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Patch Delivers Low-Dose Vaccine with Full-Dose Power

Influenza virus
3-D representation of generic influenza virus (CDC.gov)

17 Mar. 2020. (Updated, 18 Mar. 2020) A clinical trial shows a polymer patch with one-sixth of the usual influenza vaccine dose generates about the same immune reaction as a full-dose injection. In addition, Vaxxas Pty Ltd, developer of the device, is receiving a $5 million award from the Bill and Melinda Gates Foundation for clinical studies of a patch to deliver a measles and rubella vaccine.

Vaxxas, in Brisbane, Australia, creates vaccination patches for infectious diseases as an alternative to conventional injections. The company’s high-density microarray patch for influenza is a polymer wafer about 10 millimeters square with some 3,100 microscale needles applied to the arm for a few seconds. The company says the patch is easier to use and can overcome fear and pain of injections, and also be stored and shipped without refrigeration, a limiting requirement for conventional vaccines.

The early-stage clinical trial tested the patch primarily for safety and tolerability, but also for its ability to generate immune reactions in participants. The study team first enrolled 60 healthy adults, age 18 to 35, in Melbourne, Australia, randomly assigned to receive either the microarray patch with 15 micrograms of an H1N1 influenza A antigen, an identical patch device without any vaccine, a standard intramuscular-injected four-strain influenza vaccine, or standard injection with 15 micrograms of H1N1 antigen.

After 22 days to review safety data, another group of 150 healthy adults were randomly assigned to receive patches with doses of 2.5 to 15 micrograms of H1N1 influenza A antigen, a patch with no vaccine, or an injected standard four-strain influenza vaccine. Results of the trial are published in today’s issue of the journal PLoS Medicine.

The researchers, led by Vaxxas chief development and operations officer Angus Forster, found the patch vaccinations generally safe and tolerable, with mild to moderate adverse reactions of headache, muscle pain, and skin irritations. Using a standard test of immune reactions, known as an hemagglutination inhibition assay, the researchers found the lowest dose of 2.5 micrograms of antigen on a microarray patch generated about the same level of antibody concentrations in participants as the full dose delivered by a standard syringe injection with six times the antigen.

Also, the full dose of influenza vaccine on a microarray patch produced faster and higher antibody concentrations compared to standard influenza injections. And the antigens on microarray patches remained stable, even when stored for 12 months in temperatures of 40 degrees C, or 104 F.

Forster notes in a company statement released through BusinessWire that with vaccine patches “shown to be stable for up to a year at 40°C, we can offer a truly differentiated platform with a global reach, particularly into low and middle income countries or in emergency use and pandemic situations.”

Vaxxas announced as well it is receiving a grant of $AU 7.5 million, ($US 5 million) from the Bill and Melinda Gates Foundation to finance clinical studies of a high-density microneedle array patch, or HD-MAP, with a vaccine for measles and rubella, also known as German measles. The funds will be used as well to stabilize the active vaccine ingredients for storage and distribution at room temperature. The Gates Foundation earlier funded preclinical development of the patch.

The HD-MAP technology is shown with other formulations to keep vaccines stable and not need refrigeration, thus removing the need for cold-chain distribution, and reducing the cost and complexity of vaccine distribution. “Building upon the recent success of our HD-MAP in human clinical studies using influenza vaccine,” says Vaxxas CEO David Hoey in a company statement, “we are committed to advancing multiple clinical programs to further validate the significant benefits the HD-MAP can bring to a range of vaccines for major diseases, including polio, bacterial infections, and cancer.”

Updated, 18 Mar. 2020. Photo of Vaxxas patch system …

Nanopatch system
Vaccine patch system in use (Vaxxas Pty Ltd)

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