Treatment with recombinant growth hormone is associated with modest improvement in CD4 lymphocyte reconstitution in HIV-infected persons on antiretroviral therapy: results of ACTG A5174

A Canadian Survey of Research on HIV-1 Latency-Where Are We Now and Where Are We Heading?

Worldwide, almost 40 million people are currently living with HIV-1. The implementation of cART inhibits HIV-1 replication and reduces viremia but fails to eliminate HIV-1 from latently infected cells. These cells are considered viral reservoirs from which HIV-1 rebounds if cART is interrupted. Several efforts have been made to identify these cells and their niches. There has been little success in diminishing the pool of latently infected cells, underscoring the urgency to continue efforts to fully understand how HIV-1 establishes and maintains a latent state. Reactivating HIV-1 expression in these cells using latency-reversing agents (LRAs) has been successful, but only in vitro. This review aims to provide a broad view of HIV-1 latency, highlighting Canadian contributions toward these aims. We will summarize the research efforts conducted in Canadian labs to understand the establishment of latently infected cells and how this informs curative strategies, by reviewing how HIV latency is established, which cells are latently infected, what methodologies have been developed to characterize them, how new compounds are discovered and evaluated as potential LRAs, and what clinical trials aim to reverse latency in people living with HIV (PLWH).

In vivo human keyhole limpet hemocyanin challenge in early phase drug development: A systematic review

Experimental exposure of healthy volunteers to the T-cell dependent neoantigen keyhole limpet hemocyanin (KLH) permits the evaluation of immunomodulatory investigational medicinal product (IMP) pharmacology prior to the recruitment of patient populations. Despite widespread use, no standardized approach to the design and conduct of such studies has been agreed. The objective of this systematic review was to survey the published literature where KLH was used as a challenge agent, describing methodology, therapeutic targets addressed, and pharmacodynamic outcome measures. We searched MEDLINE, EMBASE, clinicaltrials.gov, and Cochrane CENTRAL for studies using KLH challenge in humans between January 1, 1994, and April 1, 2022. We described key study features, including KLH formulation, dose, use of adjuvants, route of administration, co-administered IMPs, and end points. Of 2421 titles and abstracts screened, 46 met the inclusion criteria, including 14 (31%) early phase trials of IMP, of which 10 (71%) targeted T-cell co-stimulation. IMPs with diverse mechanisms demonstrated modulation of the humoral response to KLH, suggesting limited specificity of this end point. Two early phase IMP studies (14%) described the response to intradermal re-challenge (delayed type hypersensitivity). Challenge regimens for IMP assessment were often incompletely described, and exhibited marked heterogeneity, including primary KLH dose (25-fold variation: 100-2500 mcg), KLH formulation, and co-administration with adjuvants. Methodological heterogeneity and failure to exploit the access to tissue-level mechanism-relevant end points afforded by KLH challenge has impaired the translational utility of this paradigm to date. Future standardization, characterization, and methodological development is required to permit tailored, appropriately powered, mechanism-dependent study design to optimize drug development decisions.

Insulin-Like Growth Factor Is Associated with Changes in Body Composition with Antiretroviral Therapy Initiation

Growth hormone (GH)/insulin-like growth factor (IGF)-1 axis abnormalities have been associated with body composition changes among HIV-infected persons with wasting or lipodystrophy. Little is known of GH/IGF-1 axis alterations with antiretroviral therapy (ART) initiation or differing ART therapies. The AIDS Clinical Trials Group Prospective Evaluation of Antiretrovirals in Resource-Limited Settings (PEARLS) study was a prospective, randomized clinical trial of ART initiation with emtricitabine/tenofovir + efavirenz (FTC/TDF+EFV) versus lamivudine/zidovudine + efavirenz (3TC/ZDV+EFV) in HIV-1-infected individuals from resource-diverse settings. IGF-1 was measured from baseline, week 48, and week 96 stored serum samples. Multivariate models were constructed. 415 participants were included: 170 (41%) were randomized to FTC/TDF+EFV and 245 (59%) to 3TC/ZDV+EFV. The mean age was 35 years, 60% were black, 42% women. The mean IGF-1 level did not change significantly from baseline to week 96 (-0.65 ng/ml; 95% confidence interval (CI) -5.18-3.87), p = .78 and there were no differences by treatment arm at week 96, p = .74. Lower baseline IGF-1 was associated with age, non-white race, greater waist-hip ratio (WHR), low CD4 count, and lower baseline albumin (all p < .01) but not plasma HIV-1 RNA, body mass index, or treatment arm. Greater change in IGF-1 from baseline to 96 weeks was associated with female sex, smaller WHR change, lower baseline albumin, and higher baseline HIV-1 RNA (all p < .01). ART initiation with either ZDV or TDF did not significantly impact overall IGF-1 levels. Baseline and on-treatment changes in IGF-1 with ART initiation may be related to the body composition changes that occur after ART initiation.

Multifarious immunotherapeutic approaches to cure HIV-1 infection

Immunotherapy in the context of treated HIV-1 infection aims to improve immune responses to achieve better control of the virus. To date, multifaceted immunotherapeutic approaches have been shown to reduce immune activation and increase CD4 T-lymphocyte counts, further to the effects of antiretroviral therapy alone, in addition to improving HIV-1-specific T-cell responses. While sterilizing cure of HIV-1 would involve elimination of all replication-competent virus, a functional cure in which the host has long-lasting control of viral replication may be more feasible. In this commentary, we discuss novel strategies aimed at targeting the latent viral reservoir with cure of HIV-1 infection being the ultimate goal, an achievement that would have considerable impact on worldwide HIV-1 infection.

Therapeutic immunisation plus cytokine and hormone therapy improves CD4 T-cell counts, restores anti-HIV-1 responses and reduces immune activation in treated chronic HIV-1 infection

BACKGROUND

This randomised, open label, phase I, immunotherapeutic study investigated the effects of interleukin (IL)-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), recombinant human growth hormone (rhGH), and therapeutic immunisation (a Clade B DNA vaccine) on combination antiretroviral therapy (cART)-treated HIV-1-infected individuals, with the objective to reverse residual T-cell dysfunction.

METHODS

Twelve HIV-1(+) patients on suppressive cART with baseline CD4 T-cell counts >400 cells/mm(3) blood were randomised into one of three groups: (1) vaccine, IL-2, GM-CSF and rhGH (n=3); (2) vaccine alone (n=4); or (3) IL-2, GM-CSF and rhGH (n=5). Samples were collected at weeks 0, 1, 2, 4, 6, 8, 12, 16, 24 and 48. Interferon (IFN)-γ, IL-2, IL-4 and perforin ELISpot assays performed at each time point quantified functional responses to Gag p17/p24, Nef, Rev, and Tat peptides; and detailed T-cell immunophenotyping was undertaken by flow cytometry. Proviral DNA was also measured.

RESULTS

Median baseline CD4 T-cell count was 757 cells/mm(3) (interquartile range [IQR] 567-886 cells/mm(3)), median age 48 years (IQR 42-51 years), and plasma HIV-1-RNA <50 copies/ml for all subjects. Patients who received vaccine plus IL-2, GM-CSF and rhGH (group 1) showed the most marked changes. Assessing mean changes from baseline to week 48 revealed significantly elevated numbers of CD4 T cells (p=0.0083) and improved CD4/CD8 T-cell ratios (p=0.0033). This was accompanied by a significant reduction in expression of CD38 on CD4 T cells (p=0.0194), significantly increased IFN-γ and IL-2 production in response to Gag (p=0.0122) and elevated IFN-γ production in response to Tat (p=0.041) at week 48 compared to baseline. Subjects in all treatment groups showed significantly reduced PD-1 expression at week 48 compared to baseline, with some reductions in proviral DNA.

CONCLUSIONS

Multifarious immunotherapeutic approaches in the context of fully suppressive cART further reduce immune activation, and improve both CD4 T-lymphocyte counts and HIV-1-specific T-cell responses (NCT01130376).

A randomized controlled trial of palifermin (recombinant human keratinocyte growth factor) for the treatment of inadequate CD4+ T-lymphocyte recovery in patients with HIV-1 infection on antiretroviral therapy

BACKGROUND

Poor CD4 lymphocyte recovery on antiretroviral therapy (ART) is associated with reduced function of the thymus. Palifermin (keratinocyte growth factor), by providing support to the thymic epithelium, promotes lymphopoiesis in animal models of bone marrow transplantation and graft-versus-host disease.

METHODS

In AIDS Clinical Trials Group A5212, a randomized, double-blind, placebo-controlled study, 99 HIV-infected patients on ART with plasma HIV-1 RNA levels ≤200 copies per milliliter for ≥6 months and CD4 lymphocyte counts <200 cells per cubic milliliter were randomized 1:1:1:1 to receive once daily intravenous administration of placebo or 20, 40, or 60 μg/kg of palifermin on 3 consecutive days.

RESULTS

The median change in the CD4 T-cell count from baseline to week 12 was not significantly different between the placebo arm [15 (-16, 23) cells/mm] and the 20-μg/kg dose [11 (2, 32) cells/mm], the 40-μg/kg dose [12 (-2, 25) cells/mm], or the 60-μg/kg dose arm [8 (-13, 35) cells/mm] of palifermin. No significant changes were observed in thymus size or in the number of naive T cells or recent thymic emigrants.

CONCLUSIONS

Palifermin in the doses studied was not effective in improving thymic function and did not raise CD4 lymphocyte counts in HIV-infected patients with low CD4 cell counts despite virologically effective ART.

Immunodiscordant responses to HAART--mechanisms and consequences

A relevant fraction of HIV-1-infected individuals (ranging from 15 to 30%) presenting virologically successful highly active antiretroviral therapy fail to recover CD4 T-cell counts. These individuals, called immunodiscordant or immunological nonresponders, are at increased risk of clinical progression and death. Although older age, lower nadir CD4 T-cell count and HCV co-infection are some of clinical predictive factors, immunological mechanisms rely on impaired thymic production and accumulation of apoptosis-prone CD4 T cells. Indeed, immunodiscordant individuals may show increased tissue fibrosis and damage of gut-associated lymphoid tissue that results in higher hyperactivation, inflammation and immunosenescence, altered Treg/Th17 ratio and increased T-cell death. A better knowledge of the final pathogenic mechanism and factors influencing CD4 T-cell recovery will help to select the optimal therapeutic strategies for them.

Low-dose growth hormone for 40 weeks induces HIV-1-specific T cell responses in patients on effective combination anti-retroviral therapy

Recombinant human growth hormone (rhGH) administered to combination anti-retroviral therapy (cART)-treated human immunodeficiency virus-1 (HIV-1)-infected individuals has been found to reverse thymic involution, increase total and naive CD4 T cell counts and reduce the expression of activation and apoptosis markers. To date, such studies have used high, pharmacological doses of rhGH. In this substudy, samples from treated HIV-1(+) subjects, randomized to receive either a physiological dose (0·7 mg) of rhGH (n = 21) or placebo (n = 15) daily for 40 weeks, were assessed. Peptide-based enzyme-linked immunospot (ELISPOT) assays were used to enumerate HIV-1-specific interferon (IFN)-γ-producing T cells at baseline and week 40. Individuals who received rhGH demonstrated increased responses to HIV-1 Gag overlapping 20mer and Gag 9mer peptide pools at week 40 compared to baseline, whereas subjects who received placebo showed no functional changes. Subjects with the most robust responses in the ELISPOT assays had improved thymic function following rhGH administration, as determined using CD4(+) T cell receptor rearrangement excision circle (TREC ) and thymic density data from the original study. T cells from these robust responders were characterized further phenotypically, and showed decreased expression of activation and apoptosis markers at week 40 compared to baseline. Furthermore, CD4 and CD8 T cell populations were found to be shifted towards an effector and central memory phenotype, respectively. Here we report that administration of low-dose rhGH over 40 weeks with effective cART resulted in greater improvement of T lymphocyte function than observed with cART alone, and provide further evidence that such an approach could also reduce levels of immune activation.

Incomplete immune recovery in HIV infection: mechanisms, relevance for clinical care, and possible solutions

Treatment of HIV-infected patients with highly active antiretroviral therapy (HAART) usually results in diminished viral replication, increasing CD4+ cell counts, a reversal of most immunological disturbances, and a reduction in risk of morbidity and mortality. However, approximately 20% of all HIV-infected patients do not achieve optimal immune reconstitution despite suppression of viral replication. These patients are referred to as immunological nonresponders (INRs). INRs present with severely altered immunological functions, including malfunction and diminished production of cells within lymphopoetic tissue, perturbed frequencies of immune regulators such as regulatory T cells and Th17 cells, and increased immune activation, immunosenescence, and apoptosis. Importantly, INRs have an increased risk of morbidity and mortality compared to HIV-infected patients with an optimal immune reconstitution. Additional treatment to HAART that may improve immune reconstitution has been investigated, but results thus far have proved disappointing. The reason for immunological nonresponse is incompletely understood. This paper summarizes the known and unknown factors regarding the incomplete immune reconstitution in HIV infection, including mechanisms, relevance for clinical care, and possible solutions.

Growth hormone and HIV infection: contribution to disease manifestations and clinical implications

In untreated HIV patients growth hormone deficiency contributes to loss of lean and fat mass. Pharmacologic doses of growth hormone successfully reverse this wasting process. In patients responding to antiretroviral therapies several non AIDS-related complications usually common among older, uninfected persons now occur more frequently in younger HIV patients. Among these conditions are cardiovascular disease and metabolic disorders. Although their etiology is multifactorial, changes in growth hormone biology reflecting relative growth hormone deficiency occur and may be involved. In these patients truncal obesity, and associated dyslipidemia and glucose homeostasis changes contribute to impaired quality of life and increased cardiovascular risk. Treatment with growth hormone and growth hormone releasing factor leads to short-term improvement of some of these abnormalities. This paper will review abnormalities of growth hormone biology and the use of growth hormone and growth hormone releasing factor as therapeutic agents in HIV patients.