In Europe, Orphan Drug designation is granted to drugs or biologics intended to treat, diagnose, or prevent rare, life-threatening, or chronically debilitating conditions. For the European Union (EU), a “rare” condition is one which affects under 5 in every 10,000 people. After receiving this designation, the drug developer also earns a variety of incentives. These include fee reductions, protocol assistance, and 10 years of market exclusivity upon product approval. According to a news release from Taysha Gene Therapies, the company’s therapeutic candidate TSHA-120 recently earned Orphan Drug designation from the European Commission (EC) for the treatment of giant axonal neuropathy (GAN).
About TSHA-120
Taysha Gene Therapies describes TSHA-120 as:
an AAV9 self-complementary viral vector that encodes the full length human gigaxonin protein.
It is administered intrathecally (into the spinal theca). TSHA-120 received Orphan Drug designation based on quantitative data and evidence from preclinical and clinical studies. Using 53 patient years of data, researchers determined that TSHA-120 showed durable improvement in patients, including the regeneration of nerve fibers. TSHA-120 is also safe and well-tolerated. Researchers are continuing to evaluate the therapy in an ongoing study.
To assist with increased giant axonal neuropathy awareness, Taysha Gene Therapies is also taking some additional steps. For example, the company’s partnership with GeneDx would provide those at-risk or suspected of having genetic axonal neuropathy with genetic testing.
Outside of the European Union, TSHA-120 was granted Rare Pediatric Disease and Orphan Drug designations in the United States.
What is Giant Axonal Neuropathy (GAN)?
Giant axonal neuropathy (GAN) is a rare neuropathy which affects the central and peripheral nervous systems. GAN gene mutations cause this slow progressing neurodegenerative disorder. Normally, GAN encodes for the production of the gigaxonin protein. But the mutations cause this protein to malfunction and be unable to break down neurofilaments. As these neurofilaments become packed into axons, the axons become abnormally large and lose proper function.
Typically, symptoms related to giant axonal neuropathy manifest before 5 years old. Potential symptoms include:
- Frequent falls and difficulty walking
- Hypotonia (low muscle tone)
- Reduction or loss of ability to sweat
- Intellectual disability
- Hearing or vision problems
- Heat intolerance
- Muscle weakness
- Impaired muscle coordination (ataxia)
- Loss of bladder control
- Constipation
- Seizures
- Paralysis
Unfortunately, giant axonal neuropathy is often fatal by late teens to early 20s. No current approved treatment options exist. Thus, if TSHA-120 is approved in the future, it will fill a huge unmet need for this community.
