Development of stabilizing formulations of a trivalent inactivated poliovirus vaccine in a dried state for delivery in the Nanopatch™ microprojection array

The worldwide switch to inactivated polio vaccines (IPV) is a key component of the overall strategy to achieve and maintain global polio eradication. To this end, new IPV vaccine delivery systems may enhance patient convenience and compliance. In this work, we examine NanopatchTM (a solid, polymer micro-projection array) which offers potential advantages over standard needle/syringe administration including intradermal delivery and reduced antigen doses. Using trivalent IPV (tIPV) and a purpose-built evaporative dry-down system, candidate tIPV formulations were developed to stabilize tIPV during the drying process and upon storage. Identifying conditions to minimize tIPV potency losses during rehydration and potency testing was a critical first step. Various classes and types of pharmaceutical excipients (~50 total) were then evaluated to mitigate potency losses (measured through D-antigen ELISAs for IPV1, IPV2, and IPV3) during drying and storage. Various concentrations and combinations of stabilizing additives were optimized in terms of tIPV potency retention, and two candidate tIPV formulations containing a cyclodextrin and a reducing agent (e.g., glutathione), maintained ≥80% D-antigen potency during drying and subsequent storage for 4 weeks at 4˚C, and ≥60% potency for 3 weeks at room temperature with the majority of losses occurring within the first day of storage. References: * Wan, Y., et al. (in press), Development of Stabilizing Formulations of a Trivalent Inactivated Poliovirus Vaccine in a Dried State for Delivery in the Nanopatch™ Microprojection Array. Journal of Pharmaceutical Sciences. 2018. Acknowledgements: This work was funded by The World Health Organization

Safety, tolerability, and immunogenicity of influenza vaccination with a high-density microarray patch: Results from a randomized, controlled phase I clinical trial.

BACKGROUND: The Vaxxas high-density microarray patch (HD-MAP) consists of a high density of microprojections coated with vaccine for delivery into the skin. Microarray patches (MAPs) offer the possibility of improved vaccine thermostability as well as the potential to be safer, more acceptable, easier to use, and more cost-effective for the administration of vaccines than injection by needle and syringe (N&S). Here, we report a phase I trial using the Vaxxas HD-MAP to deliver a monovalent influenza vaccine that was to the best of our knowledge the first clinical trial to evaluate the safety, tolerability, and immunogenicity of lower doses of influenza vaccine delivered by MAPs. METHODS AND FINDINGS: HD-MAPs were coated with a monovalent, split inactivated influenza virus vaccine containing A/Singapore/GP1908/2015 H1N1 haemagglutinin (HA). Between February 2018 and March 2018, 60 healthy adults (age 18-35 years) in Melbourne, Australia were enrolled into part A of the study and vaccinated with either: HD-MAPs delivering 15 μg of A/Singapore/GP1908/2015 H1N1 HA antigen (A-Sing) to the volar forearm (FA); uncoated HD-MAPs; intramuscular (IM) injection of commercially available quadrivalent influenza vaccine (QIV) containing A/Singapore/GP1908/2015 H1N1 HA (15 μg/dose); or IM injection of H1N1 HA antigen (15 μg/dose). After 22 days' follow-up and assessment of the safety data, a further 150 healthy adults were enrolled and randomly assigned to 1 of 9 treatment groups. Participants (20 per group) were vaccinated with HD-MAPs delivering doses of 15, 10, 5, 2.5, or 0 μg of HA to the FA or 15 μg HA to the upper arm (UA), or IM injection of QIV. The primary objectives of the study were safety and tolerability. Secondary objectives were to assess the immunogenicity of the influenza vaccine delivered by HD-MAP. Primary and secondary objectives were assessed for up to 60 days post-vaccination. Clinical staff and participants were blind as to which HD-MAP treatment was administered and to administration of IM-QIV-15 or IM-A/Sing-15. All laboratory investigators were blind to treatment and participant allocation. Two further groups in part B (5 participants per group), not included in the main safety and immunological analysis, received HD-MAPs delivering 15 μg HA or uncoated HD-MAPs applied to the forearm. Biopsies were taken on days 1 and 4 for analysis of the cellular composition from the HD-MAP application sites. The vaccine coated onto HD-MAPs was antigenically stable when stored at 40°C for at least 12 months. HD-MAP vaccination was safe and well tolerated; any systemic or local adverse events (AEs) were mild or moderate. Observed systemic AEs were mostly headache or myalgia, and local AEs were application-site reactions, usually erythema. HD-MAP administration of 2.5 μg HA induced haemagglutination inhibition (HAI) and microneutralisation (MN) titres that were not significantly different to those induced by 15 μg HA injected IM (IM-QIV-15). HD-MAP delivery resulted in enhanced humoral responses compared with IM injection with higher HAI geometric mean titres (GMTs) at day 8 in the MAP-UA-15 (GMT 242.5, 95% CI 133.2-441.5), MAP-FA-15 (GMT 218.6, 95% CI 111.9-427.0), and MAP-FA-10 (GMT 437.1, 95% CI 254.3-751.3) groups compared with IM-QIV-15 (GMT 82.8, 95% CI 42.4-161.8), p = 0.02, p = 0.04, p < 0.001 for MAP-UA-15, MAP-FA-15, and MAP-FA-10, respectively. Higher titres were also observed at day 22 in the MAP-FA-10 (GMT 485.0, 95% CI 301.5-780.2, p = 0.001) and MAP-UA-15 (367.6, 95% CI 197.9-682.7, p = 0.02) groups compared with the IM-QIV-15 group (GMT 139.3, 95% CI 79.3-244.5). Results from a panel of exploratory immunoassays (antibody-dependent cellular cytotoxicity, CD4+ T-cell cytokine production, memory B cell (MBC) activation, and recognition of non-vaccine strains) indicated that, overall, Vaxxas HD-MAP delivery induced immune responses that were similar to, or higher than, those induced by IM injection of QIV. The small group sizes and use of a monovalent influenza vaccine were limitations of the study. CONCLUSIONS: Influenza vaccine coated onto the HD-MAP was stable stored at temperatures up to 40°C. Vaccination using the HD-MAP was safe and well tolerated and resulted in immune responses that were similar to or significantly enhanced compared with IM injection. Using the HD-MAP, a 2.5 μg dose (1/6 of the standard dose) induced HAI and MN titres similar to those induced by 15 μg HA injected IM. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR.org.au), trial ID 108 ACTRN12618000112268/U1111-1207-3550

Microarray patch delivery of un-adjuvanted influenza vaccine induces potent and broad-spectrum immune responses in a phase I clinical trial

Microarray patches (MAPs) offer the possibility of improved vaccine thermostability and dose-sparing potential as well as the potential to be safer, more acceptable, easier to use and more cost-effective for the administration of vaccines than injection by needle and syringe. Here, we report a phase I trial (ACTRN12618000112268/ U1111-1207-3550) using the Vaxxas high-density MAP (HD-MAP) to deliver a monovalent influenza vaccine to evaluate the safety, tolerability, and immunogenicity of lower doses of influenza vaccine delivered by MAPs. To the best of our knowledge, this is the first study determining dose reduction potential using MAPs in humans. Monovalent, split inactivated influenza virus vaccine containing A/Singapore/GP1908/ 2015 [H1N1] haemagglutinin (HA) was delivered by MAP into the volar forearm or upper arm, or given intramuscularly (IM) once. Participants (20 per group) received HD-MAPs delivering doses of 15, 10, 5, 2.5 or 0 µg of HA or an IM injection of quadrivalent influenza vaccine (QIV). In two subgroups, skin biopsies were taken on days 1 (pre-vaccination) and 4 for analysis of the cellular composition from the HD-MAP application sites. All laboratory investigators were blind to treatment and participant allocation. The primary objectives of the study were safety and tolerability. Secondary objectives included immunogenicity and dose de-escalation assessments of the influenza vaccine delivered by HD-MAP. Both objectives were assessed for up to 60 days post-vaccination. Please click Download on the upper right corner to see the full abstract

Role for human arylamine N-acetyltransferase 1 in the methionine salvage pathway

The Phase II drug metabolizing enzyme arylamine N-acetyltransferase 1 (NAT1) has been implicated in the growth and survival of cancer cells, although the mechanisms that underlies these effects are unknown. Here, a focused metabolomics approach was used to identify changes in folate catabolism as well as the S-adenosylmethionine (SAM) cycle following NAT1 knockdown with shRNA. Although acetylation of the folate catabolite p-aminobenzoylglutamate (pABG) was significantly decreased, there were no changes in intracellular pABG or the various components of the SAM cycle. By contrast, the flux of homocysteine in the medium was different following NAT1 knockdown after the methionine content was exhausted suggesting a need for this metabolite in methionine synthesis. Analysis of the growth of various cancer cells in methylthioadenosine-supplemented medium showed that NAT1 knockdown inhibited the methionine salvage pathway in HT-29 cells but not in HeLa or MDA-MB-436 cells. The cause of this was a low level of expression of the isomerase MRI-1 in the HT-29 cells. Knocking down both NAT1 and MRI-1 in HeLa cells with siRNA further demonstrated a redundancy between these 2 enzymes, although direct isomerase activity by NAT1 could not be demonstrated. The present study has identified a novel endogenous role for human NAT1 that might explain some of its effects in cancer cell growth and survival

Biochemical pathways for the interaction of folate metabolism and the <i>S</i>-adenosylmethionine (SAM) cycle.

<p>Dietary folate is metabolized to 5-methyltetrahydrofolate (5-MTHF), which is used by methionine synthase for the conversion of homocysteine to methionine. Methionine can also be synthesized from betaine, especially in liver tissue. Catabolism of the folates by cleavage of the C9-N10 bond produces <i>p</i>-aminobenzoylglutamate (PABG) and pterin (not shown). Murine Nat2 (and human NAT1) acetylates PABG to <i>N</i>-acetyl-PABG, which is a major folate metabolite found in the urine.</p

Tissue concentrations of SAM (A) and SAH (B) in male and female Nat2−/− C57BL/6J mice.

<p>Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations. Asterisk indicates significant difference compared to respective wild-type concentrations (p<0.05).</p

Liver and kidney concentrations of PABG (A) and <i>N</i>-acetyl-PABG (B) in C57BL/6J mice.

<p>(C) Relative NAT1 mRNA levels determined by qPCR. The open bars are male tissue samples while the solid bars are female tissue samples. Results are mean ± SEM, n = 3. Asterisk indicates significant difference compared to respective male concentrations (p<0.05).</p

Tissue concentrations of 5-MTHF (A), Hcy (B) and methionine (C) in male and female Nat2−/− C57BL/6J mice.

<p>Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations. Asterisk indicates significant difference compared to respective wild-type concentrations (p<0.05).</p

Liver and kidney concentrations of PABG in male and female Nat2−/− C57BL/6J mice.

<p>Results are mean ± SEM, n = 3, and are expressed as percentage of wild-type concentrations.</p