Bioavailability and Chemical/Functional Aspects of Synthetic MK-7 vs Fermentation-Derived MK-7 in Randomised Controlled Trials.

We investigated the bioavailability of a synthetic form of the vitamin K2 molecule menaquinone-7 (MK-7) in a randomised single-blinded two-way cross-over study. Healthy subjects (20 - 66 years of age) took a single 180 µg dose of synthetic MK-7 or fermentation-derived MK-7, and serum MK-7 concentrations were monitored for 72 hours to calculate AUC(0 - 72 h) and Cmax. We also compared the biological effects of placebo, fermentation-derived MK-7 (90 µg) and 3 doses of synthetic MK-7(45, 90 and 180 µg) in a randomised double-blinded parallel study. Healthy subjects (20 - 60 years of age) took one of the supplements daily for 43 days, and the fraction of carboxylated osteocalcin (OC) was compared between day 1 and day 43 as a marker for vitamin K activity. In the bioavailability study, the 90 % confidence interval for the ratio of the AUC(0-72 h) values for synthetic and fermentationderived MK-7 was 83 - 111, indicating bioequivalence. The 90 % confidence interval for the Cmax ratio was 83 - 131. The serum concentrations of carboxylated OC and undercarboxylated OC were increased (p = 0.01) and reduced (p = 0.02), respectively, after daily intake of 180 µg of synthetic MK-7 for 43 days, indicating increased vitamin K activity. Across both studies, only 1 participant reported an adverse event (dry mouth; 180 µg synthetic MK-7 group, functional study) that was considered possibly related to synthetic MK-7 supplementation. Our findings provide evidence that the tested synthetic form of MK-7 is bioequivalent to fermentation-derived MK-7, exhibits vitamin K activity and is well tolerated in healthy subjects.

Safety and efficacy of the peptide-based therapeutic vaccine for HIV-1, Vacc-4x: a phase 2 randomised, double-blind, placebo-controlled trial.

BACKGROUND: Present combination antiretroviral therapy (cART) alone does not cure HIV infection and requires lifelong drug treatment. The potential role of HIV therapeutic vaccines as part of an HIV cure is under consideration. Our aim was to assess the efficacy, safety, and immunogenicity of Vacc-4x, a peptide-based HIV-1 therapeutic vaccine targeting conserved domains on p24(Gag), in adults infected with HIV-1. METHODS: Between July, 2008, and June, 2010, we did a multinational double-blind, randomised, phase 2 study comparing Vacc-4x with placebo. Participants were adults infected with HIV-1 who were aged 18-55 years and virologically suppressed on cART (viral load <50 copies per mL) with CD4 cell counts of 400 × 10(6) cells per L or greater. The trial was done at 18 sites in Germany, Italy, Spain, the UK, and the USA. Participants were randomly assigned (2:1) to Vacc-4x or placebo. Group allocation was masked from participants and investigators. Four primary immunisations, weekly for 4 weeks, containing Vacc-4x (or placebo) were given intradermally after administration of adjuvant. Booster immunisations were given at weeks 16 and 18. At week 28, cART was interrupted for up to 24 weeks. The coprimary endpoints were cART resumption and changes in CD4 counts during treatment interruption. Analyses were by modified intention to treat: all participants who received one intervention. Furthermore, safety, viral load, and immunogenicity (as measured by ELISPOT and proliferation assays) were assessed. The 52 week follow-up period was completed in June, 2011. For the coprimary endpoints the proportion of participants who met the criteria for cART resumption was analysed with a logistic regression model with the treatment effect being assessed in a model including country as a covariate. This study is registered with ClinicalTrials.gov, number NCT00659789. FINDINGS: 174 individuals were screened; because of slow recruitment, enrolment stopped with 136 of a planned 345 participants and 93 were randomly assigned to receive Vacc-4x and 43 to receive placebo. There were no differences between the two groups for the primary efficacy endpoints in those participants who stopped cART at week 28. Of the participants who resumed cART, 30 (34%) were in the Vacc-4x group and 11 (29%) in the placebo group, and percentage changes in CD4 counts were not significant (mean treatment difference -5·71, 95% CI -13·01 to 1·59). However, a significant difference in viral load was noted for the Vacc-4x group both at week 48 (median 23,100 copies per mL Vacc-4x vs 71,800 copies per mL placebo; p=0·025) and week 52 (median 19,550 copies per mL vs 51,000 copies per mL; p=0·041). One serious adverse event, exacerbation of multiple sclerosis, was reported as possibly related to study treatment. Vacc-4x was immunogenic, inducing proliferative responses in both CD4 and CD8 T-cell populations. INTERPRETATION: The proportion of participants resuming cART before end of study and change in CD4 counts during the treatment interruption showed no benefit of vaccination. Vacc-4x was safe, well tolerated, immunogenic, seemed to contribute to a viral-load setpoint reduction after cART interruption, and might be worth consideration in future HIV-cure investigative strategies. FUNDING: Norwegian Research Council GLOBVAC Program and Bionor Pharma ASA.

Boosters of a therapeutic HIV-1 vaccine induce divergent T cell responses related to regulatory mechanisms.

Therapeutic human immunodeficiency virus (HIV) vaccines aim to reduce disease progression by inducing HIV-specific T cells. Vacc-4x are peptides derived from conserved domains within HIV-1 p24 Gag. Previously, Vacc-4x induced T cell responses in 90% of patients which were associated with reduced viral loads. Here we evaluate the effects of Vacc-4x boosters on T cell immunity and immune regulation seven years after primary immunization. Twenty-five patients on effective antiretroviral therapy received two Vacc-4x doses four weeks apart and were followed for 16 weeks. Vacc-4x T cell responses were measured by proliferation (CFSE), INF-γ, CD107a, Granzyme B, Delayed-Type Hypersensitivity test (DTH) and cytokines and chemokines (Luminex). Functional regulation of Vacc-4x-specific T cell proliferation was estimated in vitro using anti-IL-10 and anti-TGF-ß monoclonal antibodies. Vacc-4x-specific CD8(+) T cell proliferation increased in 80% after either the first (64%) or second (16%) booster. Only 40% remained responders after two boosters with permanently increased Vacc-4x-specific proliferative responses (p=0.005) and improved CD8(+) T cell degranulation, IFN-γ production and DTH. At baseline, responders had higher CD8(+) T cell degranulation (p=0.05) and CD4(+) INF-γ production (p=0.01), whereas non-responders had higher production of proinflammatory TNF-α, IL-1α and IL-1ß (p<0.045) and regulatory IL-10 (p=0.07). Notably, IL-10 and TGF-ß mediated downregulation of Vacc-4x-specific CD8(+) T cell proliferation increased only in non-responders (p<0.001). Downregulation during the study correlated to higher PD-1 expression on Vacc-4x-specific CD8(+) T cells (r=0.44, p=0.037), but was inversely correlated to changes in Vacc4x-specific CD8(+) T cell proliferation (r=-0.52, p=0.012). These findings show that Vacc-4x boosters can improve T cell responses in selected patients, but also induce vaccine-specific downregulation of T cell responses in others. Broad surveillance of T cell functions during immunization may help to individualize boosting, where assessment of vaccine-related immune regulation should be further explored as a potential new parameter.

Intradermal vaccination of HIV-infected patients with short HIV Gag p24-like peptides induces CD4 + and CD8 + T cell responses lasting more than seven years.

BACKGROUND: Vacc-4x contains 4 HIV p24-like short peptides. In a previous phase II trial this immunized 90% of 38 patients on antiretroviral treatment (ART) after intradermal delivery in conjunction with local granulocyte-macrophage colony-stimulating factor (GM-CSF) as adjuvant. In this study, 22 responders were retested for cellular memory at a median 7.3 y after their last immunization. All had resumed effective ART after an interspersed ART-free median interval of 2.2 y. METHODS: Vacc-4x as 15-mer overlapping by 2 amino acid panels and Vacc-4x consensus peptide sequences (4xCP) were used as antigens. Proliferation was determined as percentages of CFSE(dim)HLA-DR(+) 7AAD(-) CD3+ T cells of the CD4+ and CD8+ subsets after 6 days of culture. Frequencies of specific T cells in 6-h cultures were determined by interferon-γ (IFN)(+) CD4+ and IFN(+) CD8+, as well as degranulating bifunctional CD107a + IFN(+) CD8 + subsets. RESULTS: Proliferative CD4+ and CD8+ responses to Vacc-4x as well as 4xCP were still present in 95% and 68%, respectively. Proliferation correlated with the Vacc-4x delayed-type hypersensitivity test (DTH) obtained after completed immunizations (CD4 + r = 0.63 (p = 0.002) and CD8 + r = 0.47 (p = 0.03)), suggesting that they represent T cell memory recall responses. The proliferative CD8+ and possibly CD4 + subset responses to 4xCP peptides correlated with Vacc-4x (r = 0.46 (p = 0.03) and r = 0.38 (p = 0.08), respectively). Forty-one percent still had Vacc-4x-specific IFN + CD4 + T cells, which correlated to corresponding frequencies of 4xCP peptides (r = 0.50, p = 0.02). CD107a(+) IFN(+) CD8 + T cell responses against Vacc-4x were found in 55%. CONCLUSIONS: Evidence of long-lasting T cell memory recall responses to a peptide-based immunotherapeutic candidate for HIV-infected patients should enhance the focus on peptide-based intradermal vaccine delivery.

Delayed-type hypersensitivity responses to HIV Gag p24 relate to clinical outcome after peptide-based therapeutic immunization for chronic HIV infection.

Therapeutic immunization in chronic HIV infection aims to induce durable, HIV-specific immune responses capable of controlling disease progression, but immunological correlates of clinical efficacy are poorly defined. We have previously immunized 38 patients with a mixture of four short Gag p24-like conserved peptides (Vacc-4x) targeting skin dendritic cells. Antiretroviral treatment (ART) was initially stopped after completed immunizations and resumed post-protocol during regular clinical follow-up according to current guidelines. Four years after enrolment, Vacc-4x-specific cellular responses were evaluated in vivo by delayed-type hypersensitivity (DTH) skin test, and in vitro by a T-cell proliferation assay. Kaplan-Meier product-limit estimates were used to analyse time until ART was resumed. Peptide-specific cellular immune responses induced by Vacc-4x had persisted 4 years after the last immunization in terms of unchanged DTH independent of ART and detectable proliferative T-cell responses which correlated to the native peptides (R = 0.73, p = 0.01). Circulating bifunctional (IFN-γ and IL-10) Vacc-4x-specific T-cell clones were detected in 43% of patients. Subjects with the strongest post-immunization DTH responses appeared to start ART later compared with DTH low responders (p = 0.07). These data suggest that DTH responses should be further evaluated as a new and convenient tool for predicting clinical efficacy in trials testing therapeutic immunizations.

Long-term HIV-specific responses and delayed resumption of antiretroviral therapy after peptide immunization targeting dendritic cells.

Long-term HIV-specific immune responses and clinical outcomes were evaluated in HIV-infected patients previously immunized with p24-like peptides (Vacc-4x) targeting dendritic cells (DC). Vacc-4x-induced cellular immune responses were unchanged 1.5 years after completing immunization, and 62% were still off combined antiretroviral treatment (CART). The magnitude of early Vacc-4x responses determined whether the resumption of CART was clinically indicated 2 years after enrollment. These observations encourage further exploration of both Vacc-4x and other HIV peptide-based immunization regimens targeting DC.

Multiple antigen concentrations in delayed-type hypersensitivity (DTH) and response diversity during and after immunization with a peptide-based HIV-1 immunotherapy candidate (Vacc-4x).

Delayed-type hypersensitivity (DTH) testing represents a simple in vivo method for monitoring cellular immune responses. In a phase II clinical trial on HIV-infected patients (n = 38) of the peptide-based HIV-1 immunotherapy candidate Vacc-4x, we monitored DTH responses to three antigen concentrations of Vacc-4x. We have shown that DTH can be used quantitatively to measure immune reactions to Vacc-4x and its individual peptide components. Our data stress the qualities and differences of induration and erythema, both in discriminating individual antigens and in monitoring immunizations over time. The data also indicate that DTH baseline-status might have important impact on immunization kinetics.

Reduced viral burden amongst high responder patients following HIV-1 p24 peptide-based therapeutic immunization.

We have previously shown that HIV p24-like peptides (Vacc-4x) via activation of skin dendritic cells induced immune responses in 90% of HIV patients on highly active antiretroviral treatment (HAART). These patients (n=38) were here subjected to a final 14-week interruption of HAART. Patients with the highest delayed type hypersensitivity (DTH) responses to Vacc-4x-peptides before treatment interruption tended to achieve lower actual HIV RNA levels at the end of the study compared to Vacc-4x DTH low-responders (p=0.08) and significantly so in terms of viral loads relative to their individual pre-HAART HIV RNA set-points (p=0.04). CD4+ lymphocyte counts were maintained only among DTH high responders but decreased in the other patients during recurrent viremia (p

Divergent in vitro and in vivo correlates of HIV-specific T-cell responses during onset of HIV viraemia.

BACKGROUND: Cellular immune responses to HIV-1 have been examined mainly in peripheral blood mononuclear cells (PBMC). During onset of HIV replication and antigenaemia after discontinuation of highly active antiretroviral therapy (HAART), PBMC may theoretically contain HIV-specific T cells that are qualitatively and quantitatively different from specific T cells dominating in the tissues. PBMC responses throughout HIV immunotherapy trials may therefore be skewed during recurrent viraemia. OBJECTIVE: To compare cellular HIV-specific in vitro responses in PBMC during onset of HIV viraemia with corresponding in vivo responses, represented by classical delayed-type hypersensitivity tests (DTH). METHODS: HIV patients (n = 38), pre-immunized with four HIV-1 p24-like consensus peptides (Vacc-4x) during HAART, were subjected to a 14-week treatment interruption with recurrent HIV viraemia. Proliferative T-cell responses to Vacc-4x p24 peptides, HIV p24 protein, and cytomegalovirus (CMV) proteins were measured in PBMC. Corresponding Vacc-4x peptide DTH were expressed as skin infiltrate areas after 48 h. RESULTS: After 14 weeks without HAART, HIV-1 RNA increased to 72,500 copies/ml (median). The Vacc-4x p24 peptide- and HIV-1 p24 protein-induced T-cell proliferation concurrently decreased by 81 and 93% in PBMC during viraemia (medians, P < or = 0.03), whereas proliferative responses to CMV antigens were stable. In contrast, the Vacc-4x DTH areas, rather tended to increase by 36% (P = 0.08) and contained infiltrates dominated by proliferating T cells and macrophages. CONCLUSIONS: Divergent in vitro and in vivo HIV-specific cellular immune responses were found during recurrent HIV viraemia. The clinical relevance of both surrogate markers for HIV-related immune responses should be compared in future studies.

HLA- and dose-dependent immunogenicity of a peptide-based HIV-1 immunotherapy candidate (Vacc-4x).

OBJECTIVE: The Vacc-4x immunotherapy candidate is composed of four modified peptides corresponding to conserved domains of the HIV-1 protein p24 that preferentially include HLA-A2 restricted elements. Dose-dependent safety and immunogenicity of Vacc-4x and the significance of a HLA-A2 haplotype were examined. DESIGN: Non-AIDS, HIV-1 infected healthy patients (n = 40) stable on HAART with CD4 counts > 300 x 10 cells/l were randomized to receive either low-dose or high-dose Vacc-4x over 26 weeks in an open, prospective phase II clinical trial. METHODS: Patients received a total of 10 intradermal injections, using recombinant granulocyte-macrophage colony stimulating factor as a local adjuvant. Vacc-4x-specific cellular responses were monitored in vivo by delayed-type hypersensitivity (DTH) skin test infiltrates and in vitro by both T-cell proliferation, and induction /secretion of cytokines. RESULTS: Most patients developed Vacc-4x-specific DTHs (90%) and proliferative T-cell responses (80%) that were inter-related in magnitude. High-dose Vacc-4x generally induced stronger specific immune responses than low dose in terms of DTH areas and CD4 and CD8 T-cell proliferation. Only HLA-A2 negative patients had a definite dose advantage, and this subgroup had in fact the best overall DTH and proliferative responses. In contrast, no significant dose difference was observed for HLA-A2 positive patients. No serious adverse events were reported. CONCLUSIONS: HIV-associated specific responses were safely induced in most patients by Vacc-4x in a dose-dependent manner and were also influenced by the HLA haplotype.

Phase I trial of a therapeutic HIV type 1 vaccine, Vacc-4x, in HIV type 1-infected individuals with or without antiretroviral therapy.

Highly active antiretroviral therapy (HAART) can effectively suppress HIV-1 replication but, as soon as the drugs are withdrawn, there is a rapid rebound of replicating virus. Severe metabolic toxicities and therapy failures due to the appearance of resistant virus are becoming an increasing problem that precludes long-term continuous medication. Therapeutic immunizations represent a feasible and attractive means of supplementing or, alternatively, replacing current therapies, thereby reducing the potential for emergence of drug-resistant HIV-1 strains. We have performed an open, single-center, phase I safety study of a candidate therapeutic HIV-1 vaccine, Vacc-4x, given to 11 HIV-1-infected individuals with or without antiretroviral therapy. The immunogen consists of four synthetic peptides based on the major core protein p24. To ensure optimal exposure of the immunogen to the antigen-presenting cells (APCs), the vaccine was given intradermally together with granulocyte-macrophage colony-stimulating factor (GM-CSF). Responses to the immunization protocol were determined by delayed-type hypersensitivity (DTH) reaction, interferon gamma-secreting cells in the enzyme-linked immunospot (ELISpot) assay, and antibody production to the p24 protein and the peptides. The vaccine was safe and in general well tolerated. Plasma HIV RNA levels and CD4(+) cell counts did not change appreciably during the study. All patients showed a positive DTH response. For two of the patients, the immunization protocol induced responses to one or two of the tested peptides whereas a third patient showed reactivity to one of the peptides before immunization. A weak antibody response in the peptide-specific enzyme-linked immunosorbent assay could be seen in seven patients.