Cryo-EM structures of wild-type and E138K/M184I mutant HIV-1 RT/DNA complexed with inhibitors doravirine and rilpivirine.

Structures trapping a variety of functional and conformational states of HIV-1 reverse transcriptase (RT) have been determined by X-ray crystallography. These structures have played important roles in explaining the mechanisms of catalysis, inhibition, and drug resistance and in driving drug design. However, structures of several desired complexes of RT could not be obtained even after many crystallization or crystal soaking experiments. The ternary complexes of doravirine and rilpivirine with RT/DNA are such examples. Structural study of HIV-1 RT by single-particle cryo-electron microscopy (cryo-EM) has been challenging due to the enzyme's relatively smaller size and higher flexibility. We optimized a protocol for rapid structure determination of RT complexes by cryo-EM and determined six structures of wild-type and E138K/M184I mutant RT/DNA in complexes with the nonnucleoside inhibitors rilpivirine, doravirine, and nevirapine. RT/DNA/rilpivirine and RT/DNA/doravirine complexes have structural differences between them and differ from the typical conformation of nonnucleoside RT inhibitor (NNRTI)-bound RT/double-stranded DNA (dsDNA), RT/RNA-DNA, and RT/dsRNA complexes; the primer grip in RT/DNA/doravirine and the YMDD motif in RT/DNA/rilpivirine have large shifts. The DNA primer 3'-end in the doravirine-bound structure is positioned at the active site, but the complex is in a nonproductive state. In the mutant RT/DNA/rilpivirine structure, I184 is stacked with the DNA such that their relative positioning can influence rilpivirine in the pocket. Simultaneously, E138K mutation opens the NNRTI-binding pocket entrance, potentially contributing to a faster rate of rilpivirine dissociation by E138K/M184I mutant RT, as reported by an earlier kinetic study. These structural differences have implications for understanding molecular mechanisms of drug resistance and for drug design.

Clinical pharmacology considerations and drug-drug interactions with long-acting cabotegravir and rilpivirine relevant to sub-Saharan Africa.

Long-acting injectable (LAI) cabotegravir and rilpivirine for HIV treatment and LAI cabotegravir for pre-exposure HIV prophylaxis are being rolled out in a multitude of countries worldwide. Due to the prolonged exposure, it can be challenging to undertake 'traditional' pharmacokinetic studies and current guidance is derived from their oral equivalents or physiologically based pharmacokinetic studies. This review aims to consider pharmacokinetic characteristics of cabotegravir and rilpivirine and describe anticipated drug-drug interactions (DDIs) with frequent concomitant medications in African settings. Relevant co-medications were identified from the WHO 2021 List of Essential Medicines. All original human and physiologically based pharmacokinetic studies published in English on PubMed, discussing DDIs with LAI cabotegravir and rilpivirine prior to April 2023, were reviewed. The Liverpool HIV interaction database was also reviewed (https://www.hiv-druginteractions.org/checker). LAI cabotegravir and rilpivirine have half-lives of 6-12 and 13-28 weeks, respectively. Cabotegravir is primarily metabolized by UDP-glucuronyltransferase (UGT)-1A1 and rilpivirine by cytochrome P450 (CYP)-3A4. LAI cabotegravir and rilpivirine themselves exhibit low risk of perpetrating interactions with co-medications as they do not induce or inhibit the major drug metabolizing enzymes. However, they are victims of DDIs relating to the induction of their metabolizing enzymes by concomitantly administered medication. Noteworthy contraindicated co-medications include rifamycins, carbamazepine, phenytoin, flucloxacillin and griseofulvin, which induce CYP3A4 and/or UGT1A1, causing clinically significant reduced concentrations of rilpivirine and/or cabotegravir. In addition to virologic failure, subtherapeutic concentrations resulting from DDIs can lead to emergent drug resistance. Clinicians should be aware of potential DDIs and counsel people receiving LAI cabotegravir/rilpivirine appropriately to minimize risk.

Archived rilpivirine-associated resistance mutations among ART-naive and virologically suppressed people living with HIV-1 subtype C in Botswana: implications for cabotegravir/rilpivirine use.

OBJECTIVES: Pre-existing rilpivirine resistance-associated mutations (RVP-RAMs) have been found to predict HIV-1 virological failure in those switching to long-acting injectable cabotegravir/rilpivirine. We here evaluated the prevalence of archived RPV-RAMs in a cohort of people living with HIV (PWH). METHODS: We analysed near full-length HIV-1 pol sequences from proviral DNA for the presence of RPV-RAMs, which were defined according to the 2022 IAS-USA drug resistance mutation list and Stanford HIV drug resistance database. RESULTS: RPV-RAMs were identified in 757/5805 sequences, giving a prevalence of 13.0% (95% CI 12%-13.9%). Amongst the ART-naive group, 137/1281 (10.7%, 95% CI 9.1%-12.5%) had at least one RPV-RAM. Of the 4524 PWH with viral suppression on ART (VL <400 copies/mL), 620 (13.7%, 95% CI 12.7%-14.7%) had at least one RPV-RAM. E138A was the most prevalent RPV-RAM in the ART-naive group (7.9%) and the ART-suppressed group (9.3%). The rest of the mutations observed (L100I, K101E, E138G, E138K, E138Q, Y181C, H221Y, M230L, A98G, V179D, G190A, G190E and M230I) were below a prevalence of 1%. CONCLUSIONS: RPV-RAMs were present in 10.7% of ART-naive and 13.7% of ART-suppressed PWH in Botswana. The most common RPV-RAM in both groups was E138A. Since individuals with the E138A mutation may be more likely to fail cabotegravir/rilpivirine, monitoring RPV-RAMs will be crucial for effective cabotegravir/rilpivirine implementation in this setting.

Doravirine responses to HIV-1 viruses bearing mutations to NRTIs and NNRTIs under in vitro selective drug pressure.

OBJECTIVES: The NNRTI doravirine has been recently approved for the first-line treatment of HIV-infected patients, eliciting favourable responses against viruses bearing the K103N, Y181C and G190A mutations. This study used in vitro drug selections to elaborate the breadth of doravirine responses against viruses bearing NNRTI and NRTI resistance-associated mutations (RAMs). METHODS: WT clinical isolates (n = 6) and viruses harbouring common NRTI and NNRTI RAMs (n = 6) were serially passaged in escalating concentrations of doravirine, doravirine/islatravir, doravirine/lamivudine and rilpivirine over 24 weeks. Genotypic analysis ascertained the appearance and accumulation of NNRTI RAMs. Phenotypic drug susceptibility assays assessed resistance conferred by acquired NNRTI RAMs. RESULTS: For WT viruses, doravirine pressure led to the appearance of V108I or V106A/I/M RAMs after 8 weeks, conferring low-level (∼2-fold) resistance. After 24 weeks, the accumulation of three to six secondary RAMs, including F227L, M230L, L234I and/or Y318, resulted in high-level (>100-fold) resistance to doravirine. Notably, viruses with these doravirine RAMs remained susceptible to rilpivirine and efavirenz. This contrasted with rilpivirine where acquisition of E138K, L100I and/or K101E resulted in >50-fold cross-resistance to all NNRTIs. Doravirine selection of viruses bearing common NRTI and NNRTI RAMs showed delayed acquisition of RAMs compared with WT virus. Pairing doravirine with islatravir or lamivudine attenuated the development of NNRTI RAMs. CONCLUSIONS: Doravirine showed favourable resistance profiles against viruses harbouring NRTI and NNRTI RAMs. The high barrier to resistance to doravirine coupled with the long intracellular half-life of islatravir may provide the opportunity for long-acting treatment options.

Compassionate use of long-acting cabotegravir plus rilpivirine for people living with HIV-1 in need of parenteral antiretroviral therapy.

OBJECTIVES: Physicians could request compassionate use of oral and long-acting (LA) cabotegravir + rilpivirine for people living with HIV-1 under a single-patient request programme supported by ViiV Healthcare and Janssen. Outcomes are reported. METHODS: Eligibility criteria included need for parenteral therapy, no primary resistance mutations to cabotegravir or rilpivirine, and established retention in care. Demographic, efficacy, and safety data were obtained from standardized programme applications and quarterly clinical updates. Individuals received a loading dose of LA cabotegravir 600 mg + rilpivirine 900 mg, followed by LA maintenance doses of 400 mg/600 mg every 4 weeks; some received lead-in oral cabotegravir and rilpivirine. RESULTS: Through July 2020, 35 people living with HIV-1 had data available. The most frequent reason for compassionate use request was chronic non-adherence due to psychological conditions (n = 15). Of 35 people living with HIV-1, 28 had detectable viremia (median viral load 60 300 copies/mL) and seven were virologically suppressed at programme entry; 16/28 and 6/7 achieved or maintained virological suppression at data cutoff, respectively. Seven people living with HIV-1 discontinued for incomplete virological response, six with detectable viremia at initiation; six and four had new reverse transcriptase and integrase mutations at discontinuation, respectively. Six non-fatal serious adverse events were reported, two considered possibly treatment related. Four deaths were reported; none were treatment related. One individual reported two pregnancies and continued LA dosing. CONCLUSIONS: Most people living with HIV-1 had advanced disease and achieved (16/28) or maintained (6/7) virological suppression with LA therapy. Cabotegravir LA + rilpivirine LA as compassionate use provided a valuable treatment option for individuals with adherence issues with oral therapy and advanced disease.

Evolution of Antiretroviral Drug Rilpivirine and Approach to Oncology.

Rilpivirine is an antiretroviral drug used to treat AIDS worldwide. The drug is a non-nucleoside reverse transcriptase inhibitor that halts the cDNA elongation process and, thus, the capacity of the HIV-1 virus to replicate. With the new wave of drug repurposing in recent years, rilpivirine has been studied in this regard. This drug is useful in Zika virus treatment, with in vivo results indicating regression in neuronal effects often associated with this infection. Several cancer types have also been researched, from breast to leukemia and pancreatic cancer, and rilpivirine has proved to have inhibitory effects in various cell lines with low concentrations, causing cellular death, apoptosis, and cell cycle arrest. The pathways are not yet established, but some works have hypothesized and demonstrated that rilpivirine causes inhibition of Aurora A kinase and has effects on the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway and the vascular endothelial growth factors-receptors (VEGFs-VEGFRs) pathway, which are known to be altered in cancer and tumors and can be targeted for cancer treatment. Further testing and clinical trials are needed, but this review demonstrates the potential of rilpivirine's repurposing for cancer treatment.

Impact of Integrase Sequences from HIV-1 Subtypes A6/A1 on the In Vitro Potency of Cabotegravir or Rilpivirine.

The FLAIR study demonstrated noninferiority of monthly long-acting cabotegravir + rilpivirine versus daily oral dolutegravir/abacavir/lamivudine for maintaining virologic suppression. Three participants who received long-acting therapy had confirmed virologic failure (CVF) at Week 48, and all had HIV-1 that was originally classified as subtype A1 and contained the baseline integrase polymorphism L74I; updated classification algorithms reclassified all 3 as HIV-1 subtype A6. Retrospectively, the impact of L74I on in vitro sensitivity and durability of response to cabotegravir in HIV-1 subtype B and A6 backgrounds was studied. Site-directed L74I and mutations observed in participants with CVF were generated in HIV-1 subtype B and a consensus integrase derived from 3 subtype A6 CVF baseline sequences. Rilpivirine susceptibility was assessed in HIV-1 subtype B and A1 containing reverse transcriptase mutations observed in participants with CVF. HIV-1 subtype B L74I and L74I/G140R mutants and HIV-1 subtype A6 I74L and I74/G140R mutants remained susceptible to cabotegravir; L74I/Q148R double mutants exhibited reduced susceptibility in HIV-1 subtypes B and A6 (half maximal effective capacity fold change, 4.4 and 4.1, respectively). Reduced rilpivirine susceptibility was observed across HIV-1 subtypes B and A1 with resistance-associated mutations K101E or E138K (half maximal effective capacity fold change, 2.21 to 3.09). In cabotegravir breakthrough experiments, time to breakthrough was similar between L74 and I74 viruses across HIV-1 subtypes B and A6; Q148R was selected at low cabotegravir concentrations. Therefore, the L74I integrase polymorphism did not differentially impact in vitro sensitivity to cabotegravir across HIV-1 subtype B and A6 integrase genes (ClinicalTrials.gov identifier: NCT02938520).

Long-Acting Rilpivirine (RPV) Preexposure Prophylaxis Does Not Inhibit Vaginal Transmission of RPV-Resistant HIV-1 or Select for High-Frequency Drug Resistance in Humanized Mice.

As a long-acting formulation of the nonnucleoside reverse transcriptase inhibitor rilpivirine (RPV LA) has been proposed for use as preexposure prophylaxis (PrEP) and the prevalence of transmitted RPV-resistant viruses can be relatively high, we evaluated the efficacy of RPV LA to inhibit vaginal transmission of RPV-resistant HIV-1 in humanized mice. Vaginal challenges of wild-type (WT), Y181C, and Y181V HIV-1 were performed in mice left untreated or after RPV PrEP. Plasma viremia was measured for 7 to 10 weeks, and single-genome sequencing was performed on plasma HIV-1 RNA in mice infected during PrEP. RPV LA significantly prevented vaginal transmission of WT HIV-1 and Y181C HIV-1, which is 3-fold resistant to RPV. However, it did not prevent transmission of Y181V HIV-1, which has 30-fold RPV resistance in the viruses used for this study. RPV LA did delay WT HIV-1 dissemination in infected animals until genital and plasma RPV concentrations waned. Animals that became infected despite RPV LA PrEP did not acquire new RPV-resistant mutations above frequencies in untreated mice or untreated people living with HIV-1, and the mutations detected conferred low-level resistance. These data suggest that high, sustained concentrations of RPV were required to inhibit vaginal transmission of HIV-1 with little or no resistance to RPV but could not inhibit virus with high resistance. HIV-1 did not develop high-level or high-frequency RPV resistance in the majority of mice infected after RPV LA treatment. However, the impact of low-frequency RPV resistance on virologic outcome during subsequent antiretroviral therapy still is unclear.IMPORTANCE The antiretroviral drug rilpivirine was developed into a long-acting formulation (RPV LA) to improve adherence for preexposure prophylaxis (PrEP) to prevent HIV-1 transmission. A concern is that RPV LA will not inhibit transmission of drug-resistant HIV-1 and may select for drug-resistant virus. In female humanized mice, we found that RPV LA inhibited vaginal transmission of WT or 3-fold RPV-resistant HIV-1 but not virus with 30-fold RPV resistance. In animals that became infected despite RPV LA PrEP, WT HIV-1 dissemination was delayed until genital and plasma RPV concentrations waned. RPV resistance was detected at similar low frequencies in untreated and PrEP-treated mice that became infected. These results indicate the importance of maintaining RPV at a sustained threshold after virus exposure to prevent dissemination of HIV-1 after vaginal infection and low-frequency resistance mutations conferred low-level resistance, suggesting that RPV resistance is difficult to develop after HIV-1 infection during RPV LA PrEP.

[The analysis of the availability of fixed-dose combinations in antiretroviral therapy for HIV infection in the Russian Federation].

AIM: To analyze the features of drugs provision for special groups of treatment-nave HIV-infected patients initiating antiretroviral treatment with fixed dose combination (FDC) for once-daily single-tablet regimen, in Russian healthcare setting. MATERIALS AND METHODS: We studied the regulatory legal documents governing the provision of antiretroviral drugs in Russia and analyzed the Russian Program of State Guarantees to determine the inclusion of the investigated FDCs in the lists of regional benefits, as well as regional and federal procurement of these drugs in 2020 and 2021. We compared costs of first line therapy for special groups using FDCs regimens per year in case of regional purchases or centralized purchases. RESULTS: It was show that doravirin/tenofovir/lamivudine was the least expensive in 2020 and in 2021 among new FDCs form drugs. Worth 325.8 and 323.9 thousand rubles. per patient per year. The most expensive was bictegravir/tenofovir alafenamide/emtricitabine (401.6 and 439.9 thousand rubles, respectively). In case of Ministry of Health centralized purchases, the costs of new FDCs (doravirin/tenofovir/lamivudine and bictegravir/tenofovir alafenamide/emtricitabine), included in Vital and Essential drug list (VEDL) in 2022, will amount to 151,2 and 191.4 thousand rubles respectively, which is 52.9% and 40.4% lower than the cost per course of rilpivirine/tenofovir/emtricitabine. CONCLUSION: The inclusion of new effective and economical FDCs the whole scheme in one tablet once-daily in VEDL, expands the possibilities of simplify and effective first-line therapy for special groups of HIV-infected patients, as well as reduce the financial burden on the Program of State Guarantees budget and increases treatment coverage. All of this corresponds to the goals of the State Strategy to Combat the Spread of HIV in Russian Federation.

Rilpivirine attenuates liver fibrosis through selective STAT1-mediated apoptosis in hepatic stellate cells.

OBJECTIVE: Liver fibrosis constitutes a major health problem worldwide due to its rapidly increasing prevalence and the lack of specific and effective treatments. Growing evidence suggests that signalling through cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways regulates liver fibrosis and regeneration. Rilpivirine (RPV) is a widely used anti-HIV drug not reported to produce hepatotoxicity. We aimed to describe the potential hepatoprotective effects of RPV in different models of chronic liver injury, focusing on JAK-STAT signalling regulation. DESIGN: The effects of RPV on hepatic steatosis, inflammation and fibrogenesis were studied in a nutritional mouse model of non-alcoholic fatty liver disease, carbon tetrachloride-induced fibrosis and bile duct ligation-induced fibrosis. Primary human hepatic stellate cells (hHSC) and human cell lines LX-2 and Hep3B were used to investigate the underlying molecular mechanisms. RESULTS: RPV exerted a clear anti-inflammatory and antifibrotic effect in all the in vivo models of liver injury employed, and enhanced STAT3-dependent proliferation in hepatocytes and apoptosis in HSC through selective STAT1 activation. These results were reproduced in vitro; RPV undermined STAT3 activation and triggered STAT1-mediated pathways and apoptosis in HSC. Interestingly, this selective pro-apoptotic effect completely disappeared when STAT1 was silenced. Conditioned medium experiments showed that HSC apoptosis activated STAT3 in hepatocytes in an interleukin-6-dependent mechanism. CONCLUSION: RPV ameliorates liver fibrosis through selective STAT1-dependent induction of apoptosis in HSC, which exert paracrinal effects in hepatocytes, thus promoting liver regeneration. RPV's actions may represent an effective strategy to treat chronic liver diseases of different aetiologies and help identify novel therapeutic targets.

Effect of the anti-retroviral drug, rilpivirine, on human subcutaneous adipose cells and its nutritional management using quercetin.

Rilpivirine, a recently developed drug of choice for initial treatment of HIV-1 infection, can greatly reduce HIV-related inflammation, but in turn, may be associated with adverse secondary effects, including disturbances in lipid metabolism and ultimately in adipose tissue distribution and function. In recent years, research findings on the benefits of anti-oxidant foods and supplements have been employed in counter-acting both oxidative stress as well as inflammation in order to reduce the adverse side effects of anti-retroviral therapy. One such natural flavonoid which possesses anti-inflammatory and anti-oxidative properties is quercetin. This study investigated the effect of quercetin in overcoming the side effects incurred due to rilpivirine administration. The results show substantial reduction in the accumulation of triglyceride levels in a dose- and time-dependent manner for adipose cells treated with either rilpivirine or quercetin alone and in combination, as evidenced by morphological pictures and quantitative measurement of triglycerides throughout the differentiation process. Levels of inflammatory markers such as resistin and IL-8 were increased as compared to the untreated cells. No significant changes in leptin were observed on treatment of adipose cells with rilpivirine alone and its levels were almost comparable to control. Levels of oxidative markers like superoxide dismutase, catalase, and glutathione were also decreased. Treatment with quercetin showed a decrease in the inflammatory status and an increase in the oxidative status of adipose cells, thereby exhibiting its anti-inflammatory and anti-oxidative properties. However, further assessment of lipid metabolism and adipose tissue function in patients administered with rilpivirine-based regimes is advisable considering that totally neutral effects of rilpivirine on lipid homeostasis cannot be anticipated from the current study in vitro. It is concluded that rilpivirine causes an anti-adipogenic and pro-inflammatory response pattern but only at high concentrations, whereas quercetin has been observed to decrease inflammation and restore the levels of anti-oxidant enzymes.

Suppression of Zika Virus Infection in the Brain by the Antiretroviral Drug Rilpivirine.

Zika virus (ZIKV) infection is associated with microcephaly in neonates and Guillain-Barré syndrome in adults. ZIKV produces a class of nonstructural (NS) regulatory proteins that play a critical role in viral transcription and replication, including NS5, which possesses RNA-dependent RNA polymerase (RdRp) activity. Here we demonstrate that rilpivirine (RPV), a non-nucleoside reverse transcriptase inhibitor (NNRTI) used in the treatment of HIV-1 infection, inhibits the enzymatic activity of NS5 and suppresses ZIKV infection and replication in primary human astrocytes. Similarly, other members of the NNRTI family, including etravirine and efavirenz, showed inhibitory effects on viral infection of brain cells. Site-directed mutagenesis identified 14 amino acid residues within the NS5 RdRp domain (AA265-903), which are important for the RPV interaction and the inhibition of NS5 polymerase activity. Administration of RPV to ZIKV-infected interferon-alpha/beta receptor (IFN-A/R) knockout mice improved the clinical outcome and prevented ZIKV-induced mortality. Histopathological examination of the brains from infected animals revealed that RPV reduced ZIKV RNA levels in the hippocampus, frontal cortex, thalamus, and cerebellum. Repurposing of NNRTIs, such as RPV, for the inhibition of ZIKV replication offers a possible therapeutic strategy for the prevention and treatment of ZIKV-associated disease.

Non-nucleoside Reverse Transcriptase Inhibitors Inhibit Reverse Transcriptase through a Mutually Exclusive Interaction with Divalent Cation-dNTP Complexes.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are considered noncompetitive inhibitors that structurally alter reverse transcriptase (RT) and dramatically decrease catalysis. In this report, biochemical analysis with various divalent cations was used to demonstrate that NNRTIs and divalent cation-dNTP complexes are mutually exclusive, inhibiting each other's binding to RT/primer/template (RT-P/T) complexes. The binding of catalytically competent divalent cation-dNTP complexes to RT-P/T was measured with Mg2+, Mn2+, Zn2+, Co2+, and Ni2+ using Ca2+, a noncatalytic cation, for displacement. Binding strength order was Mn2+ ≈ Zn2+ ≫ Co2+ > Mg2+ ≈ Ni2+. Consistent with but not exclusive to mutually exclusive binding, primer extension assays showed that stronger divalent cation-dNTP complexes were more resistant to NNRTIs (efavirenz (EFV), rilpivirine (RPV), and nevirapine (NVP)). Filtration assays demonstrated that divalent cation-dNTP complexes inhibited the binding of 14C-labeled EFV to RT-P/T with stronger binding complexes formed with Mn2+ inhibiting more potently than those with Mg2+. Conversely, filter binding assays demonstrated that EFV inhibited 3H-labeled dNTP binding to RT-P/T complexes with displacement of Mn2+-dNTP complexes requiring much greater concentrations of EFV than the more weakly bound Mg2+-dNTP complexes. EFV bound relatively weakly to the NNRTI resistant K103N RT; but, binding was modestly enhanced in the presence of P/T, and EFV was easily displaced by divalent cation-dNTP complexes. This suggests that K103N overcomes EFV inhibition mostly by binding more weakly to the drug and is in contrast to other reports that indicate K103N has little to no effect on drug or dNTP binding. Overall, this biochemical analysis supports recent biophysical analyses of NNRTI-RT interactions that indicate mutually exclusive binding.

Nonnucleoside Reverse Transcriptase Inhibitor Hypersusceptibility and Resistance by Mutation of Residue 181 in HIV-1 Reverse Transcriptase.

Substitutions at residue Y181 in HIV-1 reverse transcriptase (RT), in particular, Y181C, Y181I, and Y181V, are associated with nonnucleoside RT inhibitor (NNRTI) cross-resistance. In this study, we used kinetic and thermodynamic approaches, in addition to molecular modeling, to gain insight into the mechanisms by which these substitutions confer resistance to nevirapine (NVP), efavirenz (EFV), and rilpivirine (RPV). Using pre-steady-state kinetics, we found that the dissociation constant (Kd ) values for inhibitor binding to the Y181C and Y181I RT-template/primer (T/P) complexes were significantly reduced. In the presence of saturating concentrations of inhibitor, the Y181C RT-T/P complex incorporated the next correct deoxynucleoside triphosphate (dNTP) more efficiently than the wild-type (WT) complex, and this phenotype correlated with decreased mobility of the RT on the T/P substrate. Interestingly, we found that the Y181F substitution in RT-which represents a transitional mutation between Y181 and Y181I/V, or a partial revertant-conferred hypersusceptibility to EFV and RPV at both the virus and enzyme levels. EFV and RPV bound more tightly to Y181F RT-T/P. Furthermore, inhibitor-bound Y181F RT-T/P was less efficient than the WT complex in incorporating the next correct dNTP, and this could be attributed to increased mobility of Y181F RT on the T/P substrate. Collectively, our data highlight the key role that Y181 in RT plays in NNRTI binding.

Barrier to Resistance of Dolutegravir in Two-Drug Combinations.

A major concern when using two-drug anti-HIV regimens is the risk of viral resistance. However, no techniques to evaluate the barrier to resistance of two-drug combinations in vitro have been reported. We evaluated the emergence of drug-resistant mutants in a passage study with constant concentrations of two drugs simultaneously. The barrier to resistance of dolutegravir-containing two-drug combinations was higher than the other combinations evaluated in this study.

Efficacy, safety, and tolerability of dolutegravir-rilpivirine for the maintenance of virological suppression in adults with HIV-1: phase 3, randomised, non-inferiority SWORD-1 and SWORD-2 studies.

BACKGROUND: Lifelong HIV antiretroviral therapy (ART) has prompted an interest in two-drug regimens to minimise cumulative drug exposure and toxicities. The safety, tolerability, and efficacy of dolutegravir and rilpivirine suggest potential compatibility and effectiveness as a two-drug regimen. We aimed to investigate this two-drug regimen in a phase 3 study. METHODS: We identically designed SWORD-1 and SWORD-2, which were open-label, parallel-group, multicentre, phase 3, randomised, non-inferiority studies in 12 countries evaluating efficacy and safety of once-daily dolutegravir 50 mg plus rilpivirine 25 mg versus current ART regimen (CAR). We included participants aged 18 years or older who were on first or second ART with stable plasma HIV-1 RNA (viral load <50 copies per mL) for 6 months or longer at screening. We randomly assigned participants (1:1) with stratification by third-agent class, age, and planned participation in a bone mineral density substudy. The primary endpoint was proportion of participants with viral load lower than 50 copies per mL at week 48 among those individuals who received one or more doses of study medication. Investigators monitored adverse events to assess safety. These trials are registered with ClinicalTrials.gov, numbers NCT02429791 (SWORD-1) and NCT02422797 (SWORD-2). FINDINGS: We screened for participants from April 14, 2015, to Oct 15, 2015, for SWORD-1 and from April 21, 2015, to Sept 25, 2015, for SWORD-2. We randomly assigned 516 participants to dolutegravir-rilpivirine and 512 to continue with CAR. At week 48 (last patient visit was Nov 22, 2016), in the pooled analysis of the intention-to-treat population, 95% of participants had viral loads lower than 50 copies per mL in each group (486 of 513 in the dolutegravir-rilpivirine group vs 485 of 511 in the CAR group), with an adjusted treatment difference of -0·2% (95% CI -3·0 to 2·5) and showed non-inferiority with a predefined margin of -8%. 395 (77%) of 513 participants in the dolutegravir-rilpivirine group and 364 (71%) of 511 participants in the CAR group reported adverse events. The most common adverse events were nasopharyngitis (49 [10%] for dolutegravir-rilpivirine vs 50 [10%] for CAR) and headache (41 [8%] vs 23 [5%]). More participants taking dolutegravir-rilpivirine (17 [3%]) reported adverse events leading to withdrawal than did participants taking CAR (three [<1%]). INTERPRETATION: Dolutegravir-rilpivirine was non-inferior to CAR over 48 weeks in participants with HIV suppression and showed a safety profile consistent with its components. Results support the use of this two-drug regimen to maintain HIV suppression. FUNDING: ViiV Healthcare and Janssen Pharmaceutica NV.

Impact of the mutational load on the virological response to a first-line rilpivirine-based regimen.

OBJECTIVES: To determine how the load of rilpivirine-resistant variants (mutational load) influences the virological response (VR) of HIV-1-infected patients to a rilpivirine-based first-line regimen. PATIENTS AND METHODS: Four hundred and eighty-nine patients infected with HIV-1 whose reverse transcriptase gene had been successfully resistance genotyped using next-generation sequencing were given a first-line regimen containing rilpivirine. Variables associated with the VR at 12 months were identified using a logistic model. The results were used to build a multivariate model for each mutational load threshold and the R2 variations were analysed to identify the mutational load threshold that best predicted the VR. RESULTS: The mutational load at baseline was the only variable linked to the VR at 12 months (P  < 0.01). The VR at 12 months decreased from 96.9% to 83.4% when the mutational load was >1700 copies/mL and to 50% when the mutational load was > 9000 copies/mL. The threshold of 9000 copies/mL was associated with the VR at 12 months with an OR of 36.7 (95% CI 4.7-285.1). The threshold of 1700 copies/mL was associated with the VR at 12 months with an OR of 7.2 (95% CI 1.4-36.8). CONCLUSIONS: There is quantifiable evidence that determining a mutational load threshold can be used to identify those patients on a first-line regimen containing rilpivirine who are at risk of virological failure. The clinical management of HIV-infected patients can be improved by evaluating the frequency of mutant variants at a threshold of < 20% together with the plasma HIV-1 viral load at the time of resistance genotyping.

Effects of rilpivirine, 17ß-estradiol and ß-naphthoflavone on the inflammatory status of release of adipocytokines in 3T3-L1 adipocytes in vitro.

Rilpivirine is a non-nucleoside reverse transcriptase inhibitor, recently developed as a drug of choice for initial anti-retroviral (ARV) treatment of HIV-1 infection, whereas estradiol is a major component of hormonal contraceptives. Both drugs have effects on lipid metabolism, impairment of adipocyte differentiation and alteration of adipose tissue distribution and function.This study investigated the effects of different concentrations of either rilpivirine or estradiol either alone or in combination on adipocyte differentiation and adipocytokines status in vitro in the absence and presence of ß-naphthoflavone, (BNF),a potent agonist of the aryl hydrocarbon receptor. 3T3-L1 human pre-adipocytes were cultured and differentiated with different concentrations of treatment drugs. After 10 days of differentiation procedure, cells were examined for their morphology and viability. Glycerol,adiponectin, leptin, resistin and interleukin-8 (IL-8) were quantified using commercially available kits. The results show that either rilpivirine or estradiol individually or during their combination can evoke significant increases in glycerol release and a concomitant significant decrease of adiponectin from adipocytes. These effects were dose-dependent. The effects of combined treatments were much larger than individual concentration for each drug. Both drugs had little of no effect on leptin levels, except for a small decrease with 10 µM rilpivirine alone or when combined with estradiol. In addition, both drugs evoked small increases in the release of resistin and interleukin-8 with significant values at higher doses compared to untreated adipocytes.When adipocytes were pretreated with BNF, either rilpivirine or, estradiol or when combined evoked a much larger release in glycerol and a much larger decrease in adiponectin compared to the absence of BNF. In contrast, BNF pretreatment had little of no effect on either leptin, resistin or IL-8 metabolism compared to the results obtained in the presence of either rilpivirine or estradiol alone or in combination.These results show that rilpivirine and estradiol either alone or when combined or pretreated with BNF can evoke marked effects on glycerol and cytokines levels from adipocytes. However, their mechanism (s) in inducing adipogenesis warrants further investigation of different transcription factors at gene expression levels.

Bioequivalence of a Fixed-Dose Combination Tablet of the Complete Two-Drug Regimen of Dolutegravir and Rilpivirine for Treatment of HIV-1 Infection.

A complete 2-drug regimen of dolutegravir at 50 mg and rilpivirine at 25 mg was approved to treat HIV-1 infection in virologically suppressed patients after demonstrating acceptable efficacy and tolerability. This study investigated the bioequivalence and pharmacokinetics of the fixed-dose combination tablet compared with those of separate tablets. Secondary endpoints were the tolerability and safety of the fixed-dose combination tablet. In this open-label, randomized-sequence, 2-way crossover trial, single doses of the fixed-dose combination tablet (the test treatment) and the combination of separate tablets (the reference treatment) were administered to healthy adults after a moderate-fat meal, with a 21-day washout between treatments. Pharmacokinetic samples were collected through 12 days after dosing. The primary endpoints were the area under the plasma concentration-time curve (AUC) and the maximum concentration of drug in plasma (Cmax). The study employed a prespecified sample size reestimation based on a blind midpoint review of Cmax variability to update the enrollment size to achieve statistical power. Of 118 participants enrolled, 113 received both treatments and underwent pharmacokinetic assessment. The 90% confidence intervals for the geometric least-squares mean ratios for the AUC from 0 h to infinity, the AUC from 0 h to the last quantifiable measurement, and Cmax (test treatment versus reference treatment) were within the bioequivalence range of 0.80 to 1.25 for both drugs, indicating bioequivalence. In this study, a single dose of either treatment was well tolerated overall, with 4% (n = 5) and 3% (n = 3) of participants reporting adverse events considered related to the test and reference treatments, respectively. The dolutegravir-rilpivirine fixed-dose combination tablet is bioequivalent to a combination of separate tablets, and no new safety signals emerged. (This study has been registered at ClinicalTrials.gov under identifier NCT02741557.).

Negative Regulation of Human Pregnane X Receptor by MicroRNA-18a-5p: Evidence for Suppression of MicroRNA-18a-5p Expression by Rifampin and Rilpivirine.

Small noncoding microRNAs act as post-transcriptional regulators of gene expression involved in diverse biologic functions. Pregnane X receptor (PXR, NR1I2), a member of the superfamily of nuclear receptors, is a transcription factor governing the transport and biotransformation of various drugs and other chemicals. In the present study, we identified a specific microRNA (miR) involved in regulating the expression and functionality of human PXR (hPXR). According to bioinformatics analysis employing three commonly used algorithms (TargetScan, miRanda, and DIANA-microT-CDS), miR-18a-5p was predicted to be the top candidate microRNA regulator of hPXR. Consequently, this microRNA was selected for detailed experimental investigation. As shown in cell-based dual-luciferase reporter gene assays, functional interaction occurred between miR-18a-5p and the microRNA recognition element of miR-18a-5p in the 3'-untranslated region of hPXR mRNA. Transfection of LS180 human colorectal adenocarcinoma cells with an miR-18a-5p mimic decreased hPXR mRNA and protein expression, whereas transfection of LS180 cells with an miR-18a-5p inhibitor increased hPXR mRNA and protein expression. The decrease in hPXR expression by the miR-18a-5p mimic was associated with a reduction in the extent of hPXR target gene (CYP3A4) induction by rifampin and rilpivirine. Treatment of untransfected LS180 cells with either of these hPXR agonists decreased endogenous expression of miR-18a-5p, and this preceded the onset of CYP3A4 induction. In conclusion, miR-18a-5p is a negative regulator of hPXR expression and the hPXR agonists rifampin and rilpivirine are chemical suppressors of miR-18a-5p expression.