Strategic use of salvage long-acting antiretrovirals in the setting of resistance.

DISCLAIMER: In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. PURPOSE: Long-acting cabotegravir/rilpivirine (LA-CAB/RPV) was approved for use in virally suppressed patients with human immunodeficiency virus (HIV) in January 2021. While this was a paradigm shift for many patients living with HIV, as LA-CAB/RPV was the first injectable complete regimen for the treatment of HIV, several patient populations, including those lacking virologic suppression, have not been able to easily access this advance in science and care. SUMMARY: In this article, we provide an update on 2 patients from our previous report and describe one further patient who experienced treatment failure following initiation of LA-CAB/RPV. Additionally, we review reports published to date of the clinical outcomes of patients with viremia who have accessed LA-CAB/RPV in the setting of baseline resistance-associated mutations (RAMs) to either component and any resulting RAMs at virologic failure. On the basis of this evidence, we recommend that hybrid or all-injectable regimens be considered for patients who have struggled with adherence to oral antiretroviral therapy or have partial or full resistance to one component of LA-CAB/RPV. CONCLUSION: The case series reported here adds to literature supporting the notion that LA-CAB/RPV can be successfully used in patients who are viremic.

Practical Synthesis of 7-Bromo-4-chloro-1H-indazol-3-amine: An Important Intermediate to Lenacapavir.

7-Bromo-4-chloro-1H-indazol-3-amine is a heterocyclic fragment used in the synthesis of Lenacapavir, a potent capsid inhibitor for the treatment of HIV-1 infections. In this manuscript, we describe a new approach to synthesizing 7-bromo-4-chloro-1H-indazol-3-amine from inexpensive 2,6-dichlorobenzonitrile. This synthetic method utilizes a two-step sequence including regioselective bromination and heterocycle formation with hydrazine to give the desired product in an overall isolated yield of 38-45%. The new protocol has been successfully demonstrated on hundred-gram scales without the need for column chromatography purification. This new synthesis provides a potential economical route to the large-scale production of this heterocyclic fragment of Lenacapavir.

Cell Culture Evaluation Hints Widely Available HIV Drugs Are Primed for Success if Repurposed for HTLV-1 Prevention.

With an estimated 10 million people infected, the deltaretrovirus human T-cell lymphotropic virus type 1 (HTLV-1) is the second most prevalent pathogenic retrovirus in humans after HIV-1. Like HIV-1, HTLV-1 overwhelmingly persists in a host via a reservoir of latently infected CD4+ T cells. Although most patients are asymptomatic, HTLV-1-associated pathologies are often debilitating and include adult T-cell leukaemia/lymphoma (ATLL), which presents in mature adulthood and is associated with poor prognosis with short overall survival despite treatment. Curiously, the strongest indicator for the development of ATLL is the acquisition of HTLV-1 through breastfeeding. There are no therapeutic or preventative regimens for HTLV-1. However, antiretrovirals (ARVs), which target the essential retrovirus enzymes, have been developed for and transformed HIV therapy. As the architectures of retroviral enzyme active sites are highly conserved, some HIV-specific compounds are active against HTLV-1. Here, we expand on our work, which showed that integrase strand transfer inhibitors (INSTIs) and some nucleoside reverse transcriptase inhibitors (NRTIs) block HTLV-1 transmission in cell culture. Specifically, we find that dolutegravir, the INSTI currently recommended as the basis of all new combination antiretroviral therapy prescriptions, and the latest prodrug formula of the NRTI tenofovir, tenofovir alafenamide, also potently inhibit HTLV-1 infection. Our results, if replicated in a clinical setting, could see transmission rates of HTLV-1 and future caseloads of HTLV-1-associated pathologies like ATLL dramatically cut via the simple repurposing of already widely available HIV pills in HTLV-1 endemic areas. Considering our findings with the old medical saying "it is better to prevent than cure", we highly recommend the inclusion of INSTIs and tenofovir prodrugs in upcoming HTLV-1 clinical trials as potential prophylactics.

No antagonism or cross-resistance and a high barrier to the emergence of resistance in vitro for the combination of islatravir and lenacapavir.

Islatravir (ISL) is a deoxyadenosine analog that inhibits HIV-1 reverse transcription by multiple mechanisms. Lenacapavir (LEN) is a novel capsid inhibitor that inhibits HIV-1 at multiple stages throughout the viral life cycle. ISL and LEN are being investigated as once-weekly combination oral therapy for the treatment of HIV-1. Here, we characterized ISL and LEN in vitro to assess combinatorial antiviral activity, cytotoxicity, and the potential for interactions between the two compounds. Bliss analysis revealed ISL with LEN demonstrated additive inhibition of HIV-1 replication, with no evidence of antagonism across the range of concentrations tested. ISL exhibited potent antiviral activity against variants encoding known LEN resistance-associated mutations (RAMs) with or without the presence of M184V, an ISL RAM in reverse transcriptase (RT) . Static resistance selection experiments were conducted with ISL and LEN alone and in combination, initiating with either wild-type virus or virus containing the M184I RAM in RT to further assess their barrier to the emergence of resistance. The combination of ISL with LEN more effectively suppressed viral breakthrough at lower multiples of the compounds' IC50 (half-maximal inhibitory concentration) values and fewer mutations emerged with the combination compared to either compound on its own. The known pathways for development of resistance with ISL and LEN were not altered, and no novel single mutations emerged that substantially reduced susceptibility to either compound. The lack of antagonism and cross-resistance between ISL and LEN support the ongoing evaluation of the combination for treatment of HIV-1.

Cell-free assays reveal the HIV-1 capsid protects reverse transcripts from cGAS.

Retroviruses can be detected by the innate immune sensor cyclic GMP-AMP synthase (cGAS), which recognizes reverse-transcribed DNA and activates an antiviral response. However, the extent to which HIV-1 shields its genome from cGAS recognition remains unclear. To study this process in mechanistic detail, we reconstituted reverse transcription, genome release, and innate immune sensing of HIV-1 in a cell-free system. We found that wild-type HIV-1 capsids protect their genomes from cGAS even after completion of reverse transcription. Viral DNA could be "deprotected" by thermal stress, capsid mutations, or reduced concentrations of inositol hexakisphosphate (IP6) that destabilize the capsid. Strikingly, capsid inhibitors also disrupted viral cores and dramatically potentiated cGAS activity, both in vitro and in cellular infections. Our results provide biochemical evidence that the HIV-1 capsid lattice conceals the genome from cGAS and that chemical or physical disruption of the viral core can expose HIV-1 DNA and activate innate immune signaling.

Case Series of People With HIV on the Long-Acting Combination of Lenacapavir and Cabotegravir: Call for a Trial.

Background: Injectable cabotegravir (CAB)/rilpivirine (RPV) is the only combination long-acting (LA) antiretroviral regimen approved for HIV. RPV may not be effective among individuals with non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance, which has >10% prevalence in many countries. Lenacapavir (LEN) is an LA capsid inhibitor given every 6 months, but has not been studied in combination with other LA agents. Methods: We assembled a case series from 4 US academic medical centers where patients with adherence challenges were prescribed LEN subcutaneously every 26 weeks/CAB (+/- RPV) intramuscularly every 4 or 8 weeks. Descriptive statistics, including viral load (VL) outcomes, were summarized. Results: All patients (n = 34: 76% male; 24% cis/trans female; 41% Black; 38% Latino/a; median age [range], 47 [28-75] years; 29% and 71% on CAB every 4 or 8 weeks) reported challenges adhering to oral ART. The reasons for using LEN/CAB with or without RPV were documented or suspected NNRTI mutations (n = 21, 59%), integrase mutations (n = 5, 15%), high VL (n = 6, 18%), or continued viremia on CAB/RPV alone (n = 4, 12%). Injection site reactions on LA LEN were reported in 44% (32% grade I, 12% grade 2). All patients but 2 (32/34; 94%) were suppressed (VL <75 copies/mL) after starting LEN at a median (range) of 8 (4-16) weeks, with 16/34 (47%) suppressed at baseline. Conclusions: In this case series of 34 patients on LEN/CAB, high rates of virologic suppression (94%) were observed. Reasons for using LEN/CAB included adherence challenges and underlying resistance, mostly to NNRTIs. These data support a clinical trial of LEN/CAB among persons with NNRTI resistance.

Spatiotemporal binding of cyclophilin A and CPSF6 to capsid regulates HIV-1 nuclear entry and integration.

Human immunodeficiency virus type 1 (HIV-1) capsid, which is the target of the antiviral lenacapavir, protects the viral genome and binds multiple host proteins to influence intracellular trafficking, nuclear import, and integration. Previously, we showed that capsid binding to cleavage and polyadenylation specificity factor 6 (CPSF6) in the cytoplasm is competitively inhibited by cyclophilin A (CypA) binding and regulates capsid trafficking, nuclear import, and infection. Here we determined that a capsid mutant with increased CypA binding affinity had significantly reduced nuclear entry and mislocalized integration. However, disruption of CypA binding to the mutant capsid restored nuclear entry, integration, and infection in a CPSF6-dependent manner. Furthermore, relocalization of CypA expression from the cell cytoplasm to the nucleus failed to restore mutant HIV-1 infection. Our results clarify that sequential binding of CypA and CPSF6 to HIV-1 capsid is required for optimal nuclear entry and integration targeting, informing antiretroviral therapies that contain lenacapavir.

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.

HIV-1 capsid stability and reverse transcription are finely balanced to minimize sensing of reverse transcription products via the cGAS-STING pathway.

A critical determinant for early post-entry events, the HIV-1 capsid (CA) protein forms the conical core when it rearranges around the dimeric RNA genome and associated viral proteins. Although mutations in CA have been reported to alter innate immune sensing of HIV-1, a direct link between core stability and sensing of HIV-1 nucleic acids has not been established. Herein, we assessed how manipulating the stability of the CA lattice through chemical and genetic approaches affects innate immune recognition of HIV-1. We found that destabilization of the CA lattice resulted in potent sensing of reverse transcription products when destabilization per se does not completely block reverse transcription. Surprisingly, due to the combined effects of enhanced reverse transcription and defects in nuclear entry, two separate CA mutants that form hyperstable cores induced innate immune sensing more potently than destabilizing CA mutations. At low concentrations that allowed the accumulation of reverse transcription products, CA-targeting compounds GS-CA1 and lenacapavir measurably impacted CA lattice stability in cells and modestly enhanced innate immune sensing of HIV. Interestingly, innate immune activation observed with viruses containing unstable cores was abolished by low doses of lenacapavir. Innate immune activation observed with both hyperstable and unstable CA mutants was dependent on the cGAS-STING DNA-sensing pathway and reverse transcription. Overall, our findings demonstrate that CA lattice stability and reverse transcription are finely balanced to support reverse transcription and minimize cGAS-STING-mediated sensing of the resulting viral DNA. IMPORTANCE: In HIV-1 particles, the dimeric RNA genome and associated viral proteins and enzymes are encased in a proteinaceous lattice composed of the viral capsid protein. Herein, we assessed how altering the stability of this capsid lattice through orthogonal genetic and chemical approaches impacts the induction of innate immune responses. Specifically, we found that decreasing capsid lattice stability results in more potent sensing of viral reverse transcription products, but not the genomic RNA, in a cGAS-STING-dependent manner. The recently developed capsid inhibitors lenacapavir and GS-CA1 enhanced the innate immune sensing of HIV-1. Unexpectedly, due to increased levels of reverse transcription and cytosolic accumulation of the resulting viral cDNA, capsid mutants with hyperstable cores also resulted in the potent induction of type I interferon-mediated innate immunity. Our findings suggest that HIV-1 capsid lattice stability and reverse transcription are finely balanced to minimize exposure of reverse transcription products in the cytosol of host cells.

Lenacapavir: A novel injectable HIV-1 capsid inhibitor.

Patients living with multidrug-resistant (MDR) HIV have limited antiretroviral regimen options that provide durable viral suppression. Lenacapavir is a novel first-in-class inhibitor of HIV-1 capsid function with efficacy at various stages of the viral life cycle, and it is indicated for the treatment of MDR HIV-1 infection in combination with optimized background antiretroviral therapy. The favourable pharmacokinetic profile supports an every sixth month dosing interval of subcutaneous lenacapavir after an initial oral loading dose, which may advocate for continued adherence to antiretroviral therapy (ART) through the reduction of daily pill burden. The role of lenacapavir in promoting virologic suppression has been studied in patients with MDR HIV-1 on failing ART at baseline. Lenacapavir was well tolerated in clinical trials with the most common adverse effects including mild to moderate injection site reactions, gastrointestinal symptoms, and headache. Substitutions on the capsid molecule may confer resistance to lenacapavir by changing the binding potential. Cross-resistance to other antiretrovirals has not been observed. The unique mechanism of action, pharmacokinetics, and safety and efficacy of lenacapavir support its use for the management of MDR HIV-1 infection. Current studies are ongoing to evaluate the potential use of subcutaneous lenacapavir for pre-exposure prophylaxis (PrEP). Future studies will confirm the long-term clinical safety, efficacy, and resistance data for lenacapavir.

Lenacapavir: A Novel Long-Acting Capsid Inhibitor for HIV.

OBJECTIVE: To review the efficacy, safety, and role of lenacapavir (LEN) in the treatment of HIV-1 infection. DATA SOURCES: A literature search was performed using PubMed and Google Scholar (through March 2023) with the search term LEN and GS-6207. Other resources included abstracts presented at recent conferences, the manufacturer's Web site, and prescribing information. STUDY SELECTION AND DATA EXTRACTION: All relevant articles, trial updates, and conference abstracts in the English language were included. DATA SYNTHESIS: Lenacapavir represents a new class of antiretrovirals (ARVs) with a novel mechanism of action as a capsid inhibitor and a unique twice-a-year subcutaneous administration schedule. Lenacapavir when combined with other ARVs has proven to benefit heavily treatment-experienced (HTE) patients with HIV-1 infection in achieving viral suppression and immune restoration. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON WITH EXISTING DRUGS: Lenacapavir is a new treatment option that patients who are HTE can consider adding as part of an ARV regimen. CONCLUSIONS: Lenacapavir is an effective and well-tolerated option for HTE patients which is a valuable addition to the arsenal of ARVs.

The HIV-1 Capsid-Targeted Inhibitor GSK878 Alters Selection of Target Sites for HIV DNA Integration.

Decades of effort have yielded highly effective antiviral agents to treat HIV, but viral strains have evolved resistance to each inhibitor type, focusing attention on the importance of developing new inhibitor classes. A particularly promising new target is the HIV capsid, the function of which can be disrupted by highly potent inhibitors that persist long term in treated subjects. Studies with such inhibitors have contributed to an evolving picture of the role of capsid itself-the inhibitors, like certain capsid protein (CA) amino acid substitutions, can disrupt intracellular trafficking to alter the selection of target sites for HIV DNA integration in cellular chromosomes. In this study, we compare effects on HIV integration targeting for two potent inhibitors-a new molecule targeting CA, GSK878, and the previously studied lenacapavir (LEN, formerly known as GS-6207). We find that both inhibitors reduce integration in active transcription units and near epigenetic marks associated with active transcription. A careful study of integration near repeated sequences indicated frequencies were also altered for integration within multiple repeat classes. One notable finding was increased integration in centromeric satellite repeats in the presence of LEN and GSK878, which is of interest because proviruses integrated in centromeric repeats have been associated with transcriptional repression, inducibility, and latency. These data add to the picture that CA protein remains associated with preintegration complexes through the point in infection during which target sites for integration are selected, and specify new aspects of the consequences of disrupting this mechanism.

Rapid HIV-1 genotyping assay for the detection of capsid mutations.

Human immunodeficiency virus (HIV) capsid is one of the most recent viral proteins successfully targeted for the development of antiretrovirals. Lenacapavir is a first in class HIV-1 capsid inhibitor that was recently approved for the treatment of highly treatment-experienced people with HIV in combination with other anti-HIV drugs. Owing to the novelty of the viral target, methods to characterize the potential resistance-associated mutations present in capsid upon treatment failure have not been fully established yet. Here, we describe a rapid and simple method to amplify capsid fragments and to determine their sequence from various clinical samples including diverse HIV-1 subtypes. These methods could easily be implemented in laboratories, including hospital laboratories often caring for this patient population.

Antiviral Activity of Lenacapavir Against HIV-2 Isolates and Drug-resistant HIV-2 Mutants.

The activity of lenacapavir against HIV-1 has been extensively evaluated in vitro, but comparable data for HIV-2 are scarce. We determined the anti-HIV-2 activity of lenacapavir using single-cycle infections of MAGIC-5A cells and multicycle infections of a T cell line. Lenacapavir exhibited low-nanomolar activity against HIV-2, but was 11- to 14-fold less potent against HIV-2 in comparison to HIV-1. Mutations in HIV-2 that confer resistance to other antiretrovirals did not confer cross-resistance to lenacapavir. Although lenacapavir-containing regimens might be considered for appropriate patients with HIV-2, more frequent viral load and/or CD4 testing may be needed to assess clinical response.

Pharmacological outlook of Lenacapavir: a novel first-in-class Long-Acting HIV-1 Capsid Inhibitor.

The evolution of antiretroviral therapy is now addressed to develop regimens consisting of two instead of three drugs and it is also increasingly oriented to develop long-acting parenteral formulations in order to increase treatment adherence and to reduce the multifaceted individual burden associated to daily intake of drugs. This new way was first paved by the dual association consisting of the INSTI Cabotegravir and the NNRTI Rilpivirine, whose formulations allow for a single administration every two months. In 2022 a new drug with a novel mechanism of action and a longer persistence of effective drug concentrations was made available in many countries for the treatment of drug-resistant HIV infection in association to other antiretrovirals. Lenacapavir is a first in class capsid inhibitor that exerts its inhibitory effect on HIV replication by binding to a structural protein of the capsid. This unprecedented mechanism of action actually differs from those of all prior antiretrovirals as Lenacapavir interferes with multiple stages rather than with a single enzyme. Such binding determines a series of inhibitory effects on sequential steps of the HIV life cycle and the net result is that of an impressive intrinsic antiretroviral potency, as testified both by in vitro studies and the 10-day monotherapy clinical study with single injections. The antiretroviral activity of Lenacapavir is unaffected by any mutation conferring resistance to older antiretrovirals. Lenacapavir is slowly released from the site of injection and this requires an initial coverage by its oral formulation (half-life: 10-12 days) in order to provide adequate pharmacokinetic exposure in the first days of treatment. The subcutaneous administration of Lenacapavir (half-life: 8-12 weeks) is then scheduled every 6 months. Lenacapavir is metabolized by CYP3A and UGT1A1, it is a substrate of Pgp and a moderate inhibitor of CYP3A. While co-administration with strong inducers of these enzymatic entities is contraindicated or it is not recommended in case of weaker inducers, few are the potential interactions of Lenacapavir as perpetrator (by its moderate inhibitory effect on CYP and weak inhibition of Pgp). In most such cases no preventive dosage adjustments are recommended and clinical monitoring only is advised. Lenacapavir overall characteristics thus meet the major clinical-pharmacologic expectations of this new era of antiretroviral development. A safe and truly potent antiviral drug, with a low metabolic interactive potential and a frequency of administration with the potential to be successfully employed beyond the current therapeutic indications.

Pyrazole: an emerging privileged scaffold in drug discovery.

Pyrazole or 1H-pyrazole, a five-membered 1,2-diazole, is found in several approved drugs and some bioactive natural products. A myriad number of derivatives of this small molecule have been reported in clinical and preclinical studies for the potential treatment of several diseases. The number of drugs containing a pyrazole nucleus has increased significantly in the last 10 years. Some of the best-selling drugs in this class are ibrutinib, ruxolitinib, axitinib, niraparib and baricitinib, and are used to treat different types of cancers; lenacapavir to treat HIV; riociguat to treat pulmonary hypertension; and sildenafil to treat erectile dysfunction. Several aniline-derived pyrazole compounds have been reported as potent antibacterial agents with selective activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. Here, we discuss the pyrazole-derived drugs reported up to September 2023.

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.

Capsid-host interactions for HIV-1 ingress.

The HIV-1 capsid, composed of approximately 1,200 copies of the capsid protein, encases genomic RNA alongside viral nucleocapsid, reverse transcriptase, and integrase proteins. After cell entry, the capsid interacts with a myriad of host factors to traverse the cell cytoplasm, pass through the nuclear pore complex (NPC), and then traffic to chromosomal sites for viral DNA integration. Integration may very well require the dissolution of the capsid, but where and when this uncoating event occurs remains hotly debated. Based on size constraints, a long-prevailing view was that uncoating preceded nuclear transport, but recent research has indicated that the capsid may remain largely intact during nuclear import, with perhaps some structural remodeling required for NPC traversal. Completion of reverse transcription in the nucleus may further aid capsid uncoating. One canonical type of host factor, typified by CPSF6, leverages a Phe-Gly (FG) motif to bind capsid. Recent research has shown these peptides reside amid prion-like domains (PrLDs), which are stretches of protein sequence devoid of charged residues. Intermolecular PrLD interactions along the exterior of the capsid shell impart avid host factor binding for productive HIV-1 infection. Herein we overview capsid-host interactions implicated in HIV-1 ingress and discuss important research questions moving forward. Highlighting clinical relevance, the long-acting ultrapotent inhibitor lenacapavir, which engages the same capsid binding pocket as FG host factors, was recently approved to treat people living with HIV.

Lenacapavir: A first-in-class capsid inhibitor for the treatment of highly treatment-resistant HIV.

PURPOSE: The purpose of this article is to review the pharmacology, efficacy, and safety of the capsid inhibitor lenacapavir for the treatment of multidrug-resistant human immunodeficiency virus type 1 (HIV-1) infection. SUMMARY: A review of the literature was performed by searching PubMed/MEDLINE for all relevant articles published between February 2021 and March 2023 using the keywords "lenacapavir," "Sunlenca," "human immunodeficiency virus," and "treatment" together with "multidrug resistant human immunodeficiency virus." All English-language articles describing clinical trials assessing the efficacy and safety of lenacapavir when used in humans for the treatment of HIV infection were included. Review articles, conference abstracts, and article references were evaluated for relevant information, and data were also obtained from the manufacturer's website and the package insert. Lenacapavir has been approved by the Food and Drug Administration (FDA) for the treatment of HIV-1 infection in heavily treatment-experienced adults with multidrug resistance for whom the current antiretroviral regimen is failing due to resistance, intolerance, or safety considerations. It is the first in a new class of drugs called capsid inhibitors to receive FDA approval. Lenacapavir is a long-acting subcutaneous injectable to be administered once every 6 months. The phase 3 clinical trial evaluating lenacapavir has demonstrated its efficacy in viral load reduction from baseline compared to placebo in patients receiving optimized background therapy. The most common adverse events reported in the clinical trial were injection site reactions, occurring in 63% of participants. CONCLUSION: Lenacapavir is a novel capsid inhibitor indicated, in combination with other antiretroviral therapy, for treatment of multidrug-resistant HIV-1 infection.

Highlights on the Development, Related Patents, and Prospects of Lenacapavir: The First-in-Class HIV-1 Capsid Inhibitor for the Treatment of Multi-Drug-Resistant HIV-1 Infection.

The multidrug-resistant (MDR) human immunodeficiency virus 1 (HIV-1) infection is an unmet medical need. HIV-1 capsid plays an important role at different stages of the HIV-1 replication cycle and is an attractive drug target for developing therapies against MDR HIV-1 infection. Lenacapavir (LEN) is the first-in-class HIV-1 capsid inhibitor approved by the USFDA, EMA, and Health Canada for treating MDR HIV-1 infection. This article highlights the development, pharmaceutical aspects, clinical studies, patent literature, and future directions on LEN-based therapies. The literature for this review was collected from PubMed, authentic websites (USFDA, EMA, Health Canada, Gilead, and NIH), and the free patent database (Espacenet, USPTO, and Patent scope). LEN has been developed by Gilead and is marketed as Sunlenca (tablet and subcutaneous injection). The long-acting and patient-compliant LEN demonstrated a low level of drug-related mutations, is active against MDR HIV-1 infection, and does not reveal cross-resistance to other anti-HIV drugs. LEN is also an excellent drug for patients having difficult or limited access to healthcare facilities. The literature has established additive/synergistic effects of combining LEN with rilpivirine, cabotegravir, islatravir, bictegravir, and tenofovir. HIV-1 infection may be accompanied by opportunistic infections such as tuberculosis (TB). The associated diseases make HIV treatment complex and warrant drug interaction studies (drug-drug, drug-food, and drug-disease interaction). Many inventions on different aspects of LEN have been claimed in patent literature. However, there is a great scope for developing more inventions related to the drug combination of LEN with anti-HIV/anti-TB drugs in a single dosage form, new formulations, and methods of treating HIV and TB co-infection. Additional research may provide more LEN-based treatments with favorable pharmacokinetic parameters for MDR HIV-1 infections and associated opportunistic infections such as TB.