Alterity Therapeutics Touts Functional Benefit in MSA Trial, But Imaging Goal Slips Away

Alterity reports adjusted Phase 2 data showing 52% less functional decline with ATH434 in MSA, though the trial's primary MRI endpoint was missed.

Alterity Therapeutics used this year's International Parkinson and Movement Disorder Society congress in Seoul to roll out a fresh round of Phase 2 analyses for ATH434, its experimental treatment for multiple system atrophy. The Australian biotech framed the update around a biomarker-adjusted reading of its ATH434-201 dataset, which points to a sharper slowdown in functional decline than earlier interim snapshots had suggested — even as the study's original imaging objective went unmet.

A 52% Signal on Function

The headline figure centers on patients given 50 milligrams of ATH434 twice daily for 52 weeks. Once researchers adjusted for baseline levels of cerebrospinal fluid neurofilament light chain (CSF-NfL), treated participants showed roughly 52% less functional deterioration than those on placebo, as measured by the UMSARS Part I scale. The gap between the two arms came to 4.64 points and carried statistical significance (p=0.032).

That number marks an upgrade over the company's prior disclosure from the same trial, when it reported an unadjusted 46% slowing of decline. The adjusted readout draws on a modified intention-to-treat population of 61 participants, a subset of the 77 adults enrolled across the full Phase 2 program.

Biomarker Earns a Role in Phase 3 Design

The data also underscore how predictive CSF-NfL may be. Every 1,000 pg/ml of additional baseline CSF-NfL corresponded to an extra 0.9-point worsening on UMSARS after 52 weeks (p=0.033). That relationship has convinced Alterity to bake the biomarker directly into the protocol for its planned Phase 3 study.

Safety findings offered little cause for concern: no serious adverse events were attributed to the drug, and side-effect rates tracked those seen in the placebo arm. Imaging told a more mixed story, with a heightened iron signal detected in the dentate nucleus among patients on the 50-mg dose relative to placebo (p=0.021).

The Primary Endpoint That Didn't Land

Offsetting the functional narrative is a miss on the trial's original goal. ATH434 failed to hit the primary MRI endpoint, which tracked changes in iron content within the substantia nigra. A higher 75-mg dose also fell short, delivering a non-significant minus 2.81-point difference versus controls after 52 weeks.

Management is nonetheless leaning on the overall dataset to justify pushing ahead. Alterity says the results bolster the case for a Phase 3 program now in preparation but not yet underway. Alongside the Seoul presentations, the company lodged corresponding disclosure documents with the U.S. Securities and Exchange Commission on Form 6-K.

Market Response Splits Along Two Sessions

Investors have greeted the news in contrasting fashion. Shares climbed 6.8% in one session to AUD 0.3950, then gave back 2.6% the next, settling at AUD 0.3700. Either way, the stock sits well below its summer peak — down 50% from its 52-week high on the stronger day's close, and 53% adrift on the weaker one. For the biotech, the immediate task is steering ATH434 through the regulatory handoff into late-stage testing.