In the oligonucleotide drug sector, siRNA and ASO are the two most mainstream development directions. With continuous iteration of chemical modification strategies and central delivery protocols, ASO clinical translation for central nervous system genetic diseases is accelerating, with multiple milestone clinical data being released one after another.

Zanvastro Launched: ASO Therapy for Alexander Disease Approved

On September 3, Ionis Pharmaceuticals' ASO drug Zanvestro was officially approved by the FDA for the treatment of adult and pediatric Alexander disease (AxD). This rare disease is triggered by a heterozygous mutation in the GFAP gene. After mutation, the GFAP protein accumulates abnormally, gradually destroying astrocyte function, leading to white matter lesions and a sustained decline in motor ability. For a long time, clinical practice has only relied on symptomatic supportive treatment, lacking solutions that can directly address the root causes of the disease.

Zanvestro is a centrally targeted ASO administered via intrathecal injection, with a dosing cycle of up to once per quarter. This ASO can specifically bind to GFAP mRNA, downregulate the expression of mutant GFAP proteins, and reduce abnormal protein accumulation. In pivotal clinical trials, the drug stabilized patients' walking speed and delayed the deterioration of motor function.

This approval is highly significant, proving that ASO can act safely and long-term on the central nervous system, setting a prerequisite for drug development for a range of rare central genetic diseases.

Ulefnersen Stage III Positive: New Hope for FUS-ALS Treatment

On September 22, Ionis announced positive topline data from the Phase III FUSION study of Ulefnersen for treating FUS-mutant amyotrophic lateral sclerosis (ALS). FUS-ALS is a rapidly progressing malignant hereditary ALS subtype, characterized by abnormal accumulation of FUS proteins, causing rapid motor neuron damage, and clinical treatment options are very limited.

Ulefnersen is an ASO targeting FUS mRNA, administered intrathecalally, to reduce levels of central mutant FUS proteins. This phase III study met the pre-set primary efficacy endpoint, significantly delaying neurological decline in patients while improving survival-related indicators.

From target identification, sequence screening, in vitro activity validation, and then to large-scale Phase III clinical trials, the starting point of the entire pipeline development is high-quality early screening of oligonucleotides.

Individualized ASO: Clinical Exploration of Rare Mutant ALS

On October 9, the Mayo Clinic team conducted a single-case clinical study of N-of-1, exploring customized ASO interventions for ALS carrying CHCHD10 mutations.

CHCHD10 mutation is a rare subtype of hereditary ALS; the mutated gene causes mitochondrial functional defects that drive progressive death of motor neurons. The population for these mutated cases is extremely small, making it difficult to invest resources in traditional new drug development. Individualized oligonucleotide therapy has become a highly promising solution.

The research team designed and synthesized a dedicated ASO from scratch targeting the patient's specific mutation sites, using intrathecal administration. After a period of intervention, the patient's plasma nerve filament light chain protein NfL (a core biomarker of nerve injury) decreased by about 50%, while ALSFRS-R motor function score and forced vital capacity indicators improved. No serious adverse events were observed during the trial.

This study validates a new development pathway: to rapidly design and synthesize specific ASOs for rare individualized gene mutations, and after cell-level activity validation, proceed with human trials.

Empowering industries: GentleGen's one-stop oligonucleotide platform

Whether ultimately used in routine therapies for rare diseases or individualized N-of-1 therapy, the quality of the oligonucleotide sequence itself determines the success or failure of the project.

GentleGen's one-stop oligonucleotide service platform is not simply a combination of various services, but deeply integrates core capabilities such as target evaluation, sequence design, synthesis purification, active screening, and sequence modification & conjugation, truly achieving a "just imagine and get" R&D experience.

For detailed information about related services, please send an email to marketing@gentlegen.com.