Snatch-and-Grab Inhibitors to Fight the Flu.

Transcription of viral mRNA in cells infected with influenza viruses involves capturing and cleaving the first 10-20 nucleotides of 5' capped host mRNAs to be used as primers in viral RNA synthesis. A newly developed inhibitor of the viral endonuclease responsible for this cap-snatching shows therapeutic efficacy for the treatment of influenza. To view this Bench to Bedside, open or download the PDF.

Structures of the human dopamine D3 receptor-Gi complexes.

The dopamine system, including five dopamine receptors (D1R-D5R), plays essential roles in the central nervous system (CNS), and ligands that activate dopamine receptors have been used to treat many neuropsychiatric disorders. Here, we report two cryo-EM structures of human D3R in complex with an inhibitory G protein and bound to the D3R-selective agonists PD128907 and pramipexole, the latter of which is used to treat patients with Parkinson's disease. The structures reveal agonist binding modes distinct from the antagonist-bound D3R structure and conformational signatures for ligand-induced receptor activation. Mutagenesis and homology modeling illuminate determinants of ligand specificity across dopamine receptors and the mechanisms for Gi protein coupling. Collectively our work reveals the basis of agonist binding and ligand-induced receptor activation and provides structural templates for designing specific ligands to treat CNS diseases targeting the dopaminergic system.

Site-specific incorporation of a fluorescent nucleobase analog enhances i-motif stability and allows monitoring of i-motif folding inside cells.

The i-motif is an intriguing non-canonical DNA structure, whose role in the cell is still controversial. Development of methods to study i-motif formation under physiological conditions in living cells is necessary to study its potential biological functions. The cytosine analog 1,3-diaza-2-oxophenoxazine (tCO) is a fluorescent nucleobase able to form either hemiprotonated base pairs with cytosine residues, or neutral base pairs with guanines. We show here that when tCO is incorporated in the proximity of a G:C:G:C minor groove tetrad, it induces a strong thermal and pH stabilization, resulting in i-motifs with Tm of 39ºC at neutral pH. The structural determination by NMR methods reveals that the enhanced stability is due to a large stacking interaction between the guanines of the tetrad with the tCO nucleobase, which forms a tCO:C+ in the folded structure at unusually-high pHs, leading to an increased quenching in its fluorescence at neutral conditions. This quenching is much lower when tCO is base-paired to guanines and totally disappears when the oligonucleotide is unfolded. By taking profit of this property, we have been able to monitor i-motif folding in cells.

Inhibition of Syk promotes chemical reprogramming of fibroblasts via metabolic rewiring and H2 S production.

Chemical compounds have recently been introduced as alternative and non-integrating inducers of pluripotent stem cell fate. However, chemical reprogramming is hampered by low efficiency and the molecular mechanisms remain poorly characterized. Here, we show that inhibition of spleen tyrosine kinase (Syk) by R406 significantly promotes mouse chemical reprogramming. Mechanistically, R406 alleviates Syk / calcineurin (Cn) / nuclear factor of activated T cells (NFAT) signaling-mediated suppression of glycine, serine, and threonine metabolic genes and dependent metabolites. Syk inhibition upregulates glycine level and downstream transsulfuration cysteine biosynthesis, promoting cysteine metabolism and cellular hydrogen sulfide (H2 S) production. This metabolic rewiring decreased oxidative phosphorylation and ROS levels, enhancing chemical reprogramming. In sum, our study identifies Syk-Cn-NFAT signaling axis as a new barrier of chemical reprogramming and suggests metabolic rewiring and redox homeostasis as important opportunities for controlling cell fates.

Dolutegravir in Pregnancy as Compared with Current HIV Regimens in the United States.

BACKGROUND: Data on the effectiveness and safety of dolutegravir-based antiretroviral therapy (ART) for human immunodeficiency virus type 1 (HIV-1) infection in pregnancy as compared with other ART regimens commonly used in the United States and Europe, particularly when initiated before conception, are limited. METHODS: We conducted a study involving pregnancies in persons with HIV-1 infection in the Pediatric HIV/AIDS Cohort Study whose initial ART in pregnancy included dolutegravir, atazanavir-ritonavir, darunavir-ritonavir, oral rilpivirine, raltegravir, or elvitegravir-cobicistat. Viral suppression at delivery and the risks of infants being born preterm, having low birth weight, and being small for gestational age were compared between each non-dolutegravir-based ART regimen and dolutegravir-based ART. Supplementary analyses that included participants in the Swiss Mother and Child HIV Cohort Study were conducted to improve the precision of our results. RESULTS: Of the pregnancies in the study, 120 were in participants who received dolutegravir, 464 in those who received atazanavir-ritonavir, 185 in those who received darunavir-ritonavir, 243 in those who received rilpivirine, 86 in those who received raltegravir, and 159 in those who received elvitegravir-cobicistat. The median age at conception was 29 years; 51% of the pregnancies were in participants who started ART before conception. Viral suppression was present at delivery in 96.7% of the pregnancies in participants who received dolutegravir; corresponding percentages were 84.0% for atazanavir-ritonavir, 89.2% for raltegravir, and 89.8% for elvitegravir-cobicistat (adjusted risk differences vs. dolutegravir, -13.0 percentage points [95% confidence interval {CI}, -17.0 to -6.1], -17.0 percentage points [95% CI, -27.0 to -2.4], and -7.0 percentage points [95% CI, -13.3 to -0.0], respectively). The observed risks of preterm birth were 13.6 to 17.6%. Adjusted risks of infants being born preterm, having low birth weight, or being small for gestational age did not differ substantially between non-dolutegravir-based ART and dolutegravir. Results of supplementary analyses were similar. CONCLUSIONS: Atazanavir-ritonavir and raltegravir were associated with less frequent viral suppression at delivery than dolutegravir. No clear differences in adverse birth outcomes were observed with dolutegravir-based ART as compared with non-dolutegravir-based ART, although samples were small. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others.).

Tree-based subgroup discovery using electronic health record data: heterogeneity of treatment effects for DTG-containing therapies.

The rich longitudinal individual level data available from electronic health records (EHRs) can be used to examine treatment effect heterogeneity. However, estimating treatment effects using EHR data poses several challenges, including time-varying confounding, repeated and temporally non-aligned measurements of covariates, treatment assignments and outcomes, and loss-to-follow-up due to dropout. Here, we develop the subgroup discovery for longitudinal data algorithm, a tree-based algorithm for discovering subgroups with heterogeneous treatment effects using longitudinal data by combining the generalized interaction tree algorithm, a general data-driven method for subgroup discovery, with longitudinal targeted maximum likelihood estimation. We apply the algorithm to EHR data to discover subgroups of people living with human immunodeficiency virus who are at higher risk of weight gain when receiving dolutegravir (DTG)-containing antiretroviral therapies (ARTs) versus when receiving non-DTG-containing ARTs.

Antiretroviral drug dolutegravir induces inflammation at the mouse brain barriers.

Integrase strand transfer inhibitors (INSTIs) based antiretroviral therapy (ART) is currently used as first-line regimen to treat HIV infection. Despite its high efficacy and barrier to resistance, ART-associated neuropsychiatric adverse effects remain a major concern. Recent studies have identified a potential interaction between the INSTI, dolutegravir (DTG), and folate transport pathways at the placental barrier. We hypothesized that such interactions could also occur at the two major blood-brain interfaces: blood-cerebrospinal fluid barrier (BCSFB) and blood-brain barrier (BBB). To address this question, we evaluated the effect of two INSTIs, DTG and bictegravir (BTG), on folate transporters and receptor expression at the mouse BCSFB and the BBB in vitro, ex vivo and in vivo. We demonstrated that DTG but not BTG significantly downregulated the mRNA and/or protein expression of folate transporters (RFC/SLC19A1, PCFT/SLC46A1) in human and mouse BBB models in vitro, and mouse brain capillaries ex vivo. Our in vivo study further revealed a significant downregulation in Slc19a1 and Slc46a1 mRNA expression at the BCSFB and the BBB following a 14-day DTG oral treatment in C57BL/6 mice. However, despite the observed downregulatory effect of DTG in folate transporters/receptor at both brain barriers, a 14-day oral treatment of DTG-based ART did not significantly alter the brain folate level in animals. Interestingly, DTG treatment robustly elevated the mRNA and/or protein expression of pro-inflammatory cytokines and chemokines (Cxcl1, Cxcl2, Cxcl3, Il6, Il23, Il12) in primary cultures of mouse brain microvascular endothelial cells (BBB). DTG oral treatment also significantly upregulated proinflammatory cytokines and chemokine (Il6, Il1ß, Tnfα, Ccl2) at the BCSFB in mice. We additionally observed a downregulated mRNA expression of drug efflux transporters (Abcc1, Abcc4, and Abcb1a) and tight junction protein (Cldn3) at the CP isolated from mice treated with DTG. Despite the structural similarities, BTG only elicited minor effects on the markers of interest at both the BBB and BCSFB. In summary, our current data demonstrates that DTG but not BTG strongly induced inflammatory responses in a rodent BBB and BCSFB model. Together, these data provide valuable insights into the mechanism of DTG-induced brain toxicity, which may contribute to the pathogenesis of DTG-associated neuropsychiatric adverse effect.

Structural Studies of Inhibitors with Clinically Relevant Influenza Endonuclease Variants.

Vital to the treatment of influenza is the use of antivirals such as Oseltamivir (Tamiflu) and Zanamivir (Relenza); however, antiviral resistance is becoming an increasing problem for these therapeutics. The RNA-dependent RNA polymerase acidic N-terminal (PAN) endonuclease, a critical component of influenza viral replication machinery, is an antiviral target that was recently validated with the approval of Baloxavir Marboxil (BXM). Despite its clinical success, BXM has demonstrated susceptibility to resistance mutations, specifically the I38T, E23K, and A36 V mutants of PAN. To better understand the effects of these mutations on BXM resistance and improve the design of more robust therapeutics, this study examines key differences in protein-inhibitor interactions with two inhibitors and the I38T, E23K, and A36 V mutants. Differences in inhibitor binding were evaluated by measuring changes in binding to PAN using two biophysical methods. The binding mode of two distinct inhibitors was determined crystallographically with both wild-type and mutant forms of PAN. Collectively, these studies give some insight into the mechanism of antiviral resistance of these mutants.

Twice-Daily Dosing of Dolutegravir in Infants on Rifampicin Treatment: A Pharmacokinetic Substudy of the EMPIRICAL Trial.

BACKGROUND: We evaluated dolutegravir pharmacokinetics in infants with human immunodeficiency virus (HIV) receiving dolutegravir twice daily (BID) with rifampicin-based tuberculosis (TB) treatment compared with once daily (OD) without rifampicin. METHODS: Infants with HIV aged 1-12 months, weighing ≥3 kg, and receiving dolutegravir BID with rifampicin or OD without rifampicin were eligible. Six blood samples were taken over 12 (BID) or 24 hours (OD). Dolutegravir pharmacokinetic parameters, HIV viral load (VL) data, and adverse events (AEs) were reported. RESULTS: Twenty-seven of 30 enrolled infants had evaluable pharmacokinetic curves. The median (interquartile range) age was 7.1 months (6.1-9.9), weight was 6.3 kg (5.6-7.2), 21 (78%) received rifampicin, and 11 (41%) were female. Geometric mean ratios comparing dolutegravir BID with rifampicin versus OD without rifampicin were area under curve (AUC)0-24h 0.91 (95% confidence interval, .59-1.42), Ctrough 0.95 (0.57-1.59), Cmax 0.87 (0.57-1.33). One infant (5%) receiving rifampicin versus none without rifampicin had dolutegravir Ctrough <0.32 mg/L, and none had Ctrough <0.064 mg/L. The dolutegravir metabolic ratio (dolutegravir-glucuronide AUC/dolutegravir AUC) was 2.3-fold higher in combination with rifampicin versus without rifampicin. Five of 82 reported AEs were possibly related to rifampicin or dolutegravir and resolved without treatment discontinuation. Upon TB treatment completion, HIV viral load was <1000 copies/mL in 76% and 100% of infants and undetectable in 35% and 20% of infants with and without rifampicin, respectively. CONCLUSIONS: Dolutegravir BID in infants receiving rifampicin resulted in adequate dolutegravir exposure, supporting this treatment approach for infants with HIV-TB coinfection.

Two Cases of Viral Re-suppression After M184V + R263K Selection on Dolutegravir/Lamivudine Without Treatment Modification.

Dolutegravir/lamivudine (DTG/3TC) has a high genetic barrier against the development of human immunodeficiency virus drug resistance. We report 2 cases of R263K + M184V mutations during DTG/3TC failure followed by viral suppression after adherence intervention without treatment change that we attribute to residual drug activity, reduced viral fitness, and robust immune competence.

Weight Changes and Adverse Pregnancy Outcomes With Dolutegravir- and Tenofovir Alafenamide Fumarate-Containing Antiretroviral Treatment Regimens During Pregnancy and Postpartum.

BACKGROUND: We evaluated associations between antepartum weight change and adverse pregnancy outcomes and between antiretroviral therapy (ART) regimens and week 50 postpartum body mass index in IMPAACT 2010. METHODS: Women with human immunodeficiency virus (HIV)-1 in 9 countries were randomized 1:1:1 at 14-28 weeks' gestational age (GA) to start dolutegravir (DTG) + emtricitabine (FTC)/tenofovir alafenamide fumarate (TAF) versus DTG + FTC/tenofovir disoproxil fumarate (TDF) versus efavirenz (EFV)/FTC/TDF. Insufficient antepartum weight gain was defined using Institute of Medicine guidelines. Cox-proportional hazards regression models were used to evaluate the association between antepartum weight change and adverse pregnancy outcomes: stillbirth (≥20 weeks' GA), preterm delivery (<37 weeks' GA), small size for GA (<10th percentile), and a composite of these endpoints. RESULTS: A total of 643 participants were randomized: 217 to the DTG + FTC/TAF, 215 to the DTG + FTC/TDF, and 211 to the EFV/FTC/TDF arm. Baseline medians were as follows: GA, 21.9 weeks; HIV RNA, 903 copies/mL; and CD4 cell count, 466/µL. Insufficient weight gain was least frequent with DTG + FTC/TAF (15.0%) versus DTG + FTC/TDF (23.6%) and EFV/FTC/TDF (30.4%). Women in the DTG + FTC/TAF arm had the lowest rate of composite adverse pregnancy outcome. Low antepartum weight gain was associated with higher hazard of composite adverse pregnancy outcome (hazard ratio, 1.44 [95% confidence interval, 1.04-2.00]) and small size for GA (1.48 [.99-2.22]). More women in the DTG + FTC/TAF arm had a body mass index ≥25 (calculated as weight in kilograms divided by height in meters squared) at 50 weeks postpartum (54.7%) versus the DTG + FTC/TDF (45.2%) and EFV/FTC/TDF (34.2%) arms. CONCLUSIONS: Antepartum weight gain on DTG regimens was protective against adverse pregnancy outcomes typically associated with insufficient weight gain, supportive of guidelines recommending DTG-based ART for women starting ART during pregnancy. Interventions to mitigate postpartum weight gain are needed.

Population pharmacokinetic modeling of dolutegravir/lamivudine to support a once-daily fixed-dose combination regimen in virologically suppressed adults living with HIV-1.

A fixed-dose combination (FDC) of 50 mg dolutegravir and 300 mg lamivudine is indicated for the treatment of HIV-1 infection. This analysis aimed to characterize the population pharmacokinetics (PK) of dolutegravir and lamivudine based on data from a phase 3 study (TANGO) in virologically suppressed adults living with HIV-1 switching to dolutegravir/lamivudine FDC. These analyses included 362 participants who contributed 2,629 dolutegravir and 2,611 lamivudine samples collected over 48 weeks. A one-compartment model with first-order absorption and elimination parameterized by apparent oral clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (Ka) described dolutegravir PK. Covariate search yielded body weight, bilirubin, and ethnicity as predictors of CL/F, and weight was predictive for V/F. The estimates of CL/F, V/F, and Ka were 0.858 L/h, 16.7 L, and 2.15 h-1, respectively. A two-compartment model with first-order absorption and elimination parameterized by CL/F, apparent intercompartmental clearance (Q/F), apparent central volume of distribution (V2/F), apparent peripheral volume of distribution (V3/F), and Ka described lamivudine PK. Covariate search yielded eGFR and race as predictors of CL/F, and weight was predictive for V2/F. The estimated parameter values were CL/F = 19.6 L/h, Q/F = 2.97 L/h, V2/F = V3/F = 105 L, and Ka = 2.30 h-1. The steady-state prediction suggested that the effect of covariates dolutegravir and lamivudine exposures was small (<20%) and not clinically relevant. Therefore, no dose adjustments are recommended based on these analyses. The results support the use of dolutegravir/lamivudine FDC in the treatment of HIV-1 infection in adults.CLINICAL TRIALSThis study is registered with ClinicalTrials.gov as NCT03446573.

Treatment with fostamatinib in patients with immune thrombocytopenia: Experience from the Andalusian region in Spain-The Fostasur Study.

Immune thrombocytopenia (ITP) is characterized by low platelet counts (PLTs) and an increased risk of bleeding. Fostamatinib, a spleen tyrosine kinase inhibitor, has been approved as a second-line treatment for ITP. Real-world data on fostamatinib are lacking. This observational, retrospective, multicentre study, conducted in the Andalusia region of Spain, evaluated 44 adult primary ITP patients (47.7% female; median age 58 years; newly diagnosed ITP 6.8%; persistent 13.6%; chronic 79.5%; median four prior treatments) after ≥ 4 weeks of fostamatinib therapy. The median PLT at the initiation of fostamatinib was 15 × 109/L. Common reasons for starting fostamatinib were refractoriness or intolerance to prior therapy, oral medication preference, history of thrombosis and cardiovascular risk. Dosing was individualized based on efficacy and tolerance. After 2 weeks, global response rate was 56.8% (response and complete response). Response rates were 70.5%, 62.5% and 64% at 4 weeks, 12 weeks and at the end of the study respectively. Adverse events were mild, and no patients discontinued as a result. This real-world study demonstrated a response rate similar to fostamatinib as seen in the pivotal clinical trials while including newly diagnosed patients and allowing for individualized dosing.

Dolutegravir as First- or Second-Line Treatment for HIV-1 Infection in Children.

BACKGROUND: Children with human immunodeficiency virus type 1 (HIV-1) infection have limited options for effective antiretroviral treatment (ART). METHODS: We conducted an open-label, randomized, noninferiority trial comparing three-drug ART based on the HIV integrase inhibitor dolutegravir with standard care (non-dolutegravir-based ART) in children and adolescents starting first- or second-line ART. The primary end point was the proportion of participants with virologic or clinical treatment failure by 96 weeks, as estimated by the Kaplan-Meier method. Safety was assessed. RESULTS: From September 2016 through June 2018, a total of 707 children and adolescents who weighed at least 14 kg were randomly assigned to receive dolutegravir-based ART (350 participants) or standard care (357). The median age was 12.2 years (range, 2.9 to 18.0), the median weight was 30.7 kg (range, 14.0 to 85.0), and 49% of the participants were girls. By design, 311 participants (44%) started first-line ART (with 92% of those in the standard-care group receiving efavirenz-based ART), and 396 (56%) started second-line ART (with 98% of those in the standard-care group receiving boosted protease inhibitor-based ART). The median follow-up was 142 weeks. By 96 weeks, 47 participants in the dolutegravir group and 75 in the standard-care group had treatment failure (estimated probability, 0.14 vs. 0.22; difference, -0.08; 95% confidence interval, -0.14 to -0.03; P = 0.004). Treatment effects were similar with first- and second-line therapies (P = 0.16 for heterogeneity). A total of 35 participants in the dolutegravir group and 40 in the standard-care group had at least one serious adverse event (P = 0.53), and 73 and 86, respectively, had at least one adverse event of grade 3 or higher (P = 0.24). At least one ART-modifying adverse event occurred in 5 participants in the dolutegravir group and in 17 in the standard-care group (P = 0.01). CONCLUSIONS: In this trial involving children and adolescents with HIV-1 infection who were starting first- or second-line treatment, dolutegravir-based ART was superior to standard care. (Funded by ViiV Healthcare; ODYSSEY ClinicalTrials.gov number, NCT02259127; EUDRACT number, 2014-002632-14; and ISRCTN number, ISRCTN91737921.).

Dolutegravir or Darunavir in Combination with Zidovudine or Tenofovir to Treat HIV.

BACKGROUND: The World Health Organization recommends dolutegravir with two nucleoside reverse-transcriptase inhibitors (NRTIs) for second-line treatment of human immunodeficiency virus type 1 (HIV-1) infection. Evidence is limited for the efficacy of this regimen when NRTIs are predicted to lack activity because of drug resistance, as well as for the recommended switch of an NRTI from tenofovir to zidovudine. METHODS: In a two-by-two factorial, open-label, noninferiority trial, we randomly assigned patients for whom first-line therapy was failing (HIV-1 viral load, ≥1000 copies per milliliter) to receive dolutegravir or ritonavir-boosted darunavir and to receive tenofovir or zidovudine; all patients received lamivudine. The primary outcome was a week 48 viral load of less than 400 copies per milliliter, assessed with the Food and Drug Administration snapshot algorithm (noninferiority margin for the between-group difference in the percentage of patients with the primary outcome, 12 percentage points). RESULTS: We enrolled 464 patients at seven sub-Saharan African sites. A week 48 viral load of less than 400 copies per milliliter was observed in 90.2% of the patients in the dolutegravir group (212 of 235) and in 91.7% of those in the darunavir group (210 of 229) (difference, -1.5 percentage points; 95% confidence interval [CI], -6.7 to 3.7; P = 0.58; indicating noninferiority of dolutegravir, without superiority) and in 92.3% of the patients in the tenofovir group (215 of 233) and in 89.6% of those in the zidovudine group (207 of 231) (difference, 2.7 percentage points; 95% CI, -2.6 to 7.9; P = 0.32; indicating noninferiority of tenofovir, without superiority). In the subgroup of patients with no NRTIs that were predicted to have activity, a viral load of less than 400 copies per milliliter was observed in more than 90% of the patients in the dolutegravir group and the darunavir group. The incidence of adverse events did not differ substantially between the groups in either factorial comparison. CONCLUSIONS: Dolutegravir in combination with NRTIs was effective in treating patients with HIV-1 infection, including those with extensive NRTI resistance in whom no NRTIs were predicted to have activity. Tenofovir was noninferior to zidovudine as second-line therapy. (Funded by Janssen; NADIA ClinicalTrials.gov number, NCT03988452.).

Multiomics plasma effects of switching from triple antiretroviral regimens to dolutegravir plus lamivudine.

INTRODUCTION: The DOLAM trial revealed that switching from triple antiretroviral therapy (three-drug regimen; 3DR) to dolutegravir plus lamivudine (two-drug regimen; 2DR) was virologically non-inferior to continuing 3DR after 48 weeks of follow-up. Weight increased with 2DR relative to 3DR but it did not impact on metabolic parameters. METHODS: Multiomics plasma profile was performed to gain further insight into whether this therapy switch might affect specific biological pathways. DOLAM (EudraCT 201500027435) is a Phase 4, randomized, open-label, non-inferiority trial in which virologically suppressed persons with HIV treated with 3DR were assigned (1:1) to switch to 2DR or to continue 3DR for 48 weeks. Untargeted proteomics, metabolomics and lipidomics analyses were performed at baseline and at 48 weeks. Univariate and multivariate analyses were performed to identify changes in key molecules between both therapy arms. RESULTS: Switching from 3DR to 2DR showed a multiomic impact on circulating plasma concentration of N-acetylmuramoyl-L-alanine amidase (Q96PD5), insulin-like growth factor-binding protein 3 (A6XND0), alanine and triglyceride (TG) (48:0). Correlation analyses identified an association among the up-regulation of these four molecules in persons treated with 2DR. CONCLUSIONS: Untargeted multiomics profiling studies identified molecular changes potentially associated with inflammation immune pathways, and with lipid and glucose metabolism. Although these changes could be associated with potential metabolic or cardiovascular consequences, their clinical significance remains uncertain. Further work is needed to confirm these findings and to assess their long-term clinical consequences.

Tenofovir, emtricitabine, lamivudine and dolutegravir concentrations in plasma and urine following drug intake cessation in a randomized controlled directly observed pharmacokinetic trial to aid point-of-care testing.

BACKGROUND: Poor adherence to ART and pre-exposure prophylaxis (PrEP) can impact patient and public health. Point-of-care testing (POCT) may aid monitoring and adherence interventions. OBJECTIVES: We report the pharmacokinetics of tenofovir [dosed as tenofovir disoproxil (TDF) and tenofovir alafenamide (TAF)], emtricitabine (FTC), lamivudine (3TC) and dolutegravir (DTG) in plasma and urine following drug cessation to evaluate adherence targets in urine for POCT. METHODS: Subjects were randomized (1:1) to receive DTG/FTC/TAF or DTG/3TC/TDF for 15 days. Plasma and spot urine were collected on Day 15 (0-336 h post final dose). Drug concentrations were quantified using LC-MS, and non-linear mixed-effects models applied to determine drug disposition between matrices and relationship with relevant plasma [dolutegravir protein-adjusted 90% inhibitory concentration (PA-IC90 = 64 ng/mL) and minimum effective concentration (MEC = 324 ng/mL)] and urinary thresholds [tenofovir disoproxil fumarate 1500 ng/mL]. RESULTS: Of 30 individuals enrolled, 29 were included (72% female at birth, 90% Caucasian). Median (range) predicted time to plasma dolutegravir PA-IC90 and MEC were 83.5 (41.0-152) and 49.0 h (23.7-78.9), corresponding to geometric mean (90%) urine concentrations of 5.42 (4.37-6.46) and 27.4 ng/mL (22.1-32.7). Tenofovir in urine reached 1500 ng/mL by 101 h (58.6-205) with an equivalent plasma concentration of 6.20 ng/mL (4.21-8.18). CONCLUSIONS: These data support use of a urinary tenofovir threshold of <1500 ng/mL (tenofovir disoproxil fumarate-based regimens) as a marker of three or more missed doses for a POCT platform. However, due to low dolutegravir concentrations in urine, POCT would be limited to a readout of recent dolutegravir intake (one missed dose).

Influenza A virus polymerase acidic protein E23G/K substitutions weaken key baloxavir drug-binding contacts with minimal impact on replication and transmission.

Baloxavir marboxil (BXM) is approved for treating uncomplicated influenza. The active metabolite baloxavir acid (BXA) inhibits cap-dependent endonuclease activity of the influenza virus polymerase acidic protein (PA), which is necessary for viral transcription. Treatment-emergent E23G or E23K (E23G/K) PA substitutions have been implicated in reduced BXA susceptibility, but their effect on virus fitness and transmissibility, their synergism with other BXA resistance markers, and the mechanisms of resistance have been insufficiently studied. Accordingly, we generated point mutants of circulating seasonal influenza A(H1N1)pdm09 and A(H3N2) viruses carrying E23G/K substitutions. Both substitutions caused 2- to 13-fold increases in the BXA EC50. EC50s were higher with E23K than with E23G and increased dramatically (138- to 446-fold) when these substitutions were combined with PA I38T, the dominant BXA resistance marker. E23G/K-substituted viruses exhibited slightly impaired replication in MDCK and Calu-3 cells, which was more pronounced with E23K. In ferret transmission experiments, all viruses transmitted to direct-contact and airborne-transmission animals, with only E23K+I38T viruses failing to infect 100% of animals by airborne transmission. E23G/K genotypes were predominantly stable during transmission events and through five passages in vitro. Thermostable PA-BXA interactions were weakened by E23G/K substitutions and further weakened when combined with I38T. In silico modeling indicated this was caused by E23G/K altering the placement of functionally important Tyr24 in the endonuclease domain, potentially decreasing BXA binding but at some cost to the virus. These data implicate E23G/K, alone or combined with I38T, as important markers of reduced BXM susceptibility, and such mutants could emerge and/or transmit among humans.

Efficient production of an antitumor precursor actinocin and other medicinal molecules from kynurenine pathway in Escherichia coli.

Kynurenine pathway has a potential to convert L-tryptophan into multiple medicinal molecules. This study aims to explore the biosynthetic potential of kynurenine pathway for the efficient production of actinocin, an antitumor precursor selected as a proof-of-concept target molecule. Kynurenine pathway is first constructed in Escherichia coli by testing various combinations of biosynthetic genes from four different organisms. Metabolic engineering strategies are next performed to improve the production by inhibiting a competing pathway, and enhancing intracellular supply of a cofactor S-adenosyl-L-methionine, and ultimately to produce actinocin from glucose. Metabolome analysis further suggests additional gene overexpression targets, which finally leads to the actinocin titer of 719 mg/L. E. coli strain engineered to produce actinocin is further successfully utilized to produce 350 mg/L of kynurenic acid, a neuroprotectant, and 1401 mg/L of 3-hydroxyanthranilic acid, an antioxidant, also from glucose. These competitive production titers demonstrate the biosynthetic potential of kynurenine pathway as a source of multiple medicinal molecules. The approach undertaken in this study can be useful for the sustainable production of molecules derived from kynurenine pathway, which are otherwise chemically synthesized.

Sex differences in the effectiveness and tolerability of dolutegravir plus rilpivirine as a switch strategy in people living with HIV.

INTRODUCTION: Dolutegravir + rilpivirine (DTG + RPV) is an effective antiretroviral therapy regimen approved in clinical guidelines as a switch therapy for virologically suppressed people with HIV. Our study aimed to compare the effectiveness and tolerability of DTG + RPV in women and men in real-world clinical practice. METHODS: This was a retrospective analysis of treatment-experienced people with HIV from a large HIV unit who switched to DTG + RPV. We analysed treatment effectiveness, rates of adverse events and discontinuation, and metabolic changes after 48 weeks of treatment. HIV-RNA levels <50 copies/mL were analysed at 48 weeks using both intention-to treat analysis (where missing data were interpreted as failures) and per-protocol analysis (excluding those with missing data or changes due to reasons other than virological failure). Outcomes were compared between women and men based on sex at birth. RESULTS: A total of 307 patients were selected (71 women and 236 men). No transgender people were included. At baseline, women had lived with HIV infection and received antiretroviral therapy for longer than men (23.2 vs 17.4 years and 18.9 vs 14.2 years, respectively). In the intention-to-treat analysis, 74.6% (95% confidence interval [CI] 63.4-83.3%) of women and 83.5% (95% CI 78.2-87.7) of men had HIV-RNA <50 copies/mL. In the per-protocol analysis, 96.4% (95% CI 87.7-99) of women and 99% (95% CI 98.9-99.7) of men had HIV-RNA levels <50 copies/mL. Two women and two men had HIV-RNA >50 copies/mL at 48 weeks. Discontinuation due to adverse events was more frequent in women than in men: 12.7% vs 7.2% (p < 0.02). Neuropsychiatric and gastrointestinal events were the most frequently reported. A median (interquartile range) weight gain of 1.9 kg (0-4.2) in women and 1.2 kg (-1-3.1) in men was reported (median of differences between baseline visit and week 48); the remaining changes in metabolic parameters were neutral. CONCLUSIONS: DTG + RPV exhibited good and similar virological effectiveness in women and men in real-world settings. However, poorer tolerability and more treatment interruptions were observed in women.