Emergent announces results of adjuvanted BioThrax anthrax vaccine Phase 1a trial

Emergent BioSolutions Inc. (NYSE:EBS) announced today that results from a Phase 1a clinical trial evaluating an investigational anthrax vaccine, Anthrax Vaccine Adsorbed with CPG 7909 Adjuvant mixed at bedside, have been published in Vaccine, a leading medical journal on vaccines and immunology.

In the study, which enrolled 69 subjects, the addition of the CPG 7909 adjuvant to BioThrax^® (Anthrax Vaccine Adsorbed), the only FDA-licensed anthrax vaccine, accelerated and enhanced the immune response to the vaccine in healthy volunteers. Trial subjects received three doses of either: (1) BioThrax alone, (2) 1 mg of CPG 7909 alone or (3) BioThrax plus 1 mg of CPG 7909, all given intramuscularly on study days 0, 14, and 28. Data from the trial show that BioThrax plus CPG 7909 generated peak antibody responses that were 6-fold higher than those generated by BioThrax alone (232 μg/ml with BioThrax alone; 1465 μg/ml with BioThrax plus CPG 7909). BioThrax plus CPG 7909 also accelerated the time to reach the peak immune response seen following BioThrax vaccination by three weeks. Both of these findings were statistically significant (P<0.001). Early immune responses are important due to the rapid disease progression of anthrax.

The paper, "Marked enhancement of the immune response to BioThrax by the TLR9 agonist CPG 7909 in healthy volunteers," appears in the August 26 edition of Vaccine.

Emergent has also completed dosing of the last subject in its ongoing Phase 1b clinical trial to evaluate the safety, tolerability, and immunogenicity of different formulations of BioThrax pre-formulated with a novel immunostimulatory oligodeoxynucleotide compound, CPG 7909, also known as AV7909 or NuThrax^TM (Anthrax Vaccine Adsorbed with CPG 7909 Adjuvant). The study, which was initiated in December 2010, involves 105 healthy volunteers. The company anticipates preliminary data to be available as early as Q3 2011.

"Emergent is pleased to share this information related to our anthrax vaccine development program," said Daniel J. Abdun-Nabi, president and chief operating officer of Emergent BioSolutions. "The Phase 1a data on BioThrax plus CPG 7909 add support to our hypothesis that the combination could have enhanced characteristics over BioThrax alone. Such characteristics could increase the attractiveness of this product candidate to potentially support the U.S. government's multi-product strategy in stockpiling medical countermeasures."