Pharmacokinetic interaction assessment of an HIV broadly neutralizing monoclonal antibody VRC07-523LS: a cross-protocol analysis of three phase 1 trials in people without HIV.

VRC07-523LS is a safe and well-tolerated monoclonal antibody (mAb) targeting the CD4 binding site on the HIV envelope (Env) trimer. Efficacy of VRC07-523LS, in combination with mAbs targeting other HIV epitopes, will be evaluated in upcoming trials to prevent HIV acquisition in adults. However, differences in the pharmacokinetics (PK) of VRC07-523LS when administered alone vs. in combination with other mAbs have not been formally assessed. We performed a cross-protocol analysis of three clinical trials and included data from a total of 146 adults without HIV who received intravenous (n = 95) or subcutaneous (n = 51) VRC07-523LS, either alone (single; n = 100) or in combination with 1 or 2 other mAbs (combined; n = 46). We used an open, two-compartment population PK model to describe serum concentrations of VRC07-523LS over time, accounting for inter-individual variabilities. We compared individual-level PK parameters between the combined vs. single groups using the targeted maximum likelihood estimation method to adjust for participant characteristics. No significant differences were observed in clearance rate, inter-compartmental clearance, distribution half-life, or total VRC07-523LS exposure over time. However, for the combined group, mean central volume of distribution, peripheral volume of distribution, and elimination half-life were slightly greater, corresponding to slightly lower predicted concentrations early post-administration with high levels being maintained in both groups. These results suggest potential PK interactions between VRC07-523LS and other mAbs, but with small clinical impact in the context of HIV prevention. Our findings support coadministration of VRC07-523LS with other mAbs, and the use of the developed PK models to design future trials for HIV prevention

Retrospective analysis of sex-disaggregated immune responses to ALVAC-HIV and bivalent subtype C gp120/MF59 HIV vaccines

IntroductionGenerally, individuals assigned female at birth (AFAB) develop greater immunogenicity to various vaccines than individuals assigned male at birth (AMAB). Little is known about sex-disaggregated immunogenicity to HIV-1 vaccines. We disaggregated immune responses to an experimental HIV vaccine regimen.MethodsWe retrospectively analyzed data from HVTN 100, a clinical trial conducted in South Africa during which 143 adults AMAB and 109 AFAB aged 18–40 years without HIV received ALVAC-HIV vCP2438 plus bivalent subtype C gp120/MF59 or placebo at 0, 1, 3, 6, and 12 months. Eligible data were from per-protocol vaccine recipients at month 6.5. We measured IgG binding antibodies, neutralizing antibodies, antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and CD4+ IFNγ and/or II-2 responses. We compared sex-based differences in response rates using Barnard’s test and response magnitudes using Wilcoxon Rank Sum test. P-values were Holm-adjusted for multiple comparisons.ResultsOf 185 vaccine recipients, 73 were AFAB and 112 were AMAB. Vaccine recipients AFAB had greater ADCC response rate (57.5% versus 29.5%; padj = 0.0003) and greater ADCC magnitude (area under the net % granzyme B activity vs log10 curve (AUC), 16.1 versus 11.2; padj = 0.05) to vaccine-matched antigen TV1.C gp120 compared to AMAB. Vaccine recipients AMAB had higher CD4+ T cell response rates to 2/3 vaccine-matched antigens at month 6.5 (ZM96.C gp120, [54.1% versus 36.8%; padj = 0.04]; 1086.C gp120, [44.1% versus 29.4%; padj = 0.05]) than AFAB. CD4+ T cell response magnitudes were similar by sex. IgG binding antibody response rate to B.CaseA V1V2 antigen (associated with reduced HIV acquisition risk in the RV144 trial) was 56.8% among AMAB vaccine recipients versus 38.9% among AFAB (padj = 0.08). There were no sex-based differences in neutralizing antibody or ADCP responses.DiscussionWe identified sex-based differences in immune responses to an HIV vaccine regimen, but they varied by immunologic assay. While vaccine recipients AFAB demonstrated higher ADCC responses, AMAB exhibited higher CD4+ T cell response rates. Future analyses should investigate whether vaccine factors such as platform, dosing and adjuvants contribute to sex-based differences in immunogenicity of experimental HIV vaccines

Safety, tolerability, pharmacokinetics, and immunological activity ...

This phase 1 study showed the feasibility of combining anti-HIV bnAbs targeting different sites on the HIV envelope in people living without HIV. It also showed that the dual-antibody and triple-antibody combinations were as effective as the individual antibodies at neutralisation, thus justifying a combination approach going forward for additional monoclonal antibody studies for HIV prevention. The fact that modelling predicted the combination neutralisation titre on the basis of the single antibody titres will be valuable for future trial design of different antibody combinations

Pharmacokinetic interaction assessment of an HIV broadly neutralizing monoclonal antibody VRC07-523LS: a cross-protocol analysis of three phase 1 trials in people without HIV

VRC07-523LS is a safe and well-tolerated monoclonal antibody (mAb) targeting the CD4 binding site on the HIV envelope (Env) trimer. Efficacy of VRC07-523LS, in combination with mAbs targeting other HIV epitopes, will be evaluated in upcoming trials to prevent HIV acquisition in adults. However, differences in the pharmacokinetics (PK) of VRC07-523LS when administered alone vs. in combination with other mAbs have not been formally assessed. We performed a cross-protocol analysis of three clinical trials and included data from a total of 146 adults without HIV who received intravenous (n = 95) or subcutaneous (n = 51) VRC07-523LS, either alone (‘single’; n = 100) or in combination with 1 or 2 other mAbs (‘combined’; n = 46). We used an open, two-compartment population PK model to describe serum concentrations of VRC07-523LS over time, accounting for inter-individual variabilities. We compared individual-level PK parameters between the combined vs. single groups using the targeted maximum likelihood estimation method to adjust for participant characteristics. No significant differences were observed in clearance rate, inter-compartmental clearance, distribution half-life, or total VRC07-523LS exposure over time. However, for the combined group, mean central volume of distribution, peripheral volume of distribution, and elimination half-life were slightly greater, corresponding to slightly lower predicted concentrations early post-administration with high levels being maintained in both groups. These results suggest potential PK interactions between VRC07-523LS and other mAbs, but with small clinical impact in the context of HIV prevention. Our findings support coadministration of VRC07-523LS with other mAbs, and the use of the developed PK models to design future trials for HIV prevention

Immunologic detection of <i>Giardia duodenalis</i> in a specific pathogen–free captive olive baboon (<i>Papio cynocephalus anubis</i>) colony

Several commercial Giardia immunoassays were evaluated in baboons for sensitivity and specificity as well as ease of use in a large specific pathogen–free (SPF) colony. An additional objective was to identify the assemblage(s) of Giardia duodenalis present in this baboon colony. A direct immunofluorescent antibody test (IFAT) was used as the reference test. Tests evaluated were a patient-side rapid test for dogs and cats, a human rapid test, and a well-plate ELISA designed for use with humans. Test sensitivities and specificities were compared using the McNemar paired t-test and were further evaluated for agreement using an unweighted Cohen kappa statistic. When compared to the IFAT reference, both human tests were more sensitive than the veterinary test. Based on PCR and sequencing of the G. duodenalis small-subunit ribosomal RNA and glutamate dehydrogenase loci, assemblage AI was present in this baboon colony. We found that 10 of the 110 (9%) baboons in this SPF colony were infected with a zoonotic strain of G. duodenalis. </jats:p

Comparison of diagnostic techniques for detection of Giardia duodenalis in dogs and cats

Abstract Background An evaluation of currently available in‐clinic diagnostic tests for Giardia duodenalis infection of dogs and cats has not been performed. In addition, there is discordance among published diagnostic comparisons. The absence of a true gold standard for detecting Giardia duodenalis also complicates diagnostic evaluations. Objectives To evaluate diagnostic tests commercially available in the United States for detecting Giardia duodenalis in dogs and cats, in comparison to a widely used reference test, the direct immunofluorescent assay (IFA), and also to compare the results of 2 methods of analysis: comparison of diagnostic tests to a reference test (IFA) and Bayesian analysis. Animals Fecal samples from a convenience sample of 388 cats and dogs located in Colorado, Oklahoma, and Virginia. Methods Fecal samples were tested for Giardia duodenalis by zinc sulfate centrifugal fecal flotation and 4 different commercial diagnostic immunoassays. Results were analyzed via Bayesian analysis and by comparison to the IFA as the reference test. Results Sensitivity and specificity by comparison to IFA was ≥82% and ≥90%, respectively, for all diagnostic tests in dogs and cats. When analyzed via Bayesian analysis, sensitivity and specificity were ≥83% and ≥95%, respectively. When ZnSO4 centrifugal fecal flotation results were combined with immunoassay results, there was no longer a significant difference between the sensitivities of the commercial in‐clinic immunoassays. Conclusion and Clinical Relevance The Bayesian analysis validates using IFA as the reference test. Differences in commercial in‐clinic immunoassay sensitivities can be mitigated when the results are combined with ZnSO4 centrifugal fecal flotation results

Data presented in Multi-trial analysis of HIV-1 envelope gp41-reactive antibodies among global recipients of candidate HIV-1 vaccines

This folder contains datasets analyzed in the manuscript: Multi-trial analysis of HIV-1 envelope gp41-reactive antibodies among global recipients of candidate HIV-1 vaccines. Frontiers in Immunology Sec. Vaccines and Molecular Therapeutics doi: 10.3389/fimmu.2022.983313</p