Safety and immunogenicity of a polyvalent DNA-protein HIV vaccine with matched Env immunogens delivered as a prime-boost regimen or coadministered in HIV-uninfected adults in the USA (HVTN 124): a phase 1, placebo-controlled, double-blind randomised controlled trial

BACKGROUND

An effective HIV vaccine will most likely need to have potent immunogenicity and broad cross-subtype coverage. The aim of the HIV Vaccine Trials Network (HVTN) 124 was to evaluate safety and immunogenicity of a unique polyvalent DNA-protein HIV vaccine with matching envelope (Env) immunogens.

METHODS

HVTN 124 was a randomised, phase 1, placebo-controlled, double-blind study, including participants who were HIV seronegative and aged 18-50 years at low risk for infection. The DNA vaccine comprised five plasmids: four copies expressing Env gp120 (clades A, B, C, and AE) and one gag p55 (clade C). The protein vaccine included four DNA vaccine-matched GLA-SE-adjuvanted recombinant gp120 proteins. Participants were enrolled across six clinical sites in the USA and were randomly assigned to placebo or one of two vaccine groups (ie, prime-boost or coadministration) in a 5:1 ratio in part A and a 7:1 ratio in part B. Vaccines were delivered via intramuscular needle injection. The primary outcomes were safety and tolerability, assessed via frequency, severity, and attributability of local and systemic reactogenicity and adverse events, laboratory safety measures, and early discontinuations. Part A evaluated safety. Part B evaluated safety and immunogenicity of two regimens: DNA prime (administered at months 0, 1, and 3) with protein boost (months 6 and 8), and DNA-protein coadministration (months 0, 1, 3, 6, and 8). All randomly assigned participants who received at least one dose were included in the safety analysis. The study is registered with ClinicalTrials.gov (NCT03409276) and is closed to new participants.

FINDINGS

Between April 19, 2018 and Feb 13, 2019, 60 participants (12 in part A [five men and seven women] and 48 in part B [21 men and 27 women]) were enrolled. All 60 participants received at least one dose, and 14 did not complete follow-up (six of 21 in the prime-boost group and eight of 21 in the coadminstration group). 11 clinical adverse events deemed by investigators as study-related occurred in seven of 48 participants in part B (eight of 21 in the prime-boost group and three of 21 in the coadministration group). Local reactogenicity in the vaccine groups was common, but the frequency and severity of reactogenicity signs or symptoms did not differ between the prime-boost and coadministration groups (eg, 20 [95%] of 21 in the prime-boost group vs 21 [100%] of 21 in the coadministration group had either local pain or tenderness of any severity [p=1·00], and seven [33%] vs nine [43%] had either erythema or induration [p=0·97]), nor did laboratory safety measures. There were no delayed-type hypersensitivity reactions or vasculitis or any severe clinical adverse events related to vaccination. The most frequently reported systemic reactogenicity symptoms in the active vaccine groups were malaise or fatigue (five [50%] of ten in part A and 17 [81%] of 21 in the prime-boost group vs 15 [71%] of 21 in the coadministration group in part B), headache (five [50%] and 18 [86%] vs 12 [57%]), and myalgia (four [40%] and 13 [62%] vs ten [48%]), mostly of mild or moderate severity.

INTERPRETATION

Both vaccine regimens were safe, warranting evaluation in larger trials.

FUNDING

US National Institutes of Health and US National Institute of Allergy and Infectious Diseases.

Optimizing the Immunogenicity of HIV Vaccines by Adjuvants - NIAID Workshop Report

This report summarizes the highlights of a workshop convened by the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), on April 4-5, 2022, to provide a discussion forum for sharing insights on the current status, key challenges, and next steps to advance the current landscape of promising adjuvants in preclinical and clinical human immunodeficiency virus (HIV) vaccine studies. A key goal was to solicit and share recommendations on scientific, regulatory, and operational guidelines for bridging the gaps in rational selection, access, and formulation of clinically relevant adjuvants for HIV vaccine candidates. The NIAID Vaccine Adjuvant Program working group remains committed to accentuate promising adjuvants and nurturing collaborations between adjuvant and HIV vaccine developers.

HIV-1 Vaccine Sequences Impact V1V2 Antibody Responses: A Comparison of Two Poxvirus Prime gp120 Boost Vaccine Regimens

In the RV144 trial, vaccine-induced V1V2 IgG correlated with decreased HIV-1 risk. We investigated circulating antibody specificities in two phase 1 poxvirus prime-protein boost clinical trials conducted in South Africa: HVTN 097 (subtype B/E) and HVTN 100 (subtype C). With cross-subtype peptide microarrays and multiplex binding assays, we probed the magnitude and breadth of circulating antibody responses to linear variable loop 2 (V2) and conformational V1V2 specificities. Antibodies targeting the linear V2 epitope, a correlate of decreased HIV-1 risk in RV144, were elicited up to 100% and 61% in HVTN 097 and HVTN 100, respectively. Despite higher magnitude of envelope-specific responses in HVTN 100 compared to HVTN 097 (p’s < 0.001), the magnitude and positivity for V2 linear epitope and V1V2 proteins were significantly lower in HVTN 100 compared to HVTN 097. Meanwhile, responses to other major linear epitopes including the variable 3 (V3) and constant 5 (C5) epitopes were higher in HVTN 100 compared to HVTN 097. Our data reveal substantial differences in the circulating antibody specificities induced by vaccination in these two canarypox prime-protein boost trials. Our findings suggest that the choice of viral sequences in prime-boost vaccine regimens, and potentially adjuvants and immunogen dose, influence the elicitation of V2-specific antibodies.

Safety and immune responses after a 12-month booster in healthy HIV-uninfected adults in HVTN 100 in South Africa: A randomized double-blind placebo-controlled trial of ALVAC-HIV (vCP2438) and bivalent subtype C gp120/MF59 vaccines

BACKGROUND

HVTN 100 evaluated the safety and immunogenicity of an HIV subtype C pox-protein vaccine regimen, investigating a 12-month booster to extend vaccine-induced immune responses.

METHODS AND FINDINGS

A phase 1-2 randomized double-blind placebo-controlled trial enrolled 252 participants (210 vaccine/42 placebo; median age 23 years; 43% female) between 9 February 2015 and 26 May 2015. Vaccine recipients received ALVAC-HIV (vCP2438) alone at months 0 and 1 and with bivalent subtype C gp120/MF59 at months 3, 6, and 12. Antibody (IgG, IgG3 binding, and neutralizing) and CD4+ T-cell (expressing interferon-gamma, interleukin-2, and CD40 ligand) responses were evaluated at month 6.5 for all participants and at months 12, 12.5, and 18 for a randomly selected subset. The primary analysis compared IgG binding antibody (bAb) responses and CD4+ T-cell responses to 3 vaccine-matched antigens at peak (month 6.5 versus 12.5) and durability (month 12 versus 18) timepoints; IgG responses to CaseA2_gp70_V1V2.B, a primary correlate of risk in RV144, were also compared at these same timepoints. Secondary and exploratory analyses compared IgG3 bAb responses, IgG bAb breadth scores, neutralizing antibody (nAb) responses, antibody-dependent cellular phagocytosis, CD4+ polyfunctionality responses, and CD4+ memory sub-population responses at the same timepoints. Vaccines were generally safe and well tolerated. During the study, there were 2 deaths (both in the vaccine group and both unrelated to study products). Ten participants became HIV-infected during the trial, 7% (3/42) of placebo recipients and 3% (7/210) of vaccine recipients. All 8 serious adverse events were unrelated to study products. Less waning of immune responses was seen after the fifth vaccination than after the fourth, with higher antibody and cellular response rates at month 18 than at month 12: IgG bAb response rates to 1086.C V1V2, 21.0% versus 9.7% (difference = 11.3%, 95% CI = 0.6%-22.0%, P = 0.039), and ZM96.C V1V2, 21.0% versus 6.5% (difference = 14.5%, 95% CI = 4.1%-24.9%, P = 0.004). IgG bAb response rates to all 4 primary V1V2 antigens were higher 2 weeks after the fifth vaccination than 2 weeks after the fourth vaccination: 87.7% versus 75.4% (difference = 12.3%, 95% CI = 1.7%-22.9%, P = 0.022) for 1086.C V1V2, 86.0% versus 63.2% (difference = 22.8%, 95% CI = 9.1%-36.5%, P = 0.001) for TV1c8.2.C V1V2, 67.7% versus 44.6% (difference = 23.1%, 95% CI = 10.4%-35.7%, P < 0.001) for ZM96.C V1V2, and 81.5% versus 60.0% (difference = 21.5%, 95% CI = 7.6%-35.5%, P = 0.002) for CaseA2_gp70_V1V2.B. IgG bAb response rates to the 3 primary vaccine-matched gp120 antigens were all above 90% at both peak timepoints, with no significant differences seen, except a higher response rate to ZM96.C gp120 at month 18 versus month 12: 64.5% versus 1.6% (difference = 62.9%, 95% CI = 49.3%-76.5%, P < 0.001). CD4+ T-cell response rates were higher at month 18 than month 12 for all 3 primary vaccine-matched antigens: 47.3% versus 29.1% (difference = 18.2%, 95% CI = 2.9%-33.4%, P = 0.021) for 1086.C, 61.8% versus 38.2% (difference = 23.6%, 95% CI = 9.5%-37.8%, P = 0.001) for TV1.C, and 63.6% versus 41.8% (difference = 21.8%, 95% CI = 5.1%-38.5%, P = 0.007) for ZM96.C, with no significant differences seen at the peak timepoints. Limitations were that higher doses of gp120 were not evaluated, this study was not designed to investigate HIV prevention efficacy, and the clinical significance of the observed immunological effects is uncertain.

CONCLUSIONS

In this study, a 12-month booster of subtype C pox-protein vaccines restored immune responses, and slowed response decay compared to the 6-month vaccination.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02404311. South African National Clinical Trials Registry (SANCTR number: DOH--27-0215-4796).

Subtype C ALVAC-HIV and bivalent subtype C gp120/MF59 HIV-1 vaccine in low-risk, HIV-uninfected, South African adults: a phase 1/2 trial

BACKGROUND

Modest efficacy was reported for the HIV vaccine tested in the RV144 trial, which comprised a canarypox vector (ALVAC) and envelope (env) glycoprotein (gp120). These vaccine components were adapted to express HIV-1 antigens from strains circulating in South Africa, and the adjuvant was changed to increase immunogenicity. Furthermore, 12-month immunisation was added to improve durability. In the HIV Vaccine Trials Network (HVTN) 100 trial, we aimed to assess this new regionally adapted regimen for advancement to efficacy testing.

METHODS

HVTN 100 is a phase 1/2, randomised controlled, double-blind trial at six community research sites in South Africa. We randomly allocated adults (aged 18-40 years) without HIV infection and at low risk of HIV infection to either the vaccine regimen (intramuscular injection of ALVAC-HIV vector [vCP2438] at 0, 1, 3, 6, and 12 months plus bivalent subtype C gp120 and MF59 adjuvant at 3, 6, and 12 months) or placebo, in a 5:1 ratio. Randomisation was done by computer-generated list. Participants, investigators, and those assessing outcomes were masked to random assignments. Primary outcomes included safety and immune responses associated with correlates of HIV risk in RV144, 2 weeks after vaccination at 6 months (month 6·5). We compared per-protocol participants (ie, those who completed the first four vaccinations and provided samples at month 6·5) from HVTN 100 with stored RV144 samples assayed contemporaneously. This trial is registered with the South African National Clinical Trials Registry (DOH-27-0215-4796) and ClinicalTrials.gov (NCT02404311).

FINDINGS

Between Feb 9, 2015, and May 26, 2015, 252 participants were enrolled, of whom 210 were assigned vaccine and 42 placebo. 222 participants were included in the per-protocol analysis (185 vaccine and 37 placebo). 185 (100%) vaccine recipients developed IgG binding antibodies to all three vaccine-matched gp120 antigens with significantly higher titres (3·6-8·8 fold; all p<0·0001) than the corresponding vaccine-matched responses of RV144. The CD4+ T-cell response to the ZM96.C env protein in HVTN 100 was 56·4% (n=102 responders), compared with a response of 41·4% (n=79 responders) to 92TH023.AE in RV144 (p=0·0050). The IgG response to the 1086.C variable loops 1 and 2 (V1V2) env antigen in HVTN 100 was 70·5% (95% CI 63·5-76·6; n=129 responders), lower than the response to V1V2 in RV144 (99·0%, 95% CI 96·4-99·7; n=199 responders).

INTERPRETATION

Although the IgG response to the HVTN 100 vaccine was lower than that reported in RV144, it exceeded the predicted 63% threshold needed for 50% vaccine efficacy using a V1V2 correlate of protection model. Thus, the subtype C HIV vaccine regimen qualified for phase 2b/3 efficacy testing, a critical next step of vaccine development.

FUNDING

US National Institute of Allergy and Infectious Diseases (NIAID), and Bill & Melinda Gates Foundation.

Lack of interaction of circulating T cells with phytohemagglutinin in bacillary positive untreated lepromatous leprosy patients--identification of subpopulation of lymphocytes by shifts in electrophoretic mobility

Incubation of human peripheral blood lymphocytes from normal healthy subjects with phytohamagglutinin (PHA), causes the reduction of the surface charge of a subpopulation of T cells by 1363 +/- 242 e.s.u./cm2. The affected subpopulation was predominantly the high charge-bearing cells identifiable with early (10 min) rosette-forming cells with sheep erythrocytes. Purified lymphocytes obtained from untreated bacillary-positive, lepromatous leprosy patients contained high charge-bearing T lymphocyte subpopulation. However, incubation with PHA did not result in the shift of electrophoretic mobility of these cells, suggesting the absence of interacting sites for the mitogen on the surface of these cells. The absence of mitogen-interacting sites is not an inherent trait of leprosy patients; the surface charge of lymphocytes from Dapsone-treated bacillary-negative subjects was reduced upon incubation with PHA. A close correlation was found between the number of cells whose charge alters on incubation with PHA and the transformation index obtained with this mitogen.

The effect of nutritional status on immune capacity and immune responses in preschool children in a rural community in India

Cell-mediated immune response (CMI) and several aspects of humoral immune status and response were measured and related to nutritional status in preschool children in north India. CMI was measured by means of postvaccinal (BCG) tuberculin sensitivity and leucocytic blast cell transformation. Humoral immune response was measured by means of tetanus antibody production following vaccination with diphtheria-pertussis-tetanus vaccine. Immunoglobulins A, G, and M and complement (C(3)) were also determined. CMI, serum IgA, and C(3) were found to be directly correlated with weight-for-age status.

Evaluation of cell mediated immune responses in untreated cases of leprosy

Twenty-three leprosy patients have been studied in an endemic area before institution of chemotherapy. These were comprised of ten lepromatous leprosy, four borderline lepromatous and nine tuberculoid leprosy cases on basis of clinical features, bacteriological and marphological indices. Histopathology of skin biopsies classified two as truly polar lepromatous leprosy (LL) and three as polar tuberculoid (TT), while the remaining eighteen were at various stages of evolution towards lepromatous or tuberculoid end of the spectrum. All lepromatous and borderline leprosy patients showed negative delayed hypersensitivity reaction with lepromin, but six out of fourteen patients in this category gave positive reaction with PPD. Blast transformation with PHA of peripheral leucocytes from all cases of lepromatous leprosy cultured in standard AB serum was depressed in comparison with cells from normal controls. ³H-thymidine incorporation in DNA of leucocytes in presence of leprolin was lower in cells of lepromatous leprosy group as compared to those from tuberculoid and borderline cases. There was lack of production of macrophage aggregation factor in all except one case of lepromatous leprosy while the test for this factor was positive for most of the tuberculoid leprosy patients. The homing characteristics of lymphocytes tagged with ⁵¹Chromium into liver and spleen of test mice were altered from the normal pattern in a large number of leprosy cases.

Influence of chemotherapy and serum factors on the mitogenic response of peripheral leucocytes of leprosy patients to phytohaemagglutinin

Mitogenic response to phytohaemagglutinin (PHA) of peripheral leucocytes from patients with polar forms of leprosy namely lepromatous leprosy (LL) and tuberculoid leprosy (TT) has been evaluated. No defect in blast transformation as assessed by the incorporation of ³H-thymidine into DNA was observed in tuberculoid leprosy patients. In lepromatous leprosy patients, the response varied with the status of the patient. Leucocytes from untreated cases of lepromatous leprosy showed a depressed response to PHA, whereas the leucocytes from patients treated with diaminodiphenylsulphone (DDS) gave an enhanced response. While the functional deficit was manifest in cells, the plasma factors were found to be contributory agents to the type of response elicited. Factors influencing the transformation of peripheral leucocytes have also been studied.