HIV-1 non-group M phenotypic susceptibility to integrase strand transfer inhibitors

In vitro phenotypic susceptibility of HIV-1 non-group M to CCR5 inhibitor (maraviroc): TROPI-CO study

The susceptibility of genetically divergent HIV-1 strains (HIV-1 non-M) from groups O, N, and P to the CCR5 co-receptor antagonist, maraviroc (MVC), was investigated among a large panel of 45 clinical strains, representative of the viral genetic diversity. The results were compared to the reference strains of HIV-1 group M (HIV-1/M) with known tropism. Among the non-M strains, a wide range of phenotypic susceptibilities to MVC were observed. The large majority of HIV-1/O strains (40/42) displayed a high susceptibility to MVC, with median and mean IC50 values of 1.23 and 1.33 nM, respectively, similar to the HIV-1/M R5 strain (1.89 nM). However, the two remaining HIV-1/O strains exhibited a lower susceptibility (IC50 at 482 and 496 nM), in accordance with their dual/mixed (DM) tropism. Interestingly, the two HIV-1/N strains demonstrated varying susceptibility patterns, despite always having relatively low IC50 values (2.87 and 47.5 nM). This emphasized the complexity of determining susceptibility solely based on IC50 values. Our study examined the susceptibility of all HIV-1 non-M groups to MVC and correlated these findings with virus tropism (X4, R5, or DM). The results confirm the critical significance of tropism determination before initiating MVC treatment in patients infected with HIV-1 non-M. Furthermore, we advocate for the consideration of additional parameters, such as the slope of inhibition curves, to provide a more thorough characterization of phenotypic susceptibility profiles.

IMPORTANCE

Unlike HIV-1 group M, the scarcity of studies on HIV-1 non-M groups (O, N, and P) presents challenges in understanding their susceptibility to antiretroviral treatments, particularly due to their natural resistance to non-nucleoside reverse transcriptase inhibitors. The TROPI-CO study logically complements our prior investigations into integrase inhibitors and anti-gp120 efficacy. The largest panel of 45 non-M strains existing so far yielded valuable results on maraviroc (MVC) susceptibility. The significant variations in MVC IC50 reveal a spectrum of susceptibilities, with most strains displaying R5 tropism. Notably, the absence of MVC-resistant strains suggests a potential therapeutic avenue. The study also employs a robust novel cell-based phenotropism assay and identifies distinct groups of susceptibilities based on inhibition curve slopes. Our findings emphasize the importance of determining tropism before initiating MVC and provide crucial insights for selecting effective therapeutic strategies in the delicate context of HIV-1 non-M infections.

Nicotinamide mononucleotide impacts HIV-1 infection by modulating immune activation in T lymphocytes and humanized mice

BACKGROUND

HIV-1-associated immune activation drives CD4+ T cell depletion and the development of acquired immunodeficiency syndrome. We aimed to determine the role of nicotinamide mononucleotide (NMN), the direct precursor of nicotinamide adenine dinucleotide (NAD) co-enzyme, in CD4+ T cell modulation during HIV-1 infection.

METHODS

We examined HIV-1 integrated DNA or transcribed RNA, intracellular p24 protein, and T cell activation markers in CD4+ T cells including in vitro HIV-1-infected cells, reactivated patient-derived cells, and in HIV-1-infected humanized mice, under NMN treatment. RNA-seq and CyTOF analyses were used for investigating the effect of NMN on CD4+ T cells.

FINDINGS

We found that NMN increased the intracellular NAD amount, resulting in suppressed HIV-1 p24 production and proliferation in infected CD4+ T cells, especially in activated CD25+CD4+ T cells. NMN also inhibited CD25 expression on reactivated resting CD4+ T cells derived from cART-treated people living with HIV-1 (PLWH). In HIV-1-infected humanized mice, the frequency of CD4+ T cells was reconstituted significantly by combined cART and NMN treatment as compared with cART or NMN alone, which correlated with suppressed hyperactivation of CD4+ T cells.

INTERPRETATION

Our results highlight the suppressive role of NMN in CD4+ T cell activation during HIV-1 infection. It warrants future clinical investigation of NMN as a potential treatment in combination with cART in PLWH.

FUNDING

This work was supported by the Hong Kong Research Grants Council Theme-Based Research Scheme (T11-706/18-N), University Research Committee of The University of Hong Kong, the Collaborative Research with GeneHarbor (Hong Kong) Biotechnologies Limited and National Key R&D Program of China (Grant2021YFC2301900).

HIV-1 Non-Group M Strains and ART

To eliminate HIV infection, there are several elements to take into account to limit transmission and break viral replication, such as epidemiological, preventive or therapeutic management. The UNAIDS goals of screening, treatment and efficacy should allow for this elimination if properly followed. For some infections, the difficulty is linked to the strong genetic divergence of the viruses, which can impact the virological and therapeutic management of patients. To completely eliminate HIV by 2030, we must therefore also be able to act on these atypical variants (HIV-1 non-group M) which are distinct from the group M pandemic viruses. While this diversity has had an impact on the efficacy of antiretroviral treatment in the past, recent data show that there is real hope of eliminating these forms, while maintaining vigilance and constant surveillance, so as not to allow more divergent and resistant forms to emerge. The aim of this work is therefore to share an update on the current knowledge on epidemiology, diagnosis and antiretroviral agent efficacy of HIV-1 non-M variants.

HIV-1 non-group M phenotypic susceptibility in vitro to bictegravir and cabotegravir

OBJECTIVES

HIV-1 group O (HIV-1/O) is one of the four HIV-1 groups and is endemic in Cameroon, representing 1% of HIV-1 infections in the population. Around 50% of the strains of this group naturally show a mutation (Y181C) providing them with resistance to NNRTIs and making therapeutic management more difficult. Today, the WHO recommends the use of integrase strand transfer inhibitors (INSTIs) as first-line treatment. Bictegravir and cabotegravir are the two most recent INSTIs. Because of the genetic polymorphism of HIV-1/O, studies are required to evaluate their phenotypic susceptibility to these two drugs.

PATIENTS AND METHODS

We performed a phenotypic study on a large panel including 41 HIV-1/O clinical isolates and other rare non-group M HIV-1 (2 HIV-1/N and 1 HIV-1/P) to evaluate in vitro susceptibility to bictegravir and cabotegravir.

RESULTS

The results showed an overall susceptibility of non-group M strains to the two drugs compared with HIV-1 group M. There was no difference between the mean (min-max) IC50 of HIV-1/M [1.86 (0.93-4.12) and 5.24 (1.76-12.41) nM for bictegravir and cabotegravir, respectively] and HIV-1/non-M [2.17 (0.03-9.47) and 4.88 (0.02-15.64) nM for bictegravir and cabotegravir, respectively]. However, we found a significant difference between IC50 values for bictegravir and cabotegravir in the whole panel (P value < 0.001).

CONCLUSIONS

This study has shown encouraging results regarding the clinical use of these drugs in HIV-1/non-M-infected patients, which will need to be confirmed with clinical data.

Comparative Immunovirological and Clinical Responses to Antiretroviral Therapy Between HIV-1 Group O and HIV-1 Group M Infected Patients

BACKGROUND

Little is known about impact of genetic divergence of human immunodeficiency virus type 1 group O (HIV-1/O) relative to HIV-1 group M (HIV-1/M) on therapeutic outcomes. We aimed to determine if responses to standardized combination antiretroviral therapy (cART) were similar between groups despite strain divergence.

METHODS

We performed an open nonrandomized study comparing the immunological, virological, and clinical responses to cART based on 2 nucleoside reverse transcriptase inhibitors plus 1 ritonavir-boosted protease inhibitor, in naive and paired HIV-1/O vs HIV-1/M infected (+) patients (ratio 1:2), matched on several criteria. The primary endpoint was the proportion of patients with undetectable plasma viral load (pVL, threshold 60 copies/mL) at week (W) 48. Secondary endpoints were the proportion of patients with undetectable pVL at W24 and W96 and CD4 evolution between baseline and W24, W48, and W96.

RESULTS

Forty-seven HIV-1/O+ and 94 HIV-1/M+ patients were included. Mean pVL at baseline was significantly lower by 1 log for HIV-1/O+ vs HIV-1/M+ patients. At W48, no significant difference was observed between populations with undetectable pVL and differences at W24 and W96 were not significant. A difference in CD4 gain was observed in favor of HIV-1/M at W48 and W96, but this was not significant when adjusted on both matched criteria and pVL at baseline.

CONCLUSIONS

Our data demonstrate similar immunovirological and clinical response between HIV-1/O+ and HIV-1/M+ patients. They also reveal significantly lower baseline replication for HIV-1/O variants, suggesting specific virological properties and physiopathology that now need to be addressed.

CLINICAL TRIALS REGISTRATION

NCT00658346.

Impact of natural polymorphisms of HIV-1 non-group M on genotypic susceptibility to the attachment inhibitor fostemsavir

Background

Fostemsavir belongs to the new class of attachment inhibitors (AIs); it inhibits the entry of HIV into CD4+ T-lymphocytes by blocking conformational changes in gp120. This is a promising AI, but previous phenotypic data showed that genetically divergent HIV-1 group O could present natural resistance to this drug. These data were obtained from only two strains, which are not representative of the high intra-group genetic diversity. Moreover, no data are available concerning the other divergent HIV-1 groups (N and P).

Objectives

To further investigate the natural genotypic susceptibility of HIV-1 groups O, N and P (HIV-1 non-M) to fostemsavir, using a large set of sequences.

Methods

The frequency of eight substitutions associated with decreased susceptibility to fostemsavir (L116P, A204D, S375M/H, M426L, M434I, M475I and V506M), was investigated in 111 gp120 sequences from groups O (n = 100), N (n = 9) and P (n = 2).

Results

All HIV-1 group N sequences harboured the three substitutions S375M, M426L and M434I, whereas only 1% and 10% of HIV-1 group O sequences harboured the S375H + M426L and S375H + M434I patterns, respectively. The main genetic profile of HIV-1 groups P and O combined S375H with two atypical substitutions (M426S and M434L). Five group O sequences did not display any of the eight substitutions, but had atypical residues with unknown impact.

Conclusions

The genetic polymorphisms in the gp120 of HIV-1 non-M viruses support the hypothesis that these viruses could largely be resistant to inhibition by fostemsavir. Only 5% of group O strains could display full genetic susceptibility. Extensive phenotypic studies are now required.

Virological response to integrase strand transfer inhibitor-based antiretroviral combinations in HIV-1 group O-infected patients

: Although integrase strand transfer inhibitors (INSTIs) are widely used in HIV-1 group M (HIV-1/M) infections, little is known about their efficacy against genetically divergent HIV-1 group O (HIV-1/O) strains. Previous phenotypic works have demonstrated the variable susceptibility of HIV-1/O strains, depending on INSTI drugs. Clinical data are very limited and obtained from a few patients.

OBJECTIVES

To investigate the virological success rate of an INSTI-based combination of antiretroviral therapy (cART) in a large population of HIV-1/O-infected patients, and to describe resistance-associated mutations (RAM) at virological failure.

METHODS

The virological response of 39 patients receiving INSTI-based cART during their follow-up was analysed i) at the last point of the first INSTI initiation and ii) at their most recent visit. RAM analysis was performed at virological failures. Resistance interpretation was based on the French National Agency of Research on AIDS and viral hepatitis (ANRS) rules.

RESULTS

Virological success at both time points of analysis was high, with more than 87% of the patients with undetectable plasma viral load. Among the six patients with virological failure, three selected RAM described for HIV-1/M resistance, and two had already RAM, before INSTI initiation.

CONCLUSION

Our results show that HIV-1/O infected patients receiving INSTI-based cART presented a high rate of virological success whatever their previous lines; we have also shown that resistance rules for HIV-1/M could be considered when failure occurs. These data are of importance especially in the context of WHO recommendations for a wider use of this class.