Biochemical and Genetic Basis of Guanacastane Diterpene Biosynthesis in Basidiomycete Fungi.

Guanacastane diterpenoids with an unusual 5/7/6 tricyclic skeleton mainly produced by basidiomycete fungi represent a structurally intriguing class of natural products. While the chemical synthesis of several members has been achieved, the biochemical and genetic basis of their biosynthesis remain unknown. Herein, we present the identification and characterization of two crucial enzymes in the biosynthesis of guanacastane diterpenoids in Psathyrella candolleana. Heterologous expression reveals that PsaD, a typical class I diterpene synthase, catalyzes the cyclization of geranylgeranyl diphosphate to form a new guanacastane-type diterpene, guanacasta-1,3-diene (7). Moreover, we demonstrate that PsaA, a cytochrome P450 monooxygenase, can catalyze multiple oxidations of 7 to yield guanacastepene U (8). These results provide new opportunities for genome mining and metabolic engineering of guanacastane diterpenoids.

Psathyrins: Antibacterial Diterpenoids from Psathyrella candolleana.

Two skeletally novel tetracyclic diterpenoids, psathyrins A (1) and B (2), have been characterized from cultures of the basidiomycete Psathyrella candolleana. Their structures including absolute configurations were established by means of spectroscopic methods, as well as ECD calculations. They possess a novel 5/5/4/6-fuesd ring system, for which the biosynthetic pathway is proposed. Compounds 1 and 2 inhibited the growth of Staphylococcus aureus and Salmonella enterica.

Sesquiterpenoids from Cultures of the Basidiomycetes Irpex lacteus.

Eight previously undescribed sesquiterpenoids, tremutins A-H (1-8), together with three known ones (9-11), were isolated from cultures of the basidiomycetes Irpex lacteus. Structures of the new compounds together with absolute configurations were elucidated on the basis of extensive spectroscopic methods, as well as single-crystal X-ray diffractions and equivalent circulating density calculations. Compounds 1 and 2 possess an unusual 6/7-fused ring system that might be derived from a tremulane framework. Compounds 3-7 and 9-11 are tremulane sesquiterpenoids of which 4 and 5 are the first tremulane examples with a 1,2-epoxy moiety to be reported. Compounds 6, 7, 10, and 11 possess weak activities to several human cancer cell lines. Compound 8 shows a weak inhibitory effect on NO production with a half maximal inhibitory concentration (IC50) value of 22.7 µM. Compound 1 inhibits the lipopolysaccharide (LPS)-induced proliferation of B lymphocyte cells with an IC50 value of 22.4 µM, while 2 inhibits concanavalin A (Con A)-induced T cell proliferation and LPS-induced B lymphocyte cell proliferation with IC50 values of 16.7 and 13.6 µM, respectively.

Switching to bictegravir/emtricitabine/tenofovir alafenamide maintained HIV-1 RNA suppression in participants with archived antiretroviral resistance including M184V/I.

OBJECTIVES: Studies 1878 and 1844 demonstrated non-inferior efficacy of switching suppressed HIV-1-infected adults to bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) versus continuing boosted PI-based triple regimens or dolutegravir/abacavir/lamivudine (DTG/ABC/3TC). Here, detailed analyses of pre-existing resistance in the two BIC/FTC/TAF switch studies and efficacy at week 48 are described. METHODS: Pre-existing resistance was assessed from historical genotypes (documented resistance to study drugs was excluded) and by retrospective baseline proviral archive DNA genotyping from whole blood. Outcomes were based on HIV-1 RNA at week 48 with missing values imputed using the last on-treatment observation carried forward method. RESULTS: Cumulative pre-existing resistance data from historical and proviral genotypes were obtained for 95% (543/570) of participants who switched to BIC/FTC/TAF. Altogether, 40% (217/543) had one or more pre-existing primary resistance substitutions in protease, reverse transcriptase and/or integrase. Pre-switch NRTI resistance was detected in 16% (89/543) of BIC/FTC/TAF-treated participants, with M184V or M184I detected by proviral genotyping in 10% (54/543). At week 48, 98% (561/570) of all BIC/FTC/TAF-treated participants versus 98% (213/217) with pre-existing resistance and 96% (52/54) with archived M184V/I had HIV-1 RNA <50 copies/mL. No BIC/FTC/TAF-treated participants developed treatment-emergent resistance to study drugs. CONCLUSIONS: Pre-existing resistance substitutions, notably M184V/I, were unexpectedly common among suppressed participants who switched to BIC/FTC/TAF. High rates of virological suppression were maintained in the overall study population and in those with pre-existing resistance, including M184V/I, for up to 48 weeks of BIC/FTC/TAF treatment with no resistance development. These results indicate that BIC/FTC/TAF is an effective treatment option for suppressed patients, including those with evidence of archived NRTI resistance.

Cytotoxic ergosterols from cultures of the basidiomycete Psathyrella candolleana.

Three newly isolated ergosterols, psathergosterols A-C (1-3), together with two known ones (4 and 5), have been isolated from cultures of the basdiomycete Psathyrella candolleana. Their structures with the absolute configuration were elucidated by means of spectroscopic methods and the single crystal X-ray diffraction. Compounds 2-4 exhibited certain cytotoxicities to five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW480).

Efficacy and safety of switching to fixed-dose bictegravir, emtricitabine, and tenofovir alafenamide from boosted protease inhibitor-based regimens in virologically suppressed adults with HIV-1: 48 week results of a randomised, open-label, multicentre, phase 3, non-inferiority trial.

BACKGROUND: Switching from therapy based on a boosted protease inhibitor to bictegravir, emtricitabine, and tenofovir alafenamide could avoid drug interactions and unwanted side-effects in virologically suppressed adults with HIV-1 infection, while maintaining a high barrier to resistance and providing a simplified once-daily, single-tablet regimen. Here, we report 48 week results of a phase 3 study investigating this switch. METHODS: In this multicentre, randomised, open-label, active-controlled, non-inferiority, phase 3 trial, adults with HIV-1 infection were enrolled at 121 outpatient centres in ten countries. Eligible participants were aged 18 years or older, had an estimated glomerular filtration rate of 50 mL per min or higher, had been virologically suppressed (plasma HIV-1 RNA <50 copies per mL) for 6 months or more before screening, and were on a regimen consisting of boosted atazanavir or darunavir plus either emtricitabine and tenofovir disoproxil fumarate or abacavir and lamivudine. We randomly assigned participants (1:1), using a computer-generated randomisation sequence, to switch to co-formulated once-daily bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg), herein known as the bictegravir group, or to remain on their baseline boosted protease inhibitor regimen, herein known as the boosted protease inhibitor group, for 48 weeks. Randomisation was stratified by use of tenofovir disoproxil fumarate or abacavir at screening. The primary endpoint was the proportion of participants with plasma HIV-1 RNA of 50 copies per mL or higher at week 48 (by US Food and Drug Administration snapshot algorithm), with a prespecified non-inferiority margin of 4%. Efficacy and safety analyses included all participants who received at least one dose of study drug. This study is ongoing but not actively recruiting patients and is registered with ClinicalTrials.gov, number NCT02603107. FINDINGS: Between Dec 2, 2015, and July 15, 2016, 578 participants were randomly assigned and 577 were treated (290 in the bictegravir group and 287 in the boosted protease inhibitor group). At week 48, five participants (2%) in the bictegravir group and five (2%) in the boosted protease inhibitor group had plasma HIV-1 RNA of 50 copies per mL or higher (difference 0·0%, 95·002% CI -2·5 to 2·5), thus switching to the bictegravir regimen was non-inferior to continued boosted protease inhibitor therapy. The overall incidence and severity of adverse events was similar between groups, although headache occurred more frequently in the bictegravir group than in the boosted protease inhibitor group. 233 (80%) participants in the bictegravir group and 226 (79%) in the boosted protease inhibitor group had an adverse event. Only two (1%) participants in the bictegravir group and one (<1%) in the boosted protease inhibitor group discontinued treatment because of adverse events. 54 participants (19%) in the bictegravir group had drug-related adverse events compared with six (2%) in the protease inhibitor group. INTERPRETATION: Fixed-dose bictegravir, emtricitabine, and tenofovir alafenamide might be a safe and efficacious alternative to continued boosted protease inhibitor therapy in adults with HIV-1 infection. FUNDING: Gilead Sciences.

Superior Efficacy and Improved Renal and Bone Safety After Switching from a Tenofovir Disoproxil Fumarate- to a Tenofovir Alafenamide-Based Regimen Through 96 Weeks of Treatment.

We previously demonstrated superior efficacy and safety advantages in HIV-infected, virologically suppressed adults switched to a regimen containing tenofovir alafenamide (TAF) as compared with those remaining on a tenofovir disoproxil fumarate (TDF) regimen through week 48. We now report long-term data through week 96. In this randomized, active-controlled, multicenter, open-label, noninferiority trial (ClinicalTrials.gov No. NCT01815736), we randomized virologically suppressed (HIV-1 RNA <50 copies/ml) adults (2:1) to receive a once-daily, single-tablet regimen containing elvitegravir (EVG), cobicistat (COBI), emtricitabine (FTC), and TAF group or to continue one of four TDF-containing regimens (TDF group) for 96 weeks. We evaluated efficacy (HIV-1 RNA <50 copies/ml using the FDA snapshot algorithm) and prespecified bone and renal endpoints at week 96. We randomized and treated 1,436 participants in this study (TAF n = 959, TDF n = 477). At week 96, TAF was superior to TDF in virologic efficacy, with 93% on TAF and 89% on TDF having HIV-1 RNA <50 copies/ml (difference 3.7%, 95% confidence interval: 0.4%-7.0%). Improvements in hip and spine bone mineral density for those assigned to TAF versus TDF continued through week 96 (p < .001). Significant improvements in urine protein or albumin to creatinine ratios were also seen among those in the TAF group versus TDF through week 96 (p < .001). There were no cases of investigator-reported proximal renal tubulopathy in the TAF group as compared with one case in the TDF group. Switching to EVG/COBI/FTC/TAF (E/C/F/TAF) was associated with statistically significant efficacy and safety advantages over remaining on a standard-of-care TDF-based regimen.

Atazanavir Plus Cobicistat: Week 48 and Week 144 Subgroup Analyses of a Phase 3, Randomized, Double-Blind, Active-Controlled Trial.

OBJECTIVES: Cobicistat (COBI) enhances atazanavir (ATV) pharmacokinetic parameters similarly to ritonavir (RTV) in both healthy volunteers and HIV-infected adults. Primary efficacy and safety outcomes of this Phase 3, international, randomized, double-blind, double-dummy, active- controlled trial in HIV-1-infected treatment-naïve adults (GS-US-216-0114/NCT01108510) demonstrated that ATV+COBI was non-inferior to ATV+RTV, each in combination with emtricitabine/ tenofovir disoproxil fumarate (FTC/TDF), at Weeks 48 and 144, with high rates of virologic success for both regimens (85.2% and 87.4%, respectively, at Week 48; and 72.1% and 74.1% at Week 144), and with comparable safety and tolerability. Here, we describe virologic response and treatment discontinuation by a wider range of subgroups than previously presented. METHODS: Subgroup analyses by baseline CD4 count (≤200, 201-350, >350 cells/mm3), baseline HIV-1 RNA level (≤100,000, >100,000 copies/mL), race, sex, and age (<40, ≥40 years) evaluated ATV+COBI versus ATV+RTV univariate odds ratios (ORs) for virologic success (viral load <50 copies/mL, intention-to-treat US Food and Drug Administration Snapshot algorithm) and discontinuation due to adverse events (AEs) at Weeks 48 and 144. Of 692 patients randomized, 344 received ATV+COBI and 348 ATV+RTV. RESULTS: ATV+COBI versus ATV+RTV ORs for virologic success did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.90; 95% confidence interval [CI]: 0.64, 1.26) or within subgroups, except in females, for whom ATV+COBI was favored at Week 144 (OR 2.36; 95% CI: 1.02, 5.47). However, there were more discontinuations due to withdrawal of consent and pregnancies in females receiving ATV+RTV versus ATV+COBI. ORs for discontinuation due to AEs did not significantly differ by regimen overall at Weeks 48 and 144 (OR 0.98; 95% CI: 0.61, 1.58) or within subgroups. CONCLUSION: These findings indicate that both ATV+COBI and ATV+RTV, each with FTC/TDF, are effective and well-tolerated treatment options across a wide demographic range of HIV-infected patients.

Switching from tenofovir disoproxil fumarate to tenofovir alafenamide in antiretroviral regimens for virologically suppressed adults with HIV-1 infection: a randomised, active-controlled, multicentre, open-label, phase 3, non-inferiority study.

BACKGROUND: Antiretroviral regimens containing tenofovir disoproxil fumarate have been associated with renal toxicity and reduced bone mineral density. Tenofovir alafenamide is a novel tenofovir prodrug that reduces tenofovir plasma concentrations by 90%, thereby decreasing off-target side-effects. We aimed to assess whether efficacy, safety, and tolerability were non-inferior in patients switched to a regimen containing tenofovir alafenamide versus in those remaining on one containing tenofovir disoproxil fumarate. METHODS: In this randomised, actively controlled, multicentre, open-label, non-inferiority trial, we recruited HIV-1-infected adults from Gilead clinical studies at 168 sites in 19 countries. Patients were virologically suppressed (HIV-1 RNA <50 copies per mL) with an estimated glomerular filtration rate of 50 mL per min or greater, and were taking one of four tenofovir disoproxil fumarate-containing regimens for at least 96 weeks before enrolment. With use of a third-party computer-generated sequence, patients were randomly assigned (2:1) to receive a once-a-day single-tablet containing elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir alafenamide 10 mg (tenofovir alafenamide group) or to carry on taking one of four previous tenofovir disoproxil fumarate-containing regimens (tenofovir disoproxil fumarate group) for 96 weeks. Randomisation was stratified by previous treatment regimen in blocks of six. Patients and treating physicians were not masked to the assigned study regimen; outcome assessors were masked until database lock. The primary endpoint was the proportion of patients who received at least one dose of study drug who had undetectable viral load (HIV-1 RNA <50 copies per mL) at week 48. The non-inferiority margin was 12%. This study was registered with ClinicalTrials.gov, number NCT01815736. FINDINGS: Between April 12, 2013 and April 3, 2014, we enrolled 1443 patients. 959 patients were randomly assigned to the tenofovir alafenamide group and 477 to the tenofovir disoproxil fumarate group. Viral suppression at week 48 was noted in 932 (97%) patients assigned to the tenofovir alafenamide group and in 444 (93%) assigned to the tenofovir disoproxil fumarate group (adjusted difference 4·1%, 95% CI 1·6-6·7), with virological failure noted in ten and six patients, respectively. The number of adverse events was similar between the two groups, but study drug-related adverse events were more common in the tenofovir alafenamide group (204 patients [21%] vs 76 [16%]). Hip and spine bone mineral density and glomerular filtration were each significantly improved in patients in the tenofovir alafenamide group compared with those in the tenofovir disoproxil fumarate group. INTERPRETATION: Switching to a tenofovir alafenamide-containing regimen from one containing tenofovir disoproxil fumarate was non-inferior for maintenance of viral suppression and led to improved bone mineral density and renal function. Longer term follow-up is needed to better understand the clinical impact of these changes. FUNDING: Gilead Sciences.

Long-term efficacy and safety of tenofovir disoproxil fumarate in HIV-1-infected adolescents failing antiretroviral therapy: the final results of study GS-US-104-0321.

BACKGROUND: Reports of long-term tenofovir disoproxil fumarate (TDF) treatment in HIV-infected adolescents are limited. We present final results from the open-label (OL) TDF extension following the randomized, placebo (PBO)-controlled, double-blind phase of GS-US-104-0321 (Study 321). METHODS: HIV-infected 12- to 17-year-olds treated with TDF 300 mg or PBO with an optimized background regimen (OBR) for 24-48 weeks subsequently received OL TDF plus OBR in a single arm study extension. HIV-1 RNA and safety, including bone mineral density (BMD), was assessed in all TDF recipients. RESULTS: Eighty-one subjects received TDF (median duration 96 weeks). No subject died or discontinued OL TDF for safety/tolerability. At week 144, proportions with HIV-1 RNA <50 copies/mL were 30.4% (7 of 23 subjects with baseline HIV-1 RNA >1000 c/mL initially randomized to TDF), 41.7% (5 of 12 subjects with HIV-1 RNA <1000 c/mL who switched PBO to TDF) and 0% (0 of 2 subjects failed randomized PBO plus OBR with HIV-1 RNA >1000 c/mL and switched PBO to TDF). Viral resistance to TDF occurred in 1 subject. At week 144, median decrease in estimated glomerular filtration rate was 38.1 mL/min/1.73 m (n = 25). Increases in median spine (+12.70%, n = 26) and total body less head BMD (+4.32%, n = 26) and height-age adjusted Z-scores (n = 21; +0.457 for spine, +0.152 for total body less head) were observed at week 144. Five of 81 subjects (6%) had persistent >4% BMD decreases from baseline. CONCLUSIONS: Some subjects had virologic responses to TDF plus OBR, and TDF resistance was rare. TDF was well tolerated and can be considered for treatment of HIV-infected adolescents.

A randomized phase 3 study comparing once-daily elvitegravir with twice-daily raltegravir in treatment-experienced subjects with HIV-1 infection: 96-week results.

: This 96-week, double-blind, active-controlled, phase 3 study, randomized subjects to elvitegravir once daily or raltegravir twice daily with a fully active, ritonavir-boosted protease inhibitor plus a third agent. The proportion of subjects randomized to elvitegravir that achieved and maintained HIV-1 RNA < 50 copies/mL through week 96 was 47.6% (167/351) compared with 45.0% (158/351) for raltegravir with a treatment difference of 2.6% (95% confidence interval: 4.6% to 9.9%). Both regimens were well tolerated, with comparable rates of adverse events and laboratory abnormalities through week 96. Once-daily elvitegravir was noninferior to twice-daily raltegravir, showed durable long-term efficacy, and was well tolerated in HIV+ treatment-experienced patients.

[ABA signaling mediated by PYR/PYL/RCAR in plants].

Abscisic acid (ABA) is a phytohormone that plays critical roles in numerous developmental stages as well as in adaptive responses to biotic and abiotic stresses. Recent breakthroughs in the field of ABA signaling have indicated that there are three major components, PYR/PYL/RCAR (an ABA receptor), type 2C protein phosphates (PP2C, a negative regulator), and SNF1-related protein kinase 2 (SnRK2, a positive regulator). Further results show that these three proteins construct a double negative regulatory system, PYR/PYL/RCAR-| PP2C-| SnRK2, to regulate ABA signal responses in plant cells. Moreover, the combination patterns of these components in vivo are restricted by spatio-temporal and biochemical determinants and the combinational variation in the ABA signalosome is specific to different ABA signal responses. This review summarizes recent advances of study on the molecular basis and regulatory mechanism of PYR/PYL/RCAR-mediated ABA signaling pathway and PYR/PYL/RCAR-PP2C-SnRK2 complex-mediated ABA signal regulation network in plants. The perspectives related to this study are proposed.

A randomized study of tenofovir disoproxil fumarate in treatment-experienced HIV-1 infected adolescents.

BACKGROUND: There are few data on the safety and antiviral activity of tenofovir disoproxil fumarate (TDF) in HIV-1 infected adolescents. METHODS: A randomized, double-blinded, placebo-controlled study was conducted. Ninety adolescents (12 to <18 years) who were viremic while receiving antiretroviral treatment were randomized to receive TDF 300 mg (mean, 216.8 mg/m(2)) or placebo in combination with an optimized background regimen (OBR) for 48 weeks. The primary efficacy endpoint was time-weighted average change in plasma HIV-1 RNA from baseline at week 24 RESULTS: Eighty-seven subjects (45 TDF, 42 placebo) received the study drug. Through week 24, the median time-weighted average change in plasma HIV-1 RNA was not different between the TDF and placebo groups (-1.6 versus -1.6 log(10)copies/mL, P = 0.55). The percentages of subjects who achieved HIV-1 RNA <400 copies/mL were similar at week 24 (40.9 versus 41.5%). One fourth of subjects in the TDF and placebo groups (24.4 versus 28.6%) had at least 3 active agents in the OBR. Many subjects in both groups had baseline genotypic resistance to TDF (48.9 versus 33.3%). TDF was generally safe and well tolerated. There were no statistically significant differences in changes of renal function and bone mineral density between the 2 groups. CONCLUSION: This study of TDF in combination with an OBR in antiretroviral-experienced adolescents did not meet its primary or secondary efficacy endpoints. The effectiveness of the OBR and baseline genotypic resistance to TDF in both groups may have confounded the efficacy findings. No clinically relevant TDF-related renal or bone toxicities were observed in this adolescent population.

Efficacy and safety of once daily elvitegravir versus twice daily raltegravir in treatment-experienced patients with HIV-1 receiving a ritonavir-boosted protease inhibitor: randomised, double-blind, phase 3, non-inferiority study.

BACKGROUND: Elvitegravir is a once daily inhibitor of HIV-1 integrase boosted by ritonavir. We aimed to compare the efficacy and safety of elvitegravir with raltegravir, another HIV-1 integrase inhibitor, in patients in whom previous antiretroviral treatment failed. METHODS: We conducted a randomised, double-blind, double-dummy, phase 3 study at 234 sites in 13 countries. Eligible patients had plasma HIV RNA of 1000 copies per mL or greater, any CD4 cell count, and resistance to or 6 months' experience with at least two classes of antiretroviral drugs. They received an open-label background regimen of a fully active, ritonavir-boosted protease inhibitor and a second agent. We randomly allocated patients (1:1) by computer with a block size of four to receive either elvitegravir 150 mg once daily (n=361; 85 mg dose if given with atazanavir, or lopinavir with ritonavir) or raltegravir 400 mg twice daily (n=363). Placebo tablets were given to mask the difference in daily dosing. The primary endpoint was achievement and maintenance of virological response (HIV RNA <50 copies per mL) through week 48. Non-inferiority was prespecified with a margin of 10%. We did a modified intention-to-treat analysis. This study is registered with ClinicalTrials.gov, number NCT00708162. FINDINGS: Ten patients allocated elvitegravir and 12 assigned raltegravir were excluded from the analysis (either for protocol violations or because they did not receive treatment). 207 (59%) of 351 patients allocated elvitegravir achieved virological response compared with 203 (58%) of 351 assigned raltegravir (treatment difference 1·1%, 95% CI -6·0 to 8·2), meeting the criterion for non-inferiority (p=0·001). Three patients allocated elvitegravir had serious adverse events related to study drugs compared with seven assigned raltegravir; two and eight patients died, respectively. More individuals assigned elvitegravir reported diarrhoea up to week 48 (p=0·023), and more patients assigned raltegravir had grade 3 or 4 rises in alanine aminotransferase (p=0·020) or aspartate aminotransferase (p=0·009). INTERPRETATION: Elvitegravir used in combination with a ritonavir-boosted protease inhibitor in treatment-experienced patients has similar efficacy and safety to raltegravir. Since elvitegravir can be given once a day compared with twice a day for raltegravir, elvitegravir might improve patients' adherence. FUNDING: Gilead Sciences.

Comparison of intravenous pamidronate to standard therapy for osteoporosis: use in patients unable to take oral bisphosphonates.

BACKGROUND: Bisphosphonates are potent therapies for osteoporosis, but some patients cannot tolerate oral forms. Our study sought to examine the effectiveness and safety of intravenous pamidronate as an alternate osteoporotic therapy in these patients. METHODS: We conducted a retrospective study of 26 patients treated with intermittent, intravenous pamidronate (30 mg every 3 months) and 52 matched controls treated with standard therapy, all with osteoporosis. Primary outcome was response to therapy, defined as either stabilization or increase in bone mineral density. Secondary outcomes were patient safety and tolerability. RESULTS: At an average of 16.1 months of follow up, 64% of pamidronate-treated patients responded to therapy at the lumbar spine, 65% at the femoral neck, and 63% at the trochanter. These response rates were not significantly different than those of the standard care group in which 69% were receiving oral bisphosphonates. Adverse events were uncommon and included mild, diffuse myalgias and flu-like symptoms. CONCLUSIONS: Intravenous pamidronate is a well-tolerated osteoporosis therapy that has an effect on bone density comparable to standard therapy in patients unable to take oral bisphosphonates.