Oral influenza vaccine one step closer, says Vaxart
Chief of Infectious Diseases at the University of Rochester Medical Centre, John Treanor said at the 15th Annual World Vaccine Congress in Brussels last week that “a tablet vaccine for flu could significantly change the way we administer vaccines,” and in the event of a pandemic could be manufactured and distributed faster than injectables.
His words came as California-based biotech firm Vaxarta presented Phase I data showing that a dose of its tablet H1N1 influenva vaccine is as effective at preventing infection as any jab currently on the market.
Vaxarta's solid-dose product contains an adenovirus vector encoded with an avian influenza A hemagglutinin - a glycoprotein found on the surface of the influenza virus - and a TLR3 (toll-like receptor-3) ligand used as an adjuvant.
Company CEO Wouter Latour told in-Pharmatechnologist that: “Vaxart’s vaccines are delivered to the epithelium of the small intestine where they activate the local immune system of the gut, which in turn generates a broad local and systemic immune response."
Unlike injectable vaccines Vaxarta's product does not enter the bloodstream according to Latour, who explained that this prevents neutralisation by blood or muscle tissue-based immune cells.
“The active ingredient [is a hemagglutinin protein which] is produced in a highly characterized cell line under current Good Manufacturing Practices commonly utilised in US pharmaceutical manufacturing,” Tucker told us.
“The material is freeze dried to produce a dry powder suitable for blending with a proprietary mixture of inert excipients for tableting in industry-standard, high-throughput tableting machines.”
Pipeline, partnerships and Prokarium
According to the firm’s pipeline the firm is also tackling H5N1 (pre-pandemic influenza) with a vaccine also in Phase I trials, while oral vaccines for the herpes simplex virus and the Ebola virus are in the preclinical stage.
Latour would not discuss any specific partnering activities, but he said “it is clear the industry is following this area closely.”
We asked if Vaxart was alone in developing oral vaccines. “There is at least one other company working in this space,” he said, “but as far as we know, they are not focused on seasonal influenza (H1N1).”
Last year, Prokarium received a grant of £400,000 ($600,000) from the UK’s innovation agency, the Technology Strategy Board (TSB), to help develop its oral delivery platform and two candidates targeting typhoid and Cloristidium difficile – a cause of colitis in the elderly.
An intranasal influenza vaccine, FluMist, is already available and marketed by AstraZeneca subsidiary MedImmune. Despite initial problems with uptake due to requirements that it needs to be kept refrigerated complicating distribution and administration, as well as the vaccine having been plagued by manufacturing violations, MedImmune says it has delivered 75 million doses of FluMist since 2003.
UPDATE - This article was updated to include MedImmune's comments about the number of doses delivered of FluMist, as well as changed to clarify that FluMist needs to be kept in refrigerated, not frozen, conditions.