
Clinical-stage genetic medicines company Vico Therapeutics has reported positive interim data from its ongoing Phase I/IIa clinical trial of VO659, an investigational therapy for Huntington’s disease.
The data shows a significant reduction in mutant huntingtin protein in the cerebrospinal fluid of treated patients.
VO659 is an allele-preferential antisense oligonucleotide (ASO) therapy, targeting the CAG repeat expansion that causes Huntington’s and other known polyglutamine diseases.
It aims to inhibit mRNA translation and reduce mutant protein levels, potentially halting or slowing disease progression.
Vico Therapeutics’ ongoing multi-centre trial is designed to evaluate the safety and tolerability of VO659 in participants with early manifest HD, or mild to moderate spinocerebellar ataxia type one (SCA1) or type three (SCA3).
The study also explores pharmacodynamic biomarkers, pharmacokinetics, and clinical outcomes. The interim analysis includes safety, tolerability, and pharmacodynamic data for Huntington’s participants in the 40mg cohort up to day 85.

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By GlobalDataThe interim data revealed a mean reduction of 28% in mutant huntingtin protein at day 85, with an immediate effect post-first dose at day 29. There was no significant change in Nf-L protein levels, and VO659 was generally safe and well-tolerated at the 40mg dose.
Its long half-life suggests the potential for infrequent dosing, possibly only 1-2 times per year.
Vico CEO Micah Mackison said: “We are very pleased to announce these first data from our Phase I/IIa clinical trial of VO659 in participants living with Huntington’s disease.
“It is highly encouraging that we saw immediate reductions in CSF mHTT and no changes in Nf-L protein, two key biomarkers in Huntington’s disease, in treated patients over the available follow-up period. Given VO659’s long-anticipated half-life, there is clear potential for this therapy to have an infrequent dosing schedule, and we look forward to exploring this further in clinical trials.”
Vico Therapeutics plans to discuss the future of the VO659 programme with regulators later this year.
VO659 has received orphan drug designation from both the US Food and Drug Administration and the European Medicines Agency to treat Huntington’s disease,
In April 2023, Vico Therapeutics dosed the first patient in a Phase l/lla trial of VO659 to treat the disease.