First-in-Human Randomized, Controlled Trial of Mosaic HIV-1 Immunogens Delivered via a Modified Vaccinia Ankara Vector.

Background: Mosaic immunogens are bioinformatically engineered human immunodeficiency virus type 1 (HIV-1) sequences designed to elicit clade-independent coverage against globally circulating HIV-1 strains. Methods: This phase 1, double-blinded, randomized, placebo-controlled trial enrolled healthy HIV-uninfected adults who received 2 doses of a modified vaccinia Ankara (MVA)-vectored HIV-1 bivalent mosaic immunogen vaccine or placebo on days 0 and 84. Two groups were enrolled: those who were HIV-1 vaccine naive (n = 15) and those who had received an HIV-1 vaccine (Ad26.ENVA.01) 4-6 years earlier (n = 10). We performed prespecified blinded cellular and humoral immunogenicity analyses at days 0, 14, 28, 84, 98, 112, 168, 270, and 365. Results: All 50 planned vaccinations were administered. Vaccination was safe and generally well tolerated. No vaccine-related serious adverse events occurred. Both cellular and humoral cross-clade immune responses were elicited after 1 or 2 vaccinations in all participants in the HIV-1 vaccine-naive group. Env-specific responses were induced after a single immunization in nearly all subjects who had previously received the prototype Ad26.ENVA.01 vaccine. Conclusions: No safety concerns were identified, and multiclade HIV-1-specific immune responses were elicited. Clinical Trials Registration: NCT02218125.

Assessment of the Safety and Immunogenicity of 2 Novel Vaccine Platforms for HIV-1 Prevention: A Randomized Trial.

BACKGROUND: A prophylactic HIV-1 vaccine is a global health priority. OBJECTIVE: To assess a novel vaccine platform as a prophylactic HIV-1 regimen. DESIGN: Randomized, double-blind, placebo-controlled trial. Both participants and study personnel were blinded to treatment allocation. (ClinicalTrials.gov: NCT01215149). SETTING: United States, East Africa, and South Africa. PATIENTS: Healthy adults without HIV infection. INTERVENTION: 2 HIV-1 vaccines (adenovirus serotype 26 with an HIV-1 envelope A insert [Ad26.EnvA] and adenovirus serotype 35 with an HIV-1 envelope A insert [Ad35.Env], both administered at a dose of 5 × 1010 viral particles) in homologous and heterologous combinations. MEASUREMENTS: Safety and immunogenicity and the effect of baseline vector immunity. RESULTS: 217 participants received at least 1 vaccination, and 210 (>96%) completed follow-up. No vaccine-associated serious adverse events occurred. All regimens were generally well-tolerated. All regimens elicited humoral and cellular immune responses in nearly all participants. Preexisting Ad26- or Ad35-neutralizing antibody titers had no effect on vaccine safety and little effect on immunogenicity. In both homologous and heterologous regimens, the second vaccination significantly increased EnvA antibody titers (approximately 20-fold from the median enzyme-linked immunosorbent assay titers of 30-300 to 3000). The heterologous regimen of Ad26-Ad35 elicited significantly higher EnvA antibody titers than Ad35-Ad26. T-cell responses were modest and lower in East Africa than in South Africa and the United States. LIMITATIONS: Because the 2 envelope inserts were not identical, the boosting responses were complex to interpret. Durability of the immune responses elicited beyond 1 year is unknown. CONCLUSION: Both vaccines elicited significant immune responses in all populations. Baseline vector immunity did not significantly affect responses. Second vaccinations in all regimens significantly boosted EnvA antibody titers, although vaccine order in the heterologous regimen had a modest effect on the immune response. PRIMARY FUNDING SOURCE: International AIDS Vaccine Initiative, National Institutes of Health, Ragon Institute, Crucell Holland.

Induction of HIV-1-specific mucosal immune responses following intramuscular recombinant adenovirus serotype 26 HIV-1 vaccination of humans.

BACKGROUND: Defining mucosal immune responses and inflammation to candidate human immunodeficiency virus type 1 (HIV-1) vaccines represents a current research priority for the HIV-1 vaccine field. In particular, it is unclear whether intramuscular immunization can elicit immune responses at mucosal surfaces in humans. METHODS: In this double-blind, randomized, placebo-controlled clinical trial, we evaluated systemic and mucosal immune responses to a candidate adenovirus serotype 26 (Ad26) vectored HIV-1 envelop (Env) vaccine in baseline Ad26-seronegative and Ad26-seropositive healthy volunteers. Systematic mucosal sampling with rectal Weck-Cel sponges and rectal biopsies were performed. RESULTS: Intramuscular immunization elicited both systemic and mucosal Env-specific humoral and cellular immune responses in the majority of subjects. Individuals with preexisting Ad26-specific neutralizing antibodies had vaccine-elicited immune responses comparable to those of subjects who were Ad26 seronegative. We also observed no increase in activated total or vector-specific mucosal CD4+ T lymphocytes following vaccination by either histopathology or flow cytometry. CONCLUSIONS: These data demonstrate that a single intramuscular administration of this Ad26-vectored HIV-1 Env vaccine elicited both systemic and mucosal immune responses in humans. Induction of antigen-specific humoral and cellular mucosal immunity was not accompanied by a detectable increase in mucosal inflammation. CLINICAL TRIALS REGISTRATION: NCT01103687.

First-in-human evaluation of a hexon chimeric adenovirus vector expressing HIV-1 Env (IPCAVD 002).

BACKGROUND: We report the first-in-human safety and immunogenicity assessment of a prototype hexon chimeric adenovirus (Ad) serotype 5 (Ad5) vector containing the hexon hypervariable regions of Ad serotype 48 (Ad48) and expressing human immunodeficiency virus (HIV) type 1 EnvA. METHODS: Forty-eight Ad5 and Ad48 seronegative, HIV-uninfected subjects were enrolled in a randomized, double-blind, placebo-controlled, dose escalation phase 1 study. Four groups of 12 subjects received 10(9) to 10(11) viral particles (vp) of the Ad5HVR48.EnvA.01 vaccine (n = 10 per group) or placebo (n = 2 per group) at week 0 or weeks 0, 4, and 24. Safety and immunogenicity were assessed. RESULTS: Self-limited reactogenicity was observed after the initial immunization in the highest (10(11) vp) dose group. Responses in vaccinees included Ad48 neutralizing antibody (nAb) titers higher than Ad5 nAb titers, EnvA-specific enzyme-linked immunosorbent assay titers, and EnvA-specific enzyme-linked immunospot assay responses, and these responses generally persisted at week 52. At week 28 in the 10(9), 10(10), and 10(11) vp 3-dose groups, geometric mean EnvA enzyme-linked immunosorbent assay titers were 5721, 10 929, and 3420, respectively, and Ad48 nAb titers were a median of 1.7-fold higher than for Ad5. CONCLUSIONS: Ad5HVR48.ENVA.01 was safe, well tolerated, and immunogenic at all doses tested. Vector-elicited nAb responses were greater for Ad48 than Ad5, confirming that Ad-specific nAbs in humans are primarily, but not exclusively, directed against the hexon hypervariable regions. Clinical Trials Registration. NCT00695877.

Safety and immunogenicity of modified vaccinia Ankara in hematopoietic stem cell transplant recipients: a randomized, controlled trial.

BACKGROUND: Modified vaccinia Ankara (MVA-BN, IMVAMUNE) is emerging as a primary immunogen and as a delivery system to treat or prevent a wide range of diseases. Defining the safety and immunogenicity of MVA-BN in key populations is therefore important. METHODS: We performed a dose-escalation study of MVA-BN administered subcutaneously in 2 doses, one on day 0 and another on day 28. Twenty-four hematopoietic stem cell transplant recipients were enrolled sequentially into the study, and vaccine or placebo was administered under a randomized, double-blind allocation. Ten subjects received vaccine containing 10(7) median tissue culture infective doses (TCID50) of MVA-BN, 10 subjects received vaccine containing 10(8) TCID50 of MVA-BN, and 4 subjects received placebo. RESULTS: MVA-BN was generally well tolerated at both doses. No vaccine-related serious adverse events were identified. Transient local reactogenicity was more frequently seen at the higher dose. Neutralizing antibodies (NAb) to Vaccinia virus (VACV) were elicited by both doses of MVA-BN and were greater for the higher dose. Median peak anti-VACV NAb titers were 1:49 in the lower-dose group and 1:118 in the higher-dose group. T-cell immune responses to VACV were detected by an interferon γ enzyme-linked immunosorbent spot assay and were higher in the higher-dose group. CONCLUSIONS: MVA-BN is safe, well tolerated, and immunogenic in HSCT recipients. These data support the use of 10(8) TCID50 of MVA-BN in this population. CLINICAL TRIALS REGISTRATION: NCT00565929.

Characterization of humoral and cellular immune responses elicited by a recombinant adenovirus serotype 26 HIV-1 Env vaccine in healthy adults (IPCAVD 001).

BACKGROUND: Adenovirus serotype 26 (Ad26) has been developed as a novel candidate vaccine vector for human immunodeficiency virus type 1 (HIV-1) and other pathogens. The primary safety and immunogenicity data from the Integrated Preclinical/Clinical AIDS Vaccine Development Program (IPCAVD) 001 trial, the first-in-human evaluation of a prototype Ad26 vector-based vaccine expressing clade A HIV-1 Env (Ad26.ENVA.01), are reported concurrently with this article. Here, we characterize in greater detail the humoral and cellular immune responses elicited by Ad26.ENVA.01 in humans. METHODS: Samples from the IPCAVD 001 trial were used for humoral and cellular immunogenicity assays. RESULTS: We observed a dose-dependent expansion of the magnitude, breadth, and epitopic diversity of Env-specific binding antibody responses elicited by this vaccine. Antibody-dependent cell-mediated phagocytosis, virus inhibition, and degranulation functional activity were also observed. Env-specific cellular immune responses induced by the vaccine included multiple CD8(+) and CD4(+) T-lymphocyte memory subpopulations and cytokine secretion phenotypes, although cellular immune breadth was limited. Baseline vector-specific T-lymphocyte responses were common but did not impair Env-specific immune responses in this study. CONCLUSION: Ad26.ENVA.01 elicited a broad diversity of humoral and cellular immune responses in humans. These data support the further clinical development of Ad26 as a candidate vaccine vector. CLINICAL TRIALS REGISTRATION: NCT00618605.

First-in-human evaluation of the safety and immunogenicity of a recombinant adenovirus serotype 26 HIV-1 Env vaccine (IPCAVD 001).

BACKGROUND: We report the first-in-human safety and immunogenicity assessment of a prototype Ad26 vector-based human immunodeficiency virus (HIV) vaccine in humans. METHODS: Sixty Ad26-seronegative, healthy, HIV-uninfected subjects were enrolled in a randomized, double-blinded, placebo-controlled, dose-escalation phase 1 study. Five groups of 12 subjects received 10(9)-10(11) vp of the Ad26-EnvA vaccine (N = 10/group) or placebo (N = 2/group) at weeks 0 and 24 or weeks 0, 4, and 24. Safety and immunogenicity were assessed. RESULTS: Self-limited reactogenicity was observed after the initial immunization at the highest (10(11) vp) dose. No product-related SAEs were observed. All subjects who received the Ad26-EnvA vaccine developed Ad26 NAb titers, EnvA-specific enzyme-linked immunosorbent assays (ELISA) titers, and EnvA-specific enzyme-linked immunospot assays (ELISPOT) responses. These responses persisted at week 52. At week 28 in the 10(9), 10(10), 10(11) vp 3-dose and the 10(10) and 5 × 10(10) vp 2-dose groups, geometric mean EnvA ELISA titers were 6113, 12 470, 8545, 3470, and 9655 and mean EnvA ELISPOT responses were 397, 178, 736, 196, and 1311 SFC/10(6) peripheral blood mononuclear cells, respectively. CONCLUSION: This Ad26 vectored vaccine was generally safe and immunogenic at all doses tested. Reactogenicity was minimal with doses of 5 × 10(10) vp or less. Ad26 is a promising new vaccine vector for HIV-1. CLINICAL TRIALS REGISTRATION: NCT00618605.

Timing of plasmid cytokine (IL-2/Ig) administration affects HIV-1 vaccine immunogenicity in HIV-seronegative subjects.

BACKGROUND: To investigate the potential immunostimulatory effect of interleukin (IL) 2 as a human immunodeficiency virus type 1 (HIV-1) vaccine adjuvant, we conducted a study of a plasmid coding for a fusion protein of IL-2 and immunoglobulin (IL-2/Ig). METHODS: This phase I trial evaluated an HIV-1 DNA vaccine with the plasmid cytokine adjuvant (IL-2/Ig) in 70 HIV-negative adults. Subjects received placebo (group C), adjuvant alone (group A), vaccine alone (group D), increasing doses of adjuvant concurrent with vaccine (groups T1-T4), or adjuvant given 2 days after vaccine (group T5). RESULTS: No significant differences in adverse events were observed between treatment groups. Cellular immune responses to envelope protein EnvA peptides were detected by interferon (IFN) γ and IL-2 enzyme-linked immunospot (ELISPOT) assays in 50% and 40% of subjects, respectively, in T4, and in 100% and 80% in T5. The median responses for groups T4 and T5, respectively, were 90 and 193 spot-forming cells (SFCs)/106 peripheral blood mononuclear cells (P = .004; T4 vs T5) for the IL-2 ELISPOT assay and 103 and 380 SFCs/106 PBMCs (P = .003; T4 vs T5) for the IFN-γ ELISPOT assay. A trend to more durable cellular immune responses in T5 was observed at 1 year (T5 vs T4/D; P = .07). Higher anti-Env antibody responses were detected with T5 than with T4. CONCLUSIONS: Plasmid IL-2/Ig significantly increased immune responses when administered 2 days after the DNA vaccine, compared with simultaneous administration. These observations have important implications for the development of cytokine augmentation strategies. CLINICAL TRIALS REGISTRATION: NCT00069030.

Effect of vaccination with modified vaccinia Ankara (ACAM3000) on subsequent challenge with Dryvax.

BACKGROUND: Despite the success of smallpox vaccination, the immunological correlates of protection are not fully understood. To investigate this question, we examined the effect of immunization with modified vaccinia Ankara (MVA) on subsequent challenge with replication-competent vaccinia virus (Dryvax). METHODS: Dryvax challenge by scarification was conducted in 36 healthy subjects who had received MVA (n = 29) or placebo (n = 7) in a previous study of doses and routes of immunization. Subjects were followed up for clinical take, viral shedding, and immune responses. RESULTS: MVA administration attenuated clinical takes in 21 (72%) of 29 subjects, compared with 0 of 7 placebo recipients (P = .001). Attenuation was most significant in MVA groups that received 1 x 10(7) median tissue culture infective doses (TCID(50)) intradermally (P = .001) and 1 x 10(7) TCID(50) intramuscularly (P = .001). Both duration and peak titer of viral shedding were reduced in MVA recipients. Peak neutralizing antibody responses to vaccinia virus or MVA previously induced by MVA immunization were associated with attenuated takes (P = .02) and reduced duration (P = .001) and titer (P = .005) of viral shedding. CONCLUSIONS: MVA immunization results in clinical and virologic protection against Dryvax challenge. Protection is associated with prior induction of neutralizing antibodies to MVA or vaccinia virus. MVA administered intradermally has protective and immunologic responses similar to those of a 10-fold-higher dose given subcutaneously.

Safety and immunogenicity of modified vaccinia Ankara (ACAM3000): effect of dose and route of administration.

BACKGROUND: We conducted a clinical trial of the safety and immunogenicity of modified vaccinia Ankara (MVA) to examine the effects of dose and route of administration. METHODS: Seventy-two healthy, vaccinia virus-naive subjects received 1 of 6 regimens of MVA (ACAM3000) or placebo consisting of 2 administrations given 1 month apart. RESULTS: MVA was generally well tolerated at all dose levels and by all routes. More pronounced local reactogenicity was seen with the intradermal and subcutaneous routes than with intramuscular administration. Binding antibodies to whole virus and neutralizing antibodies to the intracellular mature virion and extracellular enveloped virion forms of vaccinia virus were elicited by all routes of MVA administration and were greater for the higher dose by each route. Similar levels of neutralizing antibodies were seen at a 10-fold-lower dose given intradermally (1 x 10(7) median tissue culture infective doses [TCID(50)]), compared with responses after 1 x 10(8) TCID(50) given intramuscularly or subcutaneously. T cell immune responses to vaccinia virus were detected by an interferon gamma enzyme-linked immunospot assay but had no clear relationship to dose or route. CONCLUSIONS: These data suggest that intradermal immunization with MVA provides a dose-sparing effect by eliciting antibody responses similar in magnitude and kinetics to those elicited by the intramuscular or subcutaneous routes but at a 10-fold-lower dose.

Poststudy Point-of-Care Oral Fluid Testing in Human Immunodeficiency Virus-1 Vaccinees.

BACKGROUND: Experimental human immunodeficiency virus (HIV)-1 vaccines frequently elicit antibodies against HIV-1 that may react with commonly used HIV diagnostic tests, a phenomenon known as vaccine-induced seropositivity/seroreactivity (VISP/VISR). We sought to determine, under clinic conditions, whether a patient-controlled HIV test, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test, detected HIV-1 vaccine-induced antibodies. METHODS: Plasma assessment of HIV-1 cross-reactivity was examined in end-of-study samples from 57 healthy, HIV-uninfected participants who received a candidate vaccine that has entered Phase 2B and 3 testing. We also screened 120 healthy, HIV-uninfected, unblinded HIV-1 vaccine participants with VISP/VISR for an assessment using saliva. These participants came from 21 different parent vaccine protocols representing 17 different vaccine regimens, all of which contained an HIV-1 envelope immunogen. OraQuick ADVANCE was compared with results from concurrent blood samples using a series of commercial HIV screening immunoassays. RESULTS: Fifty-seven unique participant plasma samples were assayed in vitro, and only 1 (1.8%) was reactive by OraQuick ADVANCE. None of the 120 clinic participants (0%; 95% confidence interval, 0% to 3.7%) tested positive by OraQuick ADVANCE, and all were confirmed to be uninfected by HIV-1 viral ribonucleic acid testing. One hundred eighteen of the 120 (98.3%) participants had a reactive HIV test for VISP/VISR: 77 (64%) had at least 1 reactive fourth-generation HIV-1 diagnostic test (P < .0001 vs no reactive OraQuick ADVANCE results), and 41 (34%) only had a reactive test by the less specific third-generation Abbott Prism assay. CONCLUSIONS: These data suggest that this widely available patient-controlled test has limited reactivity to HIV-1 antibodies elicited by these candidate HIV-1 vaccines.