ARTHEx Biotech Granted FDA Fast Track Designation for ATX-01 for the Treatment of Myotonic Dystrophy Type 1 (DM1)

VALENCIA, Spain, March 11, 2026 /PRNewswire/ -- ARTHEx Biotech, a clinical-stage biotechnology company advancing RNA-based therapeutics for neuromuscular disorders, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to ATX-01 for the treatment of Myotonic Dystrophy type 1 (DM1).  ATX-01 is ARTHEx's investigational RNA therapeutic designed to address the underlying genetic cause of DM1, a highly disabling neuromuscular disorder with no known cure.  

"Receiving Fast Track Designation for ATX-01 is an important milestone for ARTHEx and the DM1 community," said Judith Walker, M.D., Chief Medical Officer of ARTHEx Biotech. "DM1 is a devastating, progressive disorder with no approved disease-modifying therapies. This designation underscores both the seriousness of the condition and the potential of ATX-01 to provide therapeutic benefit. We are committed to advancing this program with urgency to bring a meaningful therapy to patients as quickly as possible."

ATX-01 is designed to inhibit microRNA-23b (miR-23b), a natural suppressor of muscleblind-like (MBNL) protein expression. In individuals with DM1, loss of functional MBNL activity occurs through two complementary mechanisms: first, upregulation of miR-23b reduces MBNL protein expression; and second, expanded toxic DMPK mRNA sequesters MBNL proteins within the nucleus. The resulting depletion of available MBNL proteins leads to widespread RNA mis-splicing (spliceopathy), which underlies the multisystem symptoms characteristic of DM1. These symptoms primarily affect the skeletal muscle, cardiac, and central nervous systems, though additional organ systems may also be involved. Disease onset most commonly occurs during adolescence, and DM1 is associated with progressive disability and reduced life expectancy.

By inhibiting miR-23b, ARTHEx has demonstrated that ATX-01 increases MBNL production and decreases foci formation and toxic DMPK mRNA. This highly differentiated dual mechanism of action leads to a significant increase of free MBNL, improving splicing abnormalities, and ultimately restoring function in animal models.

"I am encouraged by the progress we are seeing with ATX-01 in the ongoing ArthemiR™ study," said Nicholas Johnson, M.D., M.Sci., FAAN, Professor of Neurology and Human and Molecular Genetics at Virginia Commonwealth University and co-principal investigator of the Myotonic Dystrophy Clinical Research Network. "For patients with DM1, the lack of treatment options remains a significant unmet need. ATX-01's dual mechanism targeting the underlying RNA pathology is particularly compelling, and Fast Track Designation adds important momentum as we continue enrolling patients and generating clinical data."

Fast Track designation enables more frequent interactions with the FDA to expedite the development and review process for drugs intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs.   Currently, there are no approved therapies targeting miR-23b for DM1.

ARTHEx is currently advancing ATX-01 in the Phase I/IIa ArthemiR™ study and continues to work closely with regulatory authorities, clinical investigators, and patient advocacy groups to accelerate progress. Please visit the Company's Clinical Trials and Patients pages of its website for more information.

About ARTHEx Biotech

ARTHEx Biotech is a clinical-stage company developing targeted RNA medicines designed to precisely modulate gene expression. Its proprietary platform, BOOST-ON™, pairs selective oligonucleotides with enhanced tissue delivery to reach skeletal muscle, heart, and brain. Its lead program, ATX-01, is in clinical evaluation for myotonic dystrophy type 1 (DM1), a rare neuromuscular disorder, in the Phase I/IIa ArthemiR™ trial. Building on this foundation, ARTHEx is advancing a pipeline of therapies for additional areas of high unmet need across muscular, CNS and cardiac diseases.

The Company headquarters are in Valencia, Spain. 

For more information on ArthemiR™, please visit https://www.arthemir.com or https://clintrials.gov. 
For more information, please visit www.arthexbiotech.com and engage with us on LinkedIn.

SOURCE ARTHEx Biotech