Within the United States, the FDA developed the Orphan Drug Act to incentivize companies to develop drugs and biologics intended to treat patients with rare conditions. In this case, “rare” conditions are those affecting under 200,000 Americans. After receiving Orphan Drug status, drug developers receive a variety of benefits, such as fee waivers, tax credits, increased FDA regulatory assistance, and even 7 years of market exclusivity once the therapy is approved. In a news release from late June 2021, biotechnology company VICO Therapeutics (“VICO”) shared that its investigational therapy VO659 for spinocerebellar ataxia (SCA) was granted Orphan Drug designation.

VO659

Currently, no disease-modifying therapies exist for patients with SCA. Ultimately, this is what VICO is trying to achieve: a therapy to fill this unmet need. But what exactly is VO659? This therapy is an investigational antisense oligonucleotide therapy. According to an unrelated article on ScienceDirect, antisense oligonucleotides are:

small-sized single-stranded nucleic acids [which can] bind to their target RNA sequence inside the cells and bring about gene silencing.

In this case, VO659 works to reduce or inhibit mutant proteins which can play a role in SCA. As a result, the drug is designed to prevent disease progression and improve patient outcomes. Outside of the United States, VO659 also received Orphan Drug status in Europe.

Spinocerebellar Ataxia (SCA)

Altogether, there are over 30 forms of spinocerebellar ataxia (SCA), hereditary conditions that affect the brain stem, spinal cord, and cerebellum. While these conditions share similar symptoms, each form of SCA differs based on the specific associated gene mutation. These gene mutations damage parts of the nervous system which control movement, causing neurodegeneration and other symptoms. Typically, SCA affects those older than 18.

Although symptoms may vary, common symptoms include:

• Muscle stiffness and cramping
• Progressive incoordination of walking and balance
• Irregular gait
• Difficulty processing, learning, or remembering information
• Slurred or slowed speech
• Difficulty swallowing
• Poor hand-eye coordination
• Involuntary eye movements
• Peripheral neuropathy
• Incontinence