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IntroductionVesatolimod is a Toll-like receptor-7 (TLR7) agonist in clinical development as part of a combination regimen for human immunodeficiency virus (HIV) cure. Influenza-like symptoms associated with TLR7-mediated immune activation have been reported in clinical trials of vesatolimod. Therefore, a broader understanding of the safety profile of vesatolimod and association with dose and mechanism of action will help inform future clinical studies.MethodsIn this analysis, data on flu-like adverse events of interest (AEIs) were pooled from eight clinical studies in which 606 participants either received single or multiple doses of vesatolimod (0.3–12 mg; n = 505) or placebo (n = 101). Vesatolimod pharmacokinetics, inflammatory responses, and pharmacodynamics were assessed.ResultsThe incidence of flu-like AEIs was higher with vesatolimod versus placebo (19% [96/505] vs. 8% [8/101]) and increased with vesatolimod dose and exposure. Most flu-like AEIs with vesatolimod were grade 1 or 2 severity (55% [53 of 96] grade 1; 35% [34 of 96] grade 2) with onset primarily after the first and second dose. Occurrence of flu-like AEIs after doses 1–3 was predictive of reoccurrence after later doses. Dose-dependent elevations of pharmacodynamic biomarkers (interferon-stimulated gene 15, 2′-5′-oligoadenylate synthetase 1, myxovirus resistance-1, interferon-α, interleukin-1 receptor antagonist, interferon-γ-induced protein 10, interferon-inducible T-cell-α chemoattractant) observed in participants with flu-like AEIs suggest a link with vesatolimod mechanism of action.ConclusionsFlu-like AEIs associated with vesatolimod administration were typically mild but increased with exposure, which may be predicted by the response to initial doses. The data suggest that adaptive clinical monitoring could help maximize pharmacodynamic responses and balance adverse events in future clinical trials of vesatolimod.

Building on results from the AELIX-002 trial with HIVACAT T-cell immunogen (HTI)-based vaccines, the AELIX-003 (NCT04364035) trial tested the safety of the combination of ChAdOx1.HTI (C) and MVA.HTI (M), with the TLR7 agonist vesatolimod (VES), in a double-blind, placebo-controlled, randomized clinical trial in 50 virally suppressed early-treated men with HIV-1 infection. Secondary objectives included immunogenicity and effects on viral rebound kinetics during a 24-week antiretroviral treatment interruption (ATI). The most common treatment-related adverse events were mild-to-moderate injection-site pain, influenza-like illness, headache, and fatigue. Strong, broad, and HTI-focused T-cell responses were induced by vaccination. All participants experienced viral rebound in ATI; 33.3% and 23.5% ( P  = 0.4494) of CCMM + VES and placebo recipients, respectively, remained off antiretroviral therapy for 24 weeks. Post hoc analysis confirmed a correlation between levels of HTI-specific T cells and prolonged time off antiretroviral therapy. The combination of HTI vaccines and VES was safe and elicited robust T-cell responses. Here the authors report results from a randomized clinical trial testing a combination of ChAOx1/MVA.HTI vaccines and the TLR7 agonist vesatolimod in men living with HIV-1. While the treatment showed a good safety profile and induction of HTI-focused T-cell responses, viral rebound was similar in treatment arm and placebo arm.

Integrin binding to ligand plays essential roles in the differentiation and function of mammalian cells. β2 integrins in leukocytes are needed for migration to sites of inflammation and in lymph nodes as well as for cellular events such as phagocytosis and the formation of the conjugates between T cells and antigen-presenting cells. In T cells, integrin adhesion is activated primarily by the antigen-receptor (TCR complex) and chemokines in a process known as ‘inside-out’ signalling. Great progress has been made in identifying mutations that are responsible for leukocyte adhesion deficiency (LAD) syndromes, a disorder that presents with an impaired ability to clear pathogens and recurrent life-threatening infections. LAD mutations have been identified with defects in integrins, fucosylation and in the new intracellular mediator kindlin-3. Here, we review the key players in the ‘inside-out’ and ‘outside-in’ signalling pathways that will serve as new potential targets in the design of novel therapeutics to treat various immunodeficiencies.

Background Immune cell adaptor protein ADAP (adhesion and degranulation-promoting adaptor protein) mediates aspects of T-cell adhesion and proliferation. Despite this, a connection between ADAP and infection by the HIV-1 (human immunodeficiency virus-1) has not been explored. Results In this paper, we show for the first time that ADAP and its binding to SLP-76 (SH2 domain-containing leukocyte protein of 76 kDa) regulate HIV-1 infection via two distinct mechanisms and co-receptors. siRNA down-regulation of ADAP, or expression of a mutant that is defective in associating to its binding partner SLP-76 (termed M12), inhibited the propagation of HIV-1 in T-cell lines and primary human T-cells. In one step, ADAP and its binding to SLP-76 were needed for the activation of NF-κB and its transcription of the HIV-1 long terminal repeat (LTR) in cooperation with ligation of co-receptor CD28, but not LFA-1. In a second step, the ADAP-SLP-76 module cooperated with LFA-1 to regulate conjugate formation between T-cells and dendritic cells or other T-cells as well as the development of the virological synapse (VS) and viral spread between immune cells. Conclusions These findings indicate that ADAP regulates two steps of HIV-1 infection cooperatively with two distinct receptors, and as such, serves as a new potential target in the blockade of HIV-1 infection.

The following sections are included: INTRODUCTION MECHANISM OF RNA INTERFERENCE MICRORNAS GENERAL APPLICATIONS OF RNAI RNAi as a tool for gene analysis siRNA as therapeutics RNAi as a tool for Nature Product Research CONCLUSIONS REFERENCES