Source: Agenus

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Amid an industrywide sell-off, shares in the biotech company Agenus (NASDAQ:AGEN) jumped by 10% on the open today after the company announced that positive data from a key trial was reported in the New England Journal of Medicine. Shares have since given back gains and are trading up slightly on the day.

So What: Agenus's QS-21 Stimulon is being used by GlaxoSmithKline (NYSE:GSK) to boost the efficacy on a slate of clinical stage vaccines, including a vaccine for the treatment of shingles.

Today, results from GlaxoSmithKline's phase 3 study of this vaccine show that it protects 98% of people age 70 or older and 97% of people over age 50. Overall, more than 16,000 people were studied in the trial.

According to Agenus, the vast majority of adults over age 50 are at risk of reactivating the virus responsible for causing shingles and its painful symptoms.

Now What: This marks the second apparent success for Agenus's QS-21 Stimulon. A previous phase 3 study of GlaxoSmithKline's malaria vaccine, which also uses QS-21 Stimulon, serves as the basis for a pending FDA application for approval. If that malaria vaccine is approved, Agenus will receive a milestone payment and single digit royalties on sales. Similarly, Agenus stands to receive single digit royalties on any eventual sales of this shingles vaccine, too.

Agenus's vaccine program could begin to generate much needed cash that it can use to usher along research into immuno-oncology drugs.

Earlier this year, Incyte Corp paid Agenus $25 million up front in cash and another $35 million for an equity stake in the company to partner with it on immuno-oncology research. That research is in the early stages, so there's considerable risk attached to it.

Instead, investors are best served focusing on the near term opportunity in vaccines. The company expects to release data from another trial studying a brain cancer vaccine later this year that could lead to a phase 3 trial.

Overall, Agenus is an intriguing, but high-risk company. As a result, it's best suited for risk tolerant investors, at least until royalty income begins to kick-in from GlaxoSmithKline.