Ravi Anand

Efficacy of rivastigmine in dementia with Lewy bodies: a randomised, double-blind, placebo-controlled international study

BACKGROUND Dementia with Lewy bodies is a common form of dementia in the elderly, characterised clinically by fluctuating cognitive impairment, attention deficits, visual hallucinations, parkinsonism, and other neuropsychiatric features. Neuroleptic medication can provoke severe sensitivity reactions in patients with dementia of this type. Many deficits in cholinergic neurotransmission are seen in the brain of patients with Lewy-body dementia; therefore, drugs enhancing central cholinergic function represent a rationally-based therapeutic approach to this disorder. Rivastigmine, a cholinesterase inhibitor, was tested in a group of clinically characterised patients with Lewy-body dementia. METHODS A placebo-controlled, double-blind, multicentre study was done in 120 patients with Lewy-body dementia from the UK, Spain, and Italy. Individuals were given up to 12 mg rivastigmine daily or placebo for 20 weeks, followed by 3 weeks rest. Assessment by means of the neuropsychiatric inventory was made at baseline, and again at weeks 12, 20, and 23. A computerised cognitive assessment system and neuropsychological tests were also used, and patients underwent close medical and laboratory safety analysis. FINDINGS Patients taking rivastigmine were significantly less apathetic and anxious, and had fewer delusions and hallucinations while on treatment than controls. Almost twice as many patients on rivastigmine (37, 63%), than on placebo (18, 30%), showed at least a 30% improvement from baseline. In the computerised cognitive assessment system and the neuropsychological tests, patients were significantly faster and better than those on placebo, particularly on tasks with a substantial attentional component. Both predefined primary efficacy measures differed significantly between rivastigmine and placebo. After drug discontinuation differences between rivastigmine and placebo tended to disappear. Known adverse events of cholinesterase inhibitors (nausea, vomiting, anorexia) were seen more frequently with rivastigmine than with placebo, but safety and tolerability of the drug in these mostly multimorbid patients were judged acceptable. INTERPRETATION Rivastigmine 6-12 mg daily produces statistically and clinically significant behavioural effects in patients with Lewy-body dementia, and seems safe and well tolerated if titrated individually.

A 52-Week Study of the Efficacy of Rivastigmine in Patients with Mild to Moderately Severe Alzheimer’s Disease

The efficacy of a centrally active cholinesterase inhibitor, rivastigmine tartrate (ENA 713; Exelon®), in patients with mild to moderately severe Alzheimer’s disease was evaluated in a 26-week open-label extension of a 26-week, double-blind, placebo-controlled study. By 52 weeks, patients originally treated with 6–12 mg/day rivastigmine had significantly better cognitive function than patients originally treated with placebo.

Effects of rivastigmine on cognitive function in dementia with lewy bodies: a randomised placebo-controlled international study using the cognitive drug research computerised assessment system.

This study was designed to assess the effects of rivastigmine (Exelon®) on the cognitive functioning of patients suffering from dementia with Lewy bodies. This was a prospective, multi-centre, randomised, double-blind, placebo-controlled exploratory study conducted at sites in the UK, Spain and Italy. The treatment period was 20 weeks with a 3-week posttreatment follow-up. The primary outcome measures were the Cognitive Drug Research (CDR) computerised assessment system and the Neuropsychiatric Inventory. Testing was conducted prior to dosing and then again at weeks 12, 20 and 23. Analysis of the data from the 92 patients who completed the study identified a significant pattern of benefits of rivastigmine over placebo on the CDR system. These benefits were seen on tests of attention, working memory and episodic secondary memory. Taking attention for example, patients given placebo showed a significant deterioration from predosing scores at 12 and 20 weeks, whereas patients on rivastigmine performed significantly above their predosing levels. These effects were also large in magnitude, the decline under placebo at week 12 being 19%, while the improvement under rivastigmine was 23%. The clinical relevance of this 23% improvement was that it took the patients 33% towards being normal for their age on this assessment of attention. These benefits to cognitive function were accompanied by a significant improvement of the other primary outcome measure, the Neuropsychiatric Inventory. Three weeks after discontinuation of rivastigmine, most parameters of cognitive performance returned to predrug levels.

Brain metabolic and clinical effects of rivastigmine in Alzheimer's disease

In-vivo metabolic measures with positron emission tomography using (18)F-fluorodeoxyglucose (FDG-PET) have demonstrated hypometabolism in temporal, frontal, and hippocampal areas during the early stages of Alzheimers disease (AD). Progression of the dementia in AD involves compromised cholinergic functioning. Cholinesterase inhibitors have demonstrated efficacy in improving cognition and behaviour in AD. In this study, we demonstrate the usefulness of FDG-PET in measuring the progression of untreated AD and its modification by treatment with rivastigmine (Exelon, Novartis Pharmaceuticals, East Hanover, New Jersey, USA), a centrally selective cholinesterase inhibitor of the carbamate type. Patients with mild to moderate probable AD (Mini-Mental Status Exam scores of 10-26, inclusive) were enrolled in a double-blind, placebo controlled comparison of three fixed daily doses of rivastigmine (3, 6, or 9 mg/d) or placebo for 26 wk. FDG-PET scans were obtained on 27 patients at baseline and following 26 wk of treatment using the Snodgrass Picture Naming activation task. A total of 71.4% of the patients treated with placebo deteriorated clinically compared to only 25.0% of the patients treated with rivastigmine (chi2 = 4.8; p & 0.03). Rivastigmine-responders (i.e. those who clinically improved or remained clinically stable as measured by the Clinicianaposs Interview-Based Impression of Change-plus) showed a marked increase in brain metabolism (p <0.01) involving, but not limited to, structures comprising the memory-related cortices and the prefrontal system. These metabolic changes were not observed in the placebo-treated patients or the rivastigmine non-responders. Of note is that responders increased hippocampal metabolism by 32.5% (p < 0.03) compared to a non-significant decrease in the non-responders (6.4%) and placebo-treated patients (4.1%). These results are consistent with the literature suggesting that FDG-PET can sensitively measure the progression of AD and its improvement with cholinesterase inhibitors. Rivastigmine prevented the expected deterioration in clinical status and dramatically increased brain metabolic activity in a majority of patients.

An efficacy and safety analysis of Exelon® in Alzheimer’s disease patients with concurrent vascular risk factors

We evaluated the efficacy and safety of the centrally acting cholinesterase inhibitor, rivastigmine tartrate, for patients with mild to moderately severe Alzheimer’s disease (AD) with or without concurrent vascular risk factors (VRF). Patients (45–90 years of age) were randomized to placebo (n = 235), low‐dose rivastigmine (1–4 mg/day, n = 233), or high‐dose rivastigmine (6–12 mg/day, n = 231) for 26 weeks. Efficacy measures included the Alzheimer’s Disease Assessment Scale‐Cognitive subscale (ADAS‐Cog), the Clinician’s Interview Based Impression of Change (CIBIC‐Plus), the Progressive Deterioration Scale (PDS), the Global Deterioration Scale (GDS), and the Mini‐Mental State Examination (MMSE). For efficacy and safety analysis, patients were categorized by baseline Modified Hachinski Ischemic Score (MHIS) for the determination of VRF (MHIS > 0: presence of VRF; MHIS = 0: absence of VRF). As early as 12 weeks, the mean change from the baseline ADAS‐Cog score was significantly different for those patients treated with high‐dose rivastigmine compared with placebo controls in both MHIS categories. However, the treatment difference between high‐dose rivastigmine and placebo at each time‐point was larger for patients with MHIS > 0. The proportion of responders was significantly greater in the high‐dose rivastigmine group for each level of improvement. No differences were noted between treatment groups regarding safety evaluations. Rivastigmine is effective in both categories of patients, and those with VRF experience greater clinical benefit (cognition, activities of daily living, and disease severity).

What Is Causing the Reduced Drug-Placebo Difference in Recent Schizophrenia Clinical Trials and What Can be Done About It?

On September 18, 2007, a collaborative session between the International Society for CNS Clinical Trials and Methodology and the International Society for CNS Drug Development was held in Brussels, Belgium. Both groups, with membership from industry, academia, and governmental and nongovernmental agencies, have been formed to address scientific, clinical, regulatory, and methodological challenges in the development of central nervous system therapeutic agents. The focus of this joint session was the apparent diminution of drug-placebo differences in recent multicenter trials of antipsychotic medications for schizophrenia. To characterize the nature of the problem, some presenters reported data from several recent trials that indicated higher rates of placebo response and lower rates of drug response (even to previously established, comparator drugs), when compared with earlier trials. As a means to identify the possible causes of the problem, discussions covered a range of methodological factors such as participant characteristics, trial designs, site characteristics, clinical setting (inpatient vs outpatient), inclusion/exclusion criteria, and diagnostic specificity. Finally, possible solutions were discussed, such as improving precision of participant selection criteria, improving assessment instruments and/or assessment methodology to increase reliability of outcome measures, innovative methods to encourage greater subject adherence and investigator involvement, improved rater training and accountability metrics at clinical sites to increase quality assurance, and advanced methods of pharmacokinetic/pharmacodynamic modeling to optimize dosing prior to initiating large phase 3 trials. The session closed with a roundtable discussion and recommendations for data sharing to further explore potential causes and viable solutions to be applied in future trials.

Long-term effects of rivastigmine in moderately severe Alzheimer's disease: Does early initiation of therapy offer sustained benefits?

Goals of the study included evaluating the long-term efficacy of rivastigmine in Alzheimers disease (AD) patient categories stratified by baseline dementia severity, and post hoc investigation of particular benefits of early initiation of rivastigmine treatment in moderately severe AD. Both rivastigmine-treated groups (originally randomized to 1-4 or 6-12 mg/day) experienced significantly smaller declines in Alzheimers Disease Assessment Scale-Cognitive subscale (ADAS-Cog) scores from baseline than the projected placebo group after 52 weeks. Patients receiving rivastigmine from Day 1 experienced significantly less decline compared with patients originally receiving placebo and then initiating rivastigmine treatment after a 6-month delay. Furthermore, cognitive benefits were more robust in patients with moderately severe disease compared with previous reports in mild to moderately severe AD. Findings suggest that early treatment with rivastigmine 6-12 mg/day is associated with sustained long-term cognitive benefits in patients with moderately severe AD. The results support the value of early treatment of AD patients, particularly those with moderately severe AD.

Predicting suicidal risk in schizophrenic and schizoaffective patients in a prospective two-year trial

BACKGROUND Enhanced ability to reliably identify risk factors for suicidal behavior permits more focused decisions concerning treatment interventions and support services, with potential reduction in lives lost to suicide. METHODS This study followed 980 patients at high risk for suicide in a multicenter prospective study for 2 years after randomization to clozapine or olanzapine. A priori predictors related to diagnosis, treatment resistance, and clinical constructs of disease symptoms were evaluated as possible predictors of subsequent suicide-related events. RESULTS Ten baseline univariate predictors were identified. Historical predictors were diagnosis of schizoaffective disorder, history or current use at baseline of alcohol or substance abuse, cigarette smoking, number of lifetime suicide attempts, and the number of hospitalizations in the previous 36 months to prevent suicide. Predictive clinical features included greater baseline scores on the InterSePT scale for suicidal thinking, the Covi Anxiety Scale, the Calgary Depression Scale (CDS), and severity of Parkinsonism. Subsequent multivariate analysis revealed the number of hospitalizations in the previous 36 months, baseline CDS, severity of Parkinsons, history of substance abuse, and lifetime suicide attempts. Clozapine, in general, was more effective than olanzapine in decreasing the risk of suicidality, regardless of risk factors present. CONCLUSIONS This is the first prospective analysis of predictors of suicide risk in a large schizophrenic and schizoaffective population judged to be at high risk for suicide. Assessment of these risk factors may aid clinicians in evaluating risk for suicidal behaviors so that appropriate interventions can be made.

Dementia with Lewy bodies: findings from an international multicentre study

Objectives. To describe the baseline demographic, neuropsychiatric and neurological data of a large selected clinical sample of patients with dementia with Lewy Bodies (DLB) from an international multicentre trial with rivastigmine. To examine the usefulness of the Consensus Criteria for the diagnosis of DLB in different countries.

The InterSePT scale for suicidal thinking reliability and validity

BACKGROUND The InterSePT Scale for Suicidal Thinking (ISST) is a 12-item instrument for the assessment of current suicidal ideation in patients with schizophrenia and schizoaffective disorders. We report the psychometric characteristics of this new scale based on two studies. METHOD In Study 1, 22 inpatients with schizophrenia and schizoaffective disorders, who had recently attempted suicide or engaged in suicidal ideation, were rated by three trained independent raters to examine interrater reliability. In Study 2, a total of 980 patients with schizophrenia or schizoaffective disorder with a history of suicidal ideation in the past 36 months were enrolled in a 2-year industry-sponsored suicide prevention study. At baseline, these patients were administered the ISST and the Clinical Global Impression Scale for Severity of Suicidality (CGI-SS) by the Principal Investigator (PI) and by a blinded rater (BR), who also administered the Positive and Negative Symptom Scale (PANSS), the Calgary Depression Scale (CDS), and the Scale of Functioning (SOF). Indices of internal reliability, construct and discriminant validity were examined. RESULTS The intraclass correlation coefficient (ICC) for the total ISST score for the 22 subjects in Study 1 was 0.90 and mean weighted item kappa coefficients ranged from 0.66 to 0.92. In Study 2, internal reliability (Cronbach alpha) was high, ranging from 0.86 to 0.89 for the individual items, and the overall Cronbach alpha coefficient for all items was 0.88. The ISST (PI) total score was highly correlated with the CGI-SS by the blind rater (r = 0.61, p < 0.0001). ISST total scores significantly differentiated the different levels of CGI-SS (F = 519.2; p < 0.0001). Results of construct and discriminant validity analyses are also presented. CONCLUSION The ISST is a reliable and valid instrument for the assessment of current suicidal thinking in patients with schizophrenia and schizoaffective disorder by both clinicians and researchers.