PHA-Exch> Inhaled TB vaccine under development

[Claudio Schuftan]

From: Trang Nguyen nqtrang.hanoi at gmail.com


http://www.hsph.harvard.edu/news/press-releases/2008-releases/inhaled-tuberculosis-vaccine-in-experimental-animals.html?tr=y&auid=3503848
 Press Release Inhaled Tuberculosis Vaccine More Effective than Traditional
Shot in Study Using Experimental Animals

*For Immediate Release: March 12, 2008*

Boston, MA -- A novel aerosol version of the most common tuberculosis (TB)
vaccine, administered directly to the lungs as an oral mist, offers
significantly better protection against the disease in experimental animals
than a comparable dose of the traditional injected vaccine, researchers
report this week in the *Proceedings of the National Academy of Sciences*.

The aerosol vaccine -- under development through a collaboration between
Harvard University and the international not-for-profit Medicine in Need
(MEND) -- could provide a low-cost, needle-free TB treatment that is highly
stable at room temperature.

"Rising rates of tuberculosis and drug-resistant disease in developing
countries have amply illustrated the need for more effective vaccines," says
David Edwards, the Gordon McKay Professor of the Practice of Biomedical
Engineering in Harvard's School of Engineering and Applied Sciences. "While
most new TB vaccines continue to call for needle injection, our vaccine
could provide safer, more consistent protection by eliminating these
injections and the need for refrigerated storage. We see great promise for
this new treatment."

Says Barry R. Bloom, Dean of the Harvard School of Public Health:
"Tuberculosis is one of the most resistant and challenging diseases to
protect against, and the successful results of aerosol delivery using
nanoparticle technology offers a potentially new platform for immunization.
Were the animal results here confirmed in human studies, this technology
could be used not only for TB vaccines, but those protecting against other
infectious diseases as well."

The current *PNAS* paper by Edwards, Bloom, and colleagues at the University
of North Carolina-Chapel Hill, the Aeras Global TB Vaccine Foundation, MEND
South Africa, the Harvard School of Public Health and School of Engineering
and Applied Sciences, and Manta is based on studies involving guinea pigs, a
species of rodent highly sensitive to TB.

Among guinea pigs vaccinated with the aerosol treatment and subsequently
exposed to TB, less than 1 percent of lung and spleen tissue showed effects
of the disease. By contrast, in animals treated with the same dose of the
traditional injected vaccine, some 5 percent of lung tissue and 10 percent
of spleen tissue showed symptoms following TB exposure.

Administered to 100 million infants annually, the current Bacillus
Calmette-Guérin (BCG) vaccine for TB is the world's most widely administered
childhood vaccine. Dried into a powder by freezing and delivered by needle
injection, the vaccine requires refrigerated storage and has shown variable
degrees of protection against tuberculosis in different parts of the world.
These limitations have prompted calls from public health experts and
physicians for alternative treatments.

The rapid-drying process by which the aerosol vaccine is made resembles the
technique used in the manufacture of powdered milk. In the aerosol vaccine,
particles form at micrometer and nanometer scales and in spherical and
elongated shapes, a combination that appears to improve dispersal in the
mouth.

While commonly used with food, cosmetics, and pharmaceuticals, this spray
drying of small and large molecules is seldom used for drying cellular
material. The new technique enables TB vaccines, and potentially other
bacterial and viral-based vaccines, to sidestep the traditional problems
associated with keeping vaccines chilled.

"Spray drying is lower-cost than BCG, easily scalable for manufacturing, and
ideal for needle-free use, such as via inhalation," says Edwards, an
international leader in aerosol drug and vaccine delivery. "Its greater
stability at room temperature could ultimately provide a better means of
creating and delivering vaccine throughout the world."

Edwards and Bloom's co-authors are Anthony Hickey, Lucila Garcia-Contreras,
Pavan Muttil, and Danielle Padilla, all of UNC-Chapel Hill; Yun-Ling Wong,
Jessica DeRousse, and Katharina Elbert of Harvard's School of Engineering
and Applied Sciences; Jerry Sadoff of the Aeras Global TB Vaccine
Foundation; Willem Andreas Germishuizen and Bernard Fourie of MEND South
Africa; Sunali Goonesekera of the Harvard School of Public Health; and Rich
Miller of Manta. The research was supported by a Grand Challenge Grant from
the Bill and Melinda Gates Foundation.
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