Ractigen Therapeutics announced positive preliminary data from the single ascending dose (SAD) Phase I portion of its ongoing Phase I/II clinical trial of RAG-17. RAG-17 is a novel small interfering RNA (siRNA) therapeutic in development for the treatment of amyotrophic lateral sclerosis (ALS) patients with mutations in the superoxide dismutase 1 (SOD1) gene.
The data were presented on April 19, at the 2026 American Academy of Neurology (AAN) Annual Meeting in Chicago, Illinois. The presentation was delivered by Dr. Zhi-Ying Wu, Principal Investigator of the Second Affiliated Hospital Zhejiang University School of Medicine.
RAG-17 utilizes Ractigen's proprietary Smart Chemistry-Aided Delivery (SCAD™) technology, which conjugates the siRNA duplex to an accessory oligonucleotide (ACO). This innovative architecture enables widespread central nervous system (CNS) distribution and exceptionally durable target engagement following a single intrathecal (IT) injection, potentially allowing for significantly extended dosing intervals compared to current therapies.
"The data presented at AAN this year represents a major milestone for Ractigen and, more importantly, for patients living with SOD1-ALS," said Dr. Long-Cheng Li, CEO of Ractigen Therapeutics. "Achieving an 81% reduction in plasma NfL—a critical marker of neuroaxonal damage—alongside a highly favorable safety profile from a single administration is unprecedented. Furthermore, the early signals of clinical stabilization we are observing at the highest dose level strongly validate our SCAD platform. We are thrilled to have already initiated dosing in the Phase II portion of the study to further evaluate RAG-17's transformative potential."
"SOD1-ALS is a genetically defined disease with a clear biological target, yet patients still face a very limited treatment landscape," commented Dr. Zhi-Ying Wu. "What we observed in this Phase I study—a substantial and durable reduction in CSF SOD1 protein after a single dose, accompanied by a profound decrease in plasma NfL and early stabilization of functional scores in the highest dose group—gives us strong reason for optimism. These data clearly suggest that RAG-17 is engaging its target in a highly meaningful way, and we look forward to generating further evidence in the ongoing Phase II study."
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