Development of a Virosomal RSV Vaccine Containing 3D-PHAD® Adjuvant: Formulation, Composition, and Long-Term Stability.

PURPOSE: Characterization of virosomes, in late stage preclinical development as vaccines for Respiratory Syncytial Virus (RSV), with a membrane-incorporated synthetic monophosphoryl lipid A, 3D-PHAD® adjuvant. METHODS: Virosomes were initially formed by contacting a lipid film containing 3D-PHAD® with viral membranes solubilized with the short chain phospholipid DCPC, followed by dialysis, later by adding solubilized 3D-PHAD to viral membranes, or to preformed virosomes from DMSO. RESULTS: Virosomes formed from lipid films contained the membrane glycoproteins G and F, at similar F to G ratios but lower concentrations than in virus, and the added lipids, but only a fraction of the 3D-PHAD®. By single particle tracking (SPT), the virosome size distribution resembled that seen by cryo-electron microscopy, but dynamic light scattering showed much larger particles. These differences were caused by small virosome aggregates. Measured by SPT, virosomes were stable for 300 days. 3DPHAD ® incorporation in virosomes could be enhanced by providing the adjuvant from DCPC solubilized stock, but also by adding DMSO dissolved adjuvant to pre-formed virosomes. Virosomes with 0.1 mg/mg of 3D-PHAD®/viral protein from DMSO induced antibody titers similar to those by virosomes containing 0.2 mg/mg of DCPC-solubilized 3D-PHAD®. CONCLUSIONS: Stable 3D-PHAD® adjuvanted RSV virosomes can be formulated.

Establishment of a new quality control and vaccine safety test for influenza vaccines and adjuvants using gene expression profiling.

We have previously identified 17 biomarker genes which were upregulated by whole virion influenza vaccines, and reported that gene expression profiles of these biomarker genes had a good correlation with conventional animal safety tests checking body weight and leukocyte counts. In this study, we have shown that conventional animal tests showed varied and no dose-dependent results in serially diluted bulk materials of influenza HA vaccines. In contrast, dose dependency was clearly shown in the expression profiles of biomarker genes, demonstrating higher sensitivity of gene expression analysis than the current animal safety tests of influenza vaccines. The introduction of branched DNA based-concurrent expression analysis could simplify the complexity of multiple gene expression approach, and could shorten the test period from 7 days to 3 days. Furthermore, upregulation of 10 genes, Zbp1, Mx2, Irf7, Lgals9, Ifi47, Tapbp, Timp1, Trafd1, Psmb9, and Tap2, was seen upon virosomal-adjuvanted vaccine treatment, indicating that these biomarkers could be useful for the safety control of virosomal-adjuvanted vaccines. In summary, profiling biomarker gene expression could be a useful, rapid, and highly sensitive method of animal safety testing compared with conventional methods, and could be used to evaluate the safety of various types of influenza vaccines, including adjuvanted vaccine.

Immunogenicity and protective capacity of a virosomal respiratory syncytial virus vaccine adjuvanted with monophosphoryl lipid A in mice.

Respiratory Syncytial Virus (RSV) is a major cause of viral brochiolitis in infants and young children and is also a significant problem in elderly and immuno-compromised adults. To date there is no efficacious and safe RSV vaccine, partially because of the outcome of a clinical trial in the 1960s with a formalin-inactivated RSV vaccine (FI-RSV). This vaccine caused enhanced respiratory disease upon exposure to the live virus, leading to increased morbidity and the death of two children. Subsequent analyses of this incident showed that FI-RSV induces a Th2-skewed immune response together with poorly neutralizing antibodies. As a new approach, we used reconstituted RSV viral envelopes, i.e. virosomes, with incorporated monophosphoryl lipid A (MPLA) adjuvant to enhance immunogenicity and to skew the immune response towards a Th1 phenotype. Incorporation of MPLA stimulated the overall immunogenicity of the virosomes compared to non-adjuvanted virosomes in mice. Intramuscular administration of the vaccine led to the induction of RSV-specific IgG2a levels similar to those induced by inoculation of the animals with live RSV. These antibodies were able to neutralize RSV in vitro. Furthermore, MPLA-adjuvanted RSV virosomes induced high amounts of IFNγ and low amounts of IL5 in both spleens and lungs of immunized and subsequently challenged animals, compared to levels of these cytokines in animals vaccinated with FI-RSV, indicating a Th1-skewed response. Mice vaccinated with RSV-MPLA virosomes were protected from live RSV challenge, clearing the inoculated virus without showing signs of lung pathology. Taken together, these data demonstrate that RSV-MPLA virosomes represent a safe and efficacious vaccine candidate which warrants further evaluation.

Anti-angiogenetic effects of immune-reconstituted influenza virosomes assembled with parathyroid hormone-related protein derived peptide vaccine.

BACKGROUND: C-IRIV/PTR-4 is a novel anticancer vaccine construct composed of immune-reconstituted influenza virosomes (IRIV) assembled with the PTH-rP derived peptide (PTR)-4, a synthetic CTL epitope with HLA-A(*)02.01 amino acid binding motifs. This peptide is able to generate a human PTH-rP specific CTL response with anti-tumor activity in vitro and in mice. MATERIALS AND METHODS: We have investigated the immunological and preventive anti-tumor activity of C-IRIV/PTR-4 compared with the soluble PTR-4 peptide, in HHD mice inoculated with autologous PTH-rP+ tumor cells. RESULTS: Peptide vaccination with either a soluble and an IRIV formulation showed similar immunological activity and the ability to purge the tumor tissue of tumor cell clones able to produce the target antigen (PTR-rP). The most efficient protection from tumor growth was however observed in animals vaccinated with C-IRIV/PTR-4 in which an additional IRIV related anti-angiogenetic effect was detected in the tumor tissue. CONCLUSIONS: These results confirm the immunological activity of PTR-4 vaccination and suggest a more efficacious therapeutic potential of C-IRIV/PTR-4 against bone metastases and malignancies like breast, prostate and lung which very often over-express PTH-rP.

Influenza vaccine with squalene adjuvant: new preparation. No better than available products.

(1) Injectable influenza vaccines reduce morbidity and mortality in people over 65 years. (2) A new influenza vaccine, with an adjuvant (MF59C.1) based on squalene, is now marketed in France for people over 65, and especially those with chronic conditions at risk of influenza complications. (3) The clinical evaluation dossier contains data from about twenty immunogenicity studies in more than 4000 elderly subjects. According to a meta-analysis of these studies, there is no firm evidence that the MF59C.1 adjuvant vaccine is any better than other vaccines at inducing immunity in elderly people with chronic conditions. (4) A retrospective analysis of mortality among subjects enrolled in immunogenicity studies showed no significant difference between groups receiving the squalene adjuvant vaccine and groups receiving another influenza vaccine, either in the general population or in subsets of patients with relevant chronic conditions. (5) Local adverse effects (pain, rash, induration) and systemic adverse effects (malaise, myalgia, headache) were significantly more common after the squalene adjuvant vaccine than after other influenza vaccines. Pharmacovigilance data collected by the company show no unexpected adverse events. (6) In practice, there is no reason to prefer the squalene adjuvant vaccine to existing vaccines for elderly people, whether or not they have underlying chronic conditions.

Open, randomized study to compare the immunogenicity and reactogenicity of an influenza split vaccine with an MF59-adjuvanted subunit vaccine and a virosome-based subunit vaccine in elderly.

BACKGROUND: An open, randomized, multicenter study was carried out in elderly to compare the immunogenicity and reactogenicity of a conventional influenza split vaccine (SpV) with an MF59-adjuvanted subunit vaccine (aSuV) and a virosome-based subunit vaccine (vSuV) since earlier studies reported better immunogenicity for adjuvanted and virosome-based vaccines. PATIENTS AND METHODS: A total of 840 subjects, aged 60 years or more, who had not been vaccinated or diagnosed with influenza in the preceding season were investigated. Hemagglutination-inhibition antibody titers were measured, and signs and symptoms recorded. RESULTS: The three vaccines exceeded EU efficacy requirements for subjects aged older than 60 years and seroprotective levels (titers > 1:40) were equally maintained with the three vaccines during 8 months post vaccination. SpV was as immunogenic as aSuV for the A/H3N2 strain (p < 0.0001) and significantly more immunogenic than aSuV for A/H1N1 strain (p = 0.0006). SpV was as immunogenic as vSuV for all three strains and significantly more immunogenic than vSuV for the A/H1N1 strain (p < 0.0001). In terms of reactogenicity, aSuV showed a higher rate of solicited local signs and symptoms than SpV (p = 0.021) and vSuV (p = 0.046), respectively. Incidence of solicited general symptoms was comparable on all treatments. No serious adverse event related to vaccination was reported. CONCLUSION: These findings suggest that all three vaccines are highly immunogenic with an acceptable reactogenicity profile and that they are appropriate for use in elderly.