Fostemsavir: First Approval

New Therapies and Strategies to Curb HIV Infections with a Focus on Macrophages and Reservoirs

More than 80 million people worldwide have been infected with the human immunodeficiency virus (HIV). There are now approximately 39 million individuals living with HIV/acquired immunodeficiency syndrome (AIDS). Although treatments against HIV infection are available, AIDS remains a serious disease. Combination antiretroviral therapy (cART), also known as highly active antiretroviral therapy (HAART), consists of treatment with a combination of several antiretroviral drugs that block multiple stages in the virus replication cycle. However, the increasing usage of cART is inevitably associated with the emergence of HIV drug resistance. In addition, the development of persistent cellular reservoirs of latent HIV is a critical obstacle to viral eradication since viral rebound takes place once anti-retroviral therapy (ART) is interrupted. Thus, several efforts are being applied to new generations of drugs, vaccines and new types of cART. In this review, we summarize the antiviral therapies used for the treatment of HIV/AIDS, both as individual agents and as combination therapies, and highlight the role of both macrophages and HIV cellular reservoirs and the most recent clinical studies related to this disease.

Current status of the small molecule anti-HIV drugs in the pipeline or recently approved

Human Immunodeficiency Virus (HIV) is the causative agent of Acquired Immunodeficiency Syndrome (AIDS) with high morbidity and mortality rates. Treatment of AIDS/HIV is being complicated by increasing resistance to currently used antiretroviral (ARV) drugs, mainly in low- and middle-income countries (LMICs) due to drug misuse, poor drug supply and poor treatment monitoring. However, progress has been made in the development of new ARV drugs, targeting different HIV components (Fig. 1). This review aims at presenting and discussing the progress made towards the discovery of new ARVs that are at different stages of clinical trials as of July 2024. For each compound, the mechanism of action, target biomolecule, genes associated with resistance, efficacy and safety, class, and phase of clinical trial are discussed. These compounds include analogues of nucleoside reverse transcriptase inhibitors (NRTIs) - islatravir and censavudine; non-nucleoside reverse transcriptase inhibitors (NNRTIs) - Rilpivirine, elsulfavirine and doravirine; integrase inhibitors namely cabotegravir and dolutegravir and chemokine coreceptors 5 and 2 (CC5/CCR2) antagonists for example cenicriviroc. Also, fostemsavir is being developed as an attachment inhibitor while lenacapavir, VH4004280 and VH4011499 are capsid inhibitors. Others are maturation inhibitors such as GSK-254, GSK3532795, GSK3739937, GSK2838232, and other compounds labelled as miscellaneous (do not belong to the classical groups of anti-HIV drugs or to the newer classes) such as obefazimod and BIT225. There is a considerable progress in the development of new anti-HIV drugs and the effort will continue since HIV infections has no cure or vaccine till now. Efforts are needed to reduce the toxicity of available drugs or discover new drugs with new classes which can delay the development of resistance.

Development of an extended action fostemsavir lipid nanoparticle

An extended action fostemsavir (FTR) lipid nanoparticle (LNP) formulation prevents human immunodeficiency virus type one (HIV-1) infection. This FTR formulation establishes a drug depot in monocyte-derived macrophages that extend the drug's plasma residence time. The LNP's physicochemical properties improve FTR's antiretroviral activities, which are linked to the drug's ability to withstand fluid flow forces and levels of drug cellular internalization. Each is, in measure, dependent on PEGylated lipid composition and flow rate ratios affecting the size, polydispersity, shape, zeta potential, stability, biodistribution, and antiretroviral efficacy. The FTR LNP physicochemical properties enable the drug-particle's extended actions.

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.

Mechanism of action, resistance, interaction, pharmacokinetics, pharmacodynamics, and safety of fostemsavir

The Food and Drug Administration (FDA) has licensed many antiretroviral medications to treat human immunodeficiency virus type 1 (HIV-1), however, treatment options for people with multi-drug resistant HIV remain limited. Medication resistance, undesirable effects, prior tolerance, and previous interlacement incapacity to deliver new drug classes all lead to the requirement for new medication classes and drug combination therapy. Fostemsavir (FTR) is a new CD-4 attachment inhibitor medicine that was recently authorized by the United States FDA to treat HIV-1. In individuals with multidrug-resistant (MDR) HIV-1, FTR is well tolerated and virologically active. According to recent investigations, drug combination therapy can positively affect MDR-HIV. The mechanism of action, resistance, interaction, pharmacokinetics, pharmacodynamics, and safety of FTR has been highlighted in this review.

Synthesis, cytotoxic activity evaluation and mechanistic investigation of novel 3,7-diarylsubstituted 6-azaindoles

A number of new disubstituted 6-azaindoles have been designed and synthesized bearing a crucial structural modification in respect to an analogous antiproliferative hit compound. The synthesis was performed using 2-amino-3-nitro-4-picoline, that was suitably modified and converted to 7-chloro-3-iodo-6-azaindole and this central scaffold was used for successive Suzuki-type couplings, to result in the target compounds. The evaluation of the cytotoxic activity was performed against four human cancer cell lines, as well as a normal human fibroblast strain. Certain compounds possessed strong anticancer activity without affecting normal cells. At subcytotoxic concentrations for cancer cells, these compounds displayed an anti-proliferative effect by arresting the cells at the G2/M phase of the cell cycle, which could be associated with the observed decrease in the phosphorylation levels of the MEK1- ERK1/2 pathway and/or the activation of the p53-p21WAF1 axis.

Fresh Baked: An Overview of Newly FDA-Approved Drugs for Dermatological Usage

With our better understanding of the pathogenesis of various diseases, more and more drugs and biological products are being tried and tested every day. Roughly, around 40-50 novel drugs get approved by the Food and Drug Administration (FDA) for use in the general population, making it difficult for a physician to keep track of the constant changes in therapy. This article aimed to provide a compilation of all the FDA-approved new drugs for dermatological conditions and new dermatological indications of known drugs in the recent past, especially for dermatology residents and practising dermatologists. A comprehensive analysis, based on the list of new molecular entities approved by the FDA from 2020 to 2023, as well as a thorough English language literature search from 2020 to July 2023 across multiple databases (PubMed, MEDLINE, Springer Nature, Google Scholar and Cochrane) for various keywords (alone and in combination) such as "FDA approved" OR "recent advances in therapy" OR "recent drugs" OR "novel treatment" OR "dermatology," was performed. All data extracted were incorporated into the present compilation. A total of 33 drugs, including newly approved and newly approved indications of previously known drugs, were found. Relevant information about them has been discussed in a tabulated manner. This article provides an at a glance summarised profile of the newly FDA-approved drugs, as available in the existing literature. However, with the astonishing rate of new drugs hitting the market, more and more clinical trials are required to ensure the rational use of these agents.

Green-adapted spectrophotometric determination of fostemsavir based on selective bromophenol blue extraction; reduction of hazardous consumption using computational calculations

A computationally-assisted and green spectrophotometric method has been developed for the determination of fostemsavir, a recently FDA-approved drug used in combination with antiretroviral drugs to treat multidrug-resistant HIV-1 infection. The method was developed using computational studies and solvent selection based on green chemistry principles. The density functional theory method was employed to identify bromophenol blue as the preferred acid dye for efficient extraction of fostemsavir. The solvent selection process involved a careful evaluation of the green ranking of solvents, which led to the use of water as the solvent. The method involved the extraction of fostemsavir with bromophenol blue to form a yellow ion-pair complex, which exhibited maximally sharp peaks at 418 nm, enabling sensitive visible spectrophotometric determination of fostemsavir in bulk and pharmaceutical preparations. The extraction procedures were optimized, and the method was demonstrated to be sensitive over the concentration range of 2-12 μg/mL fostemsavir. Furthermore, the method was evaluated with respect to green chemistry principles using the analytical eco-scale, the green analytical method index, and analytical greenness metric approach, all of which confirmed that the data obtained by the proposed method were environmentally acceptable.

Resistance-proof antimicrobial drug discovery to combat global antimicrobial resistance threat

Drug resistance is well-defined as a serious problem in our living world. To survive, microbes develop defense strategies against antimicrobial drugs. Drugs exhibit less or no effective results against microbes after the emergence of resistance because they are unable to cross the microbial membrane, in order to alter enzymatic systems, and/or upregulate efflux pumps, etc. Drug resistance issues can be addressed effectively if a "Resistance-Proof" or "Resistance-Resistant" antimicrobial agent is developed. This article discusses first the need for resistance-proof drugs, the imminent properties of resistance-proof drugs, current and future research progress in the discovery of resistance-proof antimicrobials, the inherent challenges, and opportunities. A molecule having imminent resistance-proof properties could target microbes efficiently, increase potency, and rule out the possibility of early resistance. This review triggers the scientific community to think about how an upsurge in drug resistance can be averted and emphasizes the discussion on the development of next-generation antimicrobials that will provide a novel effective solution to combat the global problem of drug resistance. Hence, resistance-proof drug development is not just a requirement but rather a compulsion in the drug discovery field so that resistance can be battled effectively. We discuss several properties of resistance-proof drugs which could initiate new ways of thinking about next-generation antimicrobials to resolve the drug resistance problem. This article sheds light on the issues of drug resistance and discusses solutions in terms of the resistance-proof properties of a molecule. In summary, the article is a foundation to break new ground in the development of resistance-proof therapeutics in the field of infection biology.

Applications of Isosteres of Piperazine in the Design of Biologically Active Compounds: Part 2

Applications of piperazine and homopiperazine in drug design are well-established, and these heterocycles have found use as both scaffolding and terminal elements and also as a means of introducing a water-solubilizing element into a molecule. In the accompanying review (10.1021/acs.jafc.2c00726), we summarized applications of piperazine and homopiperazine and their fused ring homologues in bioactive compound design along with illustrations of the use of 4-substituted piperidines and a sulfoximine-based mimetic. In this review, we discuss applications of pyrrolidine- and fused-pyrrolidine-based mimetics of piperazine and homopiperazine and illustrate derivatives of azetidine that include stretched and spirocyclic motifs, along with applications of a series of diaminocycloalkanes.

Synthetic Approaches to the New Drugs Approved During 2020

New drugs introduced to the market are privileged structures that have affinities for biological targets implicated in human diseases and conditions. These new chemical entities (NCEs), particularly small molecules and antibody-drug conjugates (ADCs), provide insight into molecular recognition and simultaneously function as leads for the design of future medicines. This Review is part of a continuing series presenting the most likely process-scale synthetic approaches to 44 new chemical entities approved for the first time anywhere in the world during 2020.

ADENet: a novel network-based inference method for prediction of drug adverse events

Identification of adverse drug events (ADEs) is crucial to reduce human health risks and improve drug safety assessment. With an increasing number of biological and medical data, computational methods such as network-based methods were proposed for ADE prediction with high efficiency and low cost. However, previous network-based methods rely on the topological information of known drug-ADE networks, and hence cannot make predictions for novel compounds without any known ADE. In this study, we introduced chemical substructures to bridge the gap between the drug-ADE network and novel compounds, and developed a novel network-based method named ADENet, which can predict potential ADEs for not only drugs within the drug-ADE network, but also novel compounds outside the network. To show the performance of ADENet, we collected drug-ADE associations from a comprehensive database named MetaADEDB and constructed a series of network-based prediction models. These models obtained high area under the receiver operating characteristic curve values ranging from 0.871 to 0.947 in 10-fold cross-validation. The best model further showed high performance in external validation, which outperformed a previous network-based and a recent deep learning-based method. Using several approved drugs as case studies, we found that 32-54% of the predicted ADEs can be validated by the literature, indicating the practical value of ADENet. Moreover, ADENet is freely available at our web server named NetInfer (http://lmmd.ecust.edu.cn/netinfer). In summary, our method would provide a promising tool for ADE prediction and drug safety assessment in drug discovery and development.

Novel Bent Conformation of CD4 Induced by HIV-1 Inhibitor Indirectly Prevents Productive Viral Attachment

GSK3732394 is a multi-specific biologic inhibitor of HIV entry currently under clinical evaluation. A key component of this molecule is an adnectin (6940_B01) that binds to CD4 and inhibits downstream actions of gp160. Studies were performed to determine the binding site of the adnectin on CD4 and to understand the mechanism of inhibition. Using hydrogen-deuterium exchange with mass spectrometry (HDX), CD4 peptides showed differential rates of deuteration (either enhanced or slowed) in the presence of the adnectin that mapped predominantly to the interface of domains 2 and 3 (D2-D3). In addition, an X-ray crystal structure of an ibalizumab Fab/CD4(D1-D4)/adnectin complex revealed an extensive interface between the adnectin and residues on CD4 domains D2-D4 that stabilize a novel T-shaped CD4 conformation. A cryo-EM map of the gp140/CD4/GSK3732394 complex clearly shows the bent conformation for CD4 while bound to gp140. Mutagenic analyses on CD4 confirmed that amino acid F202 forms a key interaction with the adnectin. In addition, amino acid L151 was shown to be a critical indirect determinant of the specificity for binding to the human CD4 protein over related primate CD4 molecules, as it appears to modulate CD4's flexibility to adopt the adnectin-bound conformation. The significant conformational change of CD4 upon adnectin binding brings the D1 domain of CD4 in proximity to the host cell membrane surface, thereby re-orienting the gp120 binding site in a direction that is inaccessible to incoming virus due to a steric clash between gp160 trimers on the virus surface and the target cell membrane.

Innovation in the discovery of the HIV-1 attachment inhibitor temsavir and its phosphonooxymethyl prodrug fostemsavir

The discovery and development of fostemsavir (2), the tromethamine salt of the phosphonooxymethyl prodrug of temsavir (1), encountered significant challenges at many points in the preclinical and clinical development program that, in many cases, stimulated the implementation of innovative solutions in order to enable further progression. In the preclinical program, a range of novel chemistry methodologies were developed during the course of the discovery effort that enabled a thorough examination and definition of the HIV-1 attachment inhibitor (AI) pharmacophore. These discoveries helped to address the challenges associated with realizing a molecule with all of the properties necessary to successfully advance through development and this aspect of the program is the major focus of this retrospective. Although challenges and innovation are not unusual in drug discovery and development programs, the HIV-1 AI program is noteworthy not only because of the serial nature of the challenges encountered along the development path, but also because it resulted in a compound that remains the first and only example of a mechanistically novel class of HIV-1 inhibitor that is proving to be very beneficial for controlling virus levels in highly treatment-experienced HIV-1 infected patients.

Pyrroles as Privileged Scaffolds in the Search for New Potential HIV Inhibitors

Acquired immunodeficiency syndrome (AIDS) is caused by human immunodeficiency virus (HIV) and remains a global health problem four decades after the report of its first case. Despite success in viral load suppression and the increase in patient survival due to combined antiretroviral therapy (cART), the development of new drugs has become imperative due to strains that have become resistant to antiretrovirals. In this context, there has been a continuous search for new anti-HIV agents based on several chemical scaffolds, including nitrogenated heterocyclic pyrrole rings, which have been included in several compounds with antiretroviral activity. Thus, this review aims to describe pyrrole-based compounds with anti-HIV activity as a new potential treatment against AIDS, covering the period between 2015 and 2020. Our research allowed us to conclude that pyrrole derivatives are still worth exploring, as they may provide highly active compounds targeting different steps of the HIV-1 replication cycle and act with an innovative mechanism.

Double Arylation of the Indole Side Chain of Tri- and Tetrapodal Tryptophan Derivatives Renders Highly Potent HIV-1 and EV-A71 Entry Inhibitors†

We have recently described a new generation of potent human immunodeficiency virus (HIV) and EV-A71 entry inhibitors. The prototypes contain three or four tryptophan (Trp) residues bearing an isophthalic acid moiety at the C2 position of each side-chain indole ring. This work is now extended by both shifting the position of the isophthalic acid to C7 and synthesizing doubly arylated C2/C7 derivatives. The most potent derivative (50% effective concentration (EC₅₀) HIV-1, 6 nM; EC₅₀ EV-A71, 40 nM), 33 (AL-518), is a C2/C7 doubly arylated tetrapodal compound. Its superior anti-HIV potency with respect to the previous C2-arylated prototype is in consonance with its higher affinity for the viral gp120. 33 (AL-518) showed comparable antiviral activities against X4 and R5 HIV-1 strains and seems to interact with the tip and base of the gp120 V3 loop. Taken together, these findings support the interest in 33 (AL-518) as a useful new prototype for anti-HIV/EV71 drug development.

Single-Agent and Fixed-Dose Combination HIV-1 Protease Inhibitor Drugs in Fission Yeast (Schizosaccharomyces pombe)

Successful combination antiretroviral therapies (cART) eliminate active replicating HIV-1, slow down disease progression, and prolong lives. However, cART effectiveness could be compromised by the emergence of viral multidrug resistance, suggesting the need for new drug discoveries. The objective of this study was to further demonstrate the utility of the fission yeast cell-based systems that we developed previously for the discovery and testing of HIV protease (PR) inhibitors (PIs) against wild-type or multi-PI drug resistant _M11PR that we isolated from an infected individual. All thirteen FDA-approved single-agent and fixed-dose combination HIV PI drugs were tested. The effect of these drugs on HIV PR activities was tested in pure compounds or formulation drugs. All FDA-approved PI drugs, except for a prodrug FPV, were able to suppress the wild-type PR-induced cellular and enzymatic activities. Relative drug potencies measured by EC₅₀ in fission yeast were discussed in comparison with those measured in human cells. In contrast, none of the FDA-approved drugs suppressed the multi-PI drug resistant _M11PR activities. Results of this study show that fission yeast is a reliable cell-based system for the discovery and testing of HIV PIs and further demonstrate the need for new PI drugs against viral multi-PI resistance.

Evaluating fostemsavir as a therapeutic option for patients with HIV

ABSTRACIntroduction: Despite the unquestionable success of antiretroviral therapy achieved in recent years, there are still cases of heavily treated patients who do not achieve or struggle to maintain undetectable HIV-RNA due to drug resistance. New antiretroviral options are needed to address this issue.Area covered: The authors first provide an overview of fostemsavir and its role in the treatment of HTE PLWH. Data from pre-clinical and clinical studies are reviewed and the pharmacokinetic and farmacodynamic properties are highlited. Drug-drug interactions and safety data from available clinical studies are also discussed.Expert opinion: Fostemsavir is a promising antiretroviral belonging to the class of entry inhibitors; its novel mechanism of action represents a very important innovation. Its use will be limited to the heavy-treatment-experienced patient population. This use will have to be monitored to avoid abuse and waste of a molecule that for some patients may represent a life-saving drug.

Multivalent Tryptophan- and Tyrosine-Containing [60]Fullerene Hexa-Adducts as Dual HIV and Enterovirus A71 Entry Inhibitors

Unprecedented 3D hexa‐adducts of [60]fullerene peripherally decorated with twelve tryptophan (Trp) or tyrosine (Tyr) residues have been synthesized. Studies on the antiviral activity of these novel compounds against HIV and EV71 reveal that they are much more potent against HIV and equally active against EV71 than the previously described dendrimer prototypes AL‐385 and AL‐463, which possess the same number of Trp/Tyr residues on the periphery but attached to a smaller and more flexible pentaerythritol core. These results demonstrate the relevance of the globular 3D presentation of the peripheral groups (Trp/Tyr) as well as the length of the spacer connecting them to the central core to interact with the viral envelopes, particularly in the case of HIV, and support the hypothesis that [60]fullerene can be an alternative and attractive biocompatible carbon‐based scaffold for this type of highly symmetrical dendrimers. In addition, the functionalized fullerenes here described, which display twelve peripheral negatively charged indole moieties on their globular surface, define a new and versatile class of compounds with a promising potential in biomedical applications.

New drug approvals for 2020: Synthesis and clinical applications

53 New drugs including 38 chemical entities and 15 biologics were approved by the U.S. Food and Drug Administration during 2020. Among the marketed drugs, 34 new small molecule drugs and 4 new diagnostic agents with privileged structures and novel clinical applications represent as promising leads for the development of new drugs with the similar indications and improved therapeutic efficacy. This review is mainly focused on the clinical applications and synthetic methods of 34 small-molecule drugs newly approved by the FDA in 2020.