Background Microneedle patches provide an alternative to conventional needle-and-syringe immunization, and potentially offer improved immunogenicity, simplicity, cost-effectiveness, acceptability and safety. We describe safety, immunogenicity and acceptability of the first-in-human study on single, dissolvable microneedle patch vaccination against influenza. Methods The TIV-MNP 2015 study was a phase 1, partially blinded, placebo-controlled, randomized clinical trial conducted at Emory University that enrolled non-pregnant, immunocompetent adults (age 18–49 years) from Atlanta (USA) and naïve to 2014–2015 influenza vaccine. Participants were equally randomized among four groups and received a single dose of inactivated influenza vaccine 1) by microneedle patch or 2) by intramuscular injection, or received 3) placebo by microneedle patch, all administered by an unblinded healthcare worker; or received 4) inactivated influenza vaccine by microneedle patch self-administered by study participants. Primary safety outcomes were reactogenicity, grade 3 adverse events and serious adverse events within 8, 28 and 180 days and secondary safety outcomes were new-onset chronic illnesses within 180 days and unsolicited adverse events within 28 days all analyzed by intention to treat. Secondary immunogenicity outcomes were antibody titers at day 28 as well as seroconversion and seroprotection rates all determined by hemagglutination inhibition antibody. The trial is completed and registered with ClinicalTrials.gov, NCT02438423. Findings Twenty-five participants per group were enrolled between June 23 and September 25, 2015. There were no related serious adverse events, no related grade 3 or higher adverse events and no new-onset chronic illnesses. Overall incidence of solicited and unsolicited events was similar among vaccinated groups. Reactogenicity was mild, transient and most commonly reported as tenderness at 60% (95% CI, 39– 79%) and pain at 44% (95% CI, 24–65%) after intramuscular injection and tenderness at 66% (95% CI, 51–79%), erythema at 40% (95% CI, 26–55%) and pruritus at 82% (95% CI, 69–91%) after vaccination by microneedle patch application The geometric mean titers were comparable at day 28, between the microneedle patch administered by healthcare worker and the intramuscular route with values of 1197 (95% CI, 855– 1675) and 997 (95% CI, 703–1415) (p=0.5), respectively, for the H1N1 strain; 287 (95% CI, 192–430) and 223 (95% CI, 160–312) (p=0.4), respectively, for the H3N2 strain and 126 (95% CI, 86–184) and 94 (95% CI, 73–122) (p=0.06), respectively, for the B strain. Similar GMT titers were observed in participants who self-administered the microneedle patch. The seroconversion rates were significantly higher at day 28 after microneedle patch vaccination compared to placebo and were comparable to intramuscular injection. Interpretation Use of dissolvable microneedle patches for influenza vaccination was well-tolerated and generated robust antibody responses. Funding National Institutes of Health.

To support translation of microneedle patches from pre-clinical development into clinical trials, this study examined the effect of microneedle patch application on local skin reactions, reliability of use and acceptability to patients. Placebo patches containing dissolving microneedles were administered to fifteen human participants. Microneedle patches were well tolerated in the skin with no pain or swelling and only mild erythema localized to the site of patch administration that resolved fully within seven days. Microneedle patches could be administered by hand without the need of an applicator and delivery efficiencies were similar for investigator-administration and self-administration. Microneedle patch administration was not considered painful and the large majority of subjects were somewhat or fully confident that they self-administered patches correctly. Microneedle patches were overwhelmingly preferred over conventional needle and syringe injection. Altogether, these results demonstrate that dissolving microneedle patches were well tolerated, easily usable and strongly accepted by human subjects, which will facilitate further clinical translation of this technology.

Prevention of seasonal influenza epidemics and pandemics relies on widespread vaccination coverage to induce protective immunity. In addition to a good antigenic match with the circulating viruses, the effectiveness of individual strains represented in the trivalent vaccines depends on their immunogenicity. In this study we evaluated the immunogenicity of H1N1, H3N2 and B seasonal influenza virus vaccine strains delivered individually with a novel dissolving microneedle patch and the stability of this formulation during storage at 25°C. Our data demonstrate that all strains retained their antigenic activity after incorporation in the dissolving patches as measured by SRID assay and immune responses to vaccination in BALB/c mice. After a single immunization all three antigens delivered with microneedle patches induced superior neutralizing antibody titers compared to intramuscular immunization. Cutaneous antigen delivery was especially beneficial for the less immunogenic B strain. Mice immunized with dissolving microneedle patches encapsulating influenza A/Brisbane/59/07 (H1N1) vaccine were fully protected against lethal challenge by homologous mouse-adapted influenza virus. All vaccine components retained activity during storage at room temperature for at least three months as measured in vitro by SRID assay and in vivo by mouse immunization studies. Our data demonstrate that dissolving microneedle patches are a promising advance for influenza cutaneous vaccination due to improved immune responses using less immunogenic influenza antigens and enhanced stability.

The biodegradable microneedle patch (MNP) is a novel technology for vaccine delivery that could improve the immunogenicity of vaccines. To broaden the protective efficiency of conventional influenza vaccines, a new 4M2e-tFliC fusion protein construct containing M2e sequences from different subtypes was generated. Purified fusion protein was encapsulated into MNPs with a biocompatible polymer for use as a boosting vaccine. The results demonstrated that mice receiving a conventional inactivated vaccine followed by a skin-applied dissolving 4M2e-tFliC MNP boost could better maintain the humoral antibody response than that by the conventional vaccine-prime alone. Compared with an intramuscular injection boost, mice receiving the MNP boost showed significantly enhanced cellular immune responses, hemagglutination-inhibition (HAI) titers, and neutralization titers. Increased frequency of antigen-specific plasma cells and long-lived bone marrow plasma cells was detected in the MNP boosted group as well, indicating that skin vaccination with 4M2e-tFliC facilitated a long-term antibody-mediated immunity. The 4M2e-tFliC MNP-boosted group also possessed enhanced protection against high lethal dose challenges against homologous A/PR/8/34 and A/Aichi/2/68 viruses and protection for a majority of immunized mice against a heterologous A/California/07/2009 H1N1 virus. High levels of M2e specific immune responses were observed in the 4M2e-tFliC MNP-boosted group as well. These results demonstrate that a skin-applied 4M2e-tFliC MNP boosting immunization to seasonal vaccine recipients may be a rapid approach for increasing the protective efficacy of seasonal vaccines in response to a significant drift seen in circulating viruses. The results also provide a new perspective for future exploration of universal influenza vaccines.

We recently reported a lack of interference between inactivated rotavirus vaccine (IRV) and inactivated poliovirus vaccine (IPV) and their potential dose sparing when the two vaccines were administered intramuscularly either in combination or standalone in rats and guinea pigs. In the present study, we optimized the formulations of both vaccines and investigated the feasibility of manufacturing a combined IRV-IPV dissolving microneedle patch (dMNP), assessing its compatibility and immunogenicity in rats. Our results showed that IRV delivered by dMNP alone or in combination with IPV induced similar levels of RV-specific IgG and neutralizing antibody. Likewise, IPV delivered by dMNP alone or in combination with IRV induced comparable levels of neutralizing antibody of poliovirus types 1, 2, and 3. We further demonstrated high stability of IRV-dMNP at 5, 25, and 40 °C and IPV-dMNP at 5 and 25 °C, and found that three doses of IRV or IPV when co-administered at a quarter dose was as potent as a full target dose in inducing neutralizing antibodies against corresponding rotavirus or poliovirus. We conclude that IRV-IPV dMNP did not interfere with each other in triggering an immunologic response and were highly immunogenic in rats. Our findings support the further development of this innovative approach to deliver a novel combination vaccine against rotavirus and poliovirus in children throughout the world.