Characterization of a Novel CD4 Mimetic Compound YIR-821 against HIV-1 Clinical Isolates.

Small CD4-mimetic compound (CD4mc), which inhibits the interaction between gp120 with CD4, acts as an entry inhibitor and induces structural changes in the HIV-1 envelope glycoprotein trimer (Env) through its insertion within the Phe43 cavity of gp120. We recently developed YIR-821, a novel CD4mc, that has potent antiviral activity and lower toxicity than the prototype NBD-556. To assess the possibility of clinical application of YIR-821, we tested its antiviral activity using a panel of HIV-1 pseudoviruses from different subtypes. YIR-821 displayed entry inhibitor activity against 53.5% (21/40) of the pseudoviruses tested and enhanced neutralization mediated by coreceptor binding site (CoRBS) antibodies in 50% (16/32) of these. Furthermore, when we assessed the antiviral effects using a panel of pseudoviruses and autologous plasma IgG, enhancement of antibody-mediated neutralization activity was observed for 48% (15/31) of subtype B strains and 51% (28/55) of non-B strains. The direct antiviral activity of YIR-821 as an entry inhibitor was observed in 53% of both subtype B (27/51) and non-B subtype (40/75) pseudoviruses. Enhancement of antibody-dependent cellular cytotoxicity was also observed with YIR-821 for all six selected clinical isolates, as well as for the transmitted/founder (T/F) CH58 virus-infected cells. The sequence diversity in the CD4 binding site as well as other regions, such as the gp120 inner domain layers or gp41, may be involved in the multiple mechanisms related to the sensitive/resistant phenotype of the virus to YIR-821. Our findings may facilitate the clinical application of YIR-821. IMPORTANCE Small CD4-mimetic compound (CD4mc) interacts with the Phe43 cavity and triggers conformational changes, enhancing antibody-mediated neutralization and antibody-dependent cellular cytotoxicity (ADCC). Here, we evaluated the effect of YIR-821, a novel CD4mc, against clinical isolates, including both subtype B and non-B subtype viruses. Our results confirm the desirable properties of YIR-821, which include entry inhibition, enhancement of IgG-neutralization, binding, and ADCC, in addition to low toxicity and long half-life in a rhesus macaque model, that might facilitate the clinical application of this novel CD4mc. Our observation of primary viruses that are resistant to YIR-821 suggests that further development of CD4mcs with different structural properties is required.

Dose Individualization of Cefepime for Febrile Neutropenia in Patients With Lymphoma or Multiple Myeloma: Implications for Therapeutic Drug Monitoring.

BACKGROUND: Optimal cefepime dosing is a challenge because of its dose-dependent neurotoxicity. This study aimed to determine individualized cefepime dosing for febrile neutropenia in patients with lymphoma or multiple myeloma. METHODS: This prospective study enrolled 16 patients receiving cefepime at a dose of 2 g every 12 hours. Unbound concentrations were determined at 0.5 hours, 7.2 hours [at the 60% time point of the 12 hours administration interval (C7.2h)], and 11 hours (trough concentration) after the first infusion (rate: 2 g/h). The primary and secondary end points were the predictive performance of the area under the unbound concentration-time curve (AUC unbound ) and the effect of unbound cefepime pharmacokinetic parameters on clinical response, respectively. RESULTS: The mean (SD) AUC unbound was 689.7 (226.6) mcg h/mL, which correlated with C7.2h (R 2 = 0.90), and the Bayesian posterior AUC unbound using only the trough concentration (R 2 = 0.66). Although higher exposure was more likely to show a better clinical response, each parameter did not indicate a statistical significance between positive and negative clinical responses ( P = 0.0907 for creatinine clearance (Ccr), 0.2523 for C7.2h, 0.4079 for trough concentration, and 0.1142 for AUC unbound ). Cutoff values were calculated as 80.2 mL/min for Ccr (sensitivity: 0.889, specificity: 0.714), 18.6 mcg/mL for C7.2h (sensitivity: 0.571, specificity: 1.000), and 9.2 mcg/mL for trough concentration (sensitivity: 0.571, specificity: 1.000). When aiming for a time above 100% the minimum inhibitory concentration, both continuous infusion of 4 g/d and intermittent infusion of 2 g every 8 hours achieved a probability of approximately 100% at a minimum inhibitory concentration of 8 mcg/mL. CONCLUSIONS: Therapeutic drug monitoring by sampling at C7.2h or trough can facilitate rapid dose optimization. Continuous infusion of 4 g/d was recommended. Intermittent dosing of 2 g every 8 hours was alternatively suggested for patients with a Ccr of 60-90 mL/min.

Human retroviral antisense mRNAs are retained in the nuclei of infected cells for viral persistence.

Human retroviruses, including human T cell leukemia virus type 1 (HTLV-1) and HIV type 1 (HIV-1), encode an antisense gene in the negative strand of the provirus. Besides coding for proteins, the messenger RNAs (mRNAs) of retroviral antisense genes have also been found to regulate transcription directly. Thus, it has been proposed that retroviruses likely localize their antisense mRNAs to the nucleus in order to regulate nuclear events; however, this opposes the coding function of retroviral antisense mRNAs that requires a cytoplasmic localization for protein translation. Here, we provide direct evidence that retroviral antisense mRNAs are localized predominantly in the nuclei of infected cells. The retroviral 3' LTR induces inefficient polyadenylation and nuclear retention of antisense mRNA. We further reveal that retroviral antisense RNAs retained in the nucleus associate with chromatin and have transcriptional regulatory function. While HTLV-1 antisense mRNA is recruited to the promoter of C-C chemokine receptor type 4 (CCR4) and enhances transcription from it to support the proliferation of HTLV-1-infected cells, HIV-1 antisense mRNA is recruited to the viral LTR and inhibits sense mRNA expression to maintain the latency of HIV-1 infection. In summary, retroviral antisense mRNAs are retained in nucleus, act like long noncoding RNAs instead of mRNAs, and contribute to viral persistence.

Clonality of HIV-1- and HTLV-1-Infected Cells in Naturally Coinfected Individuals.

BACKGROUND: Coinfection with human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type 1 (HTLV-1) diminishes the value of the CD4+ T-cell count in diagnosing AIDS, and increases the rate of HTLV-1-associated myelopathy. It remains elusive how HIV-1/HTLV-1 coinfection is related to such characteristics. We investigated the mutual effect of HIV-1/HTLV-1 coinfection on their integration sites (ISs) and clonal expansion. METHODS: We extracted DNA from longitudinal peripheral blood samples from 7 HIV-1/HTLV-1 coinfected, and 12 HIV-1 and 13 HTLV-1 monoinfected individuals. Proviral loads (PVL) were quantified using real-time polymerase chain reaction (PCR). Viral ISs and clonality were quantified by ligation-mediated PCR followed by high-throughput sequencing. RESULTS: PVL of both HIV-1 and HTLV-1 in coinfected individuals was significantly higher than that of the respective virus in monoinfected individuals. The degree of oligoclonality of both HIV-1- and HTLV-1-infected cells in coinfected individuals was also greater than in monoinfected subjects. ISs of HIV-1 in cases of coinfection were more frequently located in intergenic regions and transcriptionally silent regions, compared with HIV-1 monoinfected individuals. CONCLUSIONS: HIV-1/HTLV-1 coinfection makes an impact on the distribution of viral ISs and clonality of virus-infected cells and thus may alter the risks of both HTLV-1- and HIV-1-associated disease.

A Small Molecule, ACAi-028, with Anti-HIV-1 Activity Targets a Novel Hydrophobic Pocket on HIV-1 Capsid.

The human immunodeficiency virus type 1 (HIV-1) capsid (CA) is an essential viral component of HIV-1 infection and an attractive therapeutic target for antivirals. Here, we report that a small molecule, ACAi-028, inhibits HIV-1 replication by targeting a hydrophobic pocket in the N-terminal domain of CA (CA-NTD). ACAi-028 is 1 of more than 40 candidate anti-HIV-1 compounds identified by in silico screening and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Our binding model showed that ACAi-028 interacts with the Q13, S16, and T19 amino acid residues, via hydrogen bonds, in the targeting pocket of CA-NTD. Using recombinant fusion methods, TZM-bl, time-of-addition, and colorimetric reverse transcriptase (RT) assays, the compound was found to exert anti-HIV-1 activity in the early stage between reverse transcription and proviral DNA integration, without any effect on RT activity in vitro, suggesting that this compound may affect HIV-1 core disassembly (uncoating) as well as a CA inhibitor, PF74. Moreover, electrospray ionization mass spectrometry (ESI-MS) also showed that the compound binds directly and noncovalently to the CA monomer. CA multimerization and thermal stability assays showed that ACAi-028 decreased CA multimerization and thermal stability via S16 or T19 residues. These results indicate that ACAi-028 is a new CA inhibitor by binding to the novel hydrophobic pocket in CA-NTD. This study demonstrates that a compound, ACAi-028, targeting the hydrophobic pocket should be a promising anti-HIV-1 inhibitor.

A Conformational Escape Reaction of HIV-1 against an Allosteric Integrase Inhibitor.

HIV-1 often acquires drug-resistant mutations in spite of the benefits of antiretroviral therapy (ART). HIV-1 integrase (IN) is essential for the concerted integration of HIV-1 DNA into the host genome. IN further contributes to HIV-1 RNA binding, which is required for HIV-1 maturation. Non-catalytic-site integrase inhibitors (NCINIs) have been developed as allosteric IN inhibitors, which perform anti-HIV-1 activity by a multimodal mode of action such as inhibition of the IN-lens epithelium-derived growth factor (LEDGF)/p75 interaction in the early stage and disruption of functional IN multimerization in the late stage of HIV-1 replication. Here, we show that IN undergoes an adaptable conformational change to escape from NCINIs. We observed that NCINI-resistant HIV-1 variants have accumulated 4 amino acid mutations by passage 26 (P26) in the IN-encoding region. We employed high-performance liquid chromatography (HPLC), thermal stability assays, and X-ray crystallographic analysis to show that some amino acid mutations affect the stability and/or dimerization interface of the IN catalytic core domains (CCDs), potentially resulting in the severely decreased multimerization of full-length IN proteins (IN undermultimerization). This undermultimerized IN via NCINI-related mutations was stabilized by HIV-1 RNA and restored to the same level as that of wild-type HIV-1 in viral particles. Recombinant HIV-1 clones with IN undermultimerization propagated similarly to wild-type HIV-1. Our study revealed that HIV-1 can eventually counteract NCINI-induced IN overmultimerization by IN undermultimerization as one of the escape mechanisms. Our findings provide information on the understanding of IN multimerization with or without HIV-1 RNA and may influence the development of anti-HIV-1 strategies.IMPORTANCE Understanding the mechanism of HIV-1 resistance to anti-HIV-1 drugs could lead to the development of novel drugs with increased efficiency, resulting in more effective ART. ART composed of more potent and long-acting anti-HIV-1 drugs can greatly improve drug adherence and also provide HIV-1 prevention such as preexposure prophylaxis. NCINIs with a multimodal mode of action exert potent anti-HIV-1 effects through IN overmultimerization during HIV-1 maturation. However, HIV-1 can acquire some mutations that cause IN undermultimerization to alleviate NCINI-induced IN overmultimerization. This undermultimerized IN was efficiently stabilized by HIV-1 RNA and restored to the same level as that of wild-type HIV-1. Our findings revealed that HIV-1 eventually acquires such a conformational escape reaction to overcome the unique NCINI actions. The investigation into drug-resistant mutations associated with HIV-1 protein multimerization may facilitate the elucidation of its molecular mechanism and functional multimerization, allowing us to develop more potent anti-HIV-1 drugs and unique treatment strategies.

Utility of the Rapid Antigen Detection Test E. histolytica Quik Chek for the Diagnosis of Entamoeba histolytica Infection in Nonendemic Situations.

Entamoeba histolytica infection is an increasingly common sexually transmitted infection in Japan. Currently, stool ova and parasite examination (O&P) is the only approved diagnostic method. Here, we assessed the utility of the commercially available rapid antigen detection test (Quik Chek) for E. histolytica A multicenter cross-sectional study was conducted. Stool samples that had been submitted for O&P were included. The samples were subjected to both Quik Chek and PCR, and the Quik Chek results were assessed in comparison with PCR as the reference standard. E. histolytica infection was confirmed in 5.8% (38/657) of the samples and comprised 20 diarrheal and 18 nondiarrheal cases. The overall sensitivity and specificity of Quik Chek were 44.7% (95% confidence interval, 30.1 to 60.3) and 99.8% (99.1 to 100), respectively. The sensitivity of Quik Chek was higher for diarrheal cases (60.0%) than for nondiarrheal cases (27.8%). Furthermore, the combined use of Quik Chek with O&P increased the sensitivity (78.9%), especially for diarrheal cases (up to 90%). The E. histolytica burden assessed by quantitative PCR was similar between Quik Chek-positive and -negative samples. The Quik Chek assay sensitivity was lower for cyst-containing stools than for trophozoite-containing stools, although it was shown that cultured E. histolytica clinical strains from Quik Chek-negative cyst-containing stools exhibited antigenicity in vitro The present study confirmed the high specificity of Quik Chek for E. histolytica infection. Combined use with O&P increased the sensitivity of detection, facilitating the use of Quik Chek in point-of-care settings in nonendemic situations.

C-5-Modified Tetrahydropyrano-Tetrahydofuran-Derived Protease Inhibitors (PIs) Exert Potent Inhibition of the Replication of HIV-1 Variants Highly Resistant to Various PIs, including Darunavir.

UNLABELLED: We identified three nonpeptidic HIV-1 protease inhibitors (PIs), GRL-015, -085, and -097, containing tetrahydropyrano-tetrahydrofuran (Tp-THF) with a C-5 hydroxyl. The three compounds were potent against a wild-type laboratory HIV-1 strain (HIV-1(WT)), with 50% effective concentrations (EC50s) of 3.0 to 49 nM, and exhibited minimal cytotoxicity, with 50% cytotoxic concentrations (CC50) for GRL-015, -085, and -097 of 80, >100, and >100 µM, respectively. All the three compounds potently inhibited the replication of highly PI-resistant HIV-1 variants selected with each of the currently available PIs and recombinant clinical HIV-1 isolates obtained from patients harboring multidrug-resistant HIV-1 variants (HIVMDR). Importantly, darunavir (DRV) was >1,000 times less active against a highly DRV-resistant HIV-1 variant (HIV-1DRV(R) P51); the three compounds remained active against HIV-1DRV(R) P51 with only a 6.8- to 68-fold reduction. Moreover, the emergence of HIV-1 variants resistant to the three compounds was considerably delayed compared to the case of DRV. In particular, HIV-1 variants resistant to GRL-085 and -097 did not emerge even when two different highly DRV-resistant HIV-1 variants were used as a starting population. In the structural analyses, Tp-THF of GRL-015, -085, and -097 showed strong hydrogen bond interactions with the backbone atoms of active-site amino acid residues (Asp29 and Asp30) of HIV-1 protease. A strong hydrogen bonding formation between the hydroxyl moiety of Tp-THF and a carbonyl oxygen atom of Gly48 was newly identified. The present findings indicate that the three compounds warrant further study as possible therapeutic agents for treating individuals harboring wild-type HIV and/or HIVMDR. IMPORTANCE: Darunavir (DRV) inhibits the replication of most existing multidrug-resistant HIV-1 strains and has a high genetic barrier. However, the emergence of highly DRV-resistant HIV-1 strains (HIVDRV(R) ) has recently been observed in vivo and in vitro. Here, we identified three novel HIV-1 protease inhibitors (PIs) containing a tetrahydropyrano-tetrahydrofuran (Tp-THF) moiety with a C-5 hydroxyl (GRL-015, -085, and -097) which potently suppress the replication of HIVDRV(R) . Moreover, the emergence of HIV-1 strains resistant to the three compounds was considerably delayed compared to the case of DRV. The C-5 hydroxyl formed a strong hydrogen bonding interaction with the carbonyl oxygen atom of Gly48 of protease as examined in the structural analyses. Interestingly, a compound with Tp-THF lacking the hydroxyl moiety substantially decreased activity against HIVDRV(R) . The three novel compounds should be further developed as potential drugs for treating individuals harboring wild-type and multi-PI-resistant HIV variants as well as HIVDRV(R) .

Partial Splenic Embolization in a Patient with Hemophilia A and Severe Thrombocytopenia: A Case Report.

We report a patient with hemophilia A who underwent partial splenic embolization (PSE) for severe thrombocytopenia secondary to portal hypertension-induced splenomegaly, resulting in a stable long-term quality of life. The patient was diagnosed with hemophilia A and unfortunately contracted human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) from blood products. He subsequently developed progressive splenomegaly due to portal hypertension from chronic HCV, resulting in severe thrombocytopenia. PSE was performed because he had occasional subcutaneous bleeding and needed to start interferon (IFN) and ribavirin (RBV) treatment for curing his HCV infection at that time. His platelet counts increased, and no serious adverse events were observed. Currently, he continues to receive outpatient treatment, regular factor VIII (FVIII) replacement therapy for hemophilia A, and antiretroviral therapy for HIV infection. Vascular embolization has been reported to be an effective and minimally invasive treatment for bleeding in hemophilia patients. PSE also provided him with a stable quality of life without the side effects of serious infections and thrombocytopenia relapses. We conclude that PSE is a promising therapeutic option for patients with hemophilia A.

Conversion of raltegravir carrying a 1,3,4-oxadiazole ring to a hydrolysis product upon pH changes decreases its antiviral activity.

Raltegravir (RAL), a human immunodeficiency virus (HIV)-1 integrase inhibitor, has been administered as part of antiretroviral therapy. Studies in patients with HIV-1 have shown high variability in the pharmacokinetics of RAL, and in healthy volunteers, coadministration of proton-pump inhibitors has been shown to increase the plasma RAL concentrations. Here, we found that RAL containing a 1,3,4-oxadiazole ring is converted to a hydrolysis product (H-RAL) with a cleaved 1,3,4-oxadiazole ring at pH 1.0 and 13.0 conditions in vitro, thereby reducing the anti-HIV activity of the drug. The inclusion of cyclodextrins (beta-cyclodextrin [ßCD], random methyl-ßCD [RAM-ßCD], and hydroxypropyl-ßCD [HP-ßCD]) can protect RAL from pH-induced changes. The conversion of RAL to H-RAL was detected by using various mass spectrometry analyses. The chromatogram of H-RAL increased in a time-dependent manner similar to another 1,3,4-oxadiazole-containing drug, zibotentan, using high-performance liquid chromatography. Oral bioavailability and target protein interactions of H-RAL were predicted to be lower than those of RAL. Moreover, H-RAL exhibited significantly reduced anti-HIV-1 activity, whereas combinations with ßCD, RAM-ßCD, and HP-ßCD attenuated this effect in cell-based assays. These findings suggest that ßCDs can potentially protect against the conversion of RAL to H-RAL under acidic conditions in the stomach, thereby preserving the anti-HIV-1 effect of RAL. Although clinical trials are needed for evaluation, we anticipate that protective devices such as ßCDs may improve the pharmacokinetics of RAL, leading to better treatment outcomes, including reduced dosing, long-term anti-HIV-1 activity, and deeper HIV-1 suppression.

CCR5 inhibitors: emergence, success, and challenges.

INTRODUCTION: The discovery of CC-chemokine receptor 5 (CCR5) as a human immunodeficiency virus type 1 (HIV-1) coreceptor opened a new avenue to exploit CCR5 as a potential target for the intervention of HIV-1's cellular entry. AREAS COVERED: Various small-molecule CCR5 inhibitors were identified in the last decade; however, maraviroc (MVC) is the only CCR5 inhibitor currently used in the clinic. Concerns and challenges that exist for wider clinical use of CCR5 inhibitors are discussed. EXPERT OPINION: Although MVC-containing regimens have been recommended for treatment-naïve patients, MVC appears to have been used as one of drugs for salvage therapy rather than for treating drug-naïve patients. This is apparently due to MVC's twice-daily dosing schedule. Another significant disadvantage is that a costly tropism assay must be performed prior to MVC treatment. The access to inexpensive, sensitive, and rapid tropism tests should be made easily available. Only a few novel CCR5 inhibitors are presently in the pipeline. Development of potent and metabolically-stable novel CCR5 inhibitors allowing once-daily dosing regimens is needed. Development of CXCR4 inhibitors should greatly improve the treatment options available to patients infected with X4- and/or dual-tropic HIV-1 strains in combination with a CCR5 inhibitor.

t6A and ms2t6A Modified Nucleosides in Serum and Urine as Strong Candidate Biomarkers of COVID-19 Infection and Severity.

SARS-CoV-2 infection alters cellular RNA content. Cellular RNAs are chemically modified and eventually degraded, depositing modified nucleosides into extracellular fluids such as serum and urine. Here we searched for COVID-19-specific changes in modified nucleoside levels contained in serum and urine of 308 COVID-19 patients using liquid chromatography-mass spectrometry (LC-MS). We found that two modified nucleosides, N6-threonylcarbamoyladenosine (t6A) and 2-methylthio-N6-threonylcarbamoyladenosine (ms2t6A), were elevated in serum and urine of COVID-19 patients. Moreover, these levels were associated with symptom severity and decreased upon recovery from COVID-19. In addition, the elevation of similarly modified nucleosides was observed regardless of COVID-19 variants. These findings illuminate specific modified RNA nucleosides in the extracellular fluids as biomarkers for COVID-19 infection and severity.

Clinical characteristics and treatment outcomes of carbapenem-resistant Enterobacterales infections in Japan.

OBJECTIVES: The dissemination of difficult-to-treat carbapenem-resistant Enterobacterales (CRE) is of great concern. We clarified the risk factors underlying CRE infection mortality in Japan. METHODS: We conducted a retrospective, multicentre, observational cohort study of patients with CRE infections at 28 university hospitals from September 2014 to December 2016, using the Japanese National Surveillance criteria. Clinical information, including patient background, type of infection, antibiotic treatment, and treatment outcome, was collected. The carbapenemase genotype was determined using PCR sequencing. Multivariate analysis was performed to identify the risk factors for 28-day mortality. RESULTS: Among the 179 patients enrolled, 65 patients (36.3%) had bloodstream infections, with 37 (20.7%) infections occurring due to carbapenemase-producing Enterobacterales (CPE); all carbapenemases were of IMP-type (IMP-1: 32, IMP-6: 5). Two-thirds of CPE were identified as Enterobacter cloacae complex. Combination therapy was administered only in 46 patients (25.7%), and the 28-day mortality rate was 14.3%. Univariate analysis showed that solid metastatic cancer, Charlson Comorbidity Index ≥3, bloodstream infection, pneumonia, or empyema, central venous catheters, mechanical ventilation, and prior use of quinolones were significant risk factors for mortality. Multivariate analysis revealed that mechanical ventilation (OR: 6.71 [1.42-31.6], P = 0.016), solid metastatic cancers (OR: 5.63 [1.38-23.0], P = 0.016), and bloodstream infections (OR: 3.49 [1.02-12.0], P = 0.046) were independent risk factors for 28-day mortality. CONCLUSION: The significant risk factors for 28-day mortality in patients with CRE infections in Japan are mechanical ventilation, solid metastatic cancers, and bloodstream infections.

Lowered Risk of Nephrotoxicity through Intervention against the Combined Use of Vancomycin and Tazobactam/Piperacillin: A Retrospective Cohort Study.

The combined use of vancomycin (VCM) and tazobactam/piperacillin (TAZ/PIPC) is a major risk factor for nephrotoxicity. We sought to evaluate interventions against the combined use of VCM and TAZ/PIPC. This retrospective cohort study involved patients who considered the combined use of VCM and TAZ/PIPC as a treatment. Patients that had either or both antimicrobials replaced were assigned to the intervention group, whereas those who were continued on combination therapy were assigned to the comparison group. The primary endpoint was the incidence of acute kidney injury (AKI). The survival rate of patients on day 30 was evaluated as the secondary endpoint. The comparison and intervention groups were composed of 65 and 68 patients, respectively, and the incidence rates of AKI were 44.6% and 17.6%, respectively. Cox proportional hazard analysis identified the intervention as the only independent factor against AKI development, with a hazard ratio of 0.282 (95% confidence interval [CI], 0.141 to 0.565). For the incidence of AKI of grade greater than 1, the hazard ratio was 0.114 (95% CI, 0.025 to 0.497). The survival rates on day 30 in the comparison and intervention groups were 92.3% and 91.2%, respectively, with a relative risk of 0.988 (95% CI, 0.892 to 1.094). The trough VCM concentration was not associated with the incidence of AKI in patients receiving the combination therapy. This study demonstrated that intervention against the combined use of VCM and TAZ/PIPC can lower the risk of nephrotoxicity. IMPORTANCE The combined use of vancomycin (VCM) and tazobactam/piperacillin (TAZ/PIPC) is a major risk factor for nephrotoxicity. We retrospectively evaluated interventions against the combined use of VCM and TAZ/PIPC. Patients for whom either or both antimicrobials were replaced were assigned to the intervention group (65 patients), whereas those who were continued on combination therapy were assigned to the comparison group (68 patients). The primary endpoint was the incidence of acute kidney injury (AKI). The incidence rates of AKI in the intervention and comparison groups were 44.6% and 17.6%, respectively. Cox proportional hazard analysis identified intervention as the only independent factor against AKI development, with a hazard ratio of 0.282 (95% confidence interval [CI], 0.141 to 0.565). In conclusion, this study demonstrated that intervention against the combined use of VCM and TAZ/PIPC can lower the risk of nephrotoxicity.

GRL-02031, a novel nonpeptidic protease inhibitor (PI) containing a stereochemically defined fused cyclopentanyltetrahydrofuran potent against multi-PI-resistant human immunodeficiency virus type 1 in vitro.

We generated a novel nonpeptidic protease inhibitor (PI), GRL-02031, by incorporating a stereochemically defined fused cyclopentanyltetrahydrofuran (Cp-THF) which exerted potent activity against a wide spectrum of human immunodeficiency virus type 1 (HIV-1) isolates, including multidrug-resistant HIV-1 variants. GRL-02031 was highly potent against laboratory HIV-1 strains and primary clinical isolates, including subtypes A, B, C, and E (50% effective concentration [EC(50)] range, 0.015 to 0.038 microM), with minimal cytotoxicity (50% cytotoxic concentration, >100 microM in CD4(+) MT-2 cells), although it was less active against two HIV-2 strains (HIV-2(EHO) and HIV-2(ROD)) (EC(50), approximately 0.60 microM) than against HIV-1 strains. GRL-02031 at relatively low concentrations blocked the infection and replication of each of the HIV-1(NL4-3) variants exposed to and selected by up to 5 microM of saquinavir, amprenavir, indinavir, nelfinavir, or ritonavir and 1 microM of lopinavir or atazanavir (EC(50) range, 0.036 to 0.14 microM). GRL-02031 was also potent against multi-PI-resistant clinical HIV-1 variants isolated from patients who had no response to the conventional antiretroviral regimens that then existed, with EC(50)s ranging from 0.014 to 0.042 microM (changes in the EC(50)s were less than twofold the EC(50) for wild-type HIV-1). Upon selection of HIV-1(NL4-3) in the presence of GRL-02031, mutants carrying L10F, L33F, M46I, I47V, Q58E, V82I, I84V, and I85V in the protease-encoding region and G62R (within p17), L363M (p24-p2 cleavage site), R409K (within p7), and I437T (p7-p1 cleavage site) in the gag-encoding region emerged. GRL-02031 was potent against a variety of HIV-1(NL4-3)-based molecular infectious clones containing a single primary mutation reported previously or a combination of such mutations, although it was slightly less active against HIV-1 variants containing consecutive amino acid substitutions: M46I and I47V or I84V and I85V. Structural modeling analysis demonstrated a distinct bimodal binding of GRL-02031 to protease, which may provide advantages to GRL-02031 in blocking the replication of a wide spectrum of HIV-1 variants resistant to PIs and in delaying the development of resistance of HIV-1 to GRL-02031. The present data warrant the further development of GRL-02031 as a potential therapeutic agent for the treatment of infections with primary and multidrug-resistant HIV-1 variants.

Potent activity of a nucleoside reverse transcriptase inhibitor, 4'-ethynyl-2-fluoro-2'-deoxyadenosine, against human immunodeficiency virus type 1 infection in a model using human peripheral blood mononuclear cell-transplanted NOD/SCID Janus kinase 3 knockout mice.

4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA), a recently discovered nucleoside reverse transcriptase inhibitor, exhibits activity against a wide spectrum of wild-type and multidrug-resistant clinical human immunodeficiency virus type 1 (HIV-1) isolates (50% effective concentration, 0.0001 to 0.001 microM). In the present study, we used human peripheral blood mononuclear cell-transplanted, HIV-1-infected NOD/SCID/Janus kinase 3 knockout mice for in vivo evaluation of the anti-HIV activity of EFdA. Administration of EFdA decreased the replication and cytopathic effects of HIV-1 without identifiable adverse effects. In phosphate-buffered saline (PBS)-treated mice, the CD4+/CD8+ cell ratio in the spleen was low (median, 0.04; range, 0.02 to 0.49), while that in mice receiving EFdA was increased (median, 0.65; range, 0.57 to 1.43). EFdA treatment significantly suppressed the amount of HIV-1 RNA (median of 9.0 x 10(2) copies/ml [range, 8.1 x 10(2) to 1.1 x 10(3) copies/ml] versus median of 9.9 x 10(4) copies/ml [range, 8.1 x 10(2) to 1.1 x 10(3) copies/ml]; P < 0.001), the p24 level in plasma (2.5 x 10(3) pg/ml [range, 8.2 x 10(2) to 5.6 x 10(3) pg/ml] versus 2.8 x 10(2) pg/ml [range, 8.2 x 10(1) to 6.3 x 10(2) pg/ml]; P < 0.001), and the percentage of p24-expressing cells in the spleen (median of 1.90% [range, 0.33% to 3.68%] versus median of 0.11% [range, 0.00% to 1.00%]; P = 0.003) in comparison with PBS-treated mice. These data suggest that EFdA is a promising candidate for a new age of HIV-1 chemotherapy and should be developed further as a potential therapy for individuals with multidrug-resistant HIV-1 variants.

Activity and structural analysis of GRL-117C: a novel small molecule CCR5 inhibitor active against R5-tropic HIV-1s.

CCR5 is a member of the G-protein coupled receptor family that serves as an essential co-receptor for cellular entry of R5-tropic HIV-1, and is a validated target for therapeutics against HIV-1 infections. In the present study, we designed and synthesized a series of novel small CCR5 inhibitors and evaluated their antiviral activity. GRL-117C inhibited the replication of wild-type R5-HIV-1 with a sub-nanomolar IC50 value. These derivatives retained activity against vicriviroc-resistant HIV-1s, but did not show activity against maraviroc (MVC)-resistant HIV-1. Structural modeling indicated that the binding of compounds to CCR5 occurs in the hydrophobic cavity of CCR5 under the second extracellular loop, and amino acids critical for their binding were almost similar with those of MVC, which explains viral cross-resistance with MVC. On the other hand, one derivative, GRL-10018C, less potent against HIV-1, but more potent in inhibiting CC-chemokine binding, occupied the upper region of the binding cavity with its bis-THF moiety, presumably causing greater steric hindrance with CC-chemokines. Recent studies have shown additional unique features of certain CCR5 inhibitors such as immunomodulating properties and HIV-1 latency reversal properties, and thus, continuous efforts in developing new CCR5 inhibitors with unique binding profiles is necessary.

2'-deoxy-4'-C-ethynyl-2-halo-adenosines active against drug-resistant human immunodeficiency virus type 1 variants.

One of the formidable challenges in therapy of infections by human immunodeficiency virus (HIV) is the emergence of drug-resistant variants that attenuate the efficacy of highly active antiretroviral therapy (HAART). We have recently introduced 4'-ethynyl-nucleoside analogs as nucleoside reverse transcriptase inhibitors (NRTIs) that could be developed as therapeutics for treatment of HIV infections. In this study, we present 2'-deoxy-4'-C-ethynyl-2-fluoroadenosine (EFdA), a second generation 4'-ethynyl inhibitor that exerted highly potent activity against wild-type HIV-1 (EC50 approximately 0.07 nM). EFdA retains potency toward many HIV-1 resistant strains, including the multi-drug resistant clone HIV-1A62V/V75I/F77L/F116Y/Q151M. The selectivity index of EFdA (cytotoxicity/inhibitory activity) is more favorable than all approved NRTIs used in HIV therapy. Furthermore, EFdA efficiently inhibited clinical isolates from patients heavily treated with multiple anti-HIV-1 drugs. EFdA appears to be primarily phosphorylated by the cellular 2'-deoxycytidine kinase (dCK) because: (a) the antiviral activity of EFdA was reduced by the addition of dC, which competes nucleosides phosphorylated by the dCK pathway, (b) the antiviral activity of EFdA was significantly reduced in dCK-deficient HT-1080/Ara-Cr cells, but restored after dCK transduction. Further, unlike other dA analogs, EFdA is completely resistant to degradation by adenosine deaminase. Moderate decrease in susceptibility to EFdA is conferred by a combination of three RT mutations (I142V, T165R, and M184V) that result in a significant decrease of viral fitness. Molecular modeling analysis suggests that the M184V/I substitutions may reduce anti-HIV activity of EFdA through steric hindrance between its 4'-ethynyl moiety and the V/I184 beta-branched side chains. The present data suggest that EFdA, is a promising candidate for developing as a therapeutic agent for the treatment of individuals harboring multi-drug resistant HIV variants.

Potent synergistic anti-human immunodeficiency virus (HIV) effects using combinations of the CCR5 inhibitor aplaviroc with other anti-HIV drugs.

Aplaviroc (AVC), an experimental CCR5 inhibitor, potently blocks in vitro the infection of R5-tropic human immunodeficiency virus type 1 (R5-HIV-1) at subnanomolar 50% inhibitory concentrations. Although maraviroc is presently clinically available, further studies are required to determine the role of CCR5 inhibitors in combinations with other drugs. Here we determined anti-HIV-1 activity using combinations of AVC with various anti-HIV-1 agents, including four U.S. Food and Drug Administration-approved drugs, two CCR5 inhibitors (TAK779 and SCH-C) and two CXCR4 inhibitors (AMD3100 and TE14011). Combination effects were defined as synergistic or antagonistic when the activity of drug A combined with B was statistically greater or less, respectively, than the additive effects of drugs A and A combined and drugs B and B combined by using the Combo method, described in this paper, which provides (i) a flexible choice of interaction models and (ii) the use of nonparametric statistical methods. Synergistic effects against R5-HIV-1(Ba-L) and a 50:50 mixture of R5-HIV-1(Ba-L) and X4-HIV-1(ERS104pre) (HIV-1(Ba-L/104pre)) were seen when AVC was combined with zidovudine, nevirapine, indinavir, or enfuvirtide. Mild synergism and additivity were observed when AVC was combined with TAK779 and SCH-C, respectively. We also observed more potent synergism against HIV-1(Ba-L/104pre) when AVC was combined with AMD3100 or TE14011. The data demonstrate a tendency toward greater synergism with AVC plus either of the two CXCR4 inhibitors compared to the synergism obtained with combinations of AVC and other drugs, suggesting that the development of effective CXCR4 inhibitors may be important for increasing the efficacies of CCR5 inhibitors.