International multicenter validation of GES score for HCC risk stratification in chronic hepatitis C patients.

We have recently demonstrated the ability of a simple predictive model (GES) score to determine the risk of hepatocellular carcinoma (HCC) after using direct-acting antivirals. However, our results were restricted to Egyptian patients with hepatitis C virus (HCV) genotype 4. Therefore, we studied a large, independent cohort of multiethnic populations through our international collaborative activity. Depending on their GES scores, patients are stratified into low risk (≤ 6/12.5), intermediate risk (> 6-7.5/12.5), and high risk (> 7.5/12.5) for HCC. A total of 12,038 patients with chronic HCV were analyzed in this study, of whom 11,202 were recruited from 54 centers in France, Japan, India, the U.S., and Spain, and the remaining 836 were selected from the Gilead-sponsored randomized controlled trial conducted across the U.S., Europe, Canada, and Australia. Descriptive statistics and log-rank tests. The performance of the GES score was evaluated using Harrell's C-index (HCI). The GES score proved successful at stratifying all patients into 3 risk groups, namely low-risk, intermediate-risk, and high-risk. It also displayed significant predictive value for HCC development in all participants (p < .0001), with HCI ranging from 0.55 to 0.76 among all cohorts after adjusting for HCV genotypes and patient ethnicities. The GES score can be used to stratify HCV patients into 3 categories of risk for HCC, namely low-risk, intermediate-risk, and high-risk, irrespective of their ethnicities or HCV genotypes. This international multicenter validation may allow the use of GES score in individualized HCC risk-based surveillance programs.

Sofosbuvir and risk of estimated glomerular filtration rate decline or end-stage renal disease in patients with renal impairment.

BACKGROUND: Sofosbuvir, a prodrug nucleoside inhibitor of hepatitis C virus, has a predominant circulating metabolite that is renally eliminated. Whether sofosbuvir is associated with chronic kidney disease (CKD) progression is not well understood. METHODS: We performed a retrospective analysis of patients with estimated glomerular filtration rate (eGFR) 30-89 mL/min/1.73 m2 treated with sofosbuvir in 76 Phase 2/3 registrational trials. We evaluated eGFR at each study visit. Separately, we performed a retrospective analysis of an administrative claims database (IQVIA PharMetrics Plus™) to compare the risk of incident end-stage renal disease (ESRD) associated with the use of sofosbuvir or non-sofosbuvir regimens among patients with CKD using propensity score methods. Exposure, CKD status and outcomes were determined using diagnosis and medication claim codes. Cox proportional hazards methods were used to estimate ESRD risk. RESULTS: Among 4642 trial participants with baseline stage 2 CKD (eGFR 60-89 ml/min/1.73 m2 ) and 682 trial participants with stage 3 CKD (eGFR 30-59 ml/min/1.73 m2 ) mean (SD) eGFR improved from baseline to 4 weeks post-treatment (+0.7 [9.3] and +2.6 [8.8] ml/min/1.73 m2 , respectively; p < 0.001 each). In the second analysis, among 2042 patients with CKD receiving sofosbuvir-based regimens compared to 431 receiving non-sofosbuvir-based regimens, after adjusting for baseline covariates and weighting based on treatment propensity scores, there was no significant difference in risk of ESRD (adjusted HR = 0.85, 95% CI: 0.51-1.42). CONCLUSIONS: Clinical trial participants with CKD did not experience worsening eGFR during sofosbuvir-based treatment, and sofosbuvir was not associated with an increased risk of ESRD in patients with CKD in a nationally-representative administrative claims database.

Exposure-response relationships for the efficacy and safety of filgotinib and its metabolite GS-829845 in subjects with rheumatoid arthritis based on phase 2 and phase 3 studies.

AIMS: Filgotinib is a potent, oral, JAK1-preferential inhibitor for the treatment of rheumatoid arthritis (RA). This report describes exposure-response (ER) analyses of filgotinib for dose confirmation based on three phase 3 and two phase 2 studies in moderate to severe RA patients. METHODS: The pharmacokinetic exposures used in ER analyses were derived from population pharmacokinetic analysis. The exposure-efficacy relationships were assessed for efficacy endpoints (ACR20/50/70 and DAS28) over effective area under curve (AUCeff ), the combined exposures of filgotinib and GS-829845 (major, active metabolite), with nonlinear logistic regression models developed. Also, a t-test was performed to compare the exposure between subjects who achieved response and those who did not. For the ER analyses of safety, exposures were examined between subjects who experienced and who did not experience the evaluated safety events, which was conducted separately for filgotinib and GS-829845. RESULTS: The nonlinear logistic regression showed increasing response with increasing exposure, with exposures at 200 mg dose primarily residing on the curve plateau. Also, AUCeff was significantly higher in the subjects who achieved responses compared to those who did not (10 900 vs 9900 h*ng/mL for ACR20, P value < .0001). For exposure-safety analyses, filgotinib and GS-829845 exposures were similar irrespective of the presence/absence of the evaluated safety endpoints, indicating no exposure-safety relationship for common treatment-emergent adverse events (TEAEs)/laboratory abnormalities and serious TEAEs/infections. CONCLUSIONS: ER analyses confirmed that filgotinib produced more robust therapeutic effects across the exposure range observed at 200 mg once daily compared to lower doses, and collectively with the lack of exposure-safety relationship, the 200 mg once daily dose was supported for commercialization.

Sofosbuvir-Based Direct-Acting Antiviral Therapies for HCV in People Receiving Opioid Substitution Therapy: An Analysis of Phase 3 Studies.

BACKGROUND: Hepatitis C virus (HCV) direct-acting antiviral therapy is effective among people receiving opioid substitution therapy (OST), but studies are limited by small numbers of nongenotype 1 (GT1) patients. The aim of this study was to evaluate the treatment completion, adherence, SVR12, and safety of sofosbuvir-based therapies in HCV patients receiving and not receiving OST. METHODS: Ten phase 3 studies of sofosbuvir-based regimens included ION (ledipasvir/sofosbuvir ± ribavirin for 8, 12, or 24 weeks in GT1), ASTRAL (sofosbuvir/velpatasvir for 12 weeks in GT1-6), and POLARIS (sofosbuvir/velpatasvir and sofosbuvir/velpatasvir/voxilaprevir in GT1-6). Patients with clinically significant drug use (last 12 months) or noncannabinoids detected at screening were ineligible. RESULTS: Among 4743 patients, 4% (n = 194) were receiving OST (methadone; n = 113; buprenorphine, n = 75; other, n = 6). Compared with those not receiving OST (n = 4549), those receiving OST (n = 194) were younger (mean age, 48 vs 54), more often male (73% vs 61%), GT3 (38% vs 17%), treatment-naïve (78% vs 65%), and cirrhotic (36% vs 23%). Among those receiving and not receiving OST, there was no significant difference in treatment completion (97% vs 99%, P = .06), SVR12 (94% vs 97%, P = .06), relapse (0.5% vs 2.1%, P = .19), adverse events (78% vs 77%, P = .79), or serious adverse events (3.6% vs 2.4%, P = .24). There was no difference in SVR12 in patients with cirrhosis (99% vs 95%, P = .25) or those with G3 (95% vs 95%, P = .77) in those receiving OST. Among patients receiving OST, SVR12 was high among those receiving methadone (95%) and buprenorphine (96%). CONCLUSION: Sofosbuvir-based therapies are effective and safe in patients receiving OST.

Ledipasvir/sofosbuvir for treatment of hepatitis C virus in sofosbuvir-experienced, NS5A treatment-naïve patients: Findings from two randomized trials.

BACKGROUND & AIMS: We report data from two similarly designed studies that evaluated the efficacy, safety, and optimal duration of ledipasvir/sofosbuvir (LDV/SOF) ± ribavirin (RBV) for retreatment of chronic hepatitis C virus (HCV) in individuals who failed to achieve sustained virological response (SVR) with prior SOF-based, non-NS5A inhibitor-containing regimens. METHODS: The RESCUE study enrolled HCV mono-infected adults with genotype (GT) 1 or 4. Non-cirrhotic participants were randomized to 12 weeks of LDV/SOF or LDV/SOF + RBV. Compensated cirrhotic participants were randomized to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). The AIDS Clinical Trials Group A5348 study randomized genotype 1 adults with HCV/HIV co-infection to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). Both studies used SVR at 12 weeks post-treatment (SVR12) as the primary endpoint. RESULTS: In the RESCUE study, 82 participants were randomized and treated, and all completed treatment. Overall, SVR12 was 88% (72/82); 81-100% in non-cirrhotic participants treated with LDV/SOF or LDV/SOF + RBV for 12 weeks and 80-92% in cirrhotic participants treated with LDV/SOF + RBV for 12 weeks or LDV/SOF for 24 weeks. Adverse events (AEs), mostly mild-to-moderate in severity, were experienced by 78% of participants, with headache and fatigue most frequently reported. One serious AE, not related to treatment, was observed. No premature discontinuations of study drug, or deaths occurred. In the A5348 study, seven participants were randomized (cirrhotic n = 1; GT1a n = 5) and all attained SVR12, with no serious AEs or premature discontinuations. CONCLUSIONS: In this SOF-experienced, NS5A inhibitor-naïve population, which included participants with cirrhosis or HCV/HIV co-infection, high SVR12 rates were achieved.

Ledipasvir and Sofosbuvir for HCV in Patients Coinfected with HIV-1.

BACKGROUND: Effective treatment for hepatitis C virus (HCV) in patients coinfected with human immunodeficiency virus type 1 (HIV-1) remains an unmet medical need. METHODS: We conducted a multicenter, single-group, open-label study involving patients coinfected with HIV-1 and genotype 1 or 4 HCV receiving an antiretroviral regimen of tenofovir and emtricitabine with efavirenz, rilpivirine, or raltegravir. All patients received ledipasvir, an NS5A inhibitor, and sofosbuvir, a nucleotide polymerase inhibitor, as a single fixed-dose combination for 12 weeks. The primary end point was a sustained virologic response at 12 weeks after the end of therapy. RESULTS: Of the 335 patients enrolled, 34% were black, 55% had been previously treated for HCV, and 20% had cirrhosis. Overall, 322 patients (96%) had a sustained virologic response at 12 weeks after the end of therapy (95% confidence interval [CI], 93 to 98), including rates of 96% (95% CI, 93 to 98) in patients with HCV genotype 1a, 96% (95% CI, 89 to 99) in those with HCV genotype 1b, and 100% (95% CI, 63 to 100) in those with HCV genotype 4. Rates of sustained virologic response were similar regardless of previous treatment or the presence of cirrhosis. Of the 13 patients who did not have a sustained virologic response, 10 had a relapse after the end of treatment. No patient had confirmed HIV-1 virologic rebound. The most common adverse events were headache (25%), fatigue (21%), and diarrhea (11%). No patient discontinued treatment because of adverse events. CONCLUSIONS: Ledipasvir and sofosbuvir for 12 weeks provided high rates of sustained virologic response in patients coinfected with HIV-1 and HCV genotype 1 or 4. (Funded by Gilead Sciences; ION-4 ClinicalTrials.gov number, NCT02073656.).

Sofosbuvir plus ribavirin for treatment of hepatitis C virus in patients co-infected with HIV (PHOTON-2): a multicentre, open-label, non-randomised, phase 3 study.

BACKGROUND: Although interferon-free regimens are approved for patients co-infected with HIV and genotype-2 or genotype-3 hepatitis C virus (HCV), interferon-based regimens are still an option for those co-infected with HIV and HCV genotypes 1 or 4. These regimens are limited by clinically significant toxic effects and drug interactions with antiretroviral therapy. We aimed to assess the efficacy and safety of an interferon-free, all-oral regimen of sofosbuvir plus ribavirin in patients with HIV and HCV co-infection. METHODS: We did this open-label, non-randomised, uncontrolled, phase 3 study at 45 sites in seven European countries and Australia. We enrolled patients (aged ≥18 years) co-infected with stable HIV and chronic HCV genotypes 1-4, including those with compensated cirrhosis. Once-daily sofosbuvir (400 mg) plus twice-daily ribavirin (1000 mg in patients with bodyweights <75 kg and 1200 mg in those with weights ≥75 kg) was given for 24 weeks to all patients except treatment-naive patients with genotype-2 HCV, who received a 12-week regimen. The primary efficacy endpoint was sustained virological response 12 weeks after treatment. We did analysis by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT01783678. FINDINGS: Between Feb 7, 2013, and July 29, 2013, we enrolled 275 eligible patients, of whom 262 (95%) completed treatment; 274 patients were included in the final analysis. Overall rates of sustained virological response 12 weeks after treatment were 85% (95% CI 77-91) in patients with genotype-1 HCV, 88% (69-98) in patients with genotype-2 HCV, 89% (81-94) in patients with genotype-3 HCV, and 84% (66-95) in patients with genotype-4 HCV. Response rates in treatment-naive patients with HCV genotypes 2 or 3 (89% [95% CI 67-99] and 91% [81-97], respectively) were similar to those in treatment-experienced patients infected with those genotypes (83% [36-100] and 86% [73-94], respectively). There was no emergence of sofosbuvir-resistance mutations in patients with HCV viral relapse. Six (2%) patients discontinued treatment because of adverse events. The most common adverse events were fatigue, insomnia, asthenia, and headache. Four (1%) patients had serious adverse events regarded as related to study treatment. Additionally, four (1%) patients receiving antiretroviral treatment had a transient HIV viral breakthrough; however, none required changes in antiretroviral regimen. INTERPRETATION: Sofosbuvir and ribavirin provided high rates of sustained virological response after 12 weeks of treatment in treatment-naive and treatment-experienced patients co-infected with HIV and HCV genotypes 1-4. The characteristics of this interferon-free combination regimen make sofosbuvir plus ribavirin a useful treatment option for this patient population. FUNDING: Gilead Sciences.

Sofosbuvir and ribavirin for hepatitis C in patients with HIV coinfection.

IMPORTANCE: Treatment of hepatitis C virus (HCV) infection in patients also infected with human immunodeficiency virus (HIV) has been limited due to drug interactions with antiretroviral therapies (ARTs) and the need to use interferon. OBJECTIVE: To determine the rates of HCV eradication (sustained virologic response [SVR]) and adverse events in patients with HCV-HIV coinfection receiving sofosbuvir and ribavirin treatment. DESIGN, SETTING, AND PARTICIPANTS: Open-label, nonrandomized, uncontrolled phase 3 trial conducted at 34 treatment centers in the United States and Puerto Rico (August 2012-November 2013) evaluating treatment with sofosbuvir and ribavirin among patients with HCV genotypes 1, 2, or 3 and concurrent HIV. Patients were required to be receiving ART with HIV RNA values of 50 copies/mL or less and a CD4 T-cell count of more than 200 cells/µL or to have untreated HIV infection with a CD4 T-cell count of more than 500 cells/µL. Of the treatment-naive patients, 114 had HCV genotype 1 and 68 had HCV genotype 2 or 3, and 41 treatment experienced participants who had been treated with peginterferon-ribavirin had HCV genotype 2 or 3, for a total of 223 participants. INTERVENTIONS: Treatment-naive patients with HCV genotype 2 or 3 received 400 mg of sofosbuvir and weight-based ribavirin for 12 weeks and treatment-naive patients with HCV genotype 1 and treatment-experienced patients with HCV genotype 2 or 3 received the same treatment for 24 weeks. MAIN OUTCOMES AND MEASURES: The primary study outcome was the proportion of patients with SVR (serum HCV <25 copies/mL) 12 weeks (SVR12) after cessation of HCV therapy. RESULTS: Among treatment-naive participants, 87 patients (76%) of 114 (95% CI, 67%-84%) with genotype 1, 23 patients (88%) of 26 with genotype 2 (95% CI, 70%-985), and 28 patients (67%) of 42 with genotype 3 (95% CI, 51%-80%) achieved SVR12. Among treatment-experienced participants, 22 patients (92%) of 24 with genotype 2 (95% CI, 73%-99%) and 16 patients (94%) of 17 (95% CI, 71%-100%) achieved SVR12. The most common adverse events were fatigue, insomnia, headache, and nausea. Seven patients (3%) discontinued HCV treatment due to adverse events. No adverse effect on HIV disease or its treatment was observed. CONCLUSIONS AND RELEVANCE: In this open-label, nonrandomized, uncontrolled study, patients with HIV who were coinfected with HCV genotype 1, 2, or 3 who received the oral, interferon-free combination of sofosbuvir and ribavirin for 12 or 24 weeks had high rates of SVR12. Further studies of this oral regimen in diverse populations of coinfected patients are warranted. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01667731.

A randomized, double-blind study of AMG 108 (a fully human monoclonal antibody to IL-1R1) in patients with osteoarthritis of the knee.

INTRODUCTION: AMG 108 is a fully human, immunoglobulin subclass G2 (IgG2) monoclonal antibody that binds the human interleukin-1 (IL-1) receptor type 1, inhibiting the activity of IL-1a and IL-1b. In preclinical studies, IL-1 inhibition was shown to be beneficial in models of osteoarthritis (OA). The purpose of this two-part study was to evaluate the safety and pharmacokinetics (PK; Part A) and clinical effect (Part B) of AMG 108 in a double-blind, placebo-controlled, multiple-dose study in patients with OA of the knee. METHODS: In Part A, patients received placebo or AMG 108 subcutaneously (SC; 75 mg or 300 mg) or intravenously (IV; 100 mg or 300 mg) once every 4 weeks for 12 weeks; in Part B, patients received placebo or 300 mg AMG 108 SC, once every 4 weeks for 12 weeks. The clinical effect of AMG 108 was measured in Part B by using the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index pain score. RESULTS: In Part A, 68 patients were randomized, and 64 received investigational product. In Part B, 160 patients were randomized, and 159 received investigational product. AMG 108 was well tolerated. Most adverse events (AEs), infectious AEs, serious AEs and infections, as well as withdrawals from the study due to AEs occurred at similar rates in both active and placebo groups. One death was reported in an 80-year-old patient (Part A, 300 mg IV AMG 108; due to complications of lobar pneumonia). AMG 108 serum concentration-time profiles exhibited nonlinear PK. The AMG 108 group in Part B had statistically insignificant but numerically greater improvement in pain compared with the placebo group, as shown by the WOMAC pain scores (median change, -63.0 versus -37.0, respectively). CONCLUSIONS: The safety profile of AMG 108 SC and IV was comparable with placebo in patients with OA of the knee. Patients who received AMG 108 showed statistically insignificant but numerically greater improvements in pain; however, minimal, if any, clinical benefit was observed. TRIAL REGISTRATION: This study is registered with ClinicalTrials.gov with the identifier NCT00110942.

A phase 2 randomized, double-blind study of AMG 108, a fully human monoclonal antibody to IL-1R, in patients with rheumatoid arthritis.

INTRODUCTION: Preclinical work has suggested that IL-1 plays a critical role in the pathogenesis of rheumatoid arthritis (RA). The objective of the present study was to determine the effect of a long-acting IL-1 receptor inhibitor, AMG 108, in a double-blind, placebo-controlled, parallel-dosing study in patients with active RA who were receiving stable methotrexate (15 to 25 mg/week). METHODS: Patients were randomized equally to receive placebo or 50, 125, or 250 mg AMG 108 subcutaneously every 4 weeks for 6 months. The primary efficacy endpoint was a 20% improvement in the American College of Rheumatology response (ACR20) at week 24; other efficacy endpoints included the ACR50, the ACR70, and the RA disease activity score (28-joint count Disease Activity Score) responses, patient-reported outcomes, and pharmacokinetic parameters. Safety endpoints included treatment-emergent adverse events (AEs), infectious AEs, serious AEs, serious infections, injection site reactions, laboratory abnormalities, and antibodies to AMG 108. RESULTS: Of 813 patients enrolled in the study, 204 patients were randomized to the 50 mg group, 203 to the 125 mg group, 203 to the 250 mg group, and 203 to placebo. At week 24, 40.4% of the 250 mg group, 36% of the 125 mg group, 30.9% of the 50 mg group, and 29.1% of the placebo group achieved an ACR20 (P = 0.022, 250 mg vs. placebo). Of the individual ACR components, numerical dose-dependent improvements were only seen in tender joint counts, pain (visual analog scale), and the acute phase reactants, erythrocyte sedimentation rate and C-reactive protein. No dose-related increase was observed in the incidence of treatment-emergent AEs. No deaths were reported, and the incidence of AEs and infections, serious AEs and infections, and withdrawals from study for safety were similar in the AMG 108 and placebo groups. CONCLUSIONS: This large double-blind randomized trial with a long-acting IL-1 receptor blocker, AMG 108, is consistent with the experience of other IL-1 blockers, represents a definitive experiment showing that IL-1 inhibition provides only moderate symptomatic amelioration of arthritis activity in the majority of RA patients, and provides an answer to a question that has been discussed for many years in the rheumatologic community. TRIAL REGISTRATION: ClinicalTrials.gov NCT00293826.

Pharmacological blockade of the vanilloid receptor TRPV1 elicits marked hyperthermia in humans.

The vanilloid receptor TRPV1 has been identified as a molecular target for the treatment of pain associated with inflammatory diseases and cancer. Hence, TRPV1 antagonists have been considered for therapeutic evaluation in such diseases. During Phase I clinical trials with AMG 517, a highly selective TRPV1 antagonist, we found that TRPV1 blockade elicited marked, but reversible, and generally plasma concentration-dependent hyperthermia. Similar to what was observed in rats, dogs, and monkeys, hyperthermia was attenuated after repeated dosing of AMG 517 (at the highest dose tested) in humans during a second Phase I trial. However, AMG 517 administered after molar extraction (a surgical cause of acute pain) elicited long-lasting hyperthermia with maximal body temperature surpassing 40 degrees C, suggesting that TRPV1 blockade elicits undesirable hyperthermia in susceptible individuals. Mechanisms of AMG 517-induced hyperthermia were then studied in rats. AMG 517 caused hyperthermia by inducing tail skin vasoconstriction and increasing thermogenesis, which suggests that TRPV1 regulates vasomotor tone and metabolic heat production. In conclusion, these results demonstrate that: (a) TRPV1-selective antagonists like AMG 517 cannot be developed for systemic use as stand alone agents for treatment of pain and other diseases, (b) individual susceptibility influences magnitude of hyperthermia observed after TRPV1 blockade, and (c) TRPV1 plays a pivotal role as a molecular regulator for body temperature in humans.

Bioequivalence of liquid and reconstituted lyophilized etanercept subcutaneous injections.

The objective of this study was to compare the pharmacokinetics of liquid and reconstituted lyophilized etanercept. This single-center, open-label study had a 2-period crossover design in which 36 healthy subjects were randomly assigned in a 1:1 ratio to etanercept (liquid/lyo or lyo/liquid). The treatments were separated by 28 days. Blood samples were obtained predose and at 10 predetermined time points postdose. Serum concentrations were determined by enzyme-linked immunosorbent assay. Noncompartmental pharmacokinetic parameters were analyzed using a standard crossover analysis of variance model. Thirty-three subjects completed both treatment periods. Geometric mean values (adjusted) of area under the serum drug concentration-time curve from time zero to the time of the final quantifiable sample, area under the serum drug concentration-time curve from time zero to infinity, and maximum concentration obtained with the 50-mg/mL liquid etanercept injection were 93.0%, 90.7%, and 98.5% of the respective parameters for 2 injections of 25 mg/mL reconstituted formulation. All associated confidence intervals were within the predefined equivalence interval of 80% to 125%. No differences in safety profiles of the 2 formulations were apparent. Liquid etanercept was bioequivalent to the reconstituted lyophilized etanercept formulation.

An extended terminal half-life for darbepoetin alfa: results from a single-dose pharmacokinetic study in patients with chronic kidney disease not receiving dialysis.

BACKGROUND AND OBJECTIVE: Anaemia is a major and persistent manifestation of chronic kidney disease (CKD) caused by the deficient production of erythropoietin in the kidneys, the prevalence of which is proportional to the deterioration in kidney function. Darbepoetin alfa, an erythropoiesis-stimulating protein, exhibits a lower clearance and longer terminal half-life in serum than recombinant human erythropoietin, thereby allowing for a reduced dosing frequency. A recent study in patients with CKD, using a 4-week sampling period, suggested that the terminal half-life of darbepoetin alfa in serum is longer than that reported in previous studies, which were based on a 1-week sampling period. This study was conducted to characterise the pharmacokinetic profile of a single subcutaneous dose of darbepoetin alfa 1 microg/kg in patients with CKD, using a sampling duration of 4 weeks, which was hypothesised to allow better characterisation of the terminal half-life in serum. METHODS: Twenty patients with CKD not on dialysis, with a calculated glomerular filtration rate of 20-60 mL/min and who had not been treated with erythropoietic agents in the previous 12 weeks, were enrolled into this single-dose, open-label study. Patients received a single subcutaneous dose of darbepoetin alfa (Aranesp) 1 microg/kg on day 1, and blood samples were collected for pharmacokinetic analyses predose, 6 and 12 hours postdose and up to 28 days postdose. Seroreactivity sampling and further safety laboratory tests (clinical chemistry and urinalysis) were also performed. Patients were assessed for adverse events at each study visit. The primary endpoint was characterisation of the terminal half-life following a single subcutaneous dose of darbepoetin alfa 1 microg/kg. RESULTS: The mean terminal half-life in serum of darbepoetin alfa was determined to be 69.6 hours. Peak serum concentrations were reached in a median time of 36 hours postdose, and a mean apparent clearance of 3.51 mL/h/kg was comparable to that observed previously in this patient population. CONCLUSION: Based on an extended sampling schedule of 4 weeks, the terminal half-life of darbepoetin alfa was approximately 70 hours. This is longer than the 48.8 hours reported previously in patients with CKD on dialysis. These data suggest that the pharmacokinetic properties of darbepoetin alfa make this erythropoietic agent well suited to an extended dosing regimen.

Factors affecting increasing radiation dose for mammography in North Carolina from 1997 through 2001: an analysis of Food and Drug Administration annual surveys.

RATIONALE AND OBJECTIVES: To determine which factors affected the increase in average glandular dose recorded at the annual US Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 1997 to 2001. MATERIALS AND METHODS: Average glandular dose, HVL, kVp, ambient light, luminance, equipment age, processing speed, and system speed for every mammography unit at all facilities in the state were collected by state inspectors. A mixed-effect model was used to assess the average changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant increase in the average glandular dose in North Carolina in 1999, 2000, and 2001 when compared with the baseline year of 1997. Factors that were statistically significantly linked to this effect were changes in kVp, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has recently increased in North Carolina. This change is likely caused by changes in screen-film products and processing techniques.

Assessment of blinding in clinical trials.

Success of blinding is a fundamental issue in many clinical trials. The validity of a trial may be questioned if this important assumption is violated. Although thousands of ostensibly double-blind trials are conducted annually and investigators acknowledge the importance of blinding, attempts to measure the effectiveness of blinding are rarely discussed. Several published papers proposed ways to evaluate the success of blinding, but none of the methods are commonly used or regarded as standard. This paper investigates a new approach to assess the success of blinding in clinical trials. The blinding index proposed is scaled to an interval of -1 to 1, 1 being complete lack of blinding, 0 being consistent with perfect blinding and -1 indicating opposite guessing which may be related to unblinding. It has the ability to detect a relatively low degree of blinding, response bias and different behaviors in two arms. The proposed method is applied to a clinical trial of cholesterol-lowering medication in a group of elderly people.