component involving about 30 patients. The progress extends the company’s blood-cancer strategy beyond its FDA-supported myelofibrosis pathway, although the separate Australian MESSAGE study is recruiting more slowly than anticipated and preliminary results are not expected until the first half of 2027. The final AZALOX dose step builds on the AZALOX dose escalation reported earlier this year.

Cash Benefit Arrives Alongside Premises Uncertainty

Syntara received A$4.7 million through the R&D tax incentive during the quarter, helping it finish September with A$14.06 million in cash and cash equivalents, compared with A$13.562 million at the end of June. Operating cash flow was a net inflow of A$649,000, largely because of the tax refund; research and development costs were A$1.989 million and staff costs were A$1.787 million.

That cash picture contains a temporary lift rather than a clean read on underlying spending. The company reported no drawn financing facilities, while the tax refund accounted for most of the quarter’s operating inflow. Separately, Arna Pharma, the buyer of Syntara’s former mannitol respiratory business, entered liquidation after going into voluntary administration in September. Syntara now considers recovery of its remaining claim, reduced to about A$0.6 million after prior payments and offsets, unlikely. The receivable had already been fully impaired, so the company does not expect a material profit-and-loss impact.

The more practical issue is the Frenchs Forest premises. Arna Pharma’s liquidation terminated the head lease and sublease under which Syntara’s laboratories and offices operated. Syntara remains in the facility while it discusses near-term arrangements with the property owner, but says relocation is likely. That could bring transition costs and potential disruption to early-stage research programs, with the scale and timing not yet disclosed.

Scar Programs Set Up 2027 Readouts

Syntara expanded its blinded SNT-9465 hypertrophic-scar study from 20 to 30 participants after encouraging feedback from clinical sites and participant engagement. The company stressed that the decision was not based on efficacy data. Eight participants discontinued treatment because of mild, reversible local skin reactions, mainly redness and itching, and top-line results are now expected in the first quarter of 2027.

The smaller SNT-6302 keloid-scar SATELLITE study had six participants complete 12 weeks of treatment. Preliminary findings showed increased blood-vessel area density, but no observable change in scar scores or stiffness. With follow-up continuing for nine months and further end-of-treatment data outstanding, the study is not yet a basis for judging clinical activity.