Agenus' ($AGEN) vaccine for a deadly form of brain cancer helped extend patients' lives in a single-arm study, the company said, news that sent its shares up as much as 20% on hopes it can find a partner to help it into Phase III.
In the Phase II study, which had no control arm, adding Agenus' Prophage vaccine to the standard of care led to a median overall survival of about 24 months in patients with newly diagnosed glioblastoma multiforme (GBM), the company said, and half of the study's 46 participants survived for two years. Citing historical data for comparison, Agenus said standard of care alone leads to a median OS of 14.6 months with only 26% of patients making it to the two-year mark.
Single-arm studies are generally perceived as limited in their implications and tend not to move the needle much with investors and regulators. But principal investigator Andrew Parsa said Agenus' mid-stage data demonstrate Prophage's potential in GBM, setting the stage for a randomized Phase III trial to confirm the promise.
For that, Agenus will need a partner, CEO Garo Armen said, and the biotech has already crafted a sales pitch: In its statement on the Phase II data, Agenus disclosed that patient response to Prophage seemed particularly pronounced in those with under-expressed PDL-1 proteins, suggesting the vaccine could be an ideal complement to the much-hyped PD-1 immunotherapies under development by Merck ($MRK), Bristol-Myers Squibb ($BMY), Roche ($RHHBY) and others.
"We believe that Prophage may play an important role in changing the treatment paradigm for patients with GBM," Armen said in a statement.
The optimism around Prophage is welcome news for Agenus, which has endured peaks and valleys on Wall Street amid concerns over the efficacy of cancer vaccines on the whole. Clinical uncertainties for ImmunoCellular Therapeutics ($IMUC), Northwest Biotherapeutics ($NWBO) and Agenus partner GlaxoSmithKline ($GSK) have cast a pall over the field, and the commercial failure of Dendreon's ($DNDN) similar Provenge hasn't helped on the public perception front.
Agenus' vaccine is an individualized therapy derived from a patient's own resected tumor tissue. Each injection contains what the company calls an "antigenic fingerprint," precise signals that steer the immune system to attack only a patient's cancer cells.
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