Agenus mounts a comeback on positive results for its brain cancer vaccine

The cancer immunotherapy biotech Agenus ($AGEN) has continued its march back from a big R&D setback earlier in the year, seeing its share price spike 36% this morning after posting positive results for a single-arm Phase II study of one of its brain cancer vaccines.

About 90% of the 41 patients suffering from recurring glioblastoma multiforme were alive after 6 months of treatment with Prophage Series G-200, a personalized therapy. And while that figure for survivors plunges to 30% at 12 months, the biotech touted historical data indicating that the overall median survival time for patients was three to 9 months compared to the 11 months tracked in the mid-stage trial.

Single-arm studies are often criticized as inexact, not offering the kind of apples-to-apples comparison that investors and regulators like to see. But Agenus has been making headway with outside observers despite its single-arm designs, in this case touting results for a cancer vaccine that is given a personalized "antigenic fingerprint" after a tumor is surgically removed.

Agenus had been hit hard when GlaxoSmithKline's ($GSK) MAGE-A3 program suffered a failure for its first late-stage trial. Its shares were hammered as investors fled at signs of trouble for the therapy, which uses an adjuvant "booster" from the Lexington, MA-based biotech. Cancer vaccines in general have endured a number of setbacks over the past year. Just last week ImmunoCellular Therapeutics ($IMUC) put out the word that its dendritic cell-based vaccine for brain cancer flunked the key overall survival test in Phase II, news that swiftly wiped out more than half of the small biotech's market cap.

But in recent months Agenus has posted positive results for its G-100 series cancer vaccine--both use the heat shock protein gp96--as well as HerpV, a therapeutic vaccine for herpes simplex virus-2. 

"The next phase of development is underway with an NCI funded, large-scale, randomized trial investigating Prophage Series G-200 in combination with Avastin (bevacizumab)," says Andrew Parsa, chair of neurological surgery at Northwestern Memorial Hospital, in a statement. "Avastin is approved for the treatment of recurrent GBM and we believe there is the potential for a synergistic effect of a targeted anti-tumor immunotherapy and anti-angiogenic agent that could benefit patients."

- here's the press release