Alterity Reports Positive ATH434 Data in Multiple System Atrophy Study

Key Points

• Alterity reported new Phase 2 results for ATH434, an experimental treatment for multiple system atrophy, or MSA.
• The 50 mg dose slowed functional decline by about 52% versus placebo after researchers adjusted for differences in patients’ disease severity at the start of the trial.
• The result was statistically significant, with a 4.64-point benefit versus placebo on the 11-item UMSARS Part I daily-function scale after 52 weeks.
• A spinal-fluid biomarker called CSF NfL helped predict which patients were likely to decline faster.
• The study missed its primary MRI endpoint, meaning the imaging findings do not independently confirm ATH434’s intended effect on brain iron.

Alterity Therapeutics (NASDAQ: ATHE) presented additional Phase 2 data for ATH434 in people with MSA, a progressive neurological disorder. The updated analysis suggests that the 50 mg dose may help patients maintain day-to-day function longer than placebo, but the treatment will still need to succeed in a larger Phase 3 study.

ATH434 50 mg Slowed Decline in Daily Activities

Researchers measured patients’ ability to perform everyday activities using the 11-item UMSARS Part I scale. After one year, patients receiving ATH434 50 mg declined less than those receiving placebo.

When the study adjusted for differences in disease severity at the beginning of the trial, the 50 mg dose showed a 4.64-point advantage over placebo. Alterity said this equals an approximate 52% slowing of functional decline.

The result was statistically significant (p=0.032). The company also said the difference was about three times greater than the 1.5-point improvement it considers clinically meaningful on this scale.

Biomarker Helped Identify Patients at Higher Risk of Faster Decline

The analysis used cerebrospinal-fluid neurofilament light chain, or CSF NfL, as a measure of disease severity. In simple terms, people with higher CSF NfL levels at the start of the study tended to worsen more quickly over the following year.

For every 1,000 pg/mL increase in baseline CSF NfL, patients had about 0.9 additional points of worsening on the UMSARS Part I scale after 52 weeks. This relationship was statistically significant (p=0.033).

Alterity believes using CSF NfL in future trials could make it easier to measure whether ATH434 is working by accounting for differences in how advanced each patient’s MSA is at enrollment.

Higher Dose Showed a Smaller, Non-Significant Result

The 75 mg dose also showed less functional decline than placebo, but the difference was smaller and did not reach statistical significance at Week 52. The 75 mg group had a 2.81-point advantage versus placebo, with a reported p-value of 0.179.

That means the result could have occurred by chance under standard statistical thresholds. Based on the data presented, the 50 mg dose produced the clearer efficacy signal.

MRI Findings Were Mixed and Primary Endpoint Was Not Met

ATH434 is designed to act as an iron chaperone, meaning it aims to redistribute reactive iron involved in MSA disease processes. MRI analyses showed numerically lower iron changes in certain brain areas—the putamen and globus pallidus—with ATH434 than with placebo.

However, the study did not meet its primary MRI endpoint: a change in iron in the substantia nigra after 52 weeks. In the dentate nucleus, the 50 mg dose showed a relative increase in iron signal versus placebo. Alterity believes this could reflect iron being redistributed through the brain, but that interpretation remains a hypothesis.

What It Means for Investors

The strongest takeaway is the 50 mg group’s functional result after one year. It supports Alterity’s plan to move ATH434 into a Phase 3 confirmation trial and to use CSF NfL to better account for baseline disease severity.

Still, ATH434 remains experimental. The study was Phase 2, the key MRI endpoint was missed, and the treatment must show a clear benefit and acceptable safety profile in a larger confirmatory trial before it could be considered for regulatory approval.