Mitigating the Effects of Nonadherence in Clinical Trials.

Accounting for subject nonadherence and eliminating inappropriate subjects in clinical trials are critical elements of a successful study. Nonadherence can increase variance, lower study power, and reduce the magnitude of treatment effects. Inappropriate subjects (including those who do not have the illness under study, fail to report exclusionary conditions, falsely report medication adherence, or participate in concurrent trials) confound safety and efficacy signals. This paper, a product of the International Society for CNS Clinical Trial Methodology (ISCTM) Working Group on Nonadherence in Clinical Trials, explores and models nonadherence in clinical trials and puts forth specific recommendations to identify and mitigate its negative effects. These include statistical analyses of nonadherence data, novel protocol design, and the use of biomarkers, subject registries, and/or medication adherence technologies.

CNS sites cooperate to detect duplicate subjects with a clinical trial subject registry.

OBJECTIVE: To report the results of the first 1,132 subjects in a pilot project where local central nervous system trial sites collaborated in the use of a subject database to identify potential duplicate subjects. METHOD: Central nervous system sites in Los Angeles and Orange County, California, were contacted by the lead author to seek participation in the project. CTSdatabase, a central nervous system-focused trial subject registry, was utilized to track potential subjects at pre-screen. Subjects signed an institutional review board-approved authorization prior to participation, and site staff entered their identifiers by accessing a website. Sites were prompted to communicate with each other or with the database administrator when a match occurred between a newly entered subject and a subject already in the database. RESULTS: Between October 30, 2011, and August 31, 2012, 1,132 subjects were entered at nine central nervous system sites. Subjects continue to be entered, and more sites are anticipated to begin participation by the time of publication. Initially, there were concerns at a few sites over patient acceptance, financial implications, and/or legal and privacy issues, but these were eventually overcome. Patient acceptance was estimated to be above 95 percent. Duplicate Subjects (those that matched several key identifiers with subjects at different sites) made up 7.78 percent of the sample and Certain Duplicates (matching identifiers with a greater than 1 in 10 million likelihood of occurring by chance in the general population) accounted for 3.45 percent of pre-screens entered into the database. Many of these certain duplicates were not consented for studies because of the information provided by the registry. CONCLUSION: The use of a clinical trial subject registry and cooperation between central nervous system trial sites can reduce the number of duplicate and professional subjects entering clinical trials. To be fully effective, a trial subject database could be integrated into protocols across pharmaceutical companies, thereby mandating site participation and increasing the likelihood that duplicate subjects will be removed before they enter (and negatively affect) clinical trials.

Adjunctive therapy with pregabalin in generalized anxiety disorder patients with partial response to SSRI or SNRI treatment.

This study evaluated the efficacy of adjunctive pregabalin versus placebo for treatment of patients with generalized anxiety disorder (GAD) who had not optimally responded to previous or prospective monotherapies. This was a phase 3, randomized, double-blind, placebo-controlled study. Patients diagnosed with GAD who had a historical and current lack of response to pharmacotherapy [Hamilton Anxiety Rating Scale (HAM-A) of ≥ 22 at screening] were randomized to adjunctive treatment with either pregabalin (150-600 mg/day) or placebo. The primary outcome measure was the change in HAM-A total scores after 8 weeks of combination treatment. Adverse events were regularly monitored. Randomized patients (N=356) were treated with pregabalin (n=180) or placebo (n=176). Mean baseline HAM-A scores were 20.7 and 21.4, respectively. After treatment, the mean change in HAM-A was significantly greater for pregabalin compared with placebo (-7.6 vs. -6.4, respectively; P<0.05). HAM-A responder rates (≥ 50% reduction) were significantly higher for pregabalin (47.5%) versus placebo (35.2%; P=0.0145). The time-to-sustained response favored pregabalin over placebo (P=0.014). Adverse events were consistent with previous studies and discontinuations were infrequent for pregabalin (4.4%) and placebo (2.3%). The study was discontinued early after an interim analysis. The results indicate that adjunctive pregabalin is an efficacious therapy for patients with GAD who experience an inadequate response to established treatments.

Atomoxetine augmentation of cholinesterase inhibitor therapy in patients with Alzheimer disease: 6-month, randomized, double-blind, placebo-controlled, parallel-trial study.

OBJECTIVES: To examine the efficacy and tolerability of atomoxetine (ATX) in improving cognitive performance of patients with Alzheimer dementia. DESIGN: A randomized, double-blind, placebo (PLA)-controlled, parallel-groups study, starting with a 5-33-day screening and evaluation period, followed by a 6-month treatment period. SETTING: Eight independent or academic outpatient clinics in the United States. PARTICIPANTS: Male or female patients, aged 55 years and older, with mild-to-moderate Alzheimer disease (Mini-Mental State Examination score between 10 and 26) at baseline. INTERVENTION: ATX (25-80 mg/day) or PLA for up to 6 months, added to ongoing cholinesterase-inhibitor therapy. MEASUREMENTS: Alzheimer Disease Assessment Scale-Cognitive Portion (ADAS-Cog, primary measure), Clinician's Interview-Based Impression of Change score at end point, Neuropsychiatric Inventory, and Alzheimer's Disease Cooperative Study Inventory-Activities of Daily Living Inventory total score, safety measures (secondary measures). RESULTS: Patients' (N = 92) scores on assessments of cognitive function, global clinical impression, and neuropsychiatric symptoms were not significantly different between treatment groups. Neither group showed significant changes from baseline on the primary measure of efficacy, the ADAS-Cog. The ATX group showed a significantly greater increase of heart rate, and the mean increase in diastolic blood pressure and decrease in weight differed significantly from the decrease in pressure and weight increase in the PLA group. No other clinically meaningful safety results were obtained. CONCLUSIONS: Addition of ATX to ongoing cholinesterase-inhibitor therapy was generally well tolerated but did not significantly improve cognitive function.

Brasofensine treatment for Parkinson's disease in combination with levodopa/carbidopa.

OBJECTIVE: To investigate the safety, tolerability, pharmacokinetic, and pharmacodynamic properties of the dopamine transporter antagonist brasofensine (BMS-204756) in patients with Parkinson's disease receiving levodopa/carbidopa treatment. METHODS: A 4-period crossover study was performed in 8 men (mean age 66 y) with moderate Parkinson's disease (Hoehn-Yahr stage II-IV). A dose escalation study was used in which each patient was given a single oral dose of brasofensine 0.5, 1, 2, or 4 mg, which was coadministered with the patient's usual dose of levodopa/carbidopa. RESULTS: The maximum concentration (Cmax) values of brasofensine observed in plasma after oral administration were 0.35, 0.82, 2.14, and 3.27 ng/mL for the 0.5-, 1-, 2-, and 4-mg doses, respectively; these concentrations occurred 4 hours (time to Cmax) after administration in all cases. Exposure to brasofensine (based on AUC0-infinity) increased at a rate greater than proportional to dose. Based on the motor performance subscale of the Unified Parkinson's Disease Rating Scale, no change in patient disability was observed at any dose level. CONCLUSIONS: Brasofensine was safe and well tolerated in the patient cohort studied at daily doses of up to 4 mg. Adverse events were generally mild in intensity, and included headache, insomnia, phlebitis, dizziness, ecchymosis, and vomiting.