Decision making in clinical trials: Interim analyses, innovative design, and biomarkers.

The efficient and accurate execution of clinical trials testing novel treatments for Alzheimer's disease (AD) is a critical component of the field's collective efforts to develop effective disease-modifying treatments for AD. The lengthy and heterogeneous nature of clinical progression in AD contributes to the challenges inherent in demonstrating a clinically meaningful benefit of any potential new AD therapy. The failure of many large and expensive clinical trials to date has prompted a focus on optimizing all aspects of decision making, to not only expedite the development of new treatments, but also maximize the value of the information that each clinical trial yields, so that all future clinical trials (including those that are negative) will contribute toward advancing the field. To address this important topic the Alzheimer's Association Research Roundtable convened December 1-2, 2020. The goals focused around identifying new directions and actionable steps to enhance clinical trial decision making in planned future studies.

Design and Execution of Sustainable Decentralized Clinical Trials.

The decentralized clinical trial (DCT) approach is increasingly recognized as a means to accelerate the development of potential therapeutic interventions. DCTs have a crucial advantage over traditional clinical trials: patients are monitored in their environment using technology (e.g., wearables), that capture data as they continue in daily life. This narrative review outlines a gap analysis focused on the frameworks and guidance from expert working groups and regulatory agencies for the design and execution of DCTs. Eight DCT elements guided the analysis and summarized the frameworks and guidance: (1) suitability, (2) protocol, (3) investigational medicinal product (IMP) supply, (4) investigators and health care providers, (5) safety, (6) regulatory and ethics, (7) data and technology, and (8) engagement, communication, and advocacy. Based on the gap analysis, two key takeaways were identified: (1) a need for a comprehensive sustainability assessment of each DCT element; and (2) current frameworks and guidance provide recommendations on social sustainability and some on economic sustainability. DCTs are an essential evolution in healthcare research; however, more guidance related to a comprehensive assessment of designing and executing sustainable DCTs is needed. This is especially the case for environmental sustainability, including, for example, carbon footprint and disposal of IMPs and sensors.

Why are not There More Bayesian Clinical Trials? Perceived Barriers and Educational Preferences Among Medical Researchers Involved in Drug Development.

OBJECTIVE AND BACKGROUND: The clinical trials community has been hesitant to adopt Bayesian statistical methods, which are often more flexible and efficient with more naturally interpretable results than frequentist methods. We aimed to identify self-reported barriers to implementing Bayesian methods and preferences for becoming comfortable with them. METHODS: We developed a 22-question survey submitted to medical researchers (non-statisticians) from industry, academia, and regulatory agencies. Question areas included demographics, experience, comfort levels with Bayesian analyses, perceived barriers to these analyses, and preferences for increasing familiarity with Bayesian methods. RESULTS: Of the 323 respondents, most were affiliated with pharmaceutical companies (33.4%), clinical research organizations (29.7%), and regulatory agencies (18.6%). The rest represented academia, medical practice, or other. Over 56% of respondents expressed little to no comfort in interpreting Bayesian analyses. "Insufficient knowledge of Bayesian approaches" was ranked the most important perceived barrier to implementing Bayesian methods by a plurality (48%). Of the approaches listed, in-person training was the most preferred for gaining comfort with Bayesian methods. CONCLUSIONS: Based on these survey results, we recommend that introductory level training on Bayesian statistics be presented in an in-person workshop that could also be broadcast online with live Q&A. Other approaches such as online training or collaborative projects may be better suited for higher-level trainings where instructors may assume a baseline understanding of Bayesian statistics. Increased coverage of Bayesian methods at medical conferences and medical school trainings would help improve comfort and overcome the substantial knowledge barriers medical researchers face when implementing these methods.

Why are There not More Bayesian Clinical Trials? Ability to Interpret Bayesian and Conventional Statistics Among Medical Researchers.

OBJECTIVE AND BACKGROUND: We assessed current understandings in interpretation of Bayesian and traditional statistical results within the clinical researcher (non-statistician) community. METHODS: Within a 22-question survey, including demographics and experience and comfort levels with Bayesian analyses, we included questions on how to interpret both Bayesian and traditional statistical outputs. We also assessed whether Bayesian or traditional interpretations are considered more useful. RESULTS: Among the 323 respondent clinicians, 42.4% and 36.5% chose the correct interpretations of the posterior probability and 95% credible interval, respectively. Only 11.5% of respondents interpreted the p-value correctly and 23.5% interpreted the 95% confidence interval correctly. CONCLUSIONS: Based on these survey results, we conclude that most of these clinicians face uncertainty when attempting to interpret results from both Bayesian and traditional statistical outputs. When presented with accurate interpretations, clinicians generally conclude that Bayesian results are more useful than conventional ones. We believe there is a need for education of clinicians in statistical interpretation in ways that are customized to this audience.

Phase II (NAVIGATE-AD study) Results of LY3202626 Effects on Patients with Mild Alzheimer's Disease Dementia.

BACKGROUND: LY3202626 is a small molecule inhibitor of ß-site amyloid precursor protein cleaving enzyme (BACE)1 shown to reduce amyloid-ß (Aß)1-40 and Aß1-42 concentrations in plasma and cerebrospinal fluid developed for the treatment of Alzheimer's disease (AD). OBJECTIVE: To assess the change from baseline in flortaucipir positron emission tomography (PET) after treatment with LY3202626 compared with placebo in patients with mild AD dementia. METHODS: Patients received daily 3 mg or 12 mg doses of LY3202626 or placebo for 52 weeks. The primary outcome was assessment of cerebral neurofibrillary tangle load by flortaucipir PET. The study was terminated early following an interim analysis due to a low probability of identifying a statistically significant slowing of cognitive and/or functional decline. RESULTS: A total of 316 patients were randomized and 47 completed the study. There was no statistically significant difference between placebo and either dose of LY3202626 from baseline to 52 weeks, or in annualized change for flortaucipir PET. There was no clinically meaningful difference between placebo and LY3202626 doses on efficacy measures of cognition and function. No deaths or serious adverse events considered related to LY3202626 were reported. A statistically significant increase in treatment-emergent adverse events in the psychiatric disorders system organ class was reported for both LY3202626 doses compared to placebo. CONCLUSION: LY3202626 tested at doses generating 70-90% BACE inhibition was generally well tolerated in this study. LY3202626 treatment did not result in a clinically significant change in cerebral tau burden as measured by flortaucipir nor in change of functional or cognitive decline compared to placebo.

Donanemab (LY3002813) dose-escalation study in Alzheimer's disease.

INTRODUCTION: This study explored the safety and tolerability features of donanemab (LY3002813) in patients with mild cognitive impairment due to Alzheimer's disease (AD) or mild to moderate AD dementia. METHODS: Patients with AD were enrolled into the single-ascending dose phase and were administered a single, intravenous (IV) dose of donanemab (five dosing cohorts from 0.1 to 10 mg/kg) or placebo followed by a 12-week follow-up period for each dose level. After the follow-up period, the same patients proceeded into the multiple-ascending dose (MAD) phase (five cohorts) and were administered IV doses of donanemab (0.3 to 10 mg/kg) or placebo approximately once per month for up to four doses depending on the initial doses (only cohort 1 went from 0.1 mg/kg to a higher dose of 0.3 mg/kg during the MAD phase). This phase concluded with a 12-week follow-up period. The relative exposure assessment of an unblinded, single, subcutaneous 3-mg/kg dose of donanemab in patients with AD was also performed, followed by a 12-week follow-up period. One cohort of healthy subjects received an unblinded, single, IV 1-mg/kg dose of donanemab. These two cohorts did not continue to the MAD phase. RESULTS: Donanemab was generally well tolerated up to 10 mg/kg. After single-dose administration from 0.1 to 3.0 mg/kg, the mean terminal elimination half-life was ≈4 days, increasing to ≈10 days at 10 mg/kg. Only the 10-mg/kg dose showed changes in amyloid positron emission tomography. Amyloid reduction of 40% to 50% was achieved. Approximately 90% of subjects developed anti-drug antibodies at 3 months after a single intravenous dose. DISCUSSION: Intravenous donanemab 10 mg/kg can reduce amyloid deposits in AD despite having a shorter than expected half-life.

First-line treatment of patients with advanced or metastatic squamous non-small cell lung cancer: systematic review and network meta-analysis.

BACKGROUND: The objectives of this systematic review and meta-analysis were to compare the survival, toxicity, and quality of life of patients treated with necitumumab in combination with gemcitabine and cisplatin. These agents were investigated in published randomized controlled trials (RCTs) of patients with squamous non-small cell lung cancer (NSCLC) in the first-line setting. METHODS: The systematic review was executed on January 27, 2015, and updated on August 21, 2016, using a pre-specified search strategy. Searches were conducted using PubMed, Medline, and EMBASE, with supplemental searches using the Evidence Based Medicine Reviews and ClinicalTrials.gov to identify RCTs published in English from 1995-2016 and reporting at least one of the primary outcomes [overall survival (OS), progression-free survival (PFS), toxicity, or quality of life] in patients who received first-line treatment for advanced or metastatic squamous NSCLC. Study quality and risk of bias were assessed using the Physiotherapy Evidence Database (PEDro) scale and Cochrane risk of bias tool, respectively. A Baysian network meta-analysis was performed on the primary outcomes. Hazard ratios (HRs) were evaluated for the primary analysis; secondary analyses were conducted using median OS data. Planned sensitivity analyses were conducted including reanalysis using a Frequentist approach and limiting analyses to subsets based on clinical and demographic covariates. RESULTS: The systematic literature review resulted in identification of 4,016 unique publications; 40 publications (35 unique trials) were eligible for inclusion. Eight studies connected to a common network for the OS analysis using HR data. The majority of studies were not limited to squamous NSCLC, thus analyzable data were limited to a subset of data within the published trials. Carboplatin + S-1 and necitumumab in combination with gemcitabine and cisplatin were associated with lower HRs for OS versus all other comparators. Nine studies connected to the network for the PFS analysis in which necitumumab in combination with gemcitabine and cisplatin was associated with the lowest HR. Data were not available to analyze toxicity or quality of life. CONCLUSIONS: Although the results suggest that carboplatin + S-1 and necitumumab in combination with gemcitabine and cisplatin may have value in terms of OS versus other comparators, the results should be interpreted with caution due to the limited number of studies (with few focused exclusively on squamous NSCLC) and wide credible intervals.

Bayesian methods for the design and analysis of noninferiority trials.

The gold standard for evaluating treatment efficacy of a medical product is a placebo-controlled trial. However, when the use of placebo is considered to be unethical or impractical, a viable alternative for evaluating treatment efficacy is through a noninferiority (NI) study where a test treatment is compared to an active control treatment. The minimal objective of such a study is to determine whether the test treatment is superior to placebo. An assumption is made that if the active control treatment remains efficacious, as was observed when it was compared against placebo, then a test treatment that has comparable efficacy with the active control, within a certain range, must also be superior to placebo. Because of this assumption, the design, implementation, and analysis of NI trials present challenges for sponsors and regulators. In designing and analyzing NI trials, substantial historical data are often required on the active control treatment and placebo. Bayesian approaches provide a natural framework for synthesizing the historical data in the form of prior distributions that can effectively be used in design and analysis of a NI clinical trial. Despite a flurry of recent research activities in the area of Bayesian approaches in medical product development, there are still substantial gaps in recognition and acceptance of Bayesian approaches in NI trial design and analysis. The Bayesian Scientific Working Group of the Drug Information Association provides a coordinated effort to target the education and implementation issues on Bayesian approaches for NI trials. In this article, we provide a review of both frequentist and Bayesian approaches in NI trials, and elaborate on the implementation for two common Bayesian methods including hierarchical prior method and meta-analytic-predictive approach. Simulations are conducted to investigate the properties of the Bayesian methods, and some real clinical trial examples are presented for illustration.

Estimation of the inter- and intrasubject variability of the diurnal serum cortisol rhythm in healthy male subjects to evaluate the biomarker potential for drug target engagement.

OBJECTIVE: Changes in the cortisol diurnal rhythm have been found in neuropsychiatric diseases, including anxiety and depression. The aim of this study was to investigate the reliability and reproducibility of cortisol diurnal rhythm in healthy males, through determination of the inter- and intrasubject variability, to facilitate evaluation of this biomarker for drug target engagement. MATERIALS AND METHODS: This open-label, 2-period study design evaluated serum cortisol release over a 24-hour period in 18 healthy males. A cosinor model was used to model the cortisol diurnal rhythm, and the inter- and intrasubject coefficients of variation (CVs) were calculated across the 2 periods. RESULTS: Three significant cortisol concentration peaks were observed at ~7 AM, 1 PM, and 7 PM. The intersubject CVs (%) for the amplitude, acrophase, and midline estimating statistic of rhythm (MESOR) were 18.2, 19.3, and 16.8, respectively. The intrasubject CVs (%) were 11.2, 7.6, and 6.9, respectively. The inter- and intrasubject CVs (%) for the lunch-induced 1 PM peak and the >dinner-induced 7 PM peak were 22.1, 17.3, 44.7, and 22.1 respectively. CONCLUSIONS: Assessment of serum cortisol diurnal rhythm suggests that the amplitude, acrophase, and MESOR, but not the meal-induced peaks, have the potential to be a reliable biomarker in drug development targeting the hypothalamic-pituitary-adrenocortical (HPA) axis.

Study protocol: systematic review and meta-analysis of randomized controlled trials in first-line treatment of squamous non-small cell lung cancer.

BACKGROUND: There is a high unmet need for effective treatments for patients with squamous non-small cell lung cancer (NSCLC). Eli Lilly and Company is conducting a phase III, randomized, multicenter, open-label study of gemcitabine plus cisplatin plus necitumumab (GC + N) versus gemcitabine plus cisplatin (GC) for the first-line treatment of patients with stage IV squamous NSCLC. Given GC is not the only treatment commonly used for the treatment of squamous NSCLC, this study was designed to compare the survival, toxicity, and quality of life outcomes of current treatment strategies for squamous NSCLC in the first-line setting. METHODS/DESIGN: A systematic review and meta-analysis (including indirect comparisons) of treatments used in squamous NSCLC will be conducted to assess the clinical efficacy (overall and progression-free survival), health-related quality of life (HRQoL), and safety (grade 3-4 toxicity) of GC + N compared to other treatments used in squamous NSCLC. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines will be followed for all aspects of this study. A systematic literature review will be conducted to identify randomized controlled trials evaluating chemotherapy treatment in first-line NSCLC. Eligible articles will be restricted to randomized controlled trials (RCTs) among chemotherapy-naïve advanced NSCLC cancer patients that report outcome data (survival, toxicity, or quality of life) for patients with squamous histology. Following data extraction and validation, data consistency and study heterogeneity will be assessed. A network meta-analysis will be conducted based on the available hazard ratios for overall and progression-free survival, odds ratios for published toxicity data, and mean difference of HRQoL scales. Sensitivity analyses will be conducted. DISCUSSION: This is a presentation of the study protocol only. Results and conclusions are pending completion of this study. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42014008968.

Modeling and simulations to confirm a controlled hypoglycemic stress test in healthy subjects is not associated with clinically significant QT prolongations.

OBJECTIVES: A modified insulin tolerance test (ITT) can be used to simulate a physiological stress state through the induction of controlled hypoglycemia in healthy volunteers. This allows for evaluation of hypothalamic-pituitary-adrenocortical axis response to stress via a surge in cortical release. However, a consequence of severe, prolonged hypoglycemia is QT interval prolongation. The aim of this analysis was to confirm that blood glucose lowering to 60 mg/dL (previously identified as adequate for inducing stress) has low risk of inducing clinically significant QT prolongation. MATERIALS AND METHODS: Continuous ECG monitoring was conducted as a planned sub study of an open-label, 2-period study involving 18 healthy male subjects. The QTcF response to hypoglycemia was measured over 2 identical periods, ~ 7 days apart. RESULTS: An indirect- response model adequately described the pharmacological relationship between blood glucose and QTcF intervals over the time-course of the ITT. The model correctly identified the steep glucose-QT relationship as an on-off response with a large Hill coefficient of 59 and the threshold glucose, EC50, as ~ 57 mg/dL with narrow between-subject variability of 10%. Simulated QTcF profiles over the course of an ITT did not demonstrate any QTcF interval changes of clinical concern, defined as QTcF observation > 500 ms, if hypoglycemia did not reach below 60 mg/dL. The statistical prediction that the chance of a mean QTcF observation > 500 ms was < 0.0001. CONCLUSIONS: Results support that an ITT maintained at or above 60 mg/dL is unlikely to cause QT prolongation in healthy volunteers and does not warrant continuous ECG monitoring in this group of subjects.

The current state of Bayesian methods in medical product development: survey results and recommendations from the DIA Bayesian Scientific Working Group.

Bayesian applications in medical product development have recently gained popularity. Despite many advances in Bayesian methodology and computations, increase in application across the various areas of medical product development has been modest. The DIA Bayesian Scientific Working Group (BSWG), which includes representatives from industry, regulatory agencies, and academia, has adopted the vision to ensure Bayesian methods are well understood, accepted more broadly, and appropriately utilized to improve decision making and enhance patient outcomes. As Bayesian applications in medical product development are wide ranging, several sub-teams were formed to focus on various topics such as patient safety, non-inferiority, prior specification, comparative effectiveness, joint modeling, program-wide decision making, analytical tools, and education. The focus of this paper is on the recent effort of the BSWG Education sub-team to administer a Bayesian survey to statisticians across 17 organizations involved in medical product development. We summarize results of this survey, from which we provide recommendations on how to accelerate progress in Bayesian applications throughout medical product development. The survey results support findings from the literature and provide additional insight on regulatory acceptance of Bayesian methods and information on the need for a Bayesian infrastructure within an organization. The survey findings support the claim that only modest progress in areas of education and implementation has been made recently, despite substantial progress in Bayesian statistical research and software availability.

Bayesian sample size determination for a clinical trial with correlated continuous and binary outcomes.

In clinical trials, multiple outcomes are often collected in order to simultaneously assess effectiveness and safety. We develop a Bayesian procedure for determining the required sample size in a regression model where a continuous efficacy variable and a binary safety variable are observed. The sample size determination procedure is simulation based. The model accounts for correlation between the two variables. Through examples we demonstrate that savings in total sample size are possible when the correlation between these two variables is sufficiently high.

Effects of a novel mGlu2/3 receptor agonist prodrug, LY2140023 monohydrate, on central monoamine turnover as determined in human and rat cerebrospinal fluid.

RATIONALE: Accumulating evidence suggests that the primary symptoms of schizophrenia may be associated with altered central glutamate transmission. LY2140023 monohydrate is the methionine prodrug of the selective mGlu(2/3) receptor agonist LY404039 and is currently being assessed for the treatment of schizophrenia. OBJECTIVE: The objective of this study was to evaluate the central pharmacological activity of LY2140023 monohydrate in preclinical and clinical studies. METHODS: Effects on neurotransmitter/metabolite concentrations were assessed in male rats following single oral doses of LY2140023 monohydrate (microdiasylates from the prefrontal cortex), single intraperitoneal injection of LY404039 [cerebrospinal fluid (CSF)], or LY2140023 monohydrate dosed once daily for 7 days (CSF). A clinical study in 16 healthy subjects assessed the effects of LY2140023 monohydrate 40 mg orally twice daily for 14 days in lumbar CSF. RESULTS: Rat studies: Acute dosing with LY2140023 monohydrate resulted in significant dose-dependent increases in extracellular concentrations of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), but not 5-hydroxyindoleacetic acid (5-HIAA), in the prefrontal cortex. LY2140023 monohydrate dosing for 7 days elevated the concentrations of HVA in CSF, while acutely dosed LY404039 increased the concentrations of DOPAC, HVA, and methoxy-hydroxyphenylglycol (MHPG), but not 5-HIAA. Clinical study: Significant increases were seen for DOPAC, HVA, 5-HIAA, and MHPG in the CSF of subjects receiving LY2140023 monohydrate, but not placebo. CONCLUSIONS: LY2140023 monohydrate and/or LY404039 dosing potently affected dopamine turnover and also significantly affected serotonin turnover in the human and rat central nervous systems. The measurement of biogenic amine metabolites such as DOPAC and HVA may serve as useful biomarkers of LY2140023 monohydrate and/or LY404039 central pharmacodynamic activity.

Pharmacokinetics and pharmacodynamics following maintenance doses of prasugrel and clopidogrel in Chinese carriers of CYP2C19 variants.

AIMS: This open-label, two-period, randomized, crossover study was designed to determine the effect of CYP2C19 reduced function variants on exposure to active metabolites of, and platelet response to, prasugrel and clopidogrel. METHODS: Ninety healthy Chinese subjects, stratified by CYP2C19 phenotype, were randomly assigned to treatment with prasugrel 10 mg or clopidogrel 75 mg for 10 days followed by 14 day washout and 10 day treatment with the other drug. Eighty-three subjects completed both treatment periods. Blood samples were collected at specified time points for measurement of each drug's active metabolite (Pras-AM and Clop-AM) concentrations and determination of inhibition of platelet aggregation (IPA) by light transmittance aggregometry. CYP2C19 genotypes were classified into three predicted phenotype groups: rapid metabolizers [RMs (*1/*1)], heterozygous or intermediate metabolizers [IMs (*1/*2, *1/*3)] and poor metabolizers [PMs (*2/*2, *2/*3)]. RESULTS: Pras-AM exposure was similar in IMs and RMs (90% CI 0.85, 1.03) and slightly lower in PMs than IMs (90% CI 0.74, 0.99), whereas Clop-AM exposure was significantly lower in IMs compared with RMs (90% CI 0.62, 0.83), and in PMs compared with IMs (90% CI 0.53, 0.82). IPA was more consistent among RMs, IMs and PMs in prasugrel treated subjects (80.2%, 84.2% and 80.2%, respectively) than in clopidogrel treated subjects (59.7%, 56.2% and 36.8%, respectively; P < 0.001). CONCLUSIONS: Prasugrel demonstrated higher active metabolite exposure and more consistent pharmacodynamic response across all three predicted phenotype groups compared with clopidogrel, confirming observations from previous research that CYP2C19 phenotype plays an important role in variability of response to clopidogrel, but has no impact on response to prasugrel.

Pharmacodynamics and pharmacokinetics of single doses of prasugrel 30 mg and clopidogrel 300 mg in healthy Chinese and white volunteers: an open-label trial.

BACKGROUND: Prasugrel is an oral antiplatelet agent approved for the reduction of atherothrombotic cardiovascular events in patients presenting with acute coronary syndrome and undergoing percutaneous coronary intervention. Although the approved loading dose is 60 mg, earlier studies of prasugrel suggested that active-metabolite exposure and pharmacodynamic response may be higher in Asian subjects than in white subjects. OBJECTIVES: This study compared the pharmacodynamic response to a single 30-mg dose of prasugrel in healthy Chinese and white subjects and the response to a single 30-mg dose of prasugrel and a single 300-mg dose of clopidogrel in healthy Chinese subjects. The pharmacokinetics and tolerability of both drugs were also assessed. METHODS: This was an open-label, single-dose study conducted in Singapore. Chinese subjects were randomly allocated to receive prasugrel 30 mg or clopidogrel 300 mg; after a 14-day washout period, they received the alternative drug. White subjects received only prasugrel 30 mg. Blood samples for pharmaco-dynamic assessments were collected before dosing and at 0.5, 1, 2, 4, and 24 hours after dosing. Three methods were used to measure inhibition of platelet aggregation (IPA)-traditional light transmission aggregometry (LTA), the Verify Now P2Y12 (VN-P2Y12) assay, and a vasodilator-stimulated phosphoprotein (VASP) phosphorylation flow cytometry assay-and their results were compared. Blood samples for pharmacokinetic assessments were collected at 0.25, 0.5, 1, 1.5, 2, 4, 8, 12, and 24 hours after dosing. Concentrations of the active metabolite of prasugrel were measured using a validated LC-MS/MS method. RESULTS: The study enrolled 18 Chinese subjects and 14 white subjects. Chinese subjects had a mean (SD) age of 31 (10) years and a mean body weight of 65.2 (8.9) kg; 83% were male. The corresponding values for white subjects were 30 (10) years, 77.2 (12.4) kg, and 86%. Thirty of the 32 enrolled subjects completed the study. Two Chinese men were withdrawn from the study, one due to a low platelet-rich plasma count after receipt of prasugrel 30 mg and the other due to mild, intermittent rectal bleeding after bowel movements that began approximately 2 days after receipt of clopidogrel 300 mg. The mean IPA with prasugrel was significantly higher in Chinese than in white subjects at 0.5, 1, and 2 hours after dosing (P < 0.05), but not at 4 or 24 hours. In Chinese subjects, mean maximal IPA (87%) occurred 1 hour after prasugrel dosing; in white subjects, mean maximal IPA (78%) occurred 2 hours after prasugrel dosing. In Chinese subjects, the mean IPA was significantly higher at all time points after administration of prasugrel 30 mg than after administration of clopidogrel 300 mg (P <0.001). After administration of Clopidogrel 300 mg in Chinese subjects, mean maximal IPA (58%) occurred at 4 hours. The VN-P2Y12 and VASP phosphorylation assays yielded results comparable to those obtained by LTA. Mean exposure to prasugrel's active metabolite was higher in Chinese than in white subjects (geometric least squares mean ratio for AUC(0-t) = 1.47 (90% CI, 1.24-1.73). Both drugs were well tolerated. CONCLUSIONS: In this study, platelet inhibition was significantly higher in Chinese than in white subjects up to 2 hours after a single 30-mg dose of prasugrel. Platelet inhibition was significantly higher in Chinese subjects at all time points after a 30-mg dose of prasugrel than after a 300-mg dose of clopidogrel. Both treatments were generally well tolerated.

Tadalafil is efficacious and well tolerated in the treatment of erectile dysfunction (ED) in men over 65 years of age: results from Multiple Observations in Men with ED in National Tadalafil Study in the United States.

INTRODUCTION: Erectile dysfunction is increasingly common with advancing age, yet sexual activity and intimacy are important to elderly men. AIM: To assess the efficacy and tolerability of tadalafil in men over the age of 65 years. METHOD: In this multicenter open-label study, 188 men (mean age = 71.6 years) who were over age 65 and did not have diabetes mellitus or clinical depression received tadalafil 20 mg, taken on demand, for up to 12 weeks. MAIN OUTCOME MEASURES: Efficacy was assessed using the International Index of Erectile Function (IIEF) and Sexual Encounter Profile (SEP). Psychosocial outcomes were evaluated using the Psychological and Interpersonal Relationship Scale (PAIRS). RESULTS: Tadalafil treatment significantly improved all domains of the IIEF from baseline, including the erectile function (EF) domain (change = 8.8, end point = 21.6; P < 0.001). Mean per-patient percentage of "yes" responses to SEP questions concerning successful penetration (SEP2; change = 33.5%, end point = 73.5%; P < 0.001) and successful intercourse (SEP3; change = 39.6%, end point = 59.6%; P < 0.001) also improved significantly from baseline. Forty percent of the patients with baseline EF scores < 26 had normal EF (IIEF-EF domain scores > or = 26) at end point, and 81% reported improved erections in the Global Assessment Questionnaire. At least 56% of attempts at sexual intercourse were successfully completed (SEP3) at all time intervals up to 36 hours after tadalafil administration. The patients also experienced significant improvement in both the sexual self-confidence and spontaneity domains of the PAIRS. Tadalafil was well tolerated, with < 5% of the patients discontinuing because of adverse events. CONCLUSION: Tadalafil 20 mg was effective and well tolerated in elderly men with ED.

Efficacy and safety of tadalafil in men with erectile dysfunction with a high prevalence of comorbid conditions: results from MOMENTUS: multiple observations in men with erectile dysfunction in National Tadalafil Study in the US.

INTRODUCTION: Limited efficacy and safety data exist from open-label clinical trials of phosphodiesterase 5 inhibitors in men with erectile dysfunction (ED) and multiple comorbid (MCM) conditions, historically a difficult group to treat. AIM: A multicenter study (Multiple Observations in Men with Erectile Dysfunction in National Tadalafil Study in the US) assessed efficacy and safety of tadalafil in men with ED and MCM conditions. MAIN OUTCOME MEASURES: The primary end point was change from baseline in the erectile function (EF) domain of the International Index of Erectile Function. Secondary end points included the Sexual Encounter Profile, Global Assessment Questions, and Sexual Self-Confidence and Spontaneity Domains of the Psychological and Interpersonal Relationship Scales. METHODS: This was an open-label, multicenter study in men with ED. Tadalafil 20 mg was administered as needed prior to sexual activity, up to once/day, for 12 weeks following a 4-week ED-treatment-free period. The MCM group was 155 of 1,911 men enrolled in this study. Men in the MCM group met eligibility criteria but could not be included in other predefined groups: (i) Caucasian; (ii) Black American; (iii) Hispanic (groups 1-3, < or =65 years, no diabetes or depression); (iv) depression, < or =65 years, no diabetes; (v) diabetes, < or =65 years, no depression; (vi) >65 years, no diabetes or depression; and (vii) ED subsequent to traumatic spinal cord injury. RESULTS: Mean baseline EF domain score in MCM (mean age 65 +/- 9 years) was 12.2 +/- 6.5; 52% of subjects had severe ED; 72% diabetes mellitus; 67% cardiovascular disease (including hypertension); 49% hyperlipidemia; 38% depression; 84% had two or more comorbidities. At end point, there was a significant (P < 0.001) mean change of 7.6 from baseline in mean EF domain score. Among men with severe ED, 22% achieved an EF domain score > or =26. Most common adverse events were headache 5.2%; flushing 3.9% and nasal congestion 3.2%; 3% discontinued use because of an adverse event. CONCLUSIONS: In this open-label clinical trial of older men with ED and MCMs, tadalafil 20 mg significantly increased all efficacy end points and was well-tolerated.

Through the eyes of women: the partners' perspective on tadalafil.

OBJECTIVES: To evaluate patient and female partner responses on the efficacy of, and overall satisfaction with, tadalafil to treat erectile dysfunction using sexual encounter profile (SEP) diaries. METHODS: Data were pooled from four double-blind, placebo-controlled, 12-week trials that included 746 couples. Patients were randomized to placebo or tadalafil 10 or 20 mg. Efficacy was evaluated by the mean per-patient/per-partner percentage of "yes" responses to patient SEP questions 1, 2, and 5 and partner SEP questions 1 to 3 (erection achievement, penetration, and overall satisfaction with the sexual experience, respectively) for tadalafil versus placebo. For each SEP question, the number of postbaseline intercourse attempts when each couple agreed on the outcome was tabulated and divided by the total number of postbaseline attempts to calculate the mean percentage of agreement by couple. The overall satisfaction with successful postbaseline intercourse attempts was determined. RESULTS: Tadalafil significantly improved the responses for the patient and partner-evaluated SEP questions (P <0.001, both doses versus placebo). Partners tended to report greater overall satisfaction than patients at baseline and postbaseline. The mean percentage of agreement by couple was approximately 98% for erection achievement and penetration and 85% for overall satisfaction. For successful intercourse attempts, patients and partners treated with tadalafil reported more overall satisfaction than those treated with placebo (P <0.05, tadalafil versus placebo comparisons). CONCLUSIONS: Partners reported significantly improved overall sexual satisfaction and corroborated the man's report of improved erections and penetration ability with tadalafil 10 mg or 20 mg. Men reported improved erection achievement, penetration, and overall satisfaction with the sexual experience after taking tadalafil.