Next generation fixed dose combination pharmacotherapies for treating HIV

Bioequivalence of a Pediatric Fixed-Dose Combination Tablet Darunavir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Compared With Coadministration of the Separate Agents in Healthy Adults: An Open-Label, Randomized, Replicate Crossover Study

Darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg is a fixed-dose combination (FDC) for the treatment of HIV-1 infection in adults and adolescents weighing 40 kg or greater. This Phase 1, randomized, open-label, 2-treatment, 2-sequence, 4-period replicate crossover study (NCT04661397) evaluated the pivotal bioequivalence of a pediatric D/C/F/TAF 675/150/200/10-mg FDC compared with coadministration of the separate commercially available formulations in healthy adults under fed conditions. During each period, participants received either a single oral dose of D/C/F/TAF 675/150/200/10-mg FDC (test) or a single oral dose of darunavir 600 and 75 mg, cobicistat 150 mg, and emtricitabine/tenofovir alafenamide 200/10-mg FDC (reference). Thirty-seven participants were randomly assigned to one of 2 treatment sequence groups: test-reference-reference-test or reference-test-test-reference, with 7 days or more washout between periods. The 90% confidence intervals of the geometric mean ratios for maximum plasma concentration, area under the concentration-time curve from time zero to last measurable concentration, and area under the concentration-time curve extrapolated to infinity for darunavir, cobicistat, emtricitabine, and tenofovir alafenamide fell within conventional bioequivalence limits (80%-125%). No Grade 3/4 adverse events, serious adverse events, or deaths occurred. In conclusion, administration of D/C/F/TAF 675/150/200/10-mg FDC was bioequivalent to coadministration of the separate commercially available formulations.

Strategies in the Design and Development of Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

AIDS (acquired immunodeficiency syndrome) is a potentially life-threatening infectious disease caused by human immunodeficiency virus (HIV). To date, thousands of people have lost their lives annually due to HIV infection, and it continues to be a big public health issue globally. Since the discovery of the first drug, Zidovudine (AZT), a nucleoside reverse transcriptase inhibitor (NRTI), to date, 30 drugs have been approved by the FDA, primarily targeting reverse transcriptase, integrase, and/or protease enzymes. The majority of these drugs target the catalytic and allosteric sites of the HIV enzyme reverse transcriptase. Compared to the NRTI family of drugs, the diverse chemical class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) has special anti-HIV activity with high specificity and low toxicity. However, current clinical usage of NRTI and NNRTI drugs has limited therapeutic value due to their adverse drug reactions and the emergence of multidrug-resistant (MDR) strains. To overcome drug resistance and efficacy issues, combination therapy is widely prescribed for HIV patients. Combination antiretroviral therapy (cART) includes more than one antiretroviral agent targeting two or more enzymes in the life cycle of the virus. Medicinal chemistry researchers apply different optimization strategies including structure- and fragment-based drug design, prodrug approach, scaffold hopping, molecular/fragment hybridization, bioisosterism, high-throughput screening, covalent-binding, targeting highly hydrophobic channel, targeting dual site, and multi-target-directed ligand to identify and develop novel NNRTIs with high antiviral activity against wild-type (WT) and mutant strains. The formulation experts design various delivery systems with single or combination therapies and long-acting regimens of NNRTIs to improve pharmacokinetic profiles and provide sustained therapeutic effects.

Moringa oleifera Lam Leaf Extract Stimulates NRF2 and Attenuates ARV-Induced Toxicity in Human Liver Cells (HepG2)

The World Health Organization (WHO) reported that there are 37 million individuals living with the human immunodeficiency virus (HIV) worldwide, with the majority in South Africa. This chronic disease is managed by the effective use of antiretroviral (ARV) drugs. However, with prolonged use, ARV drug-induced toxicity remains a clinically complex problem. This study investigated the toxicity of ARV drugs on mitochondria and the NRF2 antioxidant pathway and its possible amelioration using Moringa oleifera Lam (MO) leaf extracts. This medicinal plant has a range of functional bioactive compounds. Liver (HepG2) cells were treated with individual ARV drugs: Tenofovir disoproxil fumarate (TDF), Emtricitabine (FTC), and Lamivudine (3TC) for 96 h, followed by MO leaf extracts for 24 h. Intracellular ROS, cytotoxicity, lipid peroxidation, total and reduced glutathione (GSH), ATP, and mitochondrial polarisation were determined. Finally, protein (pNRF2, NRF2, SOD2, CAT, and Sirt3) and mRNA (NRF2, CAT, NQO1 SOD2, Sirt3, and PGC1α) expression were measured using Western blot and qPCR, respectively. TDF, FTC, and 3TC significantly increased intracellular ROS and extracellular levels of both MDA and LDH. ARVs also reduced the GSH and ATP levels and altered the mitochondrial polarization. Further, ARVs reduced the expression of NRF2 SOD2, Sirt3, CAT, NQO1, UCP2 and PGC1α mRNA and consequently pNRF2, NRF2, SOD2, Sirt3 and CAT protein. In contrast, there was a significant reduction in the extracellular MDA and LDH levels post-MO treatment. MO significantly reduced intracellular ROS while significantly increasing GSH, ATP, and mitochondrial membrane polarization. The addition of MO to ARV-treated cells significantly upregulated the expression of NRF2, SOD2, Sirt3, CAT, UCP2, PGC1α, and NQO1 mRNA and pNRF2, NRF2, SOD2, Sirt3 proteins. Thus, MO ameliorates ARV-induced hepatotoxicity by scavenging oxidants by inducing the NRF2 antioxidant pathway. MO shows great therapeutic potential and may be considered a potential supplement to ameliorate ARV drug toxicity.

Chiral Analysis of the Key Intermediates of Tenofovir Alafenamide Fumarate

(R)-Tenofovir phenyl ester ((R)-1) and (R)-tenofovir diphenyl ester ((R)-2) are key intermediates for the practical synthesis of tenofovir alafenamide fumarate, which is a mainstay antiretroviral for the treatment of chronic hepatitis B and HIV-1 infections. This article deals with the chiral analysis of (R)-1 and (R)-2 against their respective optical impurity (S)-tenofovir phenyl ester ((S)-1) and (S)-tenofovir diphenyl ester ((S)-2) using a polysaccharide-coated chiral stationary phase (CSP) by normal-phase high-performance liquid chromatography (HPLC). To this end, a chiral synthetic strategy for (S)-2 was efficiently executed capitalizing on a classical Mitsunobu reaction to stereospecifically invert the configuration of chiral carbon in readily accessible (R)-HPA ((R)-4) to deliver (S)-HPA ((S)-4), from which (S)--tenofovir ((S)-3) was in turn prepared and further transformed into (S)-2. With reference substance (S)-2 in hand, a chiral analytical method for (R)-2 using Chiralpak AD-H as CSP by normal-phase HPLC has been developed and validated. The validation results indicated that this chiral analytical method has been achieved with satisfactory separation effect, high sensitivity, and good precision and accuracy, and thus can be deployed for the determination of optical impurities in samples of (R)-1 (via derivation to (R)-2) and (R)-2.

Fixed dose combination drugs for cardiovascular disease in a prolonged humanitarian crisis in Lebanon: an implementation study

OBJECTIVES

This pre-post implementation study evaluated the introduction of fixed dose combination (FDC) medications for atherosclerotic cardiovascular disease (ASCVD) secondary prevention into routine care in a humanitarian setting.

SETTING

Two Médecins sans Frontières (MSF) primary care clinics serving Syrian refugee and host populations in north Lebanon.

PARTICIPANTS

Consenting patients ≥18 years with existing ASCVD requiring secondary prevention medication were eligible for study enrolment. Those with FDC contraindication(s) or planning to move were excluded. Of 521 enrolled patients, 460 (88.3%) were retained at 6 months, and 418 (80.2%) switched to FDC. Of these, 84% remained on FDC (n=351), 8.1% (n=34) discontinued and 7.9% (n=33) were lost to follow-up by month 12.

INTERVENTIONS

Eligible patients, enrolled February-May 2019, were switched to Trinomia FDC (atorvastatin 20 mg, aspirin 100 mg, ramipril 2.5/5/10 mg) after 6 months' usual care. During the study, the COVID-19 pandemic, an economic crisis and clinic closures occurred.

OUTCOME MEASURES

Descriptive and regression analyses compared key outcomes at 6 and 12 months: medication adherence, non-high density lipoprotein cholesterol (non-HDL-C) and systolic blood pressure (SBP) control. We performed per-protocol, intention-to-treat and secondary analyses of non-switchers.

RESULTS

Among 385 switchers remaining at 12 months, total adherence improved 23%, from 63% (95% CI 58 to 68) at month 6, to 86% (95% CI 82 to 90) at month 12; mean non-HDL-C levels dropped 0.28 mmol/L (95% CI -0.38 to -0.18; p<0.0001), from 2.39 (95% CI 2.26 to 2.51) to 2.11 mmol/L (95% CI 2.00 to 2.22); mean SBP dropped 2.89 mm Hg (95% CI -4.49 to -1.28; p=0.0005) from 132.7 (95% CI 130.8 to 134.6) to 129.7 mm Hg (95% CI 127.9 to 131.5). Non-switchers had smaller improvements in adherence and clinical outcomes.

CONCLUSION

Implementing an ASCVD secondary prevention FDC improved adherence and CVD risk factors in MSF clinics in Lebanon, with potential for wider implementation by humanitarian actors and host health systems.

The Discovery of GSK3640254, a Next-Generation Inhibitor of HIV-1 Maturation

GSK3640254 is an HIV-1 maturation inhibitor (MI) that exhibits significantly improved antiviral activity toward a range of clinically relevant polymorphic variants with reduced sensitivity toward the second-generation MI GSK3532795 (BMS-955176). The key structural difference between GSK3640254 and its predecessor is the replacement of the para-substituted benzoic acid moiety attached at the C-3 position of the triterpenoid core with a cyclohex-3-ene-1-carboxylic acid substituted with a CH2F moiety at the carbon atom α- to the pharmacophoric carboxylic acid. This structural element provided a new vector with which to explore structure-activity relationships (SARs) and led to compounds with improved polymorphic coverage while preserving pharmacokinetic (PK) properties. The approach to the design of GSK3640254, the development of a synthetic route and its preclinical profile are discussed. GSK3640254 is currently in phase IIb clinical trials after demonstrating a dose-related reduction in HIV-1 viral load over 7-10 days of dosing to HIV-1-infected subjects.

A "Two-Birds-One-Stone" Approach toward the Design of Bifunctional Human Immunodeficiency Virus Type 1 Entry Inhibitors Targeting the CCR5 Coreceptor and gp41 N-Terminal Heptad Repeat Region

Previous studies have reported the stepwise nature of human immunodeficiency virus type 1 (HIV-1) entry and the pivotal role of coreceptor CCR5 and the gp41 N-terminal heptad repeat (NHR) region in this event. With this in mind, we herein report a dual-targeted drug compound featuring bifunctional entry inhibitors, consisting of a piperidine-4-carboxamide-based CCR5 antagonist, TAK-220, and a gp41 NHR-targeting fusion-inhibitory peptide, C34. The resultant chimeras were constructed by linking both pharmacophores with a polyethylene glycol spacer. One chimera, CP12TAK, exhibited exceptionally potent antiviral activity, about 40- and 306-fold over that of its parent inhibitors, C34 and TAK-220, respectively. In addition to R5-tropic viruses, CP12TAK also strongly inhibited infection of X4-tropic HIV-1 strains. These data are promising for the further development of CP12TAK as a new anti-HIV-1 drug. Results show that this strategy could be extended to the design of therapies against infection of other enveloped viruses.

Edoxaban and the Issue of Drug-Drug Interactions: From Pharmacology to Clinical Practice

Edoxaban, a direct factor Xa inhibitor, is the latest of the non-vitamin K antagonist oral anticoagulants (NOACs). Despite being marketed later than other NOACs, its use is now spreading in current clinical practice, being indicated for both thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF) and for the treatment and prevention of venous thromboembolism (VTE). In patients with multiple conditions, the contemporary administration of several drugs can cause relevant drug-drug interactions (DDIs), which can affect drugs' pharmacokinetics and pharmacodynamics. Usually, all the NOACs are considered to have significantly fewer DDIs than vitamin K antagonists; notwithstanding, this is actually not true, all of them are affected by DDIs with drugs that can influence the activity (induction or inhibition) of P-glycoprotein (P-gp) and cytochrome P450 3A4, both responsible for the disposition and metabolism of NOACs to a different extent. In this review/expert opinion, we focused on an extensive report of edoxaban DDIs. All the relevant drugs categories have been examined to report on significant DDIs, discussing the impact on edoxaban pharmacokinetics and pharmacodynamics, and the evidence for dose adjustment. Our analysis found that, despite a restrained number of interactions, some strong inhibitors/inducers of P-gp and drug-metabolising enzymes can affect edoxaban concentration, just as it happens with other NOACs, implying the need for a dose adjustment. However, our analysis of edoxaban DDIs suggests that given the small propensity for interactions of this agent, its use represents an acceptable clinical decision. Still, DDIs can be significant in certain clinical situations and a careful evaluation is always needed when prescribing NOACs.

The evidence for using tenofovir disoproxil fumarate plus lamivudine as a nucleoside analogue backbone for the treatment of HIV

This article evaluates the evidence supporting use of the tenofovir disoproxil fumarate (TDF) plus lamivudine (3 ​TC) combination as a dual nucleoside backbone within a triple drug antiretroviral regimen. Key trials that assess the relative efficacy, safety and resistance profile of 3 ​TC and emtricitabine (FTC) are discussed. Clinical use of 3 ​TC and FTC with two tenofovir prodrugs -TDF and tenofovir alafenamide (TAF) - is presented. Recommendations from various international guidelines for the construction of triple and emerging dual regimens are summarised. In conclusion, data suggest the therapeutic equivalence of 3 ​TC and FTC, especially when 3 ​TC is combined with TDF.

Multidomain drug delivery systems of β-casein micelles for the local oral co-administration of antiretroviral combinations

The antiretroviral (ARV) cocktailrevolved the treatment of the human immunodeficiency virus (HIV) infection. Drug combinations have been also tested to treat other infectious diseases, including the recentcoronavirus disease 2019 (COVID-19) outbreak. To simplify administration fixed-dose combinationshave been introduced, however, oral anti-HIV therapy still struggles with low oral bioavailability of many ARVs.This work investigated the co-encapsulation of two clinically relevant ARV combinations,tipranavir (TPV):efavirenz (EFV) anddarunavir (DRV):efavirenz (EFV):ritonavir (RTV),within the core of β-casein (bCN) micelles. Encapsulation efficiency in both systems was ~100%. Cryo-transmission electron microscopy and dynamic light scattering of the ARV-loaded colloidaldispersions indicatefull preservation of the spherical morphology, and x-ray diffraction confirm that the encapsulated drugs are amorphous. To prolong the physicochemical stabilitythe formulations were freeze-driedwithout cryo/lyoprotectant, and successfully redispersed, with minor changes in morphology.Then, theARV-loaded micelles were encapsulated within microparticles of Eudragit® L100, which prevented enzymatic degradation and minimized drug release under gastric-like pH conditionsin vitro. At intestinal pH, the coating polymer dissolved and released the nanocarriers and content. Overall, our results confirm the promise of this flexible and modular technology platform for oral delivery of fixed dose combinations.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs): a brief overview of clinically approved drugs and combination regimens

The non-nucleoside reverse transcriptase inhibitors (NNRTIs) are allosteric inhibitors of HIV-1 reverse transcriptase and are classified into generations depending on their discovery and resistance profiles. The NNRTIs are used in combination regimens with antiretroviral agents that target two or more enzymes in the viral life cycle. The combination regimens usually include a backbone of two nucleoside or nucleotide reverse transcriptase inhibitors and a third core agent among the NNRTIs or protease inhibitors. The combination regimens are maintained over long durations and consequently lead to long-term problems, including toxicity, drug-drug interactions, and increasing costs. This brief overview summarizes the pharmacokinetic profiles for NNRTIs and NNRTI-based combination regimens.

Co-crystals, Salts or Mixtures of Both? The Case of Tenofovir Alafenamide Fumarates

Tenofovir alafenamide fumarate (TAF) is the newest prodrug of tenofovir that constitutes several drug products used for the treatment of HIV/AIDS. Although the solid-state properties of its predecessor tenofovir disoproxil fumarate have been investigated and described in the literature, there are no data in the scientific literature on the solid state properties of TAF. In our report, we describe the preparation of two novel polymorphs II and III of tenofovir alafenamide monofumarate (TA MF2 and TA MF3). The solid-state structure of these compounds was investigated in parallel to the previously known tenofovir alafenamide monofumarate form I (TA MF1) and tenofovir alafenamide hemifumarate (TA HF). Interestingly, the single-crystal X-ray diffraction of TA HF revealed that this derivative exists as a co-crystal form. In addition, we prepared a crystalline tenofovir alafenamide free base (TA) and its hydrochloride salt (TA HCl), which enabled us to determine the structure of TA MF derivatives using ¹⁵N-ssNMR (¹⁵N-solid state nuclear magnetic resonance). Surprisingly, we observed that TA MF1 exists as a mixed ionization state complex or pure salt, while TA MF2 and TA MF3 can be obtained as pure co-crystal forms.

Fixed dose drug combinations - are they pharmacoeconomically sound? Findings and implications especially for lower- and middle-income countries

Introduction: There are positive aspects regarding the prescribing of fixed dose combinations (FDCs) versus prescribing the medicines separately. However, these have to be balanced against concerns including increased costs and their irrationality in some cases. Consequently, there is a need to review their value among lower- and middle-income countries (LMICs) which have the greatest prevalence of both infectious and noninfectious diseases and issues of affordability.Areas covered: Review of potential advantages, disadvantages, cost-effectiveness, and availability of FDCs in high priority disease areas in LMICs and possible initiatives to enhance the prescribing of valued FDCs and limit their use where there are concerns with their value.Expert commentary: FDCs are valued across LMICs. Advantages include potentially improved response rates, reduced adverse reactions, increased adherence rates, and reduced costs. Concerns include increased chances of drug:drug interactions, reduced effectiveness, potential for imprecise diagnoses and higher unjustified prices. Overall certain FDCs including those for malaria, tuberculosis, and hypertension are valued and listed in the country's essential medicine lists, with initiatives needed to enhance their prescribing where currently low prescribing rates. Proposed initiatives include robust clinical and economic data to address the current paucity of pharmacoeconomic data. Irrational FDCs persists in some countries which are being addressed.

Dolutegravir/Rilpivirine: A Review in HIV-1 Infection

Dolutegravir/rilpivirine (Juluca^®) is the first two-drug single-tablet regimen (STR) to be approved for the treatment of HIV-1 infection in adults. The fixed-dose STR combines the integrase strand transfer inhibitor dolutegravir with the non-nucleoside reverse transcriptase inhibitor rilpivirine. In two phase III non-inferiority trials (SWORD-1 and SWORD-2) in treatment-experienced patients already virologically suppressed on their current antiretroviral (ART) regimen, switching to once-daily dolutegravir plus rilpivirine maintained virological suppression over 48 weeks. Switching to a two-drug regimen of dolutegravir plus rilpivirine was also associated with high rates of virological suppression in real-world observational studies. Switching to once-daily dolutegravir plus rilpivirine was generally well tolerated and associated with more favourable renal and bone parameters than remaining on the current ART regimen. Longer-term, dolutegravir plus rilpivirine demonstrated durable maintenance of virological suppression and remained generally well tolerated for up to 100 weeks. Thus, dolutegravir/rilpivirine provides a convenient alternative treatment option for some adults with HIV-1 infection and no history of virological failure who are already virologically suppressed on (and wish to switch from) their current ART regimen.

Pathogenic Viruses Commonly Present in the Oral Cavity and Relevant Antiviral Compounds Derived from Natural Products

Many viruses, such as human herpesviruses, may be present in the human oral cavity, but most are usually asymptomatic. However, if individuals become immunocompromised by age, illness, or as a side effect of therapy, these dormant viruses can be activated and produce a variety of pathological changes in the oral mucosa. Unfortunately, available treatments for viral infectious diseases are limited, because (1) there are diseases for which no treatment is available; (2) drug-resistant strains of virus may appear; (3) incomplete eradication of virus may lead to recurrence. Rational design strategies are widely used to optimize the potency and selectivity of drug candidates, but discovery of leads for new antiviral agents, especially leads with novel structures, still relies mostly on large-scale screening programs, and many hits are found among natural products, such as extracts of marine sponges, sea algae, plants, and arthropods. Here, we review representative viruses found in the human oral cavity and their effects, together with relevant antiviral compounds derived from natural products. We also highlight some recent emerging pharmaceutical technologies with potential to deliver antivirals more effectively for disease prevention and therapy.