Immune response and reactogenicity of an unadjuvanted intradermally delivered human papillomavirus vaccine using a first generation Nanopatch™ in rhesus macaques: An exploratory, pre-clinical feasibility assessment.

The human papillomavirus (HPV) 9-valent, recombinant vaccine (Gardasil™9) helps protect young adults (males and females) against anogenital cancers and genital warts caused by certain HPV genotypes (ref. Gardasil™9 insert). This vaccine is administered intramuscularly (IM). The aim of this study was to determine preclinically whether intradermal (ID) vaccination with an unadjuvanted 9-valent recombinant HPV vaccine using a first-generation ID delivery device, the Nanopatch™, could enhance vaccine immunogenicity compared with the traditional ID route (Mantoux technique). IM injection of HPV VLPs formulated with Merck & Co., Inc., Kenilworth, NJ, USA Alum Adjuvant (MAA) were included in the rhesus study for comparison. The Nanopatch™ prototype contains a high-density array comprised of 10,000 microprojections/cm2, each 250 µm long. It was hypothesized the higher density array with shallower ID delivery may be superior to the Mantoux technique. To test this hypothesis, HPV VLPs without adjuvant were coated on the Nanopatch™, stability of the Nanopatch™ with unadjuvanted HPV VLPs were evaluated under accelerated conditions, skin delivery was verified using radiolabelled VLPs or FluoSpheres®, and the immune response and skin site reaction with the Nanopatch™ was evaluated in rhesus macaques. The immune response induced by Nanopatch™ administration, measured as HPV-specific binding antibodies, was similar to that induced using the Mantoux technique. It was also observed that a lower dose of unadjuvanted HPV VLPs delivered with the first-generation Nanopatch™ and applicator or Mantoux technique resulted in an immune response that was significantly lower compared to a higher-dose of alum adjuvanted HPV VLPs delivered IM in rhesus macaques. The study also indicated unadjuvanted HPV VLPs could be delivered with the first-generation Nanopatch™ and applicator to the skin in 15 s with a transfer efficiency of approximately 20%. This study is the first demonstration of patch administration in non-human primates with a vaccine composed of HPV VLPs.

Nanopatch targeted delivery of both antigen and adjuvant to skin synergistically drives enhanced antibody responses.

Many vaccines make use of an adjuvant to achieve stronger immune responses. Alternatively, potent immune responses have also been generated by replacing the standard needle and syringe (which places vaccine into muscle) with devices that deliver vaccine antigen to the skin's abundant immune cell population. However it is not known if the co-delivery of antigen plus adjuvant directly to thousands of skin immune cells generates a synergistic improvement of immune responses. In this paper, we investigate this idea, by testing if Nanopatch delivery of vaccine - both the antigen and the adjuvant - enhances immunogenicity, compared to intramuscular injection. As a test-case, we selected a commercial influenza vaccine as the antigen (Fluvax 2008®) and the saponin Quil-A as the adjuvant. We found, after vaccinating mice, that anti-influenza IgG antibody and haemagglutinin inhibition assay titre response induced by the Nanopatch (with delivered dose of 6.5ng of vaccine and 1.4µg of Quil-A) were equivalent to that of the conventional intramuscular injection using needle and syringe (6000ng of vaccine injected without adjuvant). Furthermore, a similar level of antigen dose sparing (up to 900 fold) - with equivalent haemagglutinin inhibition assay titre responses - was also achieved by delivering both antigen and adjuvant (1.4µg of Quil-A) to skin (using Nanopatches) instead of muscle (intramuscular injection). Collectively, the unprecedented 900 fold antigen dose sparing demonstrates the synergistic improvement to vaccines by co-delivery of both antigen and adjuvant directly to skin immune cells. Successfully extending these findings to humans with a practical delivery device - like the Nanopatch - could have a huge impact on improving vaccines.

Improving the reach of vaccines to low-resource regions, with a needle-free vaccine delivery device and long-term thermostabilization.

Dry-coated microprojections can deliver vaccine to abundant antigen-presenting cells in the skin and induce efficient immune responses and the dry-coated vaccines are expected to be thermostable at elevated temperatures. In this paper, we show that we have dramatically improved our previously reported gas-jet drying coating method and greatly increased the delivery efficiency of coating from patch to skin to from 6.5% to 32.5%, by both varying the coating parameters and removing the patch edge. Combined with our previous dose sparing report of influenza vaccine delivery in a mouse model, the results show that we now achieve equivalent protective immune responses as intramuscular injection (with the needle and syringe), but with only 1/30th of the actual dose. We also show that influenza vaccine coated microprojection patches are stable for at least 6 months at 23°C, inducing comparable immunogenicity with freshly coated patches. The dry-coated microprojection patches thus have key and unique attributes in ultimately meeting the medical need in certain low-resource regions with low vaccine affordability and difficulty in maintaining "cold-chain" for vaccine storage and transport.

Skin vaccination against cervical cancer associated human papillomavirus with a novel micro-projection array in a mouse model.

BACKGROUND: Better delivery systems are needed for routinely used vaccines, to improve vaccine uptake. Many vaccines contain alum or alum based adjuvants. Here we investigate a novel dry-coated densely-packed micro-projection array skin patch (Nanopatch™) as an alternate delivery system to intramuscular injection for delivering an alum adjuvanted human papillomavirus (HPV) vaccine (Gardasil®) commonly used as a prophylactic vaccine against cervical cancer. METHODOLOGY/PRINCIPAL FINDINGS: Micro-projection arrays dry-coated with vaccine material (Gardasil®) delivered to C57BL/6 mouse ear skin released vaccine within 5 minutes. To assess vaccine immunogenicity, doses of corresponding to HPV-16 component of the vaccine between 0.43 ± 0.084 ng and 300 ± 120 ng (mean ± SD) were administered to mice at day 0 and day 14. A dose of 55 ± 6.0 ng delivered intracutaneously by micro-projection array was sufficient to produce a maximal virus neutralizing serum antibody response at day 28 post vaccination. Neutralizing antibody titres were sustained out to 16 weeks post vaccination, and, for comparable doses of vaccine, somewhat higher titres were observed with intracutaneous patch delivery than with intramuscular delivery with the needle and syringe at this time point. CONCLUSIONS/SIGNIFICANCE: Use of dry micro-projection arrays (Nanopatch™) has the potential to overcome the need for a vaccine cold chain for common vaccines currently delivered by needle and syringe, and to reduce risk of needle-stick injury and vaccine avoidance due to the fear of the needle especially among children.