VICO Therapeutics Clinical Trial updates

Spinocerebellar ataxias (SCAs) are a group of rare, progressive hereditary genetic disorders that affects the cerebellum, brain stem and spinal cord. Currently, more than 30 types of SCAs have been identified. SCAs are caused by genetic mutations, which lead to faulty proteins being produced. This causes the degeneration of different populations of neurons, depending on the type of SCA. For more information about different SCAs, please click here.

VICO Therapeutics is a company focusing on the development of therapies for rare neurological disorders. VICO’s product VO659. VO659 is a type of therapy called an antisense oligonucleotide (ASO). ASOs target the mutated gene, to prevent it from producing the protein which ultimately causes the condition with the aim of slowing or halting disease progression. 

As of February 2026, the London site is recruiting participants for the trial. Click here to find out if you are eligible to take part in the trial.

Programme timeline

February 2021
VICO Therapeutics announced that the European Commission (EC) had granted orphan drug designation for VO659. Drugs that qualify for orphan drug designation are intended for the safe and effective treatment, diagnosis or prevention of rare diseases. Orphan drug designation gives developing companies certain benefits and incentives.  Read the press release here.  

June 2021
VICO Therapeutics announced that the Office of Orphan Products Development (OOPD) of the U.S. Food and Drug Administration (FDA) had granted orphan-drug designation for VO659. They were preparing for their in human trials, expected to start in 2022. Read the press releases here. 

April 2023
On April 3rd 2023, VICO Therapeutics announced that they have dosed the first patient in their Phase 1/2a clinical study evaluating VO659 for the treatment of SCA1, SCA3 and Huntington’s Disease (HD) at one of their sites in Europe. These three conditions are all caused by the increased length of a specific sequence called ‘CAG repeats’, which results in the production of toxic proteins that damage cells. VO659 targets these additional CAG repeats and stops them from resulting in the production of toxic proteins.  

This clinical trial is the first time that the treatment is being tested in humans and is designed to assess the safety and tolerability of different doses of VO659. This clinical trial is taking place in sites across Europe, and includes a UK site in London, at the London Ataxia Centre. For more information read the press release here. 

September 2024
On September 13th, the pharmaceutical company Vico Therapeutics announced positive interim phase 1/2a clinical data of VO659 in the treatment of Huntington’s disease. VO659 demonstrated a 28% average reduction in levels of the mutant huntingtin protein (mHTT) that causes Huntington’s disease 85 days after treatment in patients given a 40mg dose. VO659 was generally safe and well tolerated. Read the press release here.  

February 2026 
As of February 2026, the London site is recruiting participants for the trial. Click here to find out if you are eligible to take part in the trial.