Voyager CEO Al Sandrock outlines a focused strategy: remain specialists in neurology, but broaden the therapeutic modalities (gene therapy, proteins, oligonucleotides). This allows them to pursue well-validated CNS targets that are considered "undruggable" by traditional small molecules, which have historically been the only option for crossing the blood-brain barrier.

To treat Chronic Hepatitis B, nChroma uses epigenetic editing to silence viral DNA rather than cutting it. They argue this is an inherently safer approach, as it avoids the risk of chromosomal damage from making multiple DNA cuts needed to disable the virus's various reservoir forms in liver cells.

Recognizing that severe myotonic dystrophy involves CNS impairment, Arthex deliberately invested in a lipid conjugation delivery system for its RNA therapeutic. This strategic choice was made specifically to cross the blood-brain barrier, enabling the treatment of both muscular and neurological symptoms of the disease.

The next breakthrough in RNA therapeutics won't come from a single innovation. It requires combining two key elements: a 'programmable' mRNA payload designed to be active only in specific cells, and a targeted delivery system to get it there. This two-part solution represents the next generation of in-vivo therapies.

In the race to treat Friedreich's Ataxia, the choice of viral vector is a key competitive differentiator. While most use AAVs, some companies use HSV vectors for larger payload capacity or engineered AAV capsids to cross the blood-brain barrier. This highlights that the delivery system's innovation is as critical as the therapeutic gene itself.

Recognizing that eye diseases are multifactorial, the company's research team is developing bisistronic vectors. This approach packages two different transgenes into a single AAV vector, allowing a single gene therapy product to address multiple disease pathways simultaneously, a significant advancement over single-target therapies.

Unlike broad delivery systems like LNPs, Sana's Fusagen technology uses a modified viral component as a "logic gate." It is engineered to bind to a specific cell target, which then triggers a conformational change that fuses the payload directly into the cell's cytoplasm. This two-step mechanism aims for higher specificity and lasting effect.

While focused on oncology, Yosemite's portfolio company Tune Therapeutics is using epigenetic editing to develop a functional cure for Hepatitis B. This is a strategic cancer play, as chronic Hepatitis B is the leading global cause of liver cancer.

Voyager CEO Al Sandrock explains their AAV capsids are engineered to be so potent at crossing the blood-brain barrier that doses can be an order of magnitude lower than standard. Crucially, the capsids are also designed to *avoid* the liver, directly addressing the toxicity issues that have plagued the field.