Lenacapavir: a first-in-class HIV-1 capsid inhibitor

Alignment of PrEP Use With Potential HIV Exposure in Young Women and Men in Uganda

BACKGROUND

Despite high oral pre-exposure prophylaxis (PrEP) uptake among young heterosexual cisgender women, early discontinuation is frequent. It is unclear whether this aligns with potential HIV exposure.

METHODS

Young women aged 16-25 years and ≥1 of their male partners were enrolled in separate but linked longitudinal HIV PrEP studies in Kampala, Uganda, from 2018 to 2021. Data on sexual behavior, PrEP use, sexually transmitted disease positivity, and Y chromosome DNA (Yc DNA; a marker for condomless sex) were collected at enrollment and quarterly visits. Potential HIV exposure was defined as one of the following in the past 3 months: any sexually transmitted disease, detection of Yc DNA, condomless vaginal sex, or multiple sex partners. Alignment between potential HIV exposure and PrEP use by participants was examined using generalized estimating equation (GEE) regression.

RESULTS

Eighty-eight young women (median age = 20.6 years, interquartile range 19.5-22.0) and 124 male partners (median age = 23.5 years, interquartile range 21.0-26.0) were included. Women and men were dispensed PrEP in 66.9% and 60.5% of their first linked visits, respectively. PrEP dispensation was more common when women or men self-reported condomless vaginal sex and multiple sex partners or when women had Yc DNA detected in vaginal swabs. Men's self-report of multiple partners (adjusted prevalence ratio = 1.56, P = 0.012) and the detection of Yc DNA (adjusted prevalence ratio = 1.52, P = 0.040) were significantly associated with women's PrEP dispensation.

CONCLUSIONS

Women and their male partners may align their PrEP use with their HIV risk behaviors, providing some reassurance that PrEP discontinuation in young people often aligns with sexual behavior. Greater attention to measurement of and mismatches in PrEP discontinuation and potential HIV exposure is needed.

Sustained virologic suppression of multidrug-resistant HIV in an individual treated with anti-CD4 domain 1 antibody and lenacapavir

The clinical management of people with multidrug-resistant (MDR) human immunodeficiency virus (HIV) remains challenging despite continued development of antiretroviral agents. A 58-year-old male individual with MDR HIV and Kaposi sarcoma (KS) was treated with a new antiretroviral regimen consisting of anti-CD4 domain 1 antibody UB-421 and capsid inhibitor lenacapavir. The individual experienced delayed but sustained suppression of plasma viremia and a substantial increase in the CD4+ T cell count. A longitudinal examination of plasma HIV and infectious isolates showed no evidence of viral evolution or the emergence of UB-421- or lenacapavir-resistant viruses. The individual received three cycles of liposomal doxorubicin and five doses of anti-programmed cell death protein 1 (PD-1) monoclonal antibody pembrolizumab that resulted in improvement in KS with flattening of lesions. Our data demonstrate that combination therapy with UB-421 could provide sustained virologic suppression in people harboring MDR HIV with limited therapeutic alternatives.

Effect of Food Intake or Coadministration With an Acid-Reducing Agent on Lenacapavir Pharmacokinetics Following Oral Administration

Lenacapavir is a potent, long-acting HIV-1 capsid inhibitor used in combination with other antiretrovirals to treat HIV-1 infection. The pharmacokinetics of orally administered drugs may be affected by food intake or coadministration of acid-reducing agents (ARA). Two Phase 1 studies were conducted on healthy participants to evaluate the effect of food and the impact of the histamine H2-receptor antagonist famotidine in parallel cohorts. In Study 1, oral lenacapavir (300 mg) was administered under fasting conditions, after a standardized high-fat meal, and after a low-fat meal (n = 8/cohort). In Study 2, lenacapavir 300 mg was administered alone (n = 27) and 2 hours after famotidine (40 mg; n = 25), each under fasting conditions. For the high-fat meal versus fasted comparison, the percentage geometric least-squares mean (%GLSM) ratios for the lenacapavir area under the curve to infinity (AUCinf) and maximum concentration (Cmax) were 115.2 and 145.2, respectively. For the low-fat meal, the %GLSM ratios for lenacapavir AUCinf and Cmax were 98.6 and 115.8, respectively, versus the fasted state. In the famotidine study, the %GLSM ratio for lenacapavir AUC from time zero to the last quantifiable concentration was 137.4, and for Cmax was 100.6. Based on available clinical safety data, the exposure increases observed in these studies were not expected to be clinically relevant. Overall, these data support the dosing of oral lenacapavir without regard to food intake or coadministration with ARAs.

Drug interactions in people with HIV treated with antivirals for other viral illnesses

INTRODUCTION

Background: People with HIV (PWH) have benefited tremendously from effective antiretroviral(ARV) treatments. However, PWH are at increased risk for other viral infections transmitted in the same way as HIV (such as hepatitis C and MPox) or that are opportunistic (e.g. cytomegalovirus). These coinfections contribute significantly to morbidity and mortality among PWH and require effective treatments to optimize patient outcomes. However, their management is complicated by drug-drug interactions (DDIs) with ARVs.

AREAS COVERED

Metabolism pathways and DDIs between approved ARVs and selected antiviral agents used for the treatment of common and clinically relevant viral coinfections are discussed. Literature review included search of published papers, conference abstracts (IAS, CROI, IDWeek, EACS, Glasgow) as well as unpublished data from approved drug prescribing information and regulatory submissions sourced from PubMed, Google, and Google Scholar available between June 30 1981 through June 1, 2024.

EXPERT OPINION

Management of drug interactions is essential for maintaining efficacy and safety of ARV and other co-administered antiviral therapies. Longer acting agents are now available for treatment of HIV and this lengthens the period during which drug interactions may occur. Emerging novel nanoparticle-carrier targeted hepatitis C and HIV treatments may mitigate, if not eliminate, their propensity for drug-drug interactions.

A New Synthesis of Enantiopure Amine Fragment: An Important Intermediate to the Anti-HIV Drug Lenacapavir

Herein, we describe a new seven-step approach to prepare (S)-1-(3,6-dibromopyridin-2-yl)-2-(3,5-difluorophenyl)ethan-1-amine ((S)-4) from the inexpensive 2-(3,5-difluorophenyl)acetic acid. The key steps in the sequence include (1) the Weinreb amide-based ketone synthesis to provide an entry point to the core structure; (2) simple functional group transformations to afford the racemic amine 4-rac; and (3) dynamic kinetic resolution (DKR) to access the chiral amine (S)-4. This seven-step process delivered the enantiopure amine (S)-4 in an overall isolated yield of approximately 15%. The process was demonstrated on a decagram scale, and the process requires no chromatographic purifications. Single-crystal X-ray crystallography measurements verified the chiral amine structure and absolute configuration.

Susceptibility Screening of HIV-1 Viruses to Broadly Neutralizing Antibodies, Teropavimab and Zinlirvimab, in People With HIV-1 Suppressed by Antiretroviral Therapy

BACKGROUND

HIV envelope (env) diversity may result in resistance to broadly neutralizing antibodies (bNAbs). Assessment of genotypic or phenotypic susceptibility to antiretroviral treatment is often performed in people with HIV-1 (PWH) and used for clinical trial screening for HIV-1 bNAb susceptibility. Optimal bNAb susceptibility screening methods are not yet clear.

METHODS

Phenotypic and genotypic analyses were conducted on 124 screening samples from a phase 1b study of bNAbs teropavimab (3BNC117-LS) and zinlirvimab (10-1074-LS) administered with lenacapavir in virally suppressed PWH. Phenotypic analysis was conducted on integrated HIV-1 provirus and stimulated outgrowth virus, with susceptibility to bNAbs defined as 90% inhibitory concentration ≤2 μg/mL. The proviral DNA HIV env gene was genotyped using deep sequencing, and bNAb susceptibility predicted using published env amino acid signatures.

RESULTS

Proviral phenotypic results were reported for 109 of 124 samples; 75% (82/109) were susceptible to teropavimab, 65% (71/109) to zinlirvimab, and 50% (55/109) to both bNAbs. Phenotypic susceptibility of outgrowth viruses was available for 39 samples; 56% (22/39) were susceptible to teropavimab, and 64% (25/39) to zinlirvimab. Phenotypic susceptibilities correlated between these methods: teropavimab r = 0.82 ( P < 0.0001); zinlirvimab r = 0.77 ( P < 0.0001). Sixty-seven samples had genotypic and phenotypic data. Proviral genotypic signatures predicted proviral phenotypic susceptibility with high positive predictive value (68%-86% teropavimab; 63%-90% zinlirvimab).

CONCLUSIONS

bNAb susceptibility was correlated among all 3 in vitro assays used to determine teropavimab and zinlirvimab susceptibility in virally suppressed PWH. These findings may help refine PWH selection criteria for eligibility for future studies.

Drug-drug interactions potential with the HIV-1 capsid inhibitor lenacapavir

INTRODUCTION

Lenacapavir is the first HIV-1 capsid inhibitor administered subcutaneously twice yearly. While lenacapavir is currently only indicated as salvage therapy, it has the potential to become a foundation of future treatments and to revolutionize HIV prevention.

AREAS COVERED

This review summarizes the pharmacology of lenacapavir with particular emphasis placed on its drug-drug interaction (DDI) potential as it is used in treatment-experienced individuals who often present multiple comorbidities and polypharmacy. The effect of lenacapavir on drug metabolizing enzymes and transporters as well as findings of DDI studies are summarized. These data were used to predict DDIs with 1073 comedications. Finally, the management of selected DDIs is discussed. Conferences/workshops abstracts (i.e. CROI, IAS, EACS, HIV Glasgow, PK workshop) were screened using the terms: 'lenacapavir,' 'capsid inhibitor,' 'GS-6207,' and a PubMed search was used to compile data until September 2024.

EXPERT OPINION

Lenacapavir has a favorable DDI profile with 80% of evaluated comedications estimated to have no clinically significant DDIs. More studies are needed to address pharmacological gaps including the pharmacokinetics of lenacapavir in special populations, its transfer across the blood-brain barrier or the placenta as well as the possibility to manage DDIs with moderate/strong inducers by reducing lenacapavir dosing interval.

Lenacapavir: Patient and healthcare provider perceptions and the potential role for a twice-yearly injectable HIV treatment

BACKGROUND

The twice-yearly, long-acting lenacapavir (LA LEN) antiretroviral therapy (ART), when combined with an optimised background regimen, provides a subcutaneous injectable treatment option for people with HIV. This study aimed to understand the preferences, barriers and facilitators for uptake and implementation of LA LEN, with a view to informing clinical implementation.

METHODS

In-depth qualitative interviews and focus groups with purposively sampled people with HIV and healthcare workers (HCWs) from UK HIV services were conducted. Transcripts were analysed using summative and conventional content analysis.

RESULTS

Thirty-four people with HIV with varied ART experience were recruited from two HIV services. Participants included 22 (65%) identifying as cisgender men and 12 (35%) identifying as cisgender women; median age was 55 years (range 26-76 years). Fourteen HIV HCWs took part in three focus groups. Four key themes and 12 subthemes were identified: LA LEN as a treatment option; LA LEN versus oral ART; switching considerations; and administration of LA LEN. The majority (88%) of people with HIV were interested in switching to LA LEN if offered. Preference was markedly reduced if an oral ART pairing was required. Convenience of the dosing schedule, reduced pill burden and issues around stigma were reasons for interest in LA LEN, but concerns regarding efficacy, dosing interval windows, monitoring and side effects were described. HCWs felt the benefit of LA LEN was as a treatment option for those with adherence issues, drug resistance and a high pill burden. Broader use of LA LEN raised concerns over drug resistance, delivery capacity and storage.

CONCLUSIONS

LA LEN was viewed as a preferable treatment choice for many people with HIV, provided an all-injectable regimen was available. Feasibility assessments for provision of injectable ART and research on its potential for self-administration are needed.

Efficacy and Safety of Switching to Daily Bictegravir Plus Lenacapavir From a Complex Human Immunodeficiency Virus Treatment Regimen: A Randomized, Open-Label, Multicenter Phase 2 Study (ARTISTRY-1)

BACKGROUND

Complex antiretroviral therapy (ART) regimens, such as those requiring multiple tablets, several doses per day, or both, can negatively affect quality of life and treatment adherence among people with human immunodeficiency virus (HIV).

METHODS

ARTISTRY-1 is a phase 2/3, operationally seamless, randomized, open-label, multicenter, active-controlled study (GS-US-621-6289; NCT05502341). Phase 2 of the study enrolled adults with plasma HIV-1 RNA <50 copies/mL receiving a complex ART regimen for ≥6 months. Efficacy and safety outcomes were evaluated after a switch to bictegravir (BIC) (75-mg) + lenacapavir (LEN) (25- or 50-mg) regimens, compared with continuing on a complex ART regimen through 24 weeks.

RESULTS

Overall, 128 participants were assigned randomly to begin BIC 75 mg + LEN 25 mg (n = 51) or BIC 75 mg + LEN 50 mg (n = 52) or continue on their complex ART regimen (n = 25). At week 24, HIV-1 RNA was ≥50 copies/mL in 0 of 51, 1 of 52 (1.9%), and 0 of 25 participants in the 3 groups, respectively. CD4 cell counts and percentages remained stable through week 24; the median change from baseline in CD4 cell count (interquartile range) was 18 (-39 to 70), -16 (-80 to 93), and 42 (-36 to 90) cells/µL, respectively. There were no study discontinuations due to a serious adverse event through week 24. Both BIC + LEN dosing regimens were well tolerated, with similar safety profiles observed between groups.

CONCLUSIONS

These data support the continued evaluation of the combination of BIC and LEN to optimize treatment in people with HIV and virologic suppression who are receiving complex ART regimens.

"Pseudosubstrate Envelope"/Free Energy Perturbation-Guided Design and Mechanistic Investigations of Benzothiazole HIV Capsid Modulators with High Ligand Efficiency

Based on our proposed "pseudosubstrate envelope" concept, 25 benzothiazole-bearing HIV capsid protein (CA) modulators were designed and synthesized under the guidance of free energy perturbation technology. The most potent compound, IC-1k, exhibited an EC50 of 2.69 nM against HIV-1, being 393 times more potent than the positive control PF74. Notably, IC-1k emerged as the highest ligand efficiency (LE = 0.32) HIV CA modulator, surpassing that of the approved drug lenacapavir (LE = 0.21). Surface plasmon resonance assay and crystallographic analysis confirmed that IC-1k targeted HIV-1 CA within the chemical space of the "pseudosubstrate envelope". Further mechanistic studies revealed a dual-stage inhibition profile: IC-1k disrupted early-stage capsid-host-factor interactions and promoted late-stage capsid misassembly. Preliminary pharmacokinetic evaluations demonstrated significantly improved metabolic stability in human liver microsomes for IC-1k (T1/2 = 91.3 min) compared to PF74 (T1/2 = 0.7 min), alongside a favorable safety profile. Overall, IC-1k presents a promising lead compound for further optimization.

Health impact, budget impact, and price threshold for cost-effectiveness of lenacapavir for HIV pre-exposure prophylaxis in eastern and southern Africa: a modelling analysis

BACKGROUND

Injectable lenacapavir administered every 6 months is a promising product for HIV pre-exposure prophylaxis (PrEP). We aimed to estimate the health and budget impacts and threshold price at which lenacapavir could be cost-effective in eastern and southern Africa.

METHODS

We adapted an agent-based network model, EMOD-HIV, to simulate lenacapavir scale-up in Zimbabwe, South Africa, and western Kenya from 2026 to 2035. Uptake assumptions were informed by a literature review of PrEP product preferences. In the main analysis, we varied lenacapavir coverage by subgroup: female sex workers (40% coverage); male clients of female sex workers (40%); adolescent girls and young women aged 15-24 years with more than one sexual partner (32%); women aged 25 years and older with more than one sexual partner (36%); and males with more than one sexual partner (32%). We also assessed a higher coverage scenario (64-76% across subgroups) and scenarios of expanding lenacapavir use, varying from concentrated among those at highest HIV risk to broader coverage including those at medium HIV risk. We estimated the maximum per-dose lenacapavir price that achieved cost-effectiveness (

FINDINGS

In the main analysis, lenacapavir was projected to achieve from 1·6% (95% uncertainty interval [UI] 1·5-1·8) to 4·0% (3·4-5·1) population coverage across settings and to avert from 12·3% (5·4-19·5) to 18·0% (11·0-22·9) of infections over 10 years. The maximum price per dose was highest in South Africa ($106·28 [95% UI 95·72-115·87]), followed by Zimbabwe ($21·15 [17·70-24·89]), and lowest in western Kenya ($16·58 [15·44-17·70]). The 5-year budget impact was US$507·25 million (95% UI 436·14-585·42) in South Africa, $16·80 million (13·95-22·64) in Zimbabwe, and $4·09 million (3·86-4·30) in western Kenya. In the higher coverage scenario, lenacapavir distribution was projected to reach from 3·2% (95% UI 2·9-3·6) to 8·1% (6·8-10·5) population coverage and to avert from 21·2% (95% UI 14·7-18·5) to 33·3% (28·5-36·9) of HIV infections across settings over 10 years. Price thresholds were lower than in the main analysis: $88·34 (95% UI 83·02-94·19) in South Africa, $17·71 (15·61-20·05) in Zimbabwe, and $14·78 (14·33-15·30) in western Kenya. The 5-year budget impact was higher than the main analysis: $835·29 million (95% UI 736·98-962·98) in South Africa, $29·50 million (24·62-39·52) in Zimbabwe, and $7·45 million (7·11-7·85) in western Kenya. Expanding lenacapavir coverage resulted in higher HIV infections averted but lower price thresholds than scenarios of concentrated use among those with highest HIV risk.

INTERPRETATION

Our findings suggest that lenacapavir could avert substantial HIV incidence and that price thresholds and budget impacts vary by setting and coverage. These results could inform policy deliberations regarding lenacapavir pricing and resource planning.

FUNDING

The Bill & Melinda Gates Foundation.

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Key Words Collapse

MESH Headings

• Humans
• HIV Infections/prevention & control
• HIV Infections/drug therapy
• HIV Infections/epidemiology
• HIV Infections/economics
• Pre-Exposure Prophylaxis/economics
• Pre-Exposure Prophylaxis/methods
• Cost-Benefit Analysis
• Male
• Female
• Adolescent
• Adult
• Young Adult
• Anti-HIV Agents/economics
• Anti-HIV Agents/administration & dosage
• Anti-HIV Agents/therapeutic use
• Budgets
• Africa, Southern/epidemiology
• Africa, Eastern/epidemiology
• Sex Workers

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Grants Collapse

Affiliation(s)

Linxuan Wu Department of Epidemiology, University of Washington, Seattle, WA, USA
David Kaftan Department of Population Health, New York University Grossman School of Medicine, New York, NY, USA
Rachel Wittenauer CHOICE Institute, University of Washington School of Pharmacy, Seattle, WA, USA
Cory Arrouzet Department of Epidemiology, University of Washington, Seattle, WA, USA
Nishali Patel Department of Global Health, University of Washington, Seattle, WA, USA; Department of Health Metrics Sciences, University of Washington, Seattle, WA, USA
Arden L Saravis Department of Epidemiology, University of Washington, Seattle, WA, USA
Brian Pfau Department of Epidemiology, University of Washington, Seattle, WA, USA
Edinah Mudimu Department of Decision Sciences, University of South Africa, Pretoria, South Africa
Anna Bershteyn Department of Population Health, New York University Grossman School of Medicine, New York, NY, USA
Monisha Sharma Department of Global Health, University of Washington, Seattle, WA, USA.

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The significance of chirality in contemporary drug discovery-a mini review

More than half of drugs are chiral compounds with their chirality determining their molecular interactions, ecofriendly environmental safety and efficacy. Overall nearly 90% of chiral compounds are marketed as racemates consisting of an equimolar mixture of two enantiomers. Despite having identical chemical structure and bonding, racemates function differently when exposed to chiral environments and demonstrate notable variances in biological properties such as pharmacology, toxicology, metabolism and pharmacokinetics, etc. Advancements in asymmetric synthesis in recent years have led to considerable interest in the development of single enantiomers of chiral drug molecules for medicinal chemistry settings. In this review, we want to compile examples of chiral medicines approved by the FDA in the years 2022 and 2023 with an emphasis on their synthesis along with information on chiral induction as well as enantiomeric excess.

Efficacy of Integrase Strand Transfer Inhibitors and the Capsid Inhibitor Lenacapavir against HIV-2, and Exploring the Effect of Raltegravir on the Activity of SARS-CoV-2

Retroviruses perpetuate their survival by incorporating a copy of their genome into the host cell, a critical step catalyzed by the virally encoded integrase. The viral capsid plays an important role during the viral life cycle, including nuclear importation in the case of lentiviruses and integration targeting events; hence, targeting the integrase and the viral capsid is a favorable therapeutic strategy. While integrase strand transfer inhibitors (INSTIs) are recommended as first-line regimens given their high efficacy and tolerability, lenacapavir is the first capsid inhibitor and the newest addition to the HIV treatment arsenal. These inhibitors are however designed for treatment of HIV-1 infection, and their efficacy against HIV-2 remains widely understudied and inconclusive, supported only by a few limited phenotypic susceptibility studies. We therefore carried out inhibition profiling of a panel of second-generation INSTIs and lenacapavir against HIV-2 in cell culture, utilizing pseudovirion inhibition profiling assays. Our results show that the tested INSTIs and lenacapavir exerted excellent efficacy against ROD-based HIV-2 integrase. We further evaluated the efficacy of raltegravir and other INSTIs against different variants of SARS-CoV-2; however, contrary to previous in silico findings, the inhibitors did not demonstrate significant antiviral activity.

The Assembly of HTLV-1-How Does It Differ from HIV-1?

Retroviral assembly is a highly coordinated step in the replication cycle. The process is initiated when the newly synthesized Gag and Gag-Pol polyproteins are directed to the inner leaflet of the plasma membrane (PM), where they facilitate the budding and release of immature viral particles. Extensive research over the years has provided crucial insights into the molecular determinants of this assembly step. It is established that Gag targeting and binding to the PM is mediated by interactions of the matrix (MA) domain and acidic phospholipids such as phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). This binding event, along with binding to viral RNA, initiates oligomerization of Gag on the PM, a process mediated by the capsid (CA) domain. Much of the previous studies have focused on human immunodeficiency virus type 1 (HIV-1). Although the general steps of retroviral replication are consistent across different retroviruses, comparative studies revealed notable differences in the structure and function of viral components. In this review, we present recent findings on the assembly mechanisms of Human T-cell leukemia virus type 1 and highlight key differences from HIV-1, focusing particularly on the molecular determinants of Gag-PM interactions and CA assembly.

Lenacapavir Exhibits Atropisomerism-Mechanistic Pharmacokinetics and Disposition Studies of Lenacapavir Reveal Intestinal Excretion as a Major Clearance Pathway

Lenacapavir (LEN), a long-acting injectable, is the first approved human immunodeficiency virus type 1 capsid inhibitor and one of a few Food and Drug Administration-approved drugs that exhibit atropisomerism. LEN exists as a mixture of two class 2 atropisomers that interconvert at a fast rate (half-life < 2 hours) with a ratio that is stable over time and unaffected by enzymes or binding to proteins in plasma. LEN exhibits low systemic clearance (CL) in nonclinical species and humans; however, in all species, the observed CL was higher than the in vitro predicted CL. The volume of distribution was moderate in nonclinical species and consistent with the tissue distribution observed by whole-body autoradiography in rats. LEN does not distribute to brain, consistent with being a P-glycoprotein (P-gp) substrate. Mechanistic drug disposition studies with [14C]LEN in intravenously dosed bile duct-cannulated rats and dogs showed a substantial amount of unchanged LEN (31%-60% of dose) excreted in feces, indicating that intestinal excretion (IE) was a major clearance pathway for LEN in both species. Coadministration of oral elacridar, a P-gp inhibitor, in rats decreased CL and IE of LEN. Renal excretion was < 1% of dose in both species. In plasma, almost all radioactivity was unchanged LEN. Low levels of metabolites in excreta included LEN conjugates with glutathione, pentose, and glucuronic acid, which were consistent with metabolites formed in vitro in Hμrel hepatocyte cocultures and those observed in human. Our studies highlight the importance of IE for efflux substrates that are highly metabolically stable compounds with slow elimination rates. SIGNIFICANCE STATEMENT: LEN is a long-acting injectable that exists as conformationally stable atropisomers. Due to an atropisomeric interconversion rate that significantly exceeds the in vivo elimination rate, the atropisomer ratio of LEN remains constant in circulation. The disposition of LEN highlights that intestinal excretion has a substantial part in the elimination of compounds that are metabolically highly stable and efflux transporter substrates.

Exploring HIV-1 Maturation: A New Frontier in Antiviral Development

HIV-1 virion maturation is an essential step in the viral replication cycle to produce infectious virus particles. Gag and Gag-Pol polyproteins are assembled at the plasma membrane of the virus-producer cells and bud from it to the extracellular compartment. The newly released progeny virions are initially immature and noninfectious. However, once the Gag polyprotein is cleaved by the viral protease in progeny virions, the mature capsid proteins assemble to form the fullerene core. This core, harboring two copies of viral genomic RNA, transforms the virion morphology into infectious virus particles. This morphological transformation is referred to as maturation. Virion maturation influences the distribution of the Env glycoprotein on the virion surface and induces conformational changes necessary for the subsequent interaction with the CD4 receptor. Several host factors, including proteins like cyclophilin A, metabolites such as IP6, and lipid rafts containing sphingomyelins, have been demonstrated to have an influence on virion maturation. This review article delves into the processes of virus maturation and Env glycoprotein recruitment, with an emphasis on the role of host cell factors and environmental conditions. Additionally, we discuss microscopic technologies for assessing virion maturation and the development of current antivirals specifically targeting this critical step in viral replication, offering long-acting therapeutic options.

Patient-Centric Long-Acting Injectable and Implantable Platforms─An Industrial Perspective

The increasing focus on patient centricity in the pharmaceutical industry over the past decade and the changing healthcare landscape, driven by factors such as increased access to information, social media, and evolving patient demands, has necessitated a shift toward greater connectivity and understanding of patients' unique treatment needs. One pharmaceutical technology that has supported these efforts is long acting injectables (LAIs), which lower the administration frequency for the patient's provided convenience, better compliance, and hence better therapeutical treatment for the patients. Furthermore, patients with conditions like the human immunodeficiency virus and schizophrenia have positively expressed the desire for less frequent dosing, such as that obtained through LAI formulations. In this work, a comprehensive analysis of marketed LAIs across therapeutic classes and technologies is conducted. The analysis demonstrated an increasing number of new LAIs being brought to the market, recently most as aqueous suspensions and one as a solution, but many other technology platforms were applied as well, in particular, polymeric microspheres and in situ forming gels. The analysis across the technologies provided an insight into to the physicochemical properties the compounds had per technology class as well as knowledge of the excipients typically used within the individual formulation technology. The principle behind the formulation technologies was discussed with respect to the release mechanism, manufacturing approaches, and the possibility of defining predictive in vitro release methods to obtain in vitro in vivo correlations with an industrial angle. The gaps in the field are still numerous, including better systematic formulation and manufacturing investigations to get a better understanding of potential innovations, but also development of new polymers could facilitate the development of additional compounds. The biggest and most important gaps, however, seem to be the development of predictive in vitro dissolution methods utilizing pharmacopoeia described equipment to enable their use for product development and later in the product cycle for quality-based purposes.

Elasticity of the HIV-1 core facilitates nuclear entry and infection

HIV-1 infection requires passage of the viral core through the nuclear pore of the cell, a process that depends on functions of the viral capsid. Recent studies have shown that HIV-1 cores enter the nucleus prior to capsid disassembly. Interactions of the viral capsid with the nuclear pore complex are necessary but not sufficient for nuclear entry, and the mechanism by which the viral core traverses the comparably sized nuclear pore is unknown. Here we show that the HIV-1 core is highly elastic and that this property is linked to nuclear entry and infectivity. Using atomic force microscopy-based approaches, we found that purified wild type cores rapidly returned to their normal conical morphology following a severe compression. Results from independently performed molecular dynamic simulations of the mature HIV-1 capsid also revealed its elastic property. Analysis of four HIV-1 capsid mutants that exhibit impaired nuclear entry revealed that the mutant viral cores are brittle. Adaptation of two of the mutant viruses in cell culture resulted in additional substitutions that restored elasticity and rescued infectivity and nuclear entry. We also show that capsid-targeting compound PF74 and the antiviral drug Lenacapavir reduce core elasticity and block HIV-1 nuclear entry at concentrations that preserve interactions between the viral core and the nuclear envelope. Our results indicate that elasticity is a fundamental property of the HIV-1 core that enables nuclear entry, thereby facilitating infection. These results provide new insights into the role of the capsid in HIV-1 nuclear entry and the antiviral mechanisms of HIV-1 capsid inhibitors.

The Current Pipeline of Antiretroviral Therapy: Expanding Options and Filling Gaps

Highly effective antiretroviral therapy (ART) has transformed human immunodeficiency virus (HIV) care in the past 3 decades. 30 years ago, how many would have imagined that a single-tablet daily ART regimen containing different drug classes could achieve sustained HIV-1 suppression and halt disease progression to acquired immunodeficiency syndrome (AIDS)? Despite this remarkable achievement, challenges in HIV care remain that require further innovation for ART. In this review, we focus on newly approved antiretroviral agents and those undergoing phase 2/3 clinical trials. These new antiretrovirals hold great promise to expand treatment options and fill gaps in HIV care.

Viral Factors in Modulation of Host Immune Response: A Route to Novel Antiviral Agents and New Therapeutic Approaches

Viruses utilize host cells at all stages of their life cycle, from the transcription of genes and translation of viral proteins to the release of viral copies. The human immune system counteracts viruses through a variety of complex mechanisms, including both innate and adaptive components. Viruses have an ability to evade different components of the immune system and affect them, leading to disruption. This review covers contemporary knowledge about the virus-induced complex interplay of molecular interactions, including regulation of transcription and translation in host cells resulting in the modulation of immune system functions. Thorough investigation of molecular mechanisms and signaling pathways that are involved in modulating of host immune response to viral infections can help to develop novel approaches for antiviral therapy. In this review, we consider new therapeutic approaches for antiviral treatment. Modern therapeutic strategies for the treatment and cure of human immunodeficiency virus (HIV) are considered in detail because HIV is a unique example of a virus that leads to host T lymphocyte deregulation and significant modulation of the host immune response. Furthermore, peculiarities of some promising novel agents for the treatment of various viral infections are described.

Advancements in Antiviral Drug Development: Comprehensive Insights into Design Strategies and Mechanisms Targeting Key Viral Proteins

Viral infectious diseases have always been a threat to human survival and quality of life, impeding the stability and progress of human society. As such, researchers have persistently focused on developing highly efficient, low-toxicity antiviral drugs, whether for acute or chronic infectious diseases. This article presents a comprehensive review of the design concepts behind virus-targeted drugs, examined through the lens of antiviral drug mechanisms. The intention is to provide a reference for the development of new, virus-targeted antiviral drugs and guide their clinical usage.

Consensus recommendations for use of long-acting antiretroviral medications in the treatment and prevention of HIV-1: Endorsed by the American Academy of HIV Medicine, American College of Clinical Pharmacy, Canadian HIV and Viral Hepatitis Pharmacists Network, European AIDS Clinical Society, and Society of Infectious Diseases Pharmacists

Five long-acting (LA) antiretrovirals (ARVs) are currently available in a limited number of countries worldwide for HIV-1 prevention or treatment-cabotegravir, rilpivirine, lenacapavir, ibalizumab, and dapivirine. Implementing use of LA ARVs into routine clinical practice requires significant changes to the current framework of HIV-1 prevention, treatment, and service provision. Given the novelty, complexity, and interdisciplinary requirements needed to safely and optimally utilize LA ARVs, consensus recommendations on the use of LA ARVs will assist clinicians in optimizing use of these agents. The purpose of these recommendations is to provide guidance for the clinical use of LA ARVs for HIV-1 treatment and prevention. In addition, future areas of research are also identified and discussed.

An update on drug-drug interactions in older adults living with human immunodeficiency virus (HIV)

INTRODUCTION

People with HIV are living longer due to advances in antiretroviral therapy. With improved life expectancy comes an increased lifetime risk of comorbid conditions - such as cardiovascular disease and cancer - and polypharmacy. Older adults, particularly those living with HIV, are more vulnerable to drug interactions and adverse effects, resulting in negative health outcomes.

AREA COVERED

Antiretrovirals are involved in many potential drug interactions with medications used to treat common comorbidities and geriatric conditions in an aging population of people with HIV. We review the mechanisms and management of significant drug-drug interactions involving antiretroviral medications and non-antiretroviral medications commonly used among older people living with HIV. The management of these interactions may require dose adjustments, medication switches to alternatives, enhanced monitoring, and considerations of patient- and disease-specific factors.

EXPERT OPINION

Clinicians managing comorbid conditions among older people with HIV must be particularly vigilant to side effect profiles, drug-drug interactions, pill burden, and cost when optimizing treatment. To support healthier aging among people living with HIV, there is a growing need for antiretroviral stewardship, multidisciplinary care models, and advances that promote insight into the correlations between an individual, their conditions, and their medications.

Broadly neutralizing antibodies for HIV prevention: a comprehensive review and future perspectives

SUMMARYThe human immunodeficiency virus (HIV) epidemic remains a formidable global health concern, with 39 million people living with the virus and 1.3 million new infections reported in 2022. Despite anti-retroviral therapy's effectiveness in pre-exposure prophylaxis, its global adoption is limited. Broadly neutralizing antibodies (bNAbs) offer an alternative strategy for HIV prevention through passive immunization. Historically, passive immunization has been efficacious in the treatment of various diseases ranging from oncology to infectious diseases. Early clinical trials suggest bNAbs are safe, tolerable, and capable of reducing HIV RNA levels. Although challenges such as bNAb resistance have been noted in phase I trials, ongoing research aims to assess the additive or synergistic benefits of combining multiple bNAbs. Researchers are exploring bispecific and trispecific antibodies, and fragment crystallizable region modifications to augment antibody efficacy and half-life. Moreover, the potential of other antibody isotypes like IgG3 and IgA is under investigation. While promising, the application of bNAbs faces economic and logistical barriers. High manufacturing costs, particularly in resource-limited settings, and logistical challenges like cold-chain requirements pose obstacles. Preliminary studies suggest cost-effectiveness, although this is contingent on various factors like efficacy and distribution. Technological advancements and strategic partnerships may mitigate some challenges, but issues like molecular aggregation remain. The World Health Organization has provided preferred product characteristics for bNAbs, focusing on optimizing their efficacy, safety, and accessibility. The integration of bNAbs in HIV prophylaxis necessitates a multi-faceted approach, considering economic, logistical, and scientific variables. This review comprehensively covers the historical context, current advancements, and future avenues of bNAbs in HIV prevention.

Heavily treatment-experienced persons living with HIV currently in care in Italy: characteristics, risk factors, and therapeutic options-the ICONA Foundation cohort study

OBJECTIVES

Heavily treatment-experienced (HTE) people living with HIV (PLWH) pose unique challenges due to limited antiretroviral treatment (ART) options. Our study aimed to investigate the prevalence and features of HTE individuals followed up in the Italian Cohort Naïve Antiretrovirals (ICONA) cohort as of December 31, 2021.

METHODS

HTE were defined based on meeting specific conditions concerning their current ART and their ART history up to December 31, 2021. Descriptive statistics were performed by HTE status. Regression analyses explored factors associated with becoming HTE based on pre-ART patients' characteristics. Cluster dendrogram analysis provided insights into subgroups with inadequate responses based on clusters of differentiation (CD4) counts and viral load (VL) trajectories.

RESULTS

Among the 8758 PLWH actively followed in our cohort, 163 individuals (1.9%), mainly female, younger, Italian, and infected through heterosexual contact, met the HTE criteria. A lower CD4 count at ART initiation (odds ratio [OR] 1.60 per 100 cells/mmc lower CD4, 95% confidence interval [CI] 1.06-2.41, P = 0.03) and hepatitis C virus antibody positivity (OR 1.90, 95% CI 1.16-3.11, P = 0.01) were associated with higher HTE risk. Thirty PLWH exhibited ongoing immune-virological failure (18% of the HTE subgroup and 0.003% of the total population). Thirty PLWH exhibited ongoing immune-virological failure (i.e., with a current CD4 count <200 cells/mmc or VL>200 copies/mL). A cluster analysis identified 13 (43%) with a current CD4 count <200 cells/mmc. Also, notably, 19/30 (63%) had major acquired resistance-associated mutations to at least one antiretroviral drug class.

CONCLUSIONS

HTE is rare in our cohort and tends to co-exist with major resistance mutations. A focused investigation into treatment history and immuno-virological response is warranted, particularly given the availability of new antiretroviral drugs.

New perspective of small-molecule antiviral drugs development for RNA viruses

High variability and adaptability of RNA viruses allows them to spread between humans and animals, causing large-scale infectious diseases which seriously threat human and animal health and social development. At present, AIDS, viral hepatitis and other viral diseases with high incidence and low cure rate are still spreading around the world. The outbreaks of Ebola, Zika, dengue and in particular of the global pandemic of COVID-19 have presented serious challenges to the global public health system. The development of highly effective and broad-spectrum antiviral drugs is a substantial and urgent research subject to deal with the current RNA virus infection and the possible new viral infections in the future. In recent years, with the rapid development of modern disciplines such as artificial intelligence technology, bioinformatics, molecular biology, and structural biology, some new strategies and targets for antivirals development have emerged. Here we review the main strategies and new targets for developing small-molecule antiviral drugs against RNA viruses through the analysis of the new drug development progress against several highly pathogenic RNA viruses, to provide clues for development of future antivirals.

Rev Protein Diversity in HIV-1 Group M Clades

The HIV-1 Rev protein expressed in the early stage of virus replication is involved in the nuclear export of some forms of virus RNA. Naturally occurring polymorphisms in the Rev protein could influence its activity. The association between the genetic features of different virus variants and HIV infection pathogenesis has been discussed for many years. In this study, Rev diversity among HIV-1 group M clades was analyzed to note the signatures that could influence Rev activity and, subsequently, clinical characteristics. From the Los Alamos HIV Sequence Database, 4962 Rev sequences were downloaded and 26 clades in HIV-1 group M were analyzed for amino acid changes, conservation in consensus sequences, and the presence of clade-specific amino acid substitutions (CSSs) and the Wu-Kabat protein variability coefficient (WK). Subtypes G, CRF 02_AG, B, and A1 showed the largest amino acid changes and diversity. The mean conservation of the Rev protein was 80.8%. In consensus sequences, signatures that could influence Rev activity were detected. In 15 out of 26 consensus sequences, an insertion associated with the reduced export activity of the Rev protein, 95QSQGTET96, was identified. A total of 32 CSSs were found in 16 clades, wherein A6 had the 41Q substitution in the functionally significant region of Rev. The high values of WK coefficient in sites 51 and 82, located on the Rev interaction surface, indicate the susceptibility of these positions to evolutionary replacements. Thus, the noted signatures require further investigation.

Pharmacokinetics of long-acting lenacapavir in participants with hepatic or renal impairment

Lenacapavir is a novel, first-in-class, multistage inhibitor of HIV-1 capsid function approved for the treatment of multidrug-resistant HIV-1 infection in combination with other antiretrovirals for heavily treatment-experienced people with HIV. Two Phase 1, open-label, parallel-group, single-dose studies assessed the pharmacokinetics (PK) of lenacapavir in participants with moderate hepatic impairment [Child-Pugh-Turcotte (CPT) Class B: score 7-9] or severe renal impairment [15 ≤ creatinine clearance (CLcr) ≤29 mL/min] to inform lenacapavir dosing in HIV-1-infected individuals with organ impairment. In both studies, a single oral dose of 300 mg lenacapavir was administered to participants with normal (n = 10) or impaired (n = 10) hepatic/renal function who were matched for age (±10 years), sex, and body mass index (±20%). Lenacapavir exposures [area under the plasma concentration-time curve from time 0 to infinity (AUCinf) and maximum concentration (Cmax)] were approximately 1.47- and 2.61-fold higher, respectively, in participants with moderate hepatic impairment compared to those with normal hepatic function, whereas lenacapavir AUCinf and Cmax were approximately 1.84- and 2.62-fold higher, respectively, in participants with severe renal impairment compared to those with normal renal function. Increased lenacapavir exposures with moderate hepatic or severe renal impairment were not considered clinically meaningful. Lenacapavir was considered generally safe and well tolerated in both studies. These results support the use of approved lenacapavir dosing regimen in patients with mild (CPT Class A: score 5-6) or moderate hepatic impairment as well as in patients with mild (60 ≤ CLcr ≤ 89 mL/min), moderate (30 ≤ CLcr ≤ 59 mL/min), and severe renal impairment.

Discovery of low-molecular-weight phenylalanine derivatives as novel HIV capsid modulators with improved antiretroviral activity and metabolic stability

The HIV capsid (CA) protein is a promising target for anti-AIDS treatment due to its critical involvement in viral replication. Herein, we utilized the well-documented CA inhibitor PF74 as our lead compound and designed a series of low-molecular-weight phenylalanine derivatives. Among them, compound 7t exhibited remarkable antiviral activity with a high selection index (EC50 = 0.040 µM, SI = 2815), surpassing that of PF74 (EC50 = 0.50 µM, SI = 258). Furthermore, when evaluated against the HIV-2 strain, 7t (EC50 = 0.13 µM) demonstrated approximately 14-fold higher potency than that of PF74 (EC50 = 1.76 µM). Insights obtained from surface plasmon resonance (SPR) revealed that 7t exhibited stronger target affinity to the CA hexamer and monomer in comparison to PF74. The potential interactions between 7t and the HIV-1 CA were further elucidated using molecular docking and molecular dynamics simulations, providing a plausible explanation for the enhanced target affinity with 7t over PF74. Moreover, the metabolic stability assay demonstrated that 7t (T1/2 = 77.0 min) significantly outperforms PF74 (T1/2 = 0.7 min) in human liver microsome, exhibiting an improvement factor of 110-fold. In conclusion, 7t emerges as a promising drug candidate warranting further investigation.

Synthetic Approaches to the New Drugs Approved During 2022

In 2022, 23 new small molecule chemical entities were approved as drugs by the United States FDA, European Union EMA, Japan PMDA, and China NMPA. This review describes the synthetic approach demonstrated on largest scale for each new drug based on patent or primary literature. The synthetic routes highlight practical methods to construct molecules, sometimes on the manufacturing scale, to access the new drugs. Ten additional drugs approved in 2021 and one approved in 2020 are included that were not covered in the previous year's review.

A Review of FDA-Approved Anti-HIV-1 Drugs, Anti-Gag Compounds, and Potential Strategies for HIV-1 Eradication

Acquired immunodeficiency syndrome (AIDS) is an enormous global health threat stemming from human immunodeficiency virus (HIV-1) infection. Up to now, the tremendous advances in combination antiretroviral therapy (cART) have shifted HIV-1 infection from a fatal illness into a manageable chronic disorder. However, the presence of latent reservoirs, the multifaceted nature of HIV-1, drug resistance, severe off-target effects, poor adherence, and high cost restrict the efficacy of current cART targeting the distinct stages of the virus life cycle. Therefore, there is an unmet need for the discovery of new therapeutics that not only bypass the limitations of the current therapy but also protect the body's health at the same time. The main goal for complete HIV-1 eradication is purging latently infected cells from patients' bodies. A potential strategy called "lock-in and apoptosis" targets the budding phase of the life cycle of the virus and leads to susceptibility to apoptosis of HIV-1 infected cells for the elimination of HIV-1 reservoirs and, ultimately, for complete eradication. The current work intends to present the main advantages and disadvantages of United States Food and Drug Administration (FDA)-approved anti-HIV-1 drugs as well as plausible strategies for the design and development of more anti-HIV-1 compounds with better potency, favorable pharmacokinetic profiles, and improved safety issues.

HIV cure: Are we going to make history?

BACKGROUND

At present, combination antiretroviral therapy (cART) is the mainstay for the treatment of people living with HIV/AIDS. cART can suppress the viral load to a minimal level; however, the possibility of the emergence of full-blown AIDS is always there. In the latter part of the first decade of the 21st century, an HIV-positive person received stem cell transplantation (SCT) for treatment of his haematological malignancy. The patient was able to achieve remission of the haematological condition as well as of HIV following SCT. Thorough investigations of various samples including blood and biopsy could not detect the virus in the person's body. The person was declared to be the first cured case of HIV.

LITERATURE SEARCH

Over the next decade, a few more similar cases were observed and have recently been declared cured of the infection. A comprehensive search was performed in PubMed, Cochrane library and Google Scholar. Four such additional cases were found in literature.

DESCRIPTION & DISCUSSION

These cases all share a common proposed mechanism for the HIV cure, that is, transplantation of stem cells from donors carrying a homozygous mutation in a gene encoding for CCR5 (receptor utilized by HIV for entry into the host cell), denoted as CCR5△32. This mutation makes the host immune cells devoid of CCR5, causing the host to acquire resistance against HIV. To the best of our knowledge, this is the first review to look at relevant and updated information of all cured cases of HIV as well as the related landmarks in history and discusses the underlying mechanism(s).

Safety of teropavimab and zinlirvimab with lenacapavir once every 6 months for HIV treatment: a phase 1b, randomised, proof-of-concept study

BACKGROUND

Long-acting treatment for HIV has potential to improve adherence, provide durable viral suppression, and have long-term individual and public health benefits. We evaluated treatment with two antibodies that broadly and potently neutralise HIV (broadly neutralising antibodies; bNAbs), combined with lenacapavir, a long-acting capsid inhibitor, as a long-acting regimen.

METHODS

This ongoing, randomised, blind, phase 1b proof-of-concept study conducted at 11 HIV treatment centres in the USA included adults with a plasma HIV-1 RNA concentration below 50 copies per mL who had at least 18 months on oral antiretroviral therapy (ART), CD4 counts of at least 500 cells per μL, and protocol-defined susceptibility to bNAbs teropavimab (3BNC117-LS) and zinlirvimab (10-1074-LS). Participants stopped oral ART and were randomly assigned (1:1) to one dose of 927 mg subcutaneous lenacapavir plus an oral loading dose, 30 mg/kg intravenous teropavimab, and 10 mg/kg or 30 mg/kg intravenous zinlirvimab on day 1. Investigational site personnel and participants were masked to treatment assignment throughout the randomised period. The primary endpoint was incidence of serious adverse events until week 26 in all randomly assigned participants who received one dose or more of any study drug. This study is registered with ClinicalTrials.gov, NCT04811040.

FINDINGS

Between June 29 and Dec 8, 2021, 21 participants were randomly assigned, ten in each group received the complete study regimen and one withdrew before completing the regimen on day 1. 18 (86%) of 21 participants were male; participants ranged in age from 25 years to 61 years and had a median CD4 cell count of 909 (IQR 687-1270) cells per μL at study entry. No serious adverse events occurred. Two grade 3 adverse events occurred (lenacapavir injection-site erythaema and injection-site cellulitis), which had both resolved. The most common adverse events were symptoms of injection-site reactions, reported in 17 (85%) of 20 participants who received subcutaneous lenacapavir; 12 (60%) of 20 were grade 1. One (10%; 95% CI 0-45) participant had viral rebound (confirmed HIV-1 RNA concentration of ≥50 copies per mL) in the zinlirvimab 10 mg/kg group, which was resuppressed on ART, and one participant in the zinlirvimab 30 mg/kg group withdrew at week 12 with HIV RNA <50 copies per mL.

INTERPRETATION

Lenacapavir with teropavimab and zinlirvimab 10 mg/kg or 30 mg/kg was generally well tolerated with no serious adverse events. HIV-1 suppression for at least 26 weeks is feasible with this regimen at either zinlirvimab dose in selected people with HIV-1.

FUNDING

Gilead Sciences.

Pharmacological advances in anti-retroviral therapy for human immunodeficiency virus-1 infection: A comprehensive review

The discovery of anti-retroviral (ARV) drugs over the past 36 years has introduced various classes, including nucleoside/nucleotide reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitor, fusion, and integrase strand transfer inhibitors inhibitors. The introduction of combined highly active anti-retroviral therapies in 1996 was later proven to combat further ARV drug resistance along with enhancing human immunodeficiency virus (HIV) suppression. As though the development of ARV therapies was continuously expanding, the variation of action caused by ARV drugs, along with its current updates, was not comprehensively discussed, particularly for HIV-1 infection. Thus, a range of HIV-1 ARV medications is covered in this review, including new developments in ARV therapy based on the drug's mechanism of action, the challenges related to HIV-1, and the need for combination therapy. Optimistically, this article will consolidate the overall updates of HIV-1 ARV treatments and conclude the significance of HIV-1-related pharmacotherapy research to combat the global threat of HIV infection.

'Getting Better'-Is It a Feasible Strategy of Broad Pan-Antiherpesviral Drug Targeting by Using the Nuclear Egress-Directed Mechanism?

The herpesviral nuclear egress represents an essential step of viral replication efficiency in host cells, as it defines the nucleocytoplasmic release of viral capsids. Due to the size limitation of the nuclear pores, viral nuclear capsids are unable to traverse the nuclear envelope without a destabilization of this natural host-specific barrier. To this end, herpesviruses evolved the regulatory nuclear egress complex (NEC), composed of a heterodimer unit of two conserved viral NEC proteins (core NEC) and a large-size extension of this complex including various viral and cellular NEC-associated proteins (multicomponent NEC). Notably, the NEC harbors the pronounced ability to oligomerize (core NEC hexamers and lattices), to multimerize into higher-order complexes, and, ultimately, to closely interact with the migrating nuclear capsids. Moreover, most, if not all, of these NEC proteins comprise regulatory modifications by phosphorylation, so that the responsible kinases, and additional enzymatic activities, are part of the multicomponent NEC. This sophisticated basis of NEC-specific structural and functional interactions offers a variety of different modes of antiviral interference by pharmacological or nonconventional inhibitors. Since the multifaceted combination of NEC activities represents a highly conserved key regulatory stage of herpesviral replication, it may provide a unique opportunity towards a broad, pan-antiherpesviral mechanism of drug targeting. This review presents an update on chances, challenges, and current achievements in the development of NEC-directed antiherpesviral strategies.

Pharmacologic hyperstabilisation of the HIV-1 capsid lattice induces capsid failure

The HIV-1 capsid has emerged as a tractable target for antiretroviral therapy. Lenacapavir, developed by Gilead Sciences, is the first capsid-targeting drug approved for medical use. Here, we investigate the effect of lenacapavir on HIV capsid stability and uncoating. We employ a single particle approach that simultaneously measures capsid content release and lattice persistence. We demonstrate that lenacapavir's potent antiviral activity is predominantly due to lethal hyperstabilisation of the capsid lattice and resultant loss of compartmentalisation. This study highlights that disrupting capsid metastability is a powerful strategy for the development of novel antivirals.

Antiviral potency of long-acting islatravir subdermal implant in SHIV-infected macaques

Treatment nonadherence is a pressing issue in people living with HIV (PLWH), as they require lifelong therapy to maintain viral suppression. Poor adherence leads to antiretroviral (ARV) resistance, transmission to others, AIDS progression, and increased morbidity and mortality. Long-acting (LA) ARV therapy is a promising strategy to combat the clinical drawback of user-dependent dosing. Islatravir (ISL) is a promising candidate for HIV treatment given its long half-life and high potency. Here we show constant ISL release from a subdermal LA nanofluidic implant achieves viral load reduction in SHIV-infected macaques. Specifically, a mean delivery dosage of 0.21 ± 0.07 mg/kg/day yielded a mean viral load reduction of -2.30 ± 0.53 log10 copies/mL at week 2, compared to baseline. The antiviral potency of the ISL delivered from the nanofluidic implant was higher than oral ISL dosed either daily or weekly. At week 3, viral resistance to ISL emerged in 2 out of 8 macaques, attributable to M184V mutation, supporting the need of combining ISL with other ARV for HIV treatment. The ISL implant produced moderate reactivity in the surrounding tissue, indicating tolerability. Overall, we present the ISL subdermal implant as a promising approach for LA ARV treatment in PLWH.

HIV-1 capsid and viral DNA integration

IMPORTANCE

HIV-1 capsid protein (CA)-independently or by recruiting host factors-mediates several key steps of virus replication in the cytoplasm and nucleus of the target cell. Research in the recent years have established that CA is multifunctional and genetically fragile of all the HIV-1 proteins. Accordingly, CA has emerged as a validated and high priority therapeutic target, and the first CA-targeting antiviral drug was recently approved for treating multi-drug resistant HIV-1 infection. However, development of next generation CA inhibitors depends on a better understanding of CA's known roles, as well as probing of CA's novel roles, in HIV-1 replication. In this timely review, we present an updated overview of the current state of our understanding of CA's multifunctional role in HIV-1 replication-with a special emphasis on CA's newfound post-nuclear roles, highlight the pressing knowledge gaps, and discuss directions for future research.

Antiviral Agents: Structural Basis of Action and Rational Design

During the last forty years, significant progress has been made in the development of novel antiviral drugs, mainly crystallizing in the establishment of potent antiretroviral therapies and the approval of drugs eradicating hepatitis C virus infection. Although major targets of antiviral intervention involve intracellular processes required for the synthesis of viral proteins and nucleic acids, a number of inhibitors blocking virus assembly, budding, maturation, entry, or uncoating act on virions or viral capsids. In this review, we focus on the drug discovery process while presenting the currently used methodologies to identify novel antiviral drugs by means of computer-based approaches. We provide examples illustrating structure-based antiviral drug development, specifically neuraminidase inhibitors against influenza virus (e.g., oseltamivir and zanamivir) and human immunodeficiency virus type 1 protease inhibitors (i.e., the development of darunavir from early peptidomimetic compounds such as saquinavir). A number of drugs acting against hepatitis B virus and human immunodeficiency virus and their mechanism of action are presented to show how viral capsids can be exploited as targets of antiviral therapy. The recent approval of the antiretroviral drug lenacapavir illustrates the successful application of this knowledge.

Impact of Combination Antiretroviral Treatment on Liver Metabolic Health in HIV-Infected Persons

In the last three decades, there has been a considerable improvement in human immunodeficiency virus (HIV) therapy. Acquired immunodeficiency syndrome (AIDS) is no longer a common cause of death for people living with HIV (PLWH) in developed countries, and co-infections with hepatitis viruses can be effectively managed. However, metabolic syndrome and metabolic dysfunction-associated steatotic liver disease (MASLD) are emerging threats these days, especially as the HIV-positive population gets older. The factors for MASLD development in PLWH are numerous, including non-specific (common for both HIV-positive and negative) and virus-specific. We focus on what is known for both, and in particular, on the burden of antiretroviral therapy (ART) for metabolic health and liver damage. We review data on contemporary drugs, including different groups and some particular agents in those groups. Among current ART regimens, the switch from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide fumarate (TAF) and particularly its combination with integrase inhibitors (INSTIs) appear to have the most significant impact on metabolic disturbances by increasing insulin resistance, which over the years promotes the evolution of the cascade leading to metabolic syndrome (MetS), MASLD, and eventually metabolic dysfunction-associated steatohepatitis (MASH).

Discovery, Crystallographic Studies, and Mechanistic Investigations of Novel Phenylalanine Derivatives Bearing a Quinazolin-4-one Scaffold as Potent HIV Capsid Modulators

Optimization of compound 11L led to the identification of novel HIV capsid modulators, quinazolin-4-one-bearing phenylalanine derivatives, displaying potent antiviral activities against both HIV-1 and HIV-2. Notably, derivatives 12a2 and 21a2 showed significant improvements, with 2.5-fold over 11L and 7.3-fold over PF74 for HIV-1, and approximately 40-fold over PF74 for HIV-2. The X-ray co-crystal structures confirmed the multiple pocket occupation of 12a2 and 21a2 in the binding site. Mechanistic studies revealed a dual-stage inhibition profile, where the compounds disrupted capsid-host factor interactions at the early stage and promoted capsid misassembly at the late stage. Remarkably, 12a2 and 21a2 significantly promoted capsid misassembly, outperforming 11L, PF74, and LEN. The substitution of easily metabolized amide bond with quinolin-4-one marginally enhanced the stability of 12a2 in human liver microsomes compared to controls. Overall, 12a2 and 21a2 highlight their potential as potent HIV capsid modulators, paving the way for future advancements in anti-HIV drug design.

KuINins as a New Class of HIV-1 Inhibitors That Block Post-Integration DNA Repair

Integration of HIV-1 genomic cDNA results in the formation of single-strand breaks in cellular DNA, which must be repaired for efficient viral replication. Post-integration DNA repair mainly depends on the formation of the HIV-1 integrase complex with the Ku70 protein, which promotes DNA-PK assembly at sites of integration and its activation. Here, we have developed a first-class inhibitor of the integrase-Ku70 complex formation that inhibits HIV-1 replication in cell culture by acting at the stage of post-integration DNA repair. This inhibitor, named s17, does not affect the main cellular function of Ku70, namely its participation in the repair of double-strand DNA breaks through the non-homologous end-joining pathway. Using a molecular dynamics approach, we have constructed a model for the interaction of s17 with Ku70. According to this model, the interaction of two phenyl radicals of s17 with the L76 residue of Ku70 is important for this interaction. The requirement of two phenyl radicals in the structure of s17 for its inhibitory properties was confirmed using a set of s17 derivatives. We propose to stimulate compounds that inhibit post-integration repair by disrupting the integrase binding to Ku70 KuINins.

Lenacapavir: A Novel, Potent, and Selective First-in-Class Inhibitor of HIV-1 Capsid Function Exhibits Optimal Pharmacokinetic Properties for a Long-Acting Injectable Antiretroviral Agent

Lenacapavir (LEN) is a picomolar first-in-class capsid inhibitor of human immunodeficiency virus type 1 (HIV-1) with a multistage mechanism of action and no known cross resistance to other existing antiretroviral (ARV) drug classes. LEN exhibits a low aqueous solubility and exceptionally low systemic clearance following intravenous (IV) administration in nonclinical species and humans. LEN formulated in an aqueous suspension or a PEG/water solution formulation showed sustained plasma exposure levels with no unintended rapid drug release following subcutaneous (SC) administration to rats and dogs. A high total fraction dose release was observed with both formulations. The long-acting pharmacokinetics (PK) were recapitulated in humans following SC administration of both formulations. The SC PK profiles displayed two-phase absorption kinetics in both animals and humans with an initial fast-release absorption phase, followed by a slow-release absorption phase. Noncompartmental and compartmental analyses informed the LEN systemic input rate from the SC depot and exit rate from the body. Modeling-enabled deconvolution of the input rates from two processes: absorption of the soluble fraction (minor) from a direct fast-release process leading to the early PK phase and absorption of the precipitated fraction (major) from an indirect slow-release process leading to the later PK phase. LEN SC PK showed flip-flop kinetics due to the input rate being substantially slower than the systemic exit rate. LEN input rates via the slow-release process in humans were slower than those in both rats and dogs. Overall, the combination of high potency, exceptional stability, and optimal release rate from the injection depot make LEN well suited for a parenteral long-acting formulation that can be administered once up to every 6 months in humans for the prevention and treatment of HIV-1.

Use of TSAR, Thermal Shift Analysis in R, to identify Folic Acid as a Molecule that Interacts with HIV-1 Capsid

Thermal shift assay (TSA) is a versatile biophysical technique for studying protein interactions. Here, we report a free, open-source software tool TSAR (Thermal Shift Analysis in R) to expedite and automate the analysis of thermal shift data derived either from individual experiments or large screens of chemical libraries. The TSAR package incorporates multiple, dynamic workflows to facilitate the analysis of TSA data and returns publication-ready graphics or processed results. Further, the package includes a graphic user interface (GUI) that enables easy use by non-programmers, aiming to simplify TSA analysis while diversifying visualization. To exemplify the utility of TSAR we screened a chemical library of vitamins to identify molecules that interact with the capsid protein (CA) of human immunodeficiency virus type 1 (HIV-1). Our data show that hexameric CA interacts with folic acid in vitro.

A review: FDA-approved fluorine-containing small molecules from 2015 to 2022

Fluorine-containing small molecules have occupied a special position in drug discovery research. The successful clinical use of fluorinated corticosteroids in the 1950s and fluoroquinolones in the 1980s led to an ever-increasing number of approved fluorinated compounds over the last 50 years. They have shown various biological properties such as antitumor, antimicrobial, and anti-inflammatory activities. Fluoro-pharmaceuticals have been considered a strong and practical tool in the rational drug design approach due to their benefits from potency and ADME (absorption, distribution, metabolism, and excretion) points of view. Herein, approved fluorinated drugs from 2015 to 2022 were reviewed.

Development and validation of an ultra-high performance liquid chromatography-tandem mass spectrometry method for quantifying lenacapavir plasma concentrations: Application to therapeutic monitoring

Although current antiretroviral therapy (ART) effectively suppresses HIV in the blood, regimens may fail due to suboptimal treatment history and non-adherence to ART. In these scenarios, accumulation of viral resistance mutations to ART drug classes may occur. For these treatment-experienced people living with HIV (PLWH), activity against resistant viral strains is required; lack of therapeutic efficacy will result in continued viral replication and progression to acquired immunodeficiency syndrome. New treatment options have emerged. Lenacapavir is a first-in-class long-acting HIV-1 capsid inhibitor approved for the treatment of HIV in treatment-experienced patients. Lenacapavir is approved with an initiation regimen of oral and subcutaneous injection dosing followed by subcutaneous self-injection every 6 months. With infrequent dosing, therapeutic drug monitoring may be necessary to ensure adequate concentrations are consistently achieved in the plasma to assure treatment adherence and prevent further HIV resistance formation. To this end, we developed and validated a highly selective ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to quantify lenacapavir concentrations in human plasma. A simple protein precipitation with acetonitrile followed by supernatant dilution was performed. Lenacapavir and its stable labeled internal standard were separated at 1.90 min using a multi-step UPLC gradient. The assay for lenacapavir quantification was extensively validated according to the United States Food and Drug Administration Bioanalytical Guidelines over a clinically relevant range of 0.1 to 500 ng/mL with excellent linearity (R2 ≥ 0.9960). This analytical method achieves acceptable performance of trueness (89.7-104.1 %), repeatability, and precision (CV < 15 %). We applied this method to quantify a clinical sample and to determine the percent protein-unbound. This method can be utilized for the therapeutic monitoring of lenacapavir in human plasma for monitoring HIV treatment efficacy.

New drug approvals for 2022: Synthesis and clinical applications

The U.S. Food and Drug Administration has approved a total of 37 new drugs in 2022, which are composed of 20 chemical entities and 17 biologics. In particular, 20 chemical entities, including 17 small molecule drugs, 1 radiotherapy, and 2 diagnostic agents, provide privileged scaffolds, breakthrough clinical benefits, and a new mechanism of action for the discovery of more potent clinical candidates. The structure-based drug development with clear targets and fragment-based drug development with privileged scaffolds have always been the important modules in the field of drug discovery, which could easily bypass the patent protection and bring about improved biological activity. Therefore, we summarized the relevant valuable information about clinical application, mechanism of action, and chemical synthesis of 17 newly approved small molecule drugs in 2022. We hope this timely and comprehensive review could bring about creative and elegant inspiration on the synthetic methodologies and mechanism of action for the discovery of new drugs with novel chemical scaffolds and extended clinical indications.

Current drugs for HIV-1: from challenges to potential in HIV/AIDS

The human immunodeficiency virus (HIV) persists in latently infected CD4+T cells and integrates with the host genome until cell death. Acquired immunodeficiency syndrome (AIDS) is associated with HIV-1. Possibly, treating HIV/AIDS is an essential but challenging clinical goal. This review provides a detailed account of the types and mechanisms of monotherapy and combination therapy against HIV-1 and describes nanoparticle and hydrogel delivery systems. In particular, the recently developed capsid inhibitor (Lenacapavir) and the Ainuovirine/tenofovir disoproxil fumarate/lamivudine combination (ACC008) are described. It is interestingly to note that the lack of the multipass transmembrane proteins serine incorporator 3 (SERINC3) and the multipass transmembrane proteins serine incorporator 5 (SERINC5) may be one of the reasons for the enhanced infectivity of HIV-1. This discovery of SERINC3 and SERINC5 provides new ideas for HIV-1 medication development. Therefore, we believe that in treating AIDS, antiviral medications should be rationally selected for pre-exposure and post-exposure prophylaxis to avoid the emergence of drug resistance. Attention should be paid to the research and development of new drugs to predict HIV mutations as accurately as possible and to develop immune antibodies to provide multiple guarantees for the cure of AIDS.

Inhibitors of mpox VP39 2'-O methyltransferase efficiently inhibit the monkeypox virus

The RNA 2'-O methyltransferase (MTase) VP39 of the monkeypox virus (MpxV) participates in RNA capping within poxviruses. Sub-micromolar inhibitors targeting this enzyme were already reported. However, these 7-deaza analogs of S-adenosyl methionine (SAH) had not been tested in cellular assays until now. In this study, we employed plaque assays and cytopathic effect-based assays to evaluate the effectiveness of these compounds. All tested compounds demonstrated antiviral activity against MpxV, with EC50 values ranging from 0.06 to 2.7 μM. Nevertheless, some of these compounds also exhibited cytotoxicity in HeLa cells, while others showed no toxicity. Notably, the non-toxic compounds featured a large aromatic substituent at the 7-deaza position, whereas the toxic compounds had a small substituent at the same position. These findings suggest that VP39 represents a bona fide target for the development of antiviral drugs against MpxV.

Elasticity of the HIV-1 Core Facilitates Nuclear Entry and Infection

HIV-1 infection requires passage of the viral core through the nuclear pore of the cell, a process that depends on functions of the viral capsid 1,2 . Recent studies have shown that HIV- 1 cores enter the nucleus prior to capsid disassembly 3-5 . Interactions with the nuclear pore complex are necessary but not sufficient for nuclear entry, and the mechanism by which the viral core traverses the comparably sized nuclear pore is unknown. Here we show that the HIV-1 core is highly elastic and that this property is linked to nuclear entry and infectivity. Using atomic force microscopy-based approaches, we found that purified wild type cores rapidly returned to their normal conical morphology following a severe compression. Results from independently performed molecular dynamic simulations of the mature HIV-1 capsid also revealed its elastic property. Analysis of four HIV-1 capsid mutants that exhibit impaired nuclear entry revealed that the mutant viral cores are brittle. Suppressors of the mutants restored elasticity and rescued infectivity and nuclear entry. Elasticity was also reduced by treatment of cores with the capsid-targeting compound PF74 and the antiviral drug lenacapavir. Our results indicate that capsid elasticity is a fundamental property of the HIV-1 core that enables its passage through the nuclear pore complex, thereby facilitating infection. These results provide new insights into the mechanisms of HIV-1 nuclear entry and the antiviral mechanisms of HIV-1 capsid inhibitors.