Anthrax Contract Better Positions Pfenex In Biodefense
This article was originally published in Scrip
An anthrax vaccine contract with the US federal government, which eventually could be worth $143.5m, has better positioned Pfenex in the lucrative biodefense arena with other players, like Emergent Biosolutions.
The contract the San Diego-based biotech snagged is from the Biomedical Advanced Research and Development Authority (BARDA), part of the US Department of Health and Human Services, under which Pfenex is set to receive an initial $15.9m over 30 months to study its mutant recombinant protective antigen anthrax vaccine, known as Px563L, in a small number of healthy human volunteers.
Shares of Pfenex climbed nearly 15% on Aug. 17 on news of the BARDA contract, before closing at $21.04, up 8.7%, or $1.69.
A big share of Pfenex's business actually is focused on developing its lead product, PF582, a biosimilar of the eye disease drug Lucentis (ranibizumab), which sold by Roche and its US unit Genentech.
Pfenex's pipeline also includes the pursuit of other biosimilars, generic drugs, next-generation biologics and other vaccines, including one to protect against malaria, known as Px533.
The company insisted its technology platform allows it to develop and produce vaccines faster, in larger quantities and of a higher quality than other pharmaceutical developers.
The BARDA contract, said Pfenex CEO Bertrand Liang, offers the potential for a "dramatic improvement in the rapid production of large amounts of a high-value stable recombinant anthrax vaccine for the U.S. government."
Currently, the only FDA-licensed anthrax vaccine, Emergent's BioThrax, is available for pre-exposure protection.
But Robin Robinson, BARDA's director, said his agency's goal is to have an anthrax vaccine that could be given post-exposure that could provide protection "as quickly as possible to save lives."
The agency has been pursuing next-generation recombinant vaccines that target the anthrax cell-binding protein, or protective antigen, which stimulates an immune response.
Vaccines using a purified recombinant form of protective antigen have the potential to reduce both the number of doses needed for the vaccine and the costs associated with manufacturing each dose, which could result in significant cost savings over time, BARDA said.
BARDA noted that in nonclinical studies, Pfenex's vaccine was effective after two doses administered 28 days apart post-exposure.
If that finding is replicated in humans, protection could occur with fewer doses than BioThrax, which requires three doses administered over four weeks.
To use BioThrax for post-exposure prophylaxis, however, the FDA must issue an emergency use authorization.
BARDA's Robinson told Scrip in an email response to questions that if successful, Pfenex's anthrax vaccine could be eligible for purchase under the US government's Project BioShield for the Strategic National Stockpile – a cache of medical products intended for large-scale emergencies – but would supplement, not replace BioThrax.
Pfenex's BARDA contract could be extended to five years – bringing the total worth to $143.5m – under which the company would conduct additional clinical trials to determine how well the vaccine stimulates the human immune system and the minimum number of doses required to achieve the desired immune response.