Long-acting drugs and formulations for the treatment and prevention of HIV infection

An injectable, nanostructured implant for the delivery of adenosine triphosphate: towards long-acting formulations of small, hydrophilic drugs

While long-acting injectable treatments are gaining increasing interest in managing chronic diseases, the available drug delivery systems almost exclusively rely on hydrophobic matrixes, limiting their application to either hydrophobic drugs or large and hydrophilic molecules such as peptides. To address the technological lock for long-acting delivery systems tailored to small, hydrophilic drugs such as anticancer and antiviral nucleoside/nucleotide analogues, we have synthesized and characterized an original approach with a multi-scale structure: (i) a nucleotide (adenosine triphosphate, ATP) is first incorporated in hydrophilic chitosan-Fe(III) nanogels; (ii) these nanogels are then transferred by freeze-drying and resuspension into a water-free, hydrophobic medium containing PLGA and an organic solvent, N-methyl-2-pyrrolidone. We show that this specific association allows an injectable and homogeneous dispersion, able to form in situ implants upon injection in physiological or aqueous environments. This system releases ATP in vitro without any burst effect in a two-step mechanism, first as nanogels acting as an intermediate reservoir over a week, then as free drug over several weeks. In vivo studies confirmed the potential of such nanostructured implants for sustained drug release following subcutaneous injection to mice hock, opening perspectives for sustained and targeted delivery through the lymphatic system.

Identification of Determinants and Implementation Strategies to Increase Long-Acting Injectable PrEP for HIV Prevention Among Latino Men Who Have Sex with Men (MSM)

BACKGROUND

Latino men who have sex with men (LMSM) are disproportionally affected by HIV infections in the USA. The uptake rate of pre-exposure prophylaxis (PrEP) for HIV prevention has remained low among LMSM. Long-acting injectable PrEP (LAI-PrEP) may have the potential to improve structural, behavioral, and cognitive barriers to adherence. Given the potential benefits of LAI-PrEP and the limited data with this population, the aim of our study was to explore experiences and attitudes of LAI-PrEP among LMSM and identify implementation barriers compared to the standard oral presentation, align proposed implementation strategies, and propose outcomes to monitor and assess impact.

METHODS

In this qualitative study, guided by the Consolidated Framework for Implementation Research, we explored health care providers perspectives on facilitators and barriers to LAI-PrEP implementation strategies for LMSM. Interviews were recorded, transcribed, and analyzed using thematic content analysis.

RESULTS

Fear of immigration policies, ability to conceal PrEP medication, health insurance coverage, health information fatigue, lack of culturally adapted information, and provider's lack of knowledge were among the main barriers to LAI-PrEP. Most providers discussed the need for adapted and/or tailored training materials for and suggested designing marketing materials and specific clinical recommendations for LAI-PrEP.

CONCLUSION

In order to ensure an effective adaptation process that encompasses local and national goals of HIV prevention, future interventions should be designed in a way that incorporates culturally relevant information for LMSM. This study provides an implementation research logic model to guide future studies.

Human immunodeficiency virus infection challenges: Current therapeutic limitations and strategies for improved management through long-acting injectable formulation

HIV infection has been a severe global health burden, with millions living with the virus and continuing new infections each year. Antiretroviral therapy can effectively suppress HIV replication but requires strict lifelong adherence to daily oral medication regimens, which presents a significant challenge. Long-acting formulations of antiretroviral drugs administered infrequently have emerged as a promising strategy to improve treatment outcomes and adherence to HIV therapy and prevention. Long-acting injectable (LAI) formulations are designed to gradually release drugs over extended periods of weeks or months following a single injection. Critical advantages of LAIs over conventional oral dosage forms include less frequent dosing requirements, enhanced patient privacy, reduced stigma associated with daily pill regimens, and optimised pharmacokinetic/pharmacodynamic profiles. Several LAI antiretroviral products have recently gained regulatory approval, such as the integrase strand transfer inhibitor cabotegravir for HIV preexposure prophylaxis and the Cabotegravir/Rilpivirine combination for HIV treatment. A leading approach for developing long-acting antiretroviral depots involves encapsulating drug compounds in polymeric microspheres composed of biocompatible, biodegradable materials like poly (lactic-co-glycolic acid). These injectable depot formulations enable high drug loading with customisable extended-release kinetics controlled by the polymeric matrix. Compared to daily oral therapies, LAI antiretroviral formulations leveraging biodegradable polymeric microspheres offer notable benefits, including prolonged therapeutic effects, reduced dosing frequency for improved adherence, and the potential to kerb the initial HIV transmission event. The present manuscript aims to review the pathogenesis of the virus and its progression and propose therapeutic targets and long-acting drug delivery strategies that hold substantial promise for enhancing outcomes in HIV treatment and prevention.

In Situ Forming, Enzyme-Responsive Peptoid-Peptide Hydrogels: An Advanced Long-Acting Injectable Drug Delivery System

Long-acting drug delivery systems are promising platforms to improve patient adherence to medication by delivering drugs over sustained periods and removing the need for patients to comply with oral regimens. This research paper provides a proof-of-concept for the development of a new optimized in situ forming injectable depot based on a tetrabenzylamine-tetraglycine-d-lysine-O-phospho-d-tyrosine peptoid-D-peptide formulation ((NPhe)4GGGGk(AZT)y(p)-OH). The chemical versatility of the peptoid-peptide motif allows low-molecular-weight drugs to be precisely and covalently conjugated. After subcutaneous injection, a hydrogel depot forms from the solubilized peptoid-peptide-drug formulation in response to phosphatase enzymes present within the skin space. This system is able to deliver clinically relevant concentrations of a model drug, the antiretroviral zidovudine (AZT), for 35 days in Sprague-Dawley rats. Oscillatory rheology demonstrated that hydrogel formation began within ∼30 s, an important characteristic of in situ systems for reducing initial drug bursts. Gel formation continued for up to ∼90 min. Small-angle neutron scattering data reveal narrow-radius fibers (∼0.78-1.8 nm) that closely fit formation via a flexible cylinder elliptical model. The inclusion of non-native peptoid monomers and D-variant amino acids confers protease resistance, enabling enhanced biostability to be demonstrated in vitro. Drug release proceeds via hydrolysis of an ester linkage under physiological conditions, releasing the drug in an unmodified form and further reducing the initial drug burst. Subcutaneous administration of (NPhe)4GGGGk(AZT)y(p)-OH to Sprague-Dawley rats resulted in zidovudine blood plasma concentrations within the 90% maximal inhibitory concentration (IC90) range (30-130 ng mL-1) for 35 days.

Evaluating HIV-1 Infectivity and Virion Maturation across Varied Producer Cells with a Novel FRET-Based Detection and Quantification Assay

The maturation of HIV-1 virions is a crucial process in viral replication. Although T-cells are a primary source of virus production, much of our understanding of virion maturation comes from studies using the HEK293T human embryonic kidney cell line. Notably, there is a lack of comparative analyses between T-cells and HEK293T cells in terms of virion maturation efficiency in existing literature. We previously developed an advanced virion visualization system based on the FRET principle, enabling the effective distinction between immature and mature virions via fluorescence microscopy. In this study, we utilized pseudotyped, single-round infectious viruses tagged with FRET labels (HIV-1 Gag-iFRET∆Env) derived from Jurkat (a human T-lymphocyte cell line) and HEK293T cells to evaluate their virion maturation rates. HEK293T-derived virions demonstrated a maturity rate of 81.79%, consistent with other studies and our previous findings. However, virions originating from Jurkat cells demonstrated a significantly reduced maturation rate of 68.67% (p < 0.0001). Correspondingly, viruses produced from Jurkat cells exhibited significantly reduced infectivity compared to those derived from HEK293T cells, with the relative infectivity measured at 65.3%. This finding is consistent with the observed relative maturation rate of viruses produced by Jurkat cells. These findings suggest that initiation of virion maturation directly correlates with viral infectivity. Our observation highlights the dynamic nature of virus-host interactions and their implications for virion production and infectivity.

Evaluating HIV-1 Infectivity and Virion Maturation Across Varied Producer Cells with a Novel FRET-Based Detection and Quantification Assay

The maturation of HIV-1 virions is a crucial process in viral replication. Although T cells are a primary source of virus production, much of our understanding of virion maturation comes from studies using the HEK293T human embryonic kidney cell line. Notably, there is a lack of comparative analyses between T cells and HEK293T cells in terms of virion maturation efficiency in existing literature. We previously developed an advanced virion visualization system based on the FRET principle, enabling the effective distinction between immature and mature virions via fluorescence microscopy. In this study, we utilized pseudotyped, single-round infectious viruses tagged with FRET labels (HIV-1 Gag-iFRETΔEnv) derived from Jurkat (a human T lymphocyte cell line) and HEK293T cells to evaluate their virion maturation rates. HEK293T-derived virions demonstrated a maturity rate of 81.79%, consistent with other studies and our previous findings. However, virions originating from Jurkat cells demonstrated a significantly reduced maturation rate of 68.67% (p < 0.0001). Correspondingly, viruses produced from Jurkat cells exhibited significantly reduced infectivity compared to those derived from HEK293T cells, with the relative infectivity measured at 65.3%. This finding is consistent with the observed relative maturation rate of viruses produced by Jurkat cells. These findings suggest that initiation of virion maturation directly correlates with viral infectivity. Our observation highlights the dynamic nature of virus-host interactions and their implications for virion production and infectivity.

Key informant views on potential acceptability and feasibility of long-acting antiretroviral treatment for HIV in Kenya

BACKGROUND

In 2020, 14% of diagnosed persons living with HIV (PLWH) in Kenya were not taking antiretroviral therapy (ART), and 19% of those on ART had unsuppressed viral loads. Long-acting antiretroviral therapy (LA-ART) may increase viral suppression by promoting ART uptake and adherence. We conducted key informant (KI) interviews with HIV experts in Kenya to identify product and delivery attributes related to the acceptability and feasibility of providing LA-ART to PLWH in Kenya.

METHODS

Interviews were conducted via Zoom on potential LA-ART options including intra-muscular (IM) injections, subcutaneous (SC) injections, implants, and LA oral pills. KI were asked to discuss the products they were most and least excited about, as well as barriers and facilitators to LA-ART roll-out. In addition, they were asked about potential delivery locations for LA-ART products such as homes, pharmacies, and clinics. Interviews were recorded and transcribed, and data were analyzed using a combination of inductive and deductive coding.

RESULTS

Twelve KI (5 women, 7 men) participated between December 2021 and February 2022. Overall, participants reported that LA-ART would be acceptable and preferable to PLWH because of fatigue with daily oral pills. They viewed IM injections and LA oral pills as the most exciting options to ease pill burden and improve adherence. KI felt that populations who could benefit most were adolescents in boarding schools and stigmatized populations such as sex workers. SC injections and implants were less favored, as they would require new training initiatives for patients or healthcare workers on administration. In addition, SC injections would require refrigeration and needle disposal after use. Some KI thought patients, especially men, might worry that IM injections and implants would impact fertility, given their role in family planning. Pharmacies were perceived by most KI as suboptimal delivery locations; however, given ongoing work in Kenya to include pharmacies in antiretroviral delivery, they recommended asking patients their views.

CONCLUSION

There is interest and support for LA-ART in Kenya, especially IM injections and LA oral pills. Identifying patient preferences for modes and delivery locations and addressing misconceptions about specific products as they become available will be important before wide-scale implementation.

Assessing Preferences for Long-Acting Injectable Pre-Exposure Prophylaxis Among Young Adult Sexual Minority Men and Transgender Women

OBJECTIVE

Oral pre-exposure prophylaxis (PrEP) is effective in preventing HIV transmission. However, oral PrEP uptake is low, particularly among sexual and gender minority youth who are vulnerable to HIV infection. Alternative methods of PrEP delivery, such as long-acting injectable (LAI) PrEP may overcome barriers and be preferred. However, attitudes and preferences of younger sexual and gender minorities towards LAI PrEP have not been well studied. The purpose of this study is to describe preferences for initiating LAI PrEP among sexual and gender minority youth.

METHODS

We analyzed data collected as part of an HIV prevention randomized trial from January 2022 to February 2023, using multiple regression to identify factors associated with a preference for LAI PrEP.

RESULTS

The study sample (N = 265) was 50% youth of color, mean age 25 years (SD=3.4, range=18-31), and primarily identified as gay (71%) and male (91%). Forty two percent had heard of LAI PrEP and 31% preferred LAI PrEP over other prevention methods. In multiple regression analysis, LAI PrEP preference was associated with identifying as White, previous PrEP experience, and perceived LAI PrEP efficacy.

CONCLUSIONS

We conclude that gaps in awareness exist for LAI PrEP, however it may be preferred over other prevention methods especially in White youth, those with PrEP experience and higher perceptions of its efficacy. More education and outreach are needed to prevent extension of existing race and ethnicity disparities in use of oral daily PrEP to LAI PrEP.

Preferences of people living with HIV for injectable and oral antiretroviral treatment in the Netherlands: a discrete choice experiment

ABSTRACTInjectable antiretroviral treatment (ART) represents a new effective and potentially more convenient alternative to oral ART for people living with HIV (PLWH). This study assessed preferences of PLWH for long-acting injectable compared with oral ART in the Netherlands. A labelled discrete choice experiment presented 12 choice sets of long-acting injectable and oral ART. PLWH were asked to select their preferred ART, described by six attributes: location of administration, dosing frequency, risk of short-term side effects, drug-drug interaction, forgivability, and food and mealtime restrictions. Random parameters logit and latent class models were used to estimate preferences of PLWH. 98.6% of 76 respondents were experienced oral ART users that had taken ART for a median of 12 years (Q1-Q3: 7.0-20.0). 30 (39.5%) respondents chose long-acting injectable ART in all choice tasks and 22 (28.9%) always chose oral ART. The random parameter model showed that, on average, respondents significantly favoured long-acting injectable ART over oral ART, preferred administration of the long-acting injectable ART at home, and a less frequent regimen. The latent class model confirmed one class strongly preferring long-acting injectable ART and one class slightly preferring oral ART. This study highlights the value for both long-acting injectable and oral ART.

HIV pre-exposure prophylaxis programme preferences among sexually active HIV-negative transgender and gender diverse adults in the United States: a conjoint analysis

INTRODUCTION

Current implementation efforts have failed to achieve equitable HIV pre-exposure prophylaxis (PrEP) provision for transgender and gender-diverse (trans) populations. We conducted a choice-based conjoint analysis to measure preferences for key attributes of hypothetical PrEP delivery programmes among a diverse online sample predominantly comprised of transmasculine and nonbinary individuals in the United States.

METHODS

Between April 2022 and June 2022, a national online survey with an embedded conjoint analysis experiment was conducted among 304 trans individuals aged ≥18 years in the United States to assess five PrEP programme attributes: out-of-pocket cost; dispensing venue; frequency of visits for PrEP-related care; travel time to PrEP provider; and ability to bundle PrEP-related care with gender-affirming hormone therapy services. Participants responded to five questions, each of which presented two PrEP programme scenarios and one opt-out option per question and selected their preferred programme in each question. We used hierarchical Bayes estimation and multinomial logistic regression to measure part-worth utility scores for the total sample and by respondents' PrEP status.

RESULTS

The median age was 24 years (range 18-56); 75% were assigned female sex at birth; 54% identified as transmasculine; 32% as nonbinary; 14% as transfeminine. Out-of-pocket cost had the highest attribute importance score (44.3%), followed by the ability to bundle with gender-affirming hormone therapy services (18.7%). Minimal cost-sharing ($0 out-of-pocket cost) most positively influenced the attribute importance of cost (average conjoint part-worth utility coefficient of 2.5 [95% CI 2.4-2.6]). PrEP-experienced respondents preferred PrEP delivery in primary care settings (relative utility score 4.7); however, PrEP-naïve respondents preferred pharmacies (relative utility score 5.1).

CONCLUSIONS

Participants preferred programmes that offered PrEP services without cost-sharing and bundled with gender-affirming hormone therapy services. Bolstering federal regulations to cover PrEP services and prioritizing programmes to expand low-barrier PrEP provision are critical to achieving equitable PrEP provision. Community-engaged implementation research conducted by and in close collaboration with trans community stakeholders and researchers are needed to streamline the design of patient-centred PrEP programmes and develop implementation strategies that are salient to the diverse sexual health needs of trans patients.

Improving Adherence to the Target Window for Cabotegravir + Rilpivirine Long-Acting Injections Through the CHORUS™ App and Web Portal: A Cluster Randomized Trial

BACKGROUND

We evaluated the impact of the CHORUS™ app on adherence to the cabotegravir and rilpivirine long-acting injectable (CAB + RPV LAI) monthly injections schedule.

METHODS

Healthcare centers (HCCs) were randomized to access CHORUS™ CAB + RPV LAI features (intervention) or not (control) from 01OCT2021-31JAN2022. Target window adherence (maintenance injections ≤7 days before/after target day) was assessed with multivariate logistic regression (generalized estimating equations).

RESULTS

CAB + RPV LAI was administered to 188 and 79 individuals at intervention and control HCCs, respectively. Intervention was not associated with improved target window adherence (adjusted odds ratio: 0.61 [95% CI: 0.30-1.25]). However, app use was associated with increased odds of adherence compared to no app use among all intervention HCCs (2.98 [1.26-7.06]) and at smaller HCCs (3.58 [1.31-9.80]).

CONCLUSIONS

While access to CHORUS™ CAB + RPV LAI features did not improve target window adherence, app use did, especially at smaller HCCs which may not have established LAI management procedures.

TRIAL REGISTRATION

https://clinicaltrials.gov/show/NCT04863261.

Considerations for long-acting antiretroviral therapy in older persons with HIV

People with HIV (PWH) can now enjoy longer, healthier lives due to safe and highly effective antiretroviral therapy (ART), and improved care and prevention strategies. New drug formulations such as long-acting injectables (LAI) may overcome some limitations and issues with oral antiretroviral therapy and strengthen medication adherence. However, challenges and questions remain regarding their use in aging populations. Here, we review unique considerations for LAI-ART for the treatment of HIV in older PWH, including benefits, risks, pharmacological considerations, implementation challenges, knowledge gaps, and identify factors that may facilitate uptake of LA-ART in this population.

Bibliometric analysis and visualization of research trends on HIV-1 capsid inhibitors (2000-2022)

Background: Acquired immunodeficiency syndrome (AIDS) has seriously endangered human life and health, the main pathogenic agent is human immunodeficiency virus type 1 (HIV-1). The combination antiretroviral therapy (cART) has shown serious drug resistance and side effects, and the discovery of HIV-1 capsid inhibitors is an effective way to solve the problem. Recent studies have shown significant progress in the research of HIV-1 capsid inhibitors. However, there is still a lack of comprehensive overview of bibliometric analysis in this field. This study aimed to provide the research trends and hotspots of HIV-1 capsid inhibitors. Method: Publications related to HIV-1 capsid inhibitors from 2000 to 2022 were searched on the Web of Science Core Collection (WoSCC) database and screened according to inclusion criteria. VOSviewer was conducted to evaluate the results. Results: 96 publications from 25 countries were finally included, and the number of annual publications related to HIV-1 capsid inhibitors showed an increasing trend. The United States was the most productive country with the most publication number, H-index, and total citation number, as well as the widest international cooperation. The most popular journal in this field was Journal of Virology. Drexel University was the most productive institution, and Simon Cocklin participated in the most publications. Keywords co-occurrence analysis exhibited that studying the molecular mechanism of capsid protein, discovering drug candidates, and improving antiretroviral therapy are the main and hot topics in this field. Conclusion: This is the first bibliometric study in the field of HIV-1 capsid inhibitors, which comprehensively analyzed the research trends and hotspots in this direction. This work is expected to provide the scientific community with new insights to promote the research of HIV-1 capsid inhibitors.

Clinically relevant atovaquone-resistant human malaria parasites fail to transmit by mosquito

Long-acting injectable medications, such as atovaquone, offer the prospect of a "chemical vaccine" for malaria, combining drug efficacy with vaccine durability. However, selection and transmission of drug-resistant parasites is of concern. Laboratory studies have indicated that atovaquone resistance disadvantages parasites in mosquitoes, but lack of data on clinically relevant Plasmodium falciparum has hampered integration of these variable findings into drug development decisions. Here we generate atovaquone-resistant parasites that differ from wild type parent by only a Y268S mutation in cytochrome b, a modification associated with atovaquone treatment failure in humans. Relative to wild type, Y268S parasites evidence multiple defects, most marked in their development in mosquitoes, whether from Southeast Asia (Anopheles stephensi) or Africa (An. gambiae). Growth of asexual Y268S P. falciparum in human red cells is impaired, but parasite loss in the mosquito is progressive, from reduced gametocyte exflagellation, to smaller number and size of oocysts, and finally to absence of sporozoites. The Y268S mutant fails to transmit from mosquitoes to mice engrafted with human liver cells and erythrocytes. The severe-to-lethal fitness cost of clinically relevant atovaquone resistance to P. falciparum in the mosquito substantially lessens the likelihood of its transmission in the field.

The New Era of Long-Acting Antiretroviral Therapy: When and Why to Make the Switch

PURPOSE OF REVIEW

Despite the availability of safe and effective oral combination antiretroviral therapy, barriers to maintaining viral suppression remain a challenge to ending the HIV epidemic. Long-acting injectable antiretroviral therapy was developed as an alternative to daily oral therapy. This review summarizes the current literature on the efficacy of long-acting cabotegravir plus rilpivirine for the treatment of HIV-1, reasons to switch to injectable therapy, and barriers to switching.

RECENT FINDINGS

Long-acting cabotegravir plus rilpivirine is safe and effective in maintaining HIV-1 virologic suppression. Ideal candidates for switching to long-acting cabotegravir plus rilpivirine are virologically suppressed on oral regimens with good adherence and no history of virologic failure or baseline resistance. Indications to switch to injectable therapy include patient preference, the potential for improved adherence, and avoidance of adverse effects. Implementation research is needed to assess and overcome system barriers. Long-acting cabotegravir plus rilpivirine is a novel alternative to oral antiretrovirals, with the potential to improve adherence and quality of life in people with HIV.

Drug delivery breakthrough technologies - A perspective on clinical and societal impact

The way a drug molecule is administered has always had a profound impact on people requiring medical interventions - from vaccine development to cancer therapeutics. In the Controlled Release Society Fall Symposium 2022, a trans-institutional group of scientists from industry, academia, and non-governmental organizations discussed what a breakthrough in the field of drug delivery constitutes. On the basis of these discussions, we classified drug delivery breakthrough technologies into three categories. In category 1, drug delivery systems enable treatment for new molecular entities per se, for instance by overcoming biological barriers. In category 2, drug delivery systems optimize efficacy and/or safety of an existing drug, for instance by directing distribution to their target tissue, by replacing toxic excipients, or by changing the dosing reqimen. In category 3, drug delivery systems improve global access by fostering use in low-resource settings, for instance by facilitating drug administration outside of a controlled health care institutional setting. We recognize that certain breakthroughs can be classified in more than one category. It was concluded that in order to create a true breakthrough technology, multidisciplinary collaboration is mandated to move from pure technical inventions to true innovations addressing key current and emerging unmet health care needs.

The Integrase: An Overview of a Key Player Enzyme in the Antiviral Scenario

Integration of a desossiribonucleic acid (DNA) copy of the viral ribonucleic acid (RNA) into host genomes is a fundamental step in the replication cycle of all retroviruses. The highly conserved virus-encoded Integrase enzyme (IN; EC 2.7.7.49) catalyzes such a process by means of two consecutive reactions named 3'-processing (3-P) and strand transfer (ST). The Authors report and discuss the major discoveries and advances which mainly contributed to the development of Human Immunodeficiency Virus (HIV) -IN targeted inhibitors for therapeutic applications. All the knowledge accumulated over the years continues to serve as a valuable resource for the design and development of effective antiretroviral drugs.

Drug-drug interactions between COVID-19 therapeutics and antiretroviral treatment: the evidence to date

INTRODUCTION

With new effective treatments for SARS-CoV-2, patient outcomes have greatly improved. However, new medications bring a risk of drug interactions with other medications. People living with HIV (PLWH) are at particular risk for these interactions due to heightened risk of immunosuppression, polypharmacy, and overlap in affected organs. It is critical to identify drug interactions are a significant barrier to care for PLWH. Establishing a better understanding of the pharmacologic relationships between COVID-19 therapies and antiretrovirals will improve patient-centered care in COVID-19.

AREAS COVERED

Potential drug-drug interactions between Human Immunodeficiency Virus (HIV) and COVID-19 treatments are detailed and reviewed here. The mechanisms seen in these interactions include alterations in metabolic enzymes, drug transporters, pharmacoenhancement, and organ toxicities. We also review the limitations and solutions that can be used to combat drug-drug interactions between these two disease states.

EXPERT OPINION

While current drug interactions are relatively mild between HIV and COVID-19 therapies, improvements in identifying these beforehand must take place as new therapies are approved. Antiretroviral therapy (ART) is essential in PLWH and must be maintained when treating COVID-19. As advancements in care occur, there is the possibility that newly approved drugs may have additional unknown interactions.

Barriers to Pre-Exposure Prophylaxis (PrEP) use for HIV: an integrative review

OBJECTIVES

to identify and synthesize scientific evidence on the barriers and difficulties for Pre-exposure Prophylaxis (PrEP) use and compliance for HIV.

METHODS

an integrative literature review, using the MEDLINE/PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Academic Search Premier and Scopus (Elsevier) databases.

RESULTS

all (100%) the articles included identified that PrEP users experience some type of structural barrier related to health services such as long distance from the units, suboptimal logistics for taking pills and professional resistance to prescribing PrEP. Furthermore, 63.21% identified social barriers, such as stigma about sexuality and HIV, in addition to individual barriers such as alcohol use, adverse effects, and concerns about long-term toxicity.

CONCLUSIONS

the barriers to PrEP use are multifactorial. Effective interventions are needed to support PrEP users in accessing, complying with, and retaining health services.

Creation of a ready-to-use brexpiprazole suspension and the inflammation-mediated pharmacokinetics by intramuscular administration

Brexpiprazole (BPZ), which is approved for the treatment of schizophrenia and major depressive disorder, has the potential to meet diverse clinical needs. This study aimed to develop a long-acting injectable (LAI) formulation of BPZ that could provide sustained therapeutic benefits. A library of BPZ prodrugs was screened through esterification, and BPZ laurate (BPZL) was identified as an optimal candidate. To achieve stable aqueous suspensions, a pressure- and nozzle size-controlled microfluidization homogenizer was utilized. The pharmacokinetics (PK) profiles, considering dose and particle size modulation, were investigated following a single intramuscular injection in beagles and rats. BPZL treatment resulted in sustained plasma concentrations above the median effective concentration (EC₅₀) for 2∼3 weeks, without exhibiting an initial burst release. Histological examination of foreign body reaction (FBR) in rats revealed the morphological evolution of an inflammation-mediated drug depot, confirming the sustained release mechanism of BPZL. These findings provide strong support for the further development of a ready-to-use LAI suspension of BPZL, which could potentially enhance treatment outcomes, improve patient adherence, and address the clinical challenges associated with long-term regimens of schizophrenia spectrum disorders (SSD).

Modelling the impact of treatment adherence on the transmission of HIV drug resistance

INTRODUCTION

A lower adherence rate (percentage of individuals taking drugs as prescribed) to ART may increase the risk of emergence and transmission of HIV drug resistance, decrease treatment efficacy, and increase mortality rate. Exploring the impact of ART adherence on the transmission of drug resistance could provide insights in controlling the HIV epidemic.

METHODS

We proposed a dynamic transmission model incorporating the CD4 cell count-dependent rates of diagnosis, treatment and adherence with transmitted drug resistance (TDR) and acquired drug resistance. This model was calibrated and validated by 2008-2018 HIV/AIDS surveillance data and prevalence of TDR among newly diagnosed treatment-naive individuals from Guangxi, China, respectively. We aimed to identify the impact of adherence on drug resistance and deaths during expanding ART.

RESULTS

In the base case (ART at 90% adherence and 79% coverage), we projected the cumulative total new infections, new drug-resistant infections, and HIV-related deaths between 2022 and 2050 would be 420 539, 34 751 and 321 671. Increasing coverage to 95% would reduce the above total new infections (deaths) by 18.85% (15.75%). Reducing adherence to below 57.08% (40.84%) would offset these benefits of increasing coverage to 95% in reducing infections (deaths). Every 10% decrease in adherence would need 5.07% (3.62%) increase in coverage to avoid an increase in infections (deaths). Increasing coverage to 95% with 90% (80%) adherence would increase the above drug-resistant infections by 11.66% (32.98%).

CONCLUSIONS

A decrease in adherence might offset the benefits of ART expansion and exacerbate the transmission of drug resistance. Ensuring treated patients' adherence might be as important as expanding ART to untreated individuals.

Pharmacokinetics of Antiretroviral Agents in Pregnant Individuals Living With HIV: Current Status and Considerations for Study Design and Interpretation

Determining the appropriate dosing regimens of antiretroviral (ARV) drugs for pregnant individuals living with HIV-1 infection is critical to maximize maternal health and prevent perinatal HIV transmission. Throughout pregnancy, pharmacokinetics (PK) of ARVs can be significantly altered due to physiological, anatomic, and metabolic changes. As such, conducting PK studies of ARVs during pregnancy is crucial to optimize dosing regimens. In this article, we summarize available data, key issues, challenges, and considerations in interpreting results of ARV PK studies in pregnant individuals. Discussion topics include the choice of the reference population (postpartum vs historical control), pregnancy trimester-dependent changes in ARV PK, effects of pregnancy on once- versus twice-daily dosing, factors to consider for ARVs that are administered with a PK booster such as ritonavir and cobicistat, and considerations when evaluating the effects of pregnancy on unbound ARV concentrations. Common approaches for the translation of the results into clinical recommendations and rationales and considerations when making clinical recommendations are summarized. Currently, limited PK data in pregnancy are available with long-acting ARVs. Collection of PK data to characterize the PK profile of long-acting ARVs is an important goal shared by many stakeholders.

Long-acting Parenteral Drug Delivery Systems for the Treatment of Chronic Diseases

The management of chronic conditions often requires patients to take daily medication for an extended duration. However, the need for daily dosing can lead to nonadherence to the therapy, which can result in the recurrence of the disease. Long-acting parenteral drug delivery systems have the potential to improve the treatment of chronic conditions. These systems use various technologies, such as oil-based injectables, PLGA-based microspheres, and in situ forming gel-based depots, to deliver different types of drugs. The use of long-acting parenteral formulations for the treatment of chronic infections such as HIV/AIDS and tuberculosis is a recent development in the field. Researchers are also exploring the use of long-acting parenteral formulations for the treatment of malaria, with the aim of reducing dosing frequency and improving adherence to treatment. This review discusses various aspects of long-acting formulation development, including the impact of the physicochemical properties of the drug, the type of long-acting formulation, and the route of administration. The clinical significance of long-acting formulations and recent advances in the field, such as long-acting nanoformulations and long-acting products currently in clinical trials, have also been highlighted.

Development of Drug Release Model for Suspensions in ESCAR (Emulator of SubCutaneous Absorption and Release)

We recently developed an in vitro testing system, namely, ESCAR (Emulator of SubCutaneous Absorption and Release). The objective of this work was to investigate drug release behaviors of unmilled and milled suspensions in ESCAR. A mass transport-based model was developed to describe the multi-step drug release process, including drug dissolution, particle settling, drug distribution/partition, and drug permeation through the membrane(s). To address the particle settling effect, a correction factor was included in the model and its value was obtained by data fitting. It was found that, for both suspensions, (i) the experimental data of various dose/formulation combinations could be fit by the developed model; (ii) the dose effect on drug release was offset by the particle settling effect. This model may help to reduce experimental efforts and facilitate subcutaneous suspension formulation development using ESCAR.

Approved Nanomedicine against Diseases

Nanomedicine is a branch of medicine using nanotechnology to prevent and treat diseases. Nanotechnology represents one of the most effective approaches in elevating a drug‘s treatment efficacy and reducing toxicity by improving drug solubility, altering biodistribution, and controlling the release. The development of nanotechnology and materials has brought a profound revolution to medicine, significantly affecting the treatment of various major diseases such as cancer, injection, and cardiovascular diseases. Nanomedicine has experienced explosive growth in the past few years. Although the clinical transition of nanomedicine is not very satisfactory, traditional drugs still occupy a dominant position in formulation development, but increasingly active drugs have adopted nanoscale forms to limit side effects and improve efficacy. The review summarized the approved nanomedicine, its indications, and the properties of commonly used nanocarriers and nanotechnology.

Long-Acting Antiretroviral Drug Therapy in Adolescents: Current Status and Future Prospects

Approximately 50% of human immunodeficiency virus (HIV)-infected adolescents fail to achieve complete viral suppression, largely due to nonadherence to their antiretroviral drug regimens. Numerous personal, financial, and societal barriers contribute to nonadherence, which may lead to the development of HIV drug resistance. Long-acting antiretroviral drugs hold the promise of improved adherence because they remove the need for swallowing one or more pills daily. Cabotegravir (an integrase strand transfer inhibitor) and rilpivirine (a non-nucleoside reverse transcriptase inhibitor) can now be intramuscularly co-administered to HIV-infected adolescents every 4-8 weeks if they are virologically suppressed and without resistance mutations to cabotegravir or rilpivirine. Adverse effects are few and non-severe. Widespread use of this complete antiretroviral therapy may be limited by drug costs, need for sites and skilled personnel who can administer the injections, and ethical challenges. Other long-acting medications and new antiretroviral therapy delivery systems are under active investigation and show great promise.

Transmissibility of clinically relevant atovaquone-resistant Plasmodium falciparum by anopheline mosquitoes

Rising numbers of malaria cases and deaths underscore the need for new interventions. Long-acting injectable medications, such as those now in use for HIV prophylaxis, offer the prospect of a malaria "chemical vaccine", combining the efficacy of a drug (like atovaquone) with the durability of a biological vaccine. Of concern, however, is the possible selection and transmission of drug-resistant parasites. We addressed this question by generating clinically relevant, highly atovaquone-resistant, Plasmodium falciparum mutants competent to infect mosquitoes. Isogenic paired strains, that differ only by a single Y268S mutation in cytochrome b, were evaluated in parallel in southeast Asian (Anopheles stephensi) or African (Anopheles gambiae) mosquitoes, and thence in humanized mice. Fitness costs of the mutation were evident along the lifecycle, in asexual parasite growth in vitro and in a progressive loss of parasites in the mosquito. In numerous independent experiments, microscopic exam of salivary glands from hundreds of mosquitoes failed to detect even one Y268S sporozoite, a defect not rescued by coinfection with wild type parasites. Furthermore, despite uniformly successful transmission of wild type parasites from An. stephensi to FRG NOD huHep mice bearing human hepatocytes and erythrocytes, multiple attempts with Y268S-fed mosquitoes failed: there was no evidence of parasites in mouse tissues by microscopy, in vitro culture, or PCR. These studies confirm a severe-to-lethal fitness cost of clinically relevant atovaquone-resistant P. falciparum in the mosquito, and they significantly lessen the likelihood of their transmission in the field.

Co-delivery of an HIV prophylactic and contraceptive using PGSU as a long-acting multipurpose prevention technology

OBJECTIVES

Poly(glycerol sebacate) urethane (PGSU) elastomers formulated with 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA), levonorgestrel (LNG), or a combination thereof can function as multipurpose prevention technology implants for prophylaxis against HIV and unintended pregnancies. For these public health challenges, long-acting drug delivery technologies may improve patient experience and adherence. Traditional polymers encounter challenges delivering multiple drugs with dissimilar physiochemical properties. PGSU offers an alternative option that successfully delivers hydrophilic EFdA alongside hydrophobic LNG.

METHODS

This article presents the formulation, design, and characterization of PGSU implants, highlighting the impact of API loading, dimensions, and individual- versus combination-loading on release rates.

RESULTS

Co-delivery of hydrophilic EFdA alongside hydrophobic LNG acted as a porogen to accelerate LNG release. Increasing the surface area of LNG-only implants increased LNG release. All EFdA-LNG, EFdA-only, and LNG-only formulated implants demonstrated low burst release and linear release kinetics over 245 or 122 days studied to date.

CONCLUSION

PGSU co-delivers two APIs for HIV prevention and contraception at therapeutically relevant concentrations in vitro from a single bioresorbable, elastomeric implant. A new long-acting polymer technology, PGSU demonstrates linear-release kinetics, dual delivery of APIs with disparate physiochemical properties, and biocompatibility through long-term subcutaneous implantation. PGSU can potentially meet the demands of complex MPT or fixed-dose combination products, where better solutions can serve and empower patients.

Strategies to overcome HIV drug resistance-current and future perspectives

The availability of combined antiretroviral therapy (cART) has revolutionized the course of HIV infection, suppressing HIV viremia, restoring the immune system, and improving the quality of life of HIV infected patients. However, the emergence of drug resistant and multidrug resistant strains remains an important contributor to cART failure, associated with a higher risk of HIV-disease progression and mortality. According to the latest WHO HIV Drug Resistance Report, the prevalence of acquired and transmitted HIV drug resistance in ART naive individuals has exponentially increased in the recent years, being an important obstacle in ending HIV-1 epidemic as a public health threat by 2030. The prevalence of three and four-class resistance is estimated to range from 5 to 10% in Europe and less than 3% in North America. The new drug development strategies are focused on improved safety and resistance profile within the existing antiretroviral classes, discovery of drugs with novel mechanisms of action (e.g., attachment/post-attachment inhibitors, capsid inhibitors, maturation inhibitors, nucleoside reverse transcriptase translocation inhibitors), combination therapies with improved adherence, and treatment simplification with infrequent dosing. This review highlight the current progress in the management of salvage therapy for patients with multidrug-resistant HIV-1 infection, discussing the recently approved and under development antiretroviral agents, as well as the new drug targets that are providing a new avenue for the development of therapeutic interventions in HIV infection.

Patient preferences and health state utilities associated with the treatment process of antiretroviral therapy for people living with HIV

PURPOSE

People living with HIV (PLHIV) have reported challenges associated with daily oral antiretroviral therapy (ART), including missed doses, negative psychological impact, and difficulty remaining discreet while at home or traveling. Recently approved long-acting injectable (LAI) ART may help eliminate these concerns. The purpose of this study was to examine patient preferences and estimate health state utilities associated with oral and LAI treatment for ART.

METHODS

Four health state vignettes were developed based on published literature, clinician interviews, and a pilot study. All vignettes included the same description of HIV, but differed in treatment regimens: (A) single daily oral tablet, (B) two daily oral tablets, (C) injections once monthly, and (D) injections every two months. PLHIV in the UK reported their preferences and valued the health states in time trade-off utility interviews.

RESULTS

The sample included 201 PLHIV (83.1% male; mean age = 44.9y). The health states frequently selected as most preferable were D (n = 119; 59.2%) and A (n = 75; 37.3%). Utility differences among health states were relatively small, which is typical for treatment process utilities (mean utilities: A, 0.908; B, 0.905; C, 0.900; D, 0.910). Statistically significant differences in utility were found for one vs. two tablets and injections every month vs. every two months (p < 0.001). Participants' quotations highlight the wide range of reasons for treatment process preferences.

CONCLUSIONS

Current results indicate that many PLHIV would prefer LAI ART. The reported utilities may be useful in economic modeling comparing oral vs. LAI ART.

An ultralong-acting tenofovir ProTide nanoformulation achieves monthslong HBV suppression

Treatment of chronic hepatitis B virus (HBV) requires lifelong daily therapy. However, suboptimal adherence to the existing daily therapy has led to the need for ultralong-acting antivirals. A lipophilic and hydrophobic ProTide was made by replacing the alanyl isopropyl ester present in tenofovir alafenamide (TAF) with a docosyl phenyl alanyl ester, now referred to as M1TFV. NM1TFV and nanoformulated TAF (NTAF) nanocrystals were formulated by high-pressure homogenization. A single intramuscular injection of NM1TFV, but not NTAF, delivered at a dose of TFV equivalents (168 milligrams per kilogram) demonstrated monthslong antiviral activities in both HBV-transgenic and human hepatocyte transplanted TK-NOG mice. The suppression of HBV DNA in blood was maintained for 3 months. Laboratory experiments on HBV-transfected HepG2.2.15 cells affirmed the animal results and the critical role of docosanol in the sustained NM1TFV antiviral responses. These results provide clear "proof of concept" toward an emerging therapeutic paradigm for the treatment and prevention of HBV infection.

Discovery of novel 1,2,4-triazole phenylalanine derivatives targeting an unexplored region within the interprotomer pocket of the HIV capsid protein

Human immunodeficiency virus (HIV) capsid (CA) protein is a promising target for developing novel anti-HIV drugs. Starting from highly anticipated CA inhibitors PF-74, we used scaffold hopping strategy to design a series of novel 1,2,4-triazole phenylalanine derivatives by targeting an unexplored region composed of residues 106-109 in HIV-1 CA hexamer. Compound d19 displayed excellent antiretroviral potency against HIV-1 and HIV-2 strains with EC50 values of 0.59 and 2.69 µM, respectively. Additionally, we show via surface plasmon resonance (SPR) spectrometry that d19 preferentially interacts with the hexameric form of CA, with a significantly improved hexamer/monomer specificity ratio (ratio = 59) than PF-74 (ratio = 21). Moreover, we show via SPR that d19 competes with CPSF-6 for binding to CA hexamers with IC50 value of 33.4 nM. Like PF-74, d19 inhibits the replication of HIV-1 NL4.3 pseudo typed virus in both early and late stages. In addition, molecular docking and molecular dynamics simulations provide binding mode information of d19 to HIV-1 CA and rationale for improved affinity and potency over PF-74. Overall, the lead compound d19 displays a distinct chemotype form PF-74, improved CA affinity, and anti-HIV potency.

Long-Acting Formulations for the Prevention and Treatment of Human Immunodeficiency Virus (HIV)-1 Infection: Strategic Leveraging and Integration of Multidisciplinary Knowledge to Advance Public Health

The landscape for the development of therapeutics for prevention and treatment of human immunodeficiency virus (HIV)-1 infection has pivoted towards long-acting antiretrovirals (LA-ARVs). LA-ARVs have the potential to transform global implementation of HIV-1 prevention and treatment strategies. The ability to identify potential knowledge gaps early in development, proactively address missing information or data gaps, and strategically leverage all the available information is the key to streamline the development of safe and effective LA-ARV therapeutics. The purpose of this article is to discuss some potential considerations for development of LA-ARVs. Three possible drug development scenarios are briefly discussed and include developing (1) a novel LA-ARV, (2) a novel LA formulation of an approved oral ARV, and (3) an LA pro-drug of an approved oral ARV. For each of these scenarios, we briefly describe what type(s) of information may be helpful and discuss potential opportunities to leverage available information. Additionally, we discuss some unique LA-ARV drug development considerations, including the use of an oral lead-in, and assessing the impact of residual ARV exposures on subsequent regimens and evaluation of LA-ARVs in specific populations. We strongly believe that efficient integration of multidisciplinary knowledge can advance the development, availability, and accessibility of therapeutics not only for HIV-1 prevention and treatment but also for other chronic viral infections.

The LEAP Process: Streamlining the Development of Long-Acting Products and Formulations for Infectious Diseases

Developing long-acting products and formulations for infectious diseases is a nontrivial undertaking that is frequently classified as high risk and low reward by the pharmaceutical industry. The Long-Acting/Extended Release Antiretroviral Research Resource Program (LEAP) was founded in 2015 with the support of the National Institutes of Health to encourage, promote, and accelerate the development of such products. Assessment methodology for any new proposal brought to this group is part of a framework-the LEAP Process-that includes a landscape analysis of what is currently available in the public domain. This is followed by in silico modeling and simulation offered as a service to the relevant scientific community. A variety of preclinical and clinical outcome metrics are applied to each new agent as part of a continuous feedback loop to improve product characteristics. This allows us to catalog knowledge gaps and barriers that can be addressed by engaged stakeholders. Results are communicated in scientific articles, reviews, and position papers. This undertaking serves to de-risk discovery, development, and implementation by bridging the gaps between academic, regulatory, and industrial investigators, and by engaging those in the community who will be the eventual users of these medicines. The LEAP Process has supported formulations now approved for human immunodeficiency virus, as well as products in clinical and preclinical development for tuberculosis and hepatitis viruses B and C.

A Holistic Review of the Preclinical Landscape for Long-Acting Anti-infective Drugs Using HIV as a Paradigm

Lack of predictive preclinical models is a key contributor to the steep attrition rate in drug development. Successful clinical translation may be higher for new chemical entities or existing approved drugs reformulated for long-acting (LA) administration if preclinical studies designed to identify any new uncertainties are predictive of human exposure and response. In this review, we present an overview of standard preclinical assessments deployed for LA formulations and delivery systems, using human immunodeficiency virus LA therapeutics preclinical development as a paradigm. Key progress in the preclinical development of novel LA antiretrovirals formulations and delivery systems are summarized, including bispecific broadly neutralizing monoclonal antibody and small molecule technologies for codelivery of multiple drugs with disparate solubility properties. There are new opportunities to take advantage of recent developments in tissue engineering and 3-dimensional in vitro modeling to advance preclinical modeling of anti-infective activity, developmental and reproductive toxicity assessment, and to apply quantitative modeling and simulation strategies. These developments are likely to drive the progression of more LA anti-infective drugs and multipurpose technologies into clinical development in the coming years.

Long-acting drugs: people's expectations and physicians' preparedness. Are we readying to manage it? An Italian survey

To evaluate patients' expectations regarding long-acting antiretroviral agents and preferences about where to receive them. Multicenter cross-sectional survey-based study. Through an online survey, we asked people living with human immunodeficiency virus to judge their relationship with daily antiretroviral therapy (ART) and to give their opinion about long-acting drugs. We also collected data regarding the age of the patients, their site of follow-up, time since the diagnosis, and compliance to ART. Two hundred forty-two patients aged 18 to 79 years were included in the study: 58 (24%) females, 182 (75.2%) males, and 2 (0.8%) male-to-female transgenders. 81.8% of the said population had a good relationship with ART. 33.6% of them consider daily ART an obligation and a restriction to their freedom. One hundred forty-three (59.1%) patients already knew about long-acting drugs before our interview, and 215 (88.8%) patients were interested in it. One hundred fifty-six (64.4%) interviewees said they would still be interested in hospital-available injective long-acting drugs, although 57.9% of the patients would rather receive them at home. The data emerging from our survey reveal that around 90% of the people living with HIV are interested in changing their actual treatment with a long-acting one. Moreover, for the first time to our knowledge, such a high number of patients showed an enthusiastic response to the new opportunity to be treated directly at home. The introduction of these new drugs could be revolutionary and represents an important step toward treatment simplification.

Long-acting HIV Pre-exposure Prophylaxis (PrEP) approaches: Recent advances, emerging technologies and development challenges

Introduction:

Poor or inconsistent adherence to daily oral pre-exposure prophylaxis (PrEP) has emerged as a key barrier to effective HIV prevention. The advent of potent long-acting (LA) antiretrovirals (ARVs) in conjunction with advances in controlled release technologies has enabled LA ARV drug delivery systems (DDS) capable of providing extended dosing intervals and overcome the challenge of suboptimal drug adherence with daily oral dosing.

Areas covered:

This review discusses the current state of the LA PrEP field, recent advances, and emerging technologies, including ARV prodrug modifications and new DDS. Technological challenges, knowledge gaps, preclinical testing considerations, and future directions important in the context of clinical translation and implementation of LA HIV PrEP are discussed.

Expert opinion:

The HIV prevention field is evolving faster than ever and the bar for developing next-generation LA HIV prevention options continues to rise. The requirements for viable LA PrEP products to be implemented in resource-limited settings are challenging, necessitating proactive consideration and product modifications during the design and testing of promising new candidates. If successfully translated, next-generation LA PrEP that are safe, affordable, highly effective, and accepted by both end-users and key stakeholders will offer significant potential to curb the HIV pandemic.

Recent advances in nanoformulation development of Ritonavir, a key protease inhibitor used in the treatment of HIV-AIDS

INTRODUCTION

AIDS is one of the world's most serious public health challenges. Protease inhibitors are key components of AIDS treatment regimen. Ritonavir is a well-known protease inhibitor with low aqueous solubility belonging to BCS class II category. Some of the severe adverse effects associated with this drug restricted its use in the treatment of AIDS. However, several attempts were made by researchers in the past to enhance the oral bioavailability of Ritonavir.

AREAS COVERED

The current review mainly focuses on the adverse effects of Ritonavir and recent approaches followed by researchers on the development of nanoformulations of Ritonavir. Further, various patents filed on Ritonavir have also been discussed in the current review.

EXPERT OPINION

Most research on nanoformulation development for Ritonavir is mainly focused on enhancing the solubility and oral bioavailability of the drug. Some of the researchers focused on the lymphatic targeting of the drug in order to bypass the hepatic metabolism of the drug. However, most of the research topics did not cover the toxicity evaluation of the developed formulation. Since the major issue of Ritonavir is not only oral bioavailability but also drug-induced toxicity, this area needs to be considered during the formulation development.

Antibacterial Activity of Aureonuclemycin Produced by Streptomyces aureus Strain SPRI-371

Actinomycetes play a vital role as one of the most important natural resources for both pharmaceutical and agricultural applications. The actinomycete strain SPRI-371, isolated from soil collected in Jiangsu province, China, was classified as Streptomyces aureus based on its morphological, physiological, biochemical and molecular biological characteristics. Its bacterial activity metabolites were identified as aureonuclemycin (ANM), belonging to adenosine derivatives with the molecular formula C16H19N5O9 for ANM A and C10H13N5O3 for ANM B. Simultaneously, the industrial fermentation process of a mutated S. aureus strain SPRI-371 was optimized in a 20 m3 fermentation tank, featuring a rotation speed of 170 rpm, a pressure of 0.05 MPa, an inoculum age of 36−40 h and a dissolved oxygen level maintained at 1−30% within 40−80 h and at >60% in the later period, resulting in an ANM yield of >3700 mg/L. In the industrial separation of fermentation broth, the sulfuric acid solution was selected to adjust pH and 4# resin was used for adsorption. Then, it was resolved with 20% ethanol solution and concentrated in a vacuum (60−65 °C), with excellent results. Antibacterial experiments showed that ANM was less active or inactive against Xanthomonas oryzae pv. oryzae, Xanthomonas citri subsp. citri and Xanthomonas oryzae pv. oryzicola and most bacteria, yeast and fungi in vitro. However, in vivo experiments showed that ANM exhibited extremely significant protective and therapeutic activity against diseases caused by X. oryzae pv. oryzae and X. oryzae pv. oryzicola in rice and X. citri in oranges and lemons. In field trials, ANM A 150 gai/ha + ANM B 75 gai/ha exhibited excellent therapeutic activity against rice bacterial leaf blight, citrus canker and rice bacterial leaf streak. Furthermore, as the dosage and production cost of ANM are lower than those of commercial drugs, it has good application prospects.

Aspects of Antiviral Strategies Based on Different Phototherapy Approaches: Hit by the Light

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which caused the COVID-19 pandemic spreading around the world from late 2019, served as a ruthless reminder of the threat viruses pose to global public health. The synthesis of new antiviral drugs, as well as repurposing existing products, is a long-term ongoing process which has challenged the scientific community. One solution could be an effective, accessible, and rapidly available antiviral treatment based on phototherapy (PT). PT has been used to treat several diseases, and relies on the absorption of light by endogenous molecules or exogenous photosensitizers (PS). PT has often been used in cancer treatment and prophylaxis, and as a complement to established chemotherapy and immunotherapy in combined therapeutic strategy. Besides significant applications in anticancer treatment, studies have demonstrated the beneficial impact of PT on respiratory, systemic, emerging, and oncogenic viral infections. The aim of this review was to highlight the potential of PT to combat viral infections by summarizing current progress in photodynamic, photothermal, and photoacoustic approaches. Attention is drawn to the virucidal effect of PT on systemic viruses such as the human immunodeficiency virus and human herpes viruses, including the causative agent of Kaposi sarcoma, human herpes virus (HHV8). PT has good potential for disinfection in anti-norovirus research and against pandemic viruses like SARS-CoV-2.

The future of long-acting agents for preexposure prophylaxis

PURPOSE OF REVIEW

The main reason for the failure of oral preexposure prophylaxis (PrEP) regimens for HIV is poor adherence. Intramuscular cabotegravir was recently approved for PrEP, and a number of other long-acting antiretroviral formulations and products are currently in clinical development. This includes subcutaneous and intravenous injections, implants, and microarray (microneedle) patches, as well as extended duration oral drugs. The success and future uptake of these products will depend on a variety of factors.

RECENT FINDINGS

Long-acting delivery of antiretroviral agents for PrEP confers significant advantages over short-acting oral delivery. This is exemplified by the superior efficacy of intramuscular cabotegravir given every eight weeks as compared to daily oral co-formulated tenofovir disoproxil fumarate and emtricitabine. There is also evidence for PrEP efficacy for a broadly neutralizing monoclonal antibody given intravenously every eight weeks. One of the leading candidates for long-acting PrEP, islatravir, was being studied as a monthly oral drug or a nonerodable subcutaneous implant inserted for up to 12 months. However, clinical studies of this agent were put on hold in late 2021 because of unanticipated lymphopenia.

SUMMARY

Long-acting antiretroviral products have substantial promise for PrEP and have particular advantages over daily oral drugs based mainly on improved adherence. However, there are barriers to further uptake that include the need for more intensive interaction with systems of healthcare delivery, greater expense and complexity of implementation, and unexpected long-term toxicities.

The future of long-acting cabotegravir plus rilpivirine therapy: Deeds and misconceptions

HIV infection is currently managed as a chronic disease thanks to the improvement of antiretroviral therapy (ART). In this light, treatment is lifelong. Therefore, switch to new regimens is a natural event during long-term therapies to avoid problems related to toxicity, adherence, failure and potential selection of drug resistance. In this context, coformulations of multiple agents in one pill and the development of novel drug classes and drugs with high genetic barrier to resistance are now available. The recent approval of the long-acting once monthly or bimonthly injectable combination of the second-generation strand transfer integrase inhibitor (InSTI) cabotegravir (CAB) together with the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV) represents the most recent achievement along the line of potent and convenient ART. Several pivotal trials (such as LATTE-2, ATLAS, FLAIR, and ATLAS-2M) largely demonstrated the high efficacy and safety of this long-acting formulation used as an induction-maintenance strategy. Few confirmed virological failures (CVF) have been observed. The combination of at least two baseline factors among HIV-1 subtype A6/A1, a body mass index ≥30 kg/m², and RPV resistance associated mutations, was associated with an increased risk of CVF at week 48. Available data indicate that this long-acting therapeutic strategy is attractive and potent, thus defining the most appropriate patient and how to handle practical issues is warranted.

Ultra-long-acting antivirals as chemical vaccines to prevent viral diseases

For two centuries, vaccines have been successful in the fight against viruses, triggering immune protection. Indeed, the elimination of smallpox, the only infectious disease eradicated to date, was made possible through vaccination. For measles, polio and hepatitis B, vaccines are available but significant challenges exist for universal coverage. For other viruses, such as HIV and hepatitis C, vaccines have remained elusive. Recent advances in medicinal chemistry have resulted in the production of antivirals that can extend activity for months. We envision the use of ultra-long-acting antivirals for the prevention of certain viral illnesses, halting either contagions or reactivations under immunosuppression. Such 'chemical vaccines' would fill an immediate need in providing protection when classic vaccines do not exist, responses are suboptimal, escape mutants emerge or immunity wanes.

Physiologically Based Pharmacokinetic Modeling of 3 HIV Drugs in Combination and the Role of Lymphatic System after Subcutaneous Dosing. Part 2: Model for the Drug-combination Nanoparticles

We previously developed a mechanism-based pharmacokinetic (MBPK) model to characterize the PK of a lymphocyte-targeted, long-acting 3 HIV drug-combination nanoparticle (DcNP) formulation of lopinavir, ritonavir, and tenofovir. MBPK describes time-courses of plasma drug concentration and has provided an initial hypothesis for the lymphatic PK of DcNP. Because anatomical and physiological interpretation of MBPK is limited, in this Part 2, we report the development of a Physiologically Based Pharmacokinetic (PBPK) model for a detailed evaluation of the systemic and lymphatic PK of drugs associated with DcNP. The DcNP model is linked to the PBPK model presented earlier in Part 1 to account for the disposition of released free drugs. A key feature of the DcNP model is the uptake of the injected dose from the subcutaneous site to the adjacent lymphoid depot, routing through the nodes within and throughout the lymphatic network, and its subsequent passage into the blood circulation. Furthermore, the model accounts for DcNP transport to the lymph by lymphatic recirculation and mononuclear cell migration. The present PBPK model can be extended to other nano-drug combinations that target or transit through the lymphatic system. The PBPK model may allow scaling and prediction of DcNP PK in humans.

Non-nucleoside structured compounds with antiviral activity—past 10 years (2010–2020)

Nucleosides and their derivatives are a well-known and well-described class of compounds with antiviral activity. Currently, in the era of the COVID-19 pandemic, scientists are also looking for compounds not related to nucleosides with antiviral properties. This review aims to provide an overview of selected synthetic antiviral agents not associated to nucleosides developed against human viruses and introduced to preclinical and clinical trials as well as drugs approved for antiviral therapy over the last 10 years. The article describes for the first time the wide classification of such antiviral drugs and drug candidates and briefly summarizes the biological target and clinical applications of the compounds. The described compounds are arranged according to the antiviral mechanism of action. Knowledge of the drug's activity toward specific molecular targets may be the key to researching new antiviral compounds and repositioning drugs already approved for clinical use. The paper also briefly discusses the future directions of antiviral therapy. The described examples of antiviral compounds can be helpful for further drug development.

Numerical approaches for the rapid analysis of prophylactic efficacy against HIV with arbitrary drug-dosing schemes

Pre-exposure prophylaxis (PrEP) is an important pillar to prevent HIV transmission. Because of experimental and clinical shortcomings, mathematical models that integrate pharmacological, viral- and host factors are frequently used to quantify clinical efficacy of PrEP. Stochastic simulations of these models provides sample statistics from which the clinical efficacy is approximated. However, many stochastic simulations are needed to reduce the associated sampling error. To remedy the shortcomings of stochastic simulation, we developed a numerical method that allows predicting the efficacy of arbitrary prophylactic regimen directly from a viral dynamics model, without sampling. We apply the method to various hypothetical dolutegravir (DTG) prophylaxis scenarios. The approach is verified against state-of-the-art stochastic simulation. While the method is more accurate than stochastic simulation, it is superior in terms of computational performance. For example, a continuous 6-month prophylactic profile is computed within a few seconds on a laptop computer. The method’s computational performance, therefore, substantially expands the horizon of feasible analysis in the context of PrEP, and possibly other applications.

Pre-exposure prophylaxis (PrEP) is an important tool to prevent HIV transmission. However, experimental identification of parameters that determine prophylactic efficacy is extremely difficult. Clues about these parameters could prove essential for the design of next-generation PrEP compounds. Integrative mathematical models can fill this void: Based on stochastic simulation, a sample statistic can be generated, from which the prophylactic efficacy is estimated. However, for this sample statistic to be accurate, many simulations need to be performed.

Here, we introduce a numerical method to directly compute the prophylactic efficacy from a viral dynamics model, without the need for sampling. Based on several examples with dolutegravir (DTG) -based short- and long-term PrEP, as well as post-exposure prophylaxis we demonstrate the correctness of the new method and its outstanding computational performance. Due to the method’s computational performance, a number of analyses, including formal sensitivity analysis, are becoming feasible with the proposed method.

Update and latest advances in antiretroviral therapy

Since the first cases of AIDS appeared in 1981, human immunodeficiency virus type 1 (HIV-1) infection has reached pandemic proportions. Forty years later, research has led to the approval of more than 30 antiretroviral drugs, while combination therapies have turned HIV-1 infection into a chronic, but manageable disease. Still, drug toxicity and acquired and transmitted drug resistance remain as major threats to therapy success. In this review, we provide an overview on currently available anti-HIV drugs and the latest developments in antiretroviral therapy, focused on new antiretroviral agents acting on known and unexploited antiviral targets, prevention therapies aimed to improve available drug combinations, and research on new long-acting therapies, particularly those involving novel drug candidates such as lenacapavir or islatravir.