Genocea's genital herpes vaccine succeeds in PhII

There is no cure for genital herpes, but Genocea ($GNCA) is getting closer to marketing an immunotherapy that could control herpes symptoms. The Massachusetts-based company announced Wednesday that it met its goals in a Phase II study of its investigational GEN-003 vaccine.

The candidate consists of a protein and adjuvant, and works by targeting a T cell response against the HSV-2 virus. The study's aim was to find the best combination of the protein and adjuvant to reduce viral activity, measured in the viral shedding rate and the genital lesion rate.

The study put 310 herpes-infected patients into 7 groups, administering 6 different dosages as well as a placebo. Every dose of GEN-003 showed a statistically significant improvement in the viral shedding rate vs. baseline, and compared to placebo, every dose but the weakest of GEN-003 showed a statistically significant improvement in the viral shedding rate, the rate at which the virus, which lives in nerve cells, makes its way to the skin and physically sheds.

"We replicated results from the first trial and confirmed the antiviral effect of GEN-003, putting to rest any doubt that it's a viable product," Dr. Seth Hetherington, Genocea's chief medical officer, told FierceVaccines. "We found a dose that is better than the best dose from the first trial, which increases the value of the profile for this product."

Genocea CEO Chip Clark

The best performer was 60 µg per protein / 75 µg of Matrix-M2, which cut viral shedding by 55% after 28 days, compared with baseline. This is an improvement over results reported in a Phase I/IIa trial, which reported a 52% reduction in viral shedding at the same point.

"We made improvements in the manufacturing process and invested in preparing for Phase III," Hetherington said. Genocea is producing material that could be scaled up for commercialization, and will conduct a small bridging study to ensure that the current GEN-003 profile can be maintained on a large scale, he said.

The CDC estimates that in the U.S., one out of every 6 people aged 14 to 49 years has genital herpes. GEN-003 will not be a cure for herpes. It was developed as a therapy, CEO Chip Clark told FierceVaccines.

"What we know about the biology of the disease is that if you have viral shedding, you can have outbreaks and can transmit it to others. Showing we have this profound effect on viral shedding is crucial. We may show in later clinical trials that we can prevent transmission as well," Clark said.

- here's the announcement
- and FierceBiotech's take

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