Donepezil Adherence, Persistence and Time to First Discontinuation in a Three-Year Follow-Up of Older People

Population Pharmacokinetic Modeling and Simulation for Dose Optimization of GB-5001, a Long-Acting Intramuscular Injection of Donepezil, in Healthy Participants

INTRODUCTION

GB-5001 is an intramuscular (IM) formulation of donepezil under development for the treatment of Alzheimer's disease. The objective of this study was to develop a population pharmacokinetic (PK) model for donepezil in both IM and oral formulations, and to optimize the IM dosage of GB-5001 using bioequivalence (BE) simulation.

METHODS

A population PK model of donepezil was developed using NONMEM. It was based on plasma concentration data from a Phase 1 dose escalation study, which involved a single administration of donepezil IM formulation at doses of 70, 140, and 280 mg, and the oral formulation at 10 mg. The model was evaluated based on goodness-of-fit plots, conditional weighted residuals, visual predictive checks, and bootstrapping. BE simulations were conducted using a parallel design between various doses of the IM formulation and the 10-mg dose of oral formulation.

RESULTS

The PKs of donepezil were best described by a two-compartment model, which incorporated distinct absorption compartments for the IM (dual first-order absorption and simultaneous zero-order absorption with lag time) and oral (first-order absorption with lag time) formulations. Based on the simulation results, an IM dosage range of 210-215 mg in a sample size of over 92 was estimated to achieve a success rate of approximately 80% for BE.

CONCLUSION

The population PK model well explained the PKs of donepezil following administration of both the IM and oral formulations. This model could be applied for the design and dose selection of future BE trials.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT05525780.

Preventing Donepezil-Induced Adverse Effects Through N-acetylcysteine Co-Administration

Background

Drug-induced adverse symptoms affect patients' quality of life (QoL) during treatment. Understanding the underlying mechanisms of drug-induced adverse effects could help prevent them. As current drugs have limited effects in halting the progress of Alzheimer's disease (AD), patients are required to take these drugs over a long period. The main obstacles to long-term compliance are drug-elicited side effects that deteriorate patient QoL.

Objective

Donepezil, the most popular acetylcholinesterase inhibitor (AChEI) drug for AD, induces various side effects, especially at high doses. This study aimed to identify a drug that can attenuate the side effects of donepezil and investigate the underlying mechanisms.

Methods

Five-week-old Sprague-Dawley rats received daily oral donepezil and N-acetylcysteine (NAC) for four weeks. General symptoms following administration were monitored daily to address drug-related adverse effects. Cytosolic calcium influx and generation of reactive oxygen species (ROS) after drug treatment were measured in vitro using C2C12 myotubes.

Results

High-dose donepezil induced numerous adverse symptoms in male and female rats, which were markedly attenuated by co-treatment with NAC. NAC significantly reduced both acute and chronic muscle-related symptoms caused by donepezil. Additionally, in vitro studies showed that high-dose donepezil increased ROS and intracellular calcium ([Ca2+]i) levels in muscle cells, contributing to these adverse effects. NAC co-treatment dramatically reduced ROS and [Ca2+]i levels in muscle cells.

Conclusions

Combined treatment with NAC effectively diminishes the adverse effects elicited by donepezil by regulating ROS and [Ca2+]i levels in the skeletal muscle, which could contribute to improving donepezil treatment in patients.

Safety, Feasibility, and Potential Clinical Efficacy of 40 Hz Invisible Spectral Flicker versus Placebo in Patients with Mild-to-Moderate Alzheimer's Disease: A Randomized, Placebo-Controlled, Double-Blinded, Pilot Study

BACKGROUND

Recent studies suggested induction of 40 Hz neural activity as a potential treatment for Alzheimer's disease (AD). However, prolonged exposure to flickering light raises adherence and safety concerns, encouraging investigation of tolerable light stimulation protocols.

OBJECTIVE

To investigate the safety, feasibility, and exploratory measures of efficacy.

METHODS

This two-stage randomized placebo-controlled double-blinded clinical trial, recruited first cognitive healthy participants (n = 3/2 active/placebo), and subsequently patients with mild-to-moderate AD (n = 5/6, active/placebo). Participants were randomized 1:1 to receive either active intervention with 40 Hz Invisible Spectral Flicker (ISF) or placebo intervention with color and intensity matched non-flickering white light.

RESULTS

Few and mild adverse events were observed. Adherence was above 86.1% of intended treatment days, with participants remaining in front of the device for >51.3 min (60 max) and directed gaze >34.9 min. Secondary outcomes of cognition indicate a tendency towards improvement in the active group compared to placebo (mean: -2.6/1.5, SD: 6.58/6.53, active/placebo) at week 6. Changes in hippocampal and ventricular volume also showed no tendency of improvement in the active group at week 6 compared to placebo. At week 12, a potential delayed effect of the intervention was seen on the volume of the hippocampus in the active group compared to placebo (mean: 0.34/-2.03, SD: 3.26/1.18, active/placebo), and the ventricular volume active group (mean: -0.36/2.50, SD: 1.89/2.05, active/placebo), compared to placebo.

CONCLUSION

Treatment with 40 Hz ISF offers no significant safety or adherence concerns. Potential impact on secondary outcomes must be tested in larger scale clinical trials.

Unexpected Findings During Double-blind Discontinuation of Acetylcholinesterase Inhibitor Medications

PURPOSE

The long-term effects of acetylcholinesterase inhibitors (AChEIs) used in the treatment of patients with various types of dementia remain unclear, largely due to challenges in the study of their discontinuation. We present several unexpected results from a discontinuation trial that might merit further investigation.

METHODS

This double-blind, placebo-controlled study of the discontinuation of AChEI medications was conducted in 62 US veterans. Participants were randomized to receive continued treatment with their medication (sham-taper group) or to treatment discontinuation via tapering (real-taper group), over a period of 6 weeks. The primary end point was the patient's/family caregiver's decision to discontinue the study medication.

FINDINGS

The study was underpowered to detect a significant between-group difference in the primary end point, but examination of the discontinuation process generated several unexpected results: (1) recruitment proved extremely challenging for a variety of reasons, with <5% of potentially eligible participants enrolled; (2) all 3 patients with Parkinson disease-associated dementia showed a worsening of symptoms when they discontinued their AChEI medication, but they showed improvement after they restarted it; (3) changes in symptom-scale scores varied quite broadly across participants, regardless of treatment arm; (4) unusual effects were noted in the sham-taper arm; and (5) the only significant predictor of the decision to discontinue the study medication was a worsening in the caregiver's mood.

IMPLICATIONS

These findings argue for the use of caution in discontinuing AChEIs in patients with Parkinson disease-associated dementia, although there may be potential benefits of a "drug holiday." The findings also urge the consideration of distress on the part of the caregiver while making medication treatment decisions in dementia. Future research must address challenges with recruitment and symptom fluctuations. (Clin Ther. 2021;43:XXX-XXX) © 2021 Elsevier Inc.

Effect of Psychoeducational Intervention on Donepezil Retention Rate and Analysis of Reasons for the Discontinuation in Patients with Alzheimer's Dementia: A Randomized Study

PURPOSE

Medication discontinuation for patients with Alzheimer's dementia (AD) influences treatment efficacy. This study aimed to evaluate the effect of psychoeducational intervention (PI) on donepezil retention rates and identify the factors associated with donepezil continuation in patients with AD.

PATIENTS AND METHODS

One hundred and seventeen patients with AD were randomly allocated to the PI (n = 58) or standard care (SC; n = 59) groups. All patients were prescribed donepezil for 48 weeks. Primary endpoints were the 48-week donepezil retention rate and the reasons for donepezil discontinuation in the PI and SC groups. The secondary endpoint was the predictive factors, among the baseline clinical variables, for donepezil continuation in all patients.

RESULTS

The donepezil retention rate was 62.1% (36/58) in the PI group and 66.1% (39/59) in the SC group. The most common reason for discontinuation in both groups was adverse events (PI, 12.1%; SC, 10.2%). Logistic regression analysis revealed that the results of the pentagon copying test in the Mini-Mental State Examination administered at baseline was a significant predictor of donepezil continuation for all patients in both the groups (odds ratio: 0.359; 95% confidence interval: 0.154-0.839).

CONCLUSION

There was no significant difference between the PI and SC groups concerning donepezil retention rate in patients with AD. Our results demonstrate that the pentagon copying test can significantly predict donepezil continuation in patients with AD, indicating that impaired visuospatial and executive functions may reflect medication discontinuation.

TRIAL REGISTRATION

UMIN-CTR:UMIN000012617.

Discontinuation Rate of Newly Prescribed Donepezil in Alzheimer's Disease Patients in Asia

Background and Purpose

The rate of donepezil discontinuation and the underlying reasons for discontinuation in Asian patients with Alzheimer's disease (AD) are currently unknown. We aimed to determine the treatment discontinuation rates in AD patients who had newly been prescribed donepezil in routine clinical practice in Asia.

Methods

This 1-year observational study involved 38 institutions in seven Asian countries, and it evaluated 398 participants aged 50–90 years with a diagnosis of probable AD and on newly prescribed donepezil monotherapy. The primary endpoint was the rate of donepezil discontinuation over 1 year. Secondary endpoints included the reason for discontinuation, treatment duration, changes in cognitive function over the 1-year study period, and compliance as assessed using a clinician rating scale (CRS) and visual analog scale (VAS).

Results

Donepezil was discontinued in 83 (20.9%) patients, most commonly due to an adverse event (43.4%). The mean treatment duration was 103.67 days in patients who discontinued. Among patients whose cognitive function was assessed at baseline and 1 year, there were no significant changes in scores on the Mini-Mental State Examination, Montreal Cognitive Assessment, and Trail-Making Test–Black and White scores, whereas the Clinical Dementia Rating score increased significantly (p<0.001). Treatment compliance at 1 year was 96.8% (306/316) on the CRS and 92.6±14.1% (mean±standard deviation) on the VAS.

Conclusions

In patients on newly prescribed donepezil, the primary reason for discontinuation was an adverse event. Cognitive assessments revealed no significant worsening at 1 year, indicating that continuous donepezil treatment contributes to the maintenance of cognitive function.

The effects of medication adherence on study outcomes in randomized clinical trials: A role for cognitive dysfunction?

Medication nonadherence is common and has been associated with poor health outcomes. Older adults are especially likely to be non-adherent to their medications, as they often have more medications to manage and are at greater risk for cognitive dysfunction. Though less frequently examined, the association between cognitive dysfunction and nonadherence also likely extends to clinical trials research. The current study used archival data to examine the potential impact of cognitive dysfunction on adherence to a nutritional supplement as part of a 90-day randomized clinical trial in neurologically healthy middle-aged and older adults. Results showed overall cognitive performance was predictive of adherence to capsule intake when controlling for polypharmacy [F(1,157) = 6.53, p < .01]. These results suggest that cognitive dysfunction may impact findings from RCTs through its adverse impact on adherence to study protocol, possibly leading to greater treatment variance, artificially reduced treatment effects, lower study power, and distorted study outcomes and conclusions. A better understanding of methodological and statistical approaches to account for these unwanted effects are needed.

One-Year Persistence with Donepezil, Memantine, and Rivastigmine in More than 66,000 Elderly Patients Followed in Poland

BACKGROUND

Previous studies have suggested that there are substantial differences between countries in terms of persistence with antidementia drugs and that the management of dementia is likely to be population-specific.

OBJECTIVE

The aim of this study was to analyze the one-year persistence with donepezil, memantine, and rivastigmine in more than 66,000 elderly patients followed in Poland.

METHODS

This study included patients who were prescribed donepezil, memantine, or rivastigmine for the first time in general and neuropsychiatric practices in Poland between September 2016 and December 2017 (index date; N = 66,030). The primary outcome of the study was the one-year persistence with donepezil, memantine, and rivastigmine. Non-persistence was defined as a gap of at least 90 days without anti-dementia therapy. The secondary outcome was the identification of variables significantly associated with treatment non-persistence.

RESULTS

After 12 months of follow-up, 42.2% of donepezil users, 46.0% of rivastigmine users, and 65.9% of memantine users were persistent (log-rank p-value <0.001). Memantine (hazard ratio [HR] = 0.58) and rivastigmine users (HR = 0.92) were less likely to discontinue treatment one year after initiation than donepezil users. Furthermore, a younger age (60-64 years: HR = 1.32; 65-74 years: HR = 1.13) and therapy initiated by a neuropsychiatrist (HR = 1.11) were positively associated with therapy discontinuation, while we observed a negative association between the prescription of anti-psychotic drugs and non-persistence (HR = 0.81).

CONCLUSION

One-year persistence with donepezil, memantine, and rivastigmine was low in elderly patients followed in Poland, and was influenced by age, physician specialty, and co-therapy.

Time-to-First Discontinuation, Adherence and Persistence in New Users of Second-Generation Antipsychotics

Consensus guidelines which are applicable in New Zealand and worldwide recommend that the duration of exposure to antipsychotics not exceed 12 weeks, unless justified for mental illnesses like schizophrenia and severe psychotic symptoms which require longer treatment. There has been limited information on time-to-first discontinuation (TTFD) for second-generation antipsychotics (SGAs) in a real world population setting in older people. The study objective was to compare TTFD, adherence, and persistence for individual SGA new users among people 65 years and older. A cohort of 30,297 SGA new users was followed up for antipsychotic discontinuation from January 1, 2006, to December 31, 2012. Data for oral formulations were extracted using health care databases from the New Zealand Ministry of Health. The TTFD, adherence, and persistence were defined using (dispensing gap ≥ 91 days, variable medication possession ratio ≥ 0.8, and gap duration < 91 days between refills), respectively. Kaplan-Meier curves and Cox regression analysis were used to estimate and adjust for outcomes. The overall TTFD in SGA new users was 192.3 days (95% confidence interval [CI], 177.6-206.9), mean age at dispensing was 80.9 years (SD, 8.1 years), and 60.3% were women. The TTFD for was shortest for risperidone, 101.3 days (95% CI, 85.0-117.7; P = 0.03) compared with clozapine, 68.3 days (95% CI: 43.7, 92.9). The adjusted all-cause TTFD risk for risperidone, olanzapine, quetiapine, or ziprasidone (hazard ratios, 0.54, 0.29, 0.22, and 0.08, respectively) was significantly lower than clozapine. The TTFD risk in the nonadherent compared with the adherent group was more than 3 times.