Alterity Therapeutics has secured agreement from the U.S. Food and Drug Administration (FDA) on the key elements of its registrational Phase 3 program for ATH434 in Multiple System Atrophy (MSA). The FDA aligned with the proposed trial design, including the study population, dosing regimen, and treatment duration, positioning the company to initiate pivotal activities by year-end 2026. This program is designed to support a potential New Drug Application (NDA) for MSA, a rare and rapidly progressive neurodegenerative disease with no approved therapy.
The FDA concurred with the 50 mg twice daily dose of ATH434, which achieved clinically and statistically significant efficacy in the Phase 2 study. The regulator agreed to use the 11-item Unified Multiple System Atrophy Rating Scale (UMSARS) Part I as the primary endpoint. In the Phase 2 trial, this dose demonstrated a 48% slowing of disease progression compared to placebo.
Phase 3 Trial Design
The Phase 3 clinical trial will be a randomized, double-blind, placebo-controlled study. Approximately 200 patients will be assigned in a 1:1 ratio to receive either ATH434 50 mg or a matching placebo for 12 months.
| Feature |
Details |
| Patients |
Approximately 200 |
| Ratio |
1:1 |
| Treatment duration |
12 months |
| Dose |
50 mg twice daily |
| Primary endpoint |
11-item UMSARS Part I |
Key secondary endpoints include the Swallowing Disturbance Questionnaire, the Orthostatic Hypotension Symptom Assessment, and the Clinical Global Impression of Severity. The FDA indicated these endpoints were suitable to support efficacy and agreed with Alterity's proposed statistical methods for analysis.
Phase 2 Data and Regulatory Feedback
In April, Alterity Therapeutics presented new data analyses from the Phase 2 trial of ATH434, demonstrating clinical efficacy in MSA patients. The ATH434-201 trial showed meaningful results utilizing the Multi-System Atrophy Composite Assessment (MuSyCA), which demonstrated robust sensitivity to disease progression, with placebo participants worsening by approximately +9.7 points over 52 weeks. Consistent with prior data, ATH434 slowed disease progression on the MuSyCA assessment.
The company received positive regulatory feedback following an FDA Type C Meeting in April regarding its planned Phase 3 development program. Alterity received written feedback supporting its plans related to the chemistry, manufacturing, and control (CMC) elements of the program. The first Type C Meeting in March was related to clinical pharmacology and non-clinical development aspects of the program.
ATH434 has previously received Fast Track Designation and Orphan Drug Designation from the FDA for the treatment of MSA. "The successful outcome of the meeting is an important de-risking milestone and gives us confidence as we finalize the protocol and prepare to initiate trial activities by year-end 2026," said David Stamler, CEO of Alterity Therapeutics. "I am confident that ATH434 is well-positioned to become a disease-modifying therapy for individuals living with MSA."
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