SAN DIEGO, CA — December 2025 — Repeat Therapeutics, a biotechnology company developing mechanism-driven treatments for neurodegenerative diseases, today announced the first participant has been dosed in its Phase 1 clinical trial of RTX-101, the company’s lead therapeutic candidate for amyotrophic lateral sclerosis (ALS) linked to the C9orf72 hexanucleotide repeat expansion, the most common genetic cause of familial ALS.
RTX-101 is a novel, orally administered small-molecule combination therapy designed to restore cellular balance and reduce neurotoxic stress in motor neurons. The therapy modulates key biochemical processes involved in oxidative injury and cellular stress in C9orf72-mediated ALS.
The Phase 1 trial is evaluating safety, tolerability, and pharmacokinetics in healthy volunteers, followed by expansion into individuals with C9orf72-associated ALS. The study is being conducted under Australia’s TGA Clinical Trial Notification pathway with HREC approval.
A second pipeline candidate, RTX-111, builds on the same therapeutic foundation with a modified formulation intended to broaden applicability to additional neurodegenerative indications.
“Dosing our first participant is a significant milestone and the first step toward a first-in-class therapy for C9orf72 ALS,” said Susan Francia, co-founder of Repeat Therapeutics. “Our approach is rooted in a deep understanding of disease biology, purposeful design, and a commitment to advancing this work with the focus and determination it demands, given the substantial unmet medical need in ALS. We’re proud to move this program forward and take a meaningful step toward bringing new hope to patients and families living with the disease.
Repeat Therapeutics is advancing a focused pipeline of disease-modifying therapies for repeat expansion disorders, with an emphasis on targeting metabolic and cellular stress pathways with novel small molecule combinations.
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