Over the last decade, adeno-associated virus (AAV) has emerged as a highly promising and attractive approach to gene therapy. AAV is a common, naturally occurring virus that has been shown to be a well-tolerated and effective gene therapy delivery vehicle in clinical trials. Advances in AAV vector design and related dosing techniques that enable widespread gene delivery in the brain and spinal cord have made AAV particularly well-suited for the treatment of neurological diseases. Since the targeted cells in the central nervous system (CNS) are long-lived, non-dividing neurons, treatments delivered in a single dose could generate long-lasting, or even lifelong, benefits. More than eight years of durable expression has been seen in the human brain following treatment with an AAV vector.
Importantly, improvements in related technology and approaches have made AAV production more easily scalable and efficient to meet clinical and commercial requirements. Voyager diligently selects and optimizes AAV vectors that are best suited for each program. We continue to invest to advance the science and technology around the three key elements of AAV vectors: capsid, promoter and transgene. We also systematically develop and optimize delivery techniques that are best suited for a particular disease.
Members of our team have co-discovered many of the known naturally occurring AAV capsids, which are the outer viral protein shells that enclose the target gene or micro RNA cassette, and have also created promising genetically engineered AAV capsids. We have efforts underway to genetically engineer capsids to yield vectors with desirable properties, such as enhanced tissue specificity and improved delivery of genes to the brain and spinal cord. Efforts are also underway at Voyager to optimize novel AAV capsids that demonstrate enhanced blood-brain barrier penetration for the potential treatment of CNS diseases following systemic administration of the AAV gene therapy vector.
We then design the vector genome, or payload, that we intend to deliver as a therapeutic, as in the case of our Friedreich’s ataxia program, or silence or knockdown, as in the case of our ALS and Huntington’s disease programs.
Identifying the optimal route of administration and delivery parameters, such as infusion volume, flow rate, vector concentration and dose and formulation for a specific disease are critical to achieving safe and effective levels of gene expression in the targeted region of the CNS. For Voyager’s current pipeline programs, we are pursuing a surgical approach for direct injection into a targeted region of the brain, coupled with real-time MRI in the case of our advanced Parkinson’s disease and Huntington’s disease programs, or injection into the cerebrospinal fluid for broader delivery to the cells within and surrounding the spinal cord for our ALS and Friedreich’s ataxia programs.
Led by pioneers in AAV gene therapy and neuroscience, we are deeply committed to developing gene therapies for severe neurological diseases that have the potential to positively impact the lives of people living with these diseases. For more information about how we engage with patients and the advocacy community, please visit our patients and caregivers page.