Single-stranded siRNAs activate RNAi in animals.

The therapeutic utility of siRNAs is limited by the requirement for complex formulations to deliver them to tissues. If potent single-stranded RNAs could be identified, they would provide a simpler path to pharmacological agents. Here, we describe single-stranded siRNAs (ss-siRNAs) that silence gene expression in animals absent lipid formulation. Effective ss-siRNAs were identified by iterative design by determining structure-activity relationships correlating chemically modified single strands and Argonaute 2 (AGO2) activities, potency in cells, nuclease stability, and pharmacokinetics. We find that the passenger strand is not necessary for potent gene silencing. The guide-strand activity requires AGO2, demonstrating action through the RNAi pathway. ss-siRNA action requires a 5' phosphate to achieve activity in vivo, and we developed a metabolically stable 5'-(E)-vinylphosphonate (5'-VP) with conformation and sterioelectronic properties similar to the natural phosphate. Identification of potent ss-siRNAs offers an additional option for RNAi therapeutics and an alternate perspective on RNAi mechanism.

Neuronal HSF-1 coordinates the propagation of fat desaturation across tissues to enable adaptation to high temperatures in C. elegans.

To survive elevated temperatures, ectotherms adjust the fluidity of membranes by fine-tuning lipid desaturation levels in a process previously described to be cell autonomous. We have discovered that, in Caenorhabditis elegans, neuronal heat shock factor 1 (HSF-1), the conserved master regulator of the heat shock response (HSR), causes extensive fat remodeling in peripheral tissues. These changes include a decrease in fat desaturase and acid lipase expression in the intestine and a global shift in the saturation levels of plasma membrane's phospholipids. The observed remodeling of plasma membrane is in line with ectothermic adaptive responses and gives worms a cumulative advantage to warm temperatures. We have determined that at least 6 TAX-2/TAX-4 cyclic guanosine monophosphate (cGMP) gated channel expressing sensory neurons, and transforming growth factor ß (TGF-ß)/bone morphogenetic protein (BMP) are required for signaling across tissues to modulate fat desaturation. We also find neuronal hsf-1 is not only sufficient but also partially necessary to control the fat remodeling response and for survival at warm temperatures. This is the first study to show that a thermostat-based mechanism can cell nonautonomously coordinate membrane saturation and composition across tissues in a multicellular animal.

A phase Ib trial of mivavotinib (TAK-659), a dual SYK/FLT3 inhibitor, in patients with relapsed/refractory acute myeloid leukemia.

Mivavotinib (TAK-659) is an investigational type 1 tyrosine kinase inhibitor with dual activity against spleen tyrosine kinase (SYK) and FMS-like tyrosine kinase 3 (FLT3). We conducted a phase Ib study to investigate the safety, tolerability, and efficacy of mivavotinib in patients with refractory and/or relapsed (R/R) acute myeloid leukemia (AML). Both daily (QD) and twice daily (BID) dosing regimens were evaluated. A total of 43 patients were enrolled, and there were 5 complete responses (4 with incomplete count recovery). In the QD dosing regimen, the maximum tolerated dose (MTD) was not reached up to 160 mg QD per protocol; 140 mg QD was identified as the recommended phase II dose. In the BID dosing regimen, the MTD was 60 mg BID. Thirty patients (70%) experienced a bleeding event on study; the majority were grades 1 or 2, were resolved without mivavotinib modification, and were not considered related to study treatment. Eleven patients (26%) experienced grade ≥3 bleeding events, which were observed most frequently with the 80 mg BID dose. We conducted platelet aggregation studies to investigate the potential role of mivavotinib-mediated SYK inhibition on platelet function. The bleeding events observed may have been the result of several confounding factors, including AML disease status, associated thrombocytopenia, and high doses of mivavotinib. Overall, these findings indicate that the activity of mivavotinib in R/R AML is modest. Furthermore, any future clinical investigation of this agent should be undertaken with caution, particularly in thrombocytopenic patients, due to the potential bleeding risk of SYK inhibition. ClinicalTrials.gov: NCT02323113.

Obesity protects against sepsis-induced and norepinephrine-induced white adipose tissue browning.

Sepsis is a dysregulated systemic response to infection and can lead to organ damage and death. Obesity is a significant problem worldwide and affects outcomes from sepsis. Our laboratory demonstrated that white adipose tissue (WAT) undergoes browning during sepsis, a process whereby WAT adopts a brown adipose tissue phenotype. However, this browning process was not observed in obese mice during sepsis. White adipose tissue browning is detrimental in patients with burn injury and cancer. We hypothesize that norepinephrine (NE) induces WAT browning in nonobese mice but not in obese mice similarly to sepsis-induced WAT browning. Six-week-old C57BL/6 male mice were randomized to a high-fat diet or normal diet. After 6-7 wk of feeding, polymicrobial sepsis was induced by cecal ligation and puncture (CLP). Norepinephrine was administered intraperitoneally via osmotic minipumps for 18 h or 72 h (no CLP) at which time tissue and plasma were harvested. Controls were mice that underwent CLP (no NE) with 18-h harvest. A separate group of mice underwent pretreatment with NE or vehicle infusion for 72 h, CLP was performed, and at 18 h had tissue and plasma harvested. Sepsis resulted in significant weight loss in both nonobese and obese mice. NE treatment alone caused weight loss in obese mice. Septic nonobese mice had higher uncoupling protein-1 (UCP1) expression compared with control and obese septic mice. NE treatment increased UCP1 expression in nonobese, but not obese mice. NE-treated obese septic mice had lower lung myeloperoxidase (MPO) activity, alanine aminotransferase (ALT), aspartate aminotransferase (AST), TNFα, and IL-6 levels compared with NE-treated nonobese septic mice. Obesity protects mice from septic-induced and NE-induced WAT browning.NEW & NOTEWORTHY White adipose tissue browning is detrimental in patients with burn injury and cancer. WAT browning occurs in nonobese mice and can be induced by ß receptor norepinephrine infusion, but obese mice are resistant to sepsis-induced and norepinephrine-induced WAT browning. We propose that the lack of WAT browning and unchanged inflammatory cytokine response may contribute to the protection of obese mice from sepsis.

Randomised trial and open-label extension study of an anti-interleukin-6 antibody in Crohn's disease (ANDANTE I and II).

OBJECTIVE: Neutralising pro-inflammatory interleukin-6 (IL-6) may effectively treat Crohn's disease (CD). Effects of PF-04236921, an anti-IL-6 antibody, in adults with CD are reported. DESIGN: Parallel-group, dose-ranging, double-blind trial with 4-week screening and 12-week treatment periods. After induction, patients entered 28-week follow-up or 48-week open-label extension (OLE) with 28-week follow-up. Adults with confirmed CD and inadequate response to anti-tumour necrosis factor (TNF) therapy were included. Induction study: 249 patients randomised 1:1:1:1 to placebo, PF-04236921 10, 50 or 200 mg by subcutaneous injection on days 1 and 28. OLE study: PF-04236921 50 mg every 8 weeks up to six doses followed by 28-week follow-up. RESULTS: 247 patients were randomised and received treatment in the induction study. The 200 mg dose was discontinued due to safety findings in another study (NCT01405196) and was not included in the primary efficacy analysis. Crohn's Disease Activity Index (CDAI)-70 response rates with PF-04236921 50 mg were significantly greater than placebo at weeks 8 (49.3% vs 30.6%, P<0.05) and 12 (47.4% vs 28.6%, P<0.05) and met the primary end point. Week 12 CDAI remission rates with PF-04236921 50 mg and placebo were 27.4% and 10.9%, respectively (16.5% difference; P<0.05). 191 subjects received treatment in the OLE. Common treatment-emergent and serious adverse events in both studies included worsening CD, abdominal pain and nasopharyngitis. CONCLUSIONS: PF-04236921 50 mg induced clinical response and remission in refractory patients with moderate-to-severe CD following failure of anti-TNF therapy. GI abscess and perforation were observed, a specific focus of attention during future clinical development. TRIAL REGISTRATION NUMBER: NCT01287897 and NCT01345318.

Quantitative Translational Analysis of Brain Kynurenic Acid Modulation via Irreversible Kynurenine Aminotransferase II Inhibition.

Kynurenic acid (KYNA) plays a significant role in maintaining normal brain function, and abnormalities in KYNA levels have been associated with various central nervous system disorders. Confirmation of its causality in human diseases requires safe and effective modulation of central KYNA levels in the clinic. The kynurenine aminotransferases (KAT) II enzyme represents an attractive target for pharmacologic modulation of central KYNA levels; however, KAT II and KYNA turnover kinetics, which could contribute to the duration of pharmacologic effect, have not been reported. In this study, the kinetics of central KYNA-lowering effect in rats and nonhuman primates (NHPs, Cynomolgus macaques) was investigated using multiple KAT II irreversible inhibitors as pharmacologic probes. Mechanistic pharmacokinetic-pharmacodynamic analysis of in vivo responses to irreversible inhibition quantitatively revealed that 1) KAT II turnover is relatively slow [16-76 hours' half-life (t1/2)], whereas KYNA is cleared more rapidly from the brain (<1 hour t1/2) in both rats and NHPs, 2) KAT II turnover is slower in NHPs than in rats (76 hours vs. 16 hours t1/2, respectively), and 3) the percent contribution of KAT II to KYNA formation is constant (∼80%) across rats and NHPs. Additionally, modeling results enabled establishment of in vitro-in vivo correlation for both enzyme turnover rates and drug potencies. In summary, quantitative translational analysis confirmed the feasibility of central KYNA modulation in humans. Model-based analysis, where system-specific properties and drug-specific properties are mechanistically separated from in vivo responses, enabled quantitative understanding of the KAT II-KYNA pathway, as well as assisted development of promising candidates to test KYNA hypothesis in humans.

Pharmacokinetics and C-reactive protein modelling of anti-interleukin-6 antibody (PF-04236921) in healthy volunteers and patients with autoimmune disease.

AIMS: The purpose of this study was to characterize pharmacokinetics (PK) of PF-04236921, a novel anti-interleukin-6 monoclonal antibody, and its pharmacokinetic/pharmacodynamic (PK/PD) relationship on serum C-reactive protein (CRP) in healthy volunteers and patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and Crohn's disease (CD). METHODS: Population modelling analyses were conducted using nonlinear mixed effects modelling. Data from two phase 1 healthy volunteer studies, a phase 1 RA study, a Phase 2 CD study and a Phase 2 SLE study were included. RESULTS: A two-compartment model with first order absorption and linear elimination and a mechanism-based indirect response model adequately described the PK and PK/PD relationships, respectively. Central compartment volume of distribution (Vc) positively correlated with body weight. Clearance (CL) negatively correlated with baseline albumin concentration and positively correlated with baseline CRP and creatinine clearance, and was slightly lower in females. After correcting for covariates, CL in CD subjects was approximately 60% higher than other populations. Maximum inhibition of PF-04236921 on CRP production (Imax ) negatively correlated with baseline albumin. Imax positively correlated with baseline CRP and the relationship was captured as a covariance structure in the PK/PD model. CONCLUSION: Integrated population PK and PK/PD models of PF-04236921 have been developed using pooled data from healthy subjects and autoimmune patients. The current model enables simulation of PF-04236921 PK and PD profiles under various dosing regimens and patient populations and should facilitate future clinical study of PF-04236921 and other anti-interleukin-6 monoclonal antibodies.

Efficacy and safety of an interleukin 6 monoclonal antibody for the treatment of systemic lupus erythematosus: a phase II dose-ranging randomised controlled trial.

OBJECTIVES: This phase II trial evaluated the efficacy and safety of an interleukin (IL) 6 monoclonal antibody for systemic lupus erythematosus (SLE). METHODS: Patients with active disease were randomised to placebo or PF-04236921 10 mg, 50 mg or 200 mg, subcutaneously, every 8 weeks with stable background therapy. SLE Responder Index (SRI-4; primary end point) and British Isles Lupus Assessment Group-based Composite Lupus Assessment (BICLA) were assessed at week 24. Post hoc analysis identified an enriched population based upon planned univariate analyses. RESULTS: 183 patients received treatment (placebo, n=45; 10 mg, n=45; 50 mg, n=47; 200 mg, n=46). The 200 mg dose was discontinued due to safety findings and not included in the primary efficacy analysis. The SRI-4 response rates were not significant for any dose compared with placebo; however, the BICLA response rate was significant for 10 mg (p=0.026). The incidence of severe flares was significantly reduced with 10 mg (n=0) and 50 mg (n=2) combined versus placebo (n=8; p<0.01). In patients with greater baseline disease activity (enriched population), the SRI-4 (p=0.004) and BICLA (p=0.012) response rates were significantly different with 10 mg versus placebo. Four deaths (200 mg, n=3; 10 mg, n=1) occurred. The most frequently reported adverse events included headache, nausea and diarrhoea. CONCLUSIONS: PF-04236921 was not significantly different from placebo for the primary efficacy end point in patients with SLE. Evidence of an effect with 10 mg was seen in a post hoc analysis. Safety was acceptable for doses up to 50 mg as the 200 mg dose was discontinued due to safety findings. TRIAL REGISTRATION NUMBER: NCT01405196; Pre-results.

A sustained dietary change increases epigenetic variation in isogenic mice.

Epigenetic changes can be induced by adverse environmental exposures, such as nutritional imbalance, but little is known about the nature or extent of these changes. Here we have explored the epigenomic effects of a sustained nutritional change, excess dietary methyl donors, by assessing genomic CpG methylation patterns in isogenic mice exposed for one or six generations. We find stochastic variation in methylation levels at many loci; exposure to methyl donors increases the magnitude of this variation and the number of variable loci. Several gene ontology categories are significantly overrepresented in genes proximal to these methylation-variable loci, suggesting that certain pathways are susceptible to environmental influence on their epigenetic states. Long-term exposure to the diet (six generations) results in a larger number of loci exhibiting epigenetic variability, suggesting that some of the induced changes are heritable. This finding presents the possibility that epigenetic variation within populations can be induced by environmental change, providing a vehicle for disease predisposition and possibly a substrate for natural selection.

A phase Ib study evaluating the recommended phase II dose, safety, tolerability, and efficacy of mivavotinib in combination with nivolumab in advanced solid tumors.

Mivavotinib (TAK-659/CB-659), a dual SYK/FLT3 inhibitor, reduced immunosuppressive immune cell populations and suppressed tumor growth in combination with anti-PD-1 therapy in cancer models. This dose-escalation/expansion study investigated the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of mivavotinib plus nivolumab in patients with advanced solid tumors. Patients received oral mivavotinib 60-100 mg once-daily plus intravenous nivolumab 3 mg/kg on days 1 and 15 in 28-day cycles until disease progression or unacceptable toxicity. The dose-escalation phase evaluated the recommended phase II dose (RP2D; primary endpoint). The expansion phase evaluated overall response rate (primary end point) at the RP2D in patients with triple-negative breast cancer (TNBC). During dose-escalation (n = 24), two dose-limiting toxicities (grade 4 lipase increased and grade 3 pyrexia) occurred in patients who received mivavotinib 80 mg and 100 mg, respectively. The determined RP2D was once-daily mivavotinib 80 mg plus nivolumab 3 mg/kg. The expansion phase was terminated at ~50% enrollment (n = 17) after failing to meet an ad hoc efficacy futility threshold. Among all 41 patients, common treatment-emergent adverse events (TEAEs) included dyspnea (48.8%), aspartate aminotransferase increased, and pyrexia (46.3% each). Common grade ≥3 TEAEs were hypophosphatemia and anemia (26.8% each). Mivavotinib plasma exposure was generally dose-proportional (60-100 mg). One patient had a partial response. Mivavotinib 80 mg plus nivolumab 3 mg/kg was well tolerated with no new safety signals beyond those of single-agent mivavotinib or nivolumab. Low response rates highlight the challenges of treating unresponsive tumor types, such as TNBC, with this combination and immunotherapies in general. TRIAL REGISTRATION ID: NCT02834247.

Expanding the spectrum of IDH1 mutations in gliomas.

Mutations in isocitrate dehydrogenase -1 or -2 (IDH1 or IDH2) are found in the majority of WHO grade II and III diffuse gliomas and secondary glioblastomas. IDH mutation screening is rapidly becoming part of the routine pathological work up of human brain tumors, providing both diagnostic and prognostic information. Here, we characterize four rare and novel IDH1 mutations identified in surgical human glioma samples: two instances of an IDH1 p.R132S mutation caused by a previously undescribed dinucleotide deletion/insertion mutation, a novel homozygous somatic IDH1 p.R132L mutation, and an IDH1 p.R100Q mutation. Characterization of novel and rare IDH mutations may provide additional insight into the mechanisms of mutant IDH in neoplasia. Furthermore, given the clinical import of IDH status, these results highlight the need for comprehensive mutation screening, beyond the targeted identification of common pathogenic variants.

Glioma microvesicles carry selectively packaged coding and non-coding RNAs which alter gene expression in recipient cells.

Interactions between glioma cells and their local environment are critical determinants of brain tumor growth, infiltration and neovascularisation. Communication with host cells and stroma via microvesicles represents one pathway by which tumors can modify their surroundings to achieve a tumor-permissive environment. Here we have taken an unbiased approach to identifying RNAs in glioma-derived microvesicles, and explored their potential to regulate gene expression in recipient cells. We find that glioma microvesicles are predominantly of exosomal origin and contain complex populations of coding and noncoding RNAs in proportions that are distinct from those in the cells from which they are derived. Microvesicles show a relative depletion in microRNA compared with their cells of origin, and are enriched in unusual or novel noncoding RNAs, most of which have no known function. Short-term exposure of brain microvascular endothelial cells to glioma microvesicles results in many gene expression changes in the endothelial cells, most of which cannot be explained by direct delivery of transcripts. Our data suggest that the scope of potential actions of tumor-derived microvesicles is much broader and more complex than previously supposed, and highlight a number of new classes of small RNA that remain to be characterized.

Population Pharmacokinetics of Mivavotinib (TAK-659), a Dual Spleen Tyrosine Kinase and FMS-Like Tyrosine Kinase 3 Inhibitor, in Patients With Advanced Solid Tumors or Hematologic Malignancies.

Mivavotinib (TAK-659), an orally administered, small-molecule, dual inhibitor of spleen tyrosine kinase and FMS-like tyrosine kinase 3 (SYK/FLT3), is under development for the treatment of patients with advanced malignancies. In this analysis, we evaluated the population pharmacokinetics (PK) of mivavotinib and its sources of variability (covariates) in adult patients with advanced solid tumors, or relapsed/refractory B-cell lymphomas or acute myeloid leukemia, using pooled data from 159 patients enrolled in 2 phase 1/2 clinical studies. A 2-compartment model with first-order linear elimination and a first-order absorption rate (and associated lag time) adequately described the PK of mivavotinib in this patient population. The population estimates of apparent clearance (CL/F) and apparent central compartment volume (Vc /F) were 31.6 L/h and 893 L, respectively, resulting in a half-life of ≈20 hours. In the final model, creatinine clearance was included as a covariate of CL/F, and sex as a covariate of Vc /F. Simulations showed that steady-state exposure to mivavotinib increased with decreasing renal function. Expanding eligibility by enrolling patients with moderate renal impairment in phase 1 increased the diversity of patients in early trials and allowed the model to inform dose adjustment in patients with moderate renal impairment in future trials. In addition, simulations showed median steady-state trough concentration of mivavotinib following 70 mg twice daily and 160 mg daily dosing to be commensurate with 100 ng/mL, the level leading to >90% FLT3 inhibition per ex vivo plasma immune assays and considered a potential exposure threshold required for FLT3-driven efficacy.

Pharmacokinetic-pharmacodynamic modeling of the D2 and 5-HT (2A) receptor occupancy of risperidone and paliperidone in rats.

PURPOSE: A pharmacokinetic-pharmacodynamic (PK-PD) model was developed to describe the time course of brain concentration and dopamine D2 and serotonin 5-HT(2A) receptor occupancy (RO) of the atypical antipsychotic drugs risperidone and paliperidone in rats. METHODS: A population approach was utilized to describe the PK-PD of risperidone and paliperidone using plasma and brain concentrations and D2 and 5-HT(2A) RO data. A previously published physiology- and mechanism-based (PBPKPD) model describing brain concentrations and D2 receptor binding in the striatum was expanded to include metabolite kinetics, active efflux from brain, and binding to 5-HT(2A) receptors in the frontal cortex. RESULTS: A two-compartment model best fit to the plasma PK profile of risperidone and paliperidone. The expanded PBPKPD model described brain concentrations and D2 and 5-HT(2A) RO well. Inclusion of binding to 5-HT(2A) receptors was necessary to describe observed brain-to-plasma ratios accurately. Simulations showed that receptor affinity strongly influences brain-to-plasma ratio pattern. CONCLUSION: Binding to both D2 and 5-HT(2A) receptors influences brain distribution of risperidone and paliperidone. This may stem from their high affinity for D2 and 5-HT(2A) receptors. Receptor affinities and brain-to-plasma ratios may need to be considered before choosing the best PK-PD model for centrally active drugs.

Mechanism-based pharmacokinetic-pharmacodynamic modeling of the dopamine D2 receptor occupancy of olanzapine in rats.

PURPOSE: A mechanism-based PK-PD model was developed to predict the time course of dopamine D(2) receptor occupancy (D(2)RO) in rat striatum following administration of olanzapine, an atypical antipsychotic drug. METHODS: A population approach was utilized to quantify both the pharmacokinetics and pharmacodynamics of olanzapine in rats using the exposure (plasma and brain concentration) and D(2)RO profile obtained experimentally at various doses (0.01-40 mg/kg) administered by different routes. A two-compartment pharmacokinetic model was used to describe the plasma pharmacokinetic profile. A hybrid physiology- and mechanism-based model was developed to characterize the D(2) receptor binding in the striatum and was fitted sequentially to the data. The parameters were estimated using nonlinear mixed-effects modeling . RESULTS: Plasma, brain concentration profiles and time course of D(2)RO were well described by the model; validity of the proposed model is supported by good agreement between estimated association and dissociation rate constants and in vitro values from literature. CONCLUSION: This model includes both receptor binding kinetics and pharmacokinetics as the basis for the prediction of the D(2)RO in rats. Moreover, this modeling framework can be applied to scale the in vitro and preclinical information to clinical receptor occupancy.

The stability of chicken nucleoside triphosphate diphosphohydrolase 8 requires both of its transmembrane domains.

Chicken nucleoside triphosphate diphosphohydrolase 8 (NTPDase8) is a cell surface ectonucleotidase with a large extracellular domain (ECD) containing the active site and is anchored to the membrane by two transmembrane domains (TMDs) at the N- and C-termini. Unlike other cell surface NTPDases that have been characterized, the chicken NTPDase8 is not susceptible to substrate inactivation or agents that cause membrane perturbation. To determine if the stability of the enzyme is inherent in its ECD, the cDNA construct of the soluble chicken NTPDase8 was expressed and the protein purified. The ATPase activity of the purified soluble chicken NTPDase8 was less than 15% of that of the purified full-length enzyme. Strikingly, in contrast to the membrane-bound enzyme, the activity of the soluble chicken NTPDase8 decreased with time in a temperature-dependent manner as a result of inactivation by ATP, ADP, and P(i). Truncated mutants in which the ECD is anchored by a single TMD at either the N- or the C-terminus by the native chicken NTPDase TMDs or a TMD from a different NTPDase, human NTPDase2, also displayed a nonlinear time course of ATP hydrolysis. While removal of the N- or C-terminal TMD affected protein expression differently, the truncated mutants were generally similar to the soluble chicken NTPDase8 with respect to ATP, ADP, and P(i) inactivation. Other biochemical characteristics, e.g., ATPase/ADPase ratios, inhibition by azide, and affinity for ATP, were also altered when one or both of the TMDs were removed from the chicken NTPDase8. These results indicate that (1) both TMDs of the chicken NTPDase8 are required to maintain stability of the enzyme and maximal catalytic activity and (2) the conformations of the ectodomain in the soluble enzyme and the truncated mutants differ from that of the full-length chicken NTPDase8.

Population pharmacokinetic modeling of PF-06439535 (a bevacizumab biosimilar) and reference bevacizumab (Avastin®) in patients with advanced non-squamous non-small cell lung cancer.

PURPOSE: The objectives of this analysis were to characterize the population pharmacokinetics (PK) of PF-06439535 (a bevacizumab biosimilar) and reference bevacizumab (Avastin®) sourced from the European Union (bevacizumab-EU) in patients with advanced non-squamous non-small cell lung cancer (NSCLC), and to quantify the difference in PK parameters between the two drug products via covariate analysis. METHODS: Pooled PF-06439535 and bevacizumab-EU serum concentration data from a comparative clinical efficacy and safety study (NCT02364999) in patients with NSCLC (N = 719) were analyzed using a non-linear mixed-effects modeling approach. Patients received PF-06439535 plus chemotherapy or bevacizumab-EU plus chemotherapy every 21 days for 4-6 cycles, followed by monotherapy with PF-06439535 or bevacizumab-EU. PF-06439535 or bevacizumab-EU was administered intravenously at a dose of 15 mg/kg. Effects of patient and disease covariates, as well as the drug product (PF-06439535 versus bevacizumab-EU), on PK were investigated. RESULTS: Overall, 8632 serum bevacizumab concentrations from 351 patients in the PF-06439535 group and 354 patients in the bevacizumab-EU group were included in the analysis. A two-compartment model adequately described the combined data. Clearance (CL) and central volume of distribution (V1) estimates were 0.0113 L/h and 2.99 L for a typical 71-kg female patient with NSCLC administered bevacizumab-EU. CL and V1 increased with body weight and were higher in males than females even after accounting for differences in body weight. The 95% confidence intervals for the effect of drug product on CL and V1 encompassed unity. CONCLUSIONS: The population PK of PF-06439535 and bevacizumab-EU were well characterized by a two-compartment model. Covariate analysis did not reveal any appreciable differences between PK parameters for PF-06439535 and bevacizumab-EU in patients with NSCLC. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02364999.

Molecular epidemiology of hepatitis C genotype 6a from patients with chronic hepatitis C from Hong Kong.

There have been relatively few studies on HCV genotype 6 compared to hepatitis C virus (HCV) genotype 1. In Hong Kong, a city of about 7 million people, most patients infected with HCV are infected with either genotype 1b or 6a. It is known that HCV 6 is of intermediate responsiveness (i.e., between that of HCV genotype 1 and HCV genotypes 2/3) to standard combination interferon/ribavirin therapy. This study examines the molecular epidemiology of chronic HCV 6a infection in Hong Kong during 1999-2005, as well as characterizing some pre- and post-treatment changes in the NS5B gene in a few patients that underwent combination treatment. Partial non-structural protein sequences (NS5B, the viral RNA-dependent RNA polymerase gene, positions 397-1,082) were cloned and sequenced in samples from 51 patients that were obtained and archived during 1999-2005. There were three patients with paired pre- and post-treatment samples available for further analysis. Within this NS5B sequence, one significant amino acid mutation was found in each of these patients: Ser272Pro (end-of-treatment response but relapsed), Met312Thr (failed treatment after 3 months due to anemia), and Arg221Lys (end-of-treatment-response but relapsed). This analysis of the pre- and post-treatment NS5B sequences, suggests that whilst post-treatment mutations were identifiable in individual patients, there was no overall characteristic mutation pattern associated with treatment that was common to all treated patients, identified in this small study. Larger studies are required to confirm these findings.

Prevalence of diarrhea viruses in hospitalized children in Hong Kong in 2008.

A total of 209 stool samples were collected from pediatric patients admitted for acute gastroenteritis in a hospital in Hong Kong, during an 8-month period from January to August 2008, and were tested for the presence of rotavirus, norovirus, sapovirus, adenovirus, and astrovirus using a multiplex RT-PCR assay. The most common virus was rotavirus group A (59 of 209, 28%, mainly serotypes G1, G2, G3, and G9), followed by norovirus group II (48 of 209, 23%), adenovirus (7 of 209, 3%, serotypes 2, 3, and 41), and sapovirus (2 of 209, 1%). Interestingly, none of the specimens in this study were positive for astrovirus. One sample was found to have a dual infection with both norovirus group II and adenovirus. The results support the importance of norovirus as a causative agent of diarrhea in children, which may be underestimated by the current routine diagnostic testing.