New trial results from Australian company Apollo Life Sciences point the way to the possibility that vaccine injections may soon be a thing of the past
Australian bio-discovery company Apollo Life Sciences has released results of preliminary trials of its needle-free vaccine technology, which delivers tetanus vaccine through the skin without the need for an injection. The technology could spell the end of injections for tetanus, flu and many other vaccines.
The trials showed that tetanus toxoid delivered by topical application to the skin using Apollo's formulation technology was more effective at generating an antibody response than injection of tetanus toxoid.
The technology has a second major application as a platform for transdermal delivery of a topical tumour necrosis factor (TNF) blocker, says Apollo ceo John Priest.
"We believe our technology will make a big difference, and so we have fast tracked its development. Both applications have the potential to reduce dramatically the cost of drugs currently delivered in other ways, including infusions and injections," says Priest. Many of the standard vaccines used to protect against childhood diseases, such as diphtheria and whooping cough as well as for global epidemics such as bird flu, are usually injected.
Apollo's topical vaccinations would potentially transform life for patients dependent on injectables by removing the pain and fear of standard vaccinations, says Priest.
"Topical vaccines could save health systems substantial amounts of money. This approach will avoid needle-stick injuries and can be delivered conveniently and easily without medical intervention. Topical vaccines are also easier and quicker to deploy and cheaper and easier to store than conventional injectable vaccines," he adds.
The current market for vaccines is worth approximately US$9bn globally with a 10-12% annual growth rate.
The company's preclinical studies compared the effectiveness of tetanus toxoid (TT) vaccinations, administered topically to pre-shaved abdominal skin using Apollo's topical formulation or injected into the quadricep muscle (IM) of mice, in generating immunity.
In these studies, three groups of 10 mice were administered either tetanus toxoid in Apollo's topical formulation, or TT via IM injection, or transdermal formulation alone.
Three vaccinations were administered at 14-day intervals. Blood samples were then taken 14 days post-vaccination and the serum from each animal assayed for total TT-specific IgG antibody by indirect enzyme linked immunosorbent assay (ELISA).
Delayed type hypersensitivity was measured for each group by measurement of footpad swelling 48 and 72 hours following injection of TT in saline into the right footpad and saline alone into the left footpad. These models are commonly used in assessing vaccination effectiveness.
The data showed that topical vaccination with tetanus toxoid induced a higher level of antibody response than injection of tetanus alone and that
topical vaccination induced an equivalent antibody response to injection of tetanus with adjuvant.
The results indicate that topical vaccination gives a better antibody response than injection of tetanus toxoid and consistently generated high antibody levels. The resulting high level of immunity was verified by the robust delayed-type hypersensitivity responses.
"The early tests show great promise for vaccination without needles," says Dr Greg Russell-Jones, Apollo's science director.
"Our initial pre-clinical studies show a high level of immune response in mice vaccinated intradermally with tetanus toxoid using our transdermal technology. This delivery method aims to stimulate the immune cells resident in the skin directly. In contrast, vaccination using traditional hypodermic syringes bypasses the very cells that can produce the best immune response.
'Apollo will continue with animal trials to optimise the formulation for tetanus vaccination to begin clinical human trials late this year,' says Dr Russell-Jones.
These studies follow the success of Apollo's earlier animal trials showing its transdermal delivery system is effective at delivering antibodies and soluble receptors through the skin to reduce inflammation.
'We are broadening the transdermal formulation technology from anti-inflammatory molecules to the more universal market of vaccines. The tetanus vaccination results represent an extension of our transdermal delivery platform,' says Priest.
'These successful initial studies pave the way for using our transdermal technology with many currently injected vaccines. In other words, vaccines that today have to be injected will be able to be rubbed on, in the future."
The company's non-invasive transdermal carrier is based on a proprietary formulation that is able to deliver large water-soluble proteins across the skin into the surrounding dermal and hypo-dermal layers. It can deliver a wide range of molecules in terms of size and water or oil solubility.
Drugs up to antibody-size have been identified as potential candidates for the technology, including leading biopharmaceuticals that have previously been considered unsuitable for transdermal delivery. The transdermal technology opens up the possibility of treating a range of diseases with topical applications.
Many of the newer biotherapeutic drugs generally have to be injected but with these latest trial results, Apollo believes it is one step closer to its ultimate aim to transform the biotherapeutics marketplace by developing large molecule delivery platforms to enable treatments such as insulin in tablet form and oral and topically applied anti-inflammatories.