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Univ. Lab, Biotech Partner on Covid-19 Vaccine Implant

Robin Shattock

Robin Shattock (Imperial College London)

18 Dec. 2020. A biotechnology company and university infectious disease lab are developing a Covid-19 vaccine given as a solid dose implant under the skin. Enesi Pharma in Oxford, U.K. and immunologist Robin Shattock, professor of infectious diseases at Imperial College London, are adapting Enesi’s and Imperial College’s vaccine technologies as way to produce Covid-19 and other RNA-based vaccines without the need for deep-freezing or refrigeration in manufacturing and distribution.

Enesi Pharma is creating a vaccine-delivery technology called ImplaVax that implants tiny doses of vaccines, formulated as solids rather than liquids, a few millimeters under the skin. The company says its system, still deemed experimental and not yet authorized for humans, delivers vaccine doses in freeze-dried form, using smaller doses of active ingredients than when given in syringe injections. With ImplaVax, says Enesi, vaccines can be formulated for rapid delivery or longer timed release into a skin layer rich with dendritic cells that present antigens to T-cells in the immune system for a response.

The company says its preclinical tests show vaccines delivered with ImplaVax are at least as effective as vaccines given as conventional intramuscular injections or subcutaneous injections under the skin. And, says Enesi, pilot tests with human subjects indicate ImplaVax vaccines are pain-free and preferred by recipients to syringes. Because the vaccines are formulated as freeze-dried solids, they remain stable in room temperatures and do not need refrigeration.

Enesi Pharma and  Shattock’s lab at Imperial College are collaborating on developing RNA-based vaccines that remain stable at room temperatures, to avoid the need for deep-freezing and refrigeration. Those requirements are complicating manufacturing and distribution processes for early deliveries of Covid-19 vaccines, based on messenger RNA, made by Pfizer/BioNTech.

Shattock and colleagues are researching self-amplifying RNA as an alternative to messenger RNA for Covid-19 vaccines. Self-amplifying RNA is made from a single strand of nucleic acid derived from benign alphaviruses to trigger an immune reaction, and shown to to provide protection against infectious diseases, like messenger RNA, but with lower doses.

Shattock’s team demonstrated in lab mice a Covid-19 vaccine formulated with self-amplifying RNA, delivered in lipid nanoparticles, and is now testing the vaccine in early-stage clinical trial. The lab is also studying a process called Polyplex for stabilizing nucleic acids like RNA with bio-friendly charged polymer molecules. Science & Enterprise reported in June on Shattock’s efforts to develop a Covid-19 vaccine for lower-resource regions.

In early work, Enesi Pharma and Imperial College researchers report they found the merging of their ImplaVax and Polyplex technologies feasible. The researchers are now expanding on that work to produce self-amplifying RNA in an ImplaVax/Polyplex form.

Shattock notes in an Enesi Pharma statement that manufacturing, distribution, and administration challenges for RNA vaccines need immediate attention. “As we make good progress towards evaluating the efficacy of our vaccine,” says Shattock, “it is critical that in parallel we explore ways to potentially address those challenges, particularly in terms of minimizing and ideally eliminating cold chain supply and the use of needle and syringes, which could be an important barrier to rapid deployment of vaccination efforts globally.”

David Hipkiss, Enesi Pharma’s CEO adds, “We believe that our ImplaVax technology may hold the key to solving these issues and we have already established in-vivo proof of concept with multiple vaccine formats currently being used and in development for a wide range of infectious diseases, including those being used for Covid-19.”

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Disclosure: the author owns shares in Pfizer.

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