Designing a trial to evaluate potential treatments for apathy in dementia: the apathy in dementia methylphenidate trial (ADMET)

Effect of Methylphenidate on Apathy in Patients With Alzheimer Disease: The ADMET 2 Randomized Clinical Trial

Importance

Apathy, characterized by diminished will or initiative and one of the most prevalent neuropsychiatric symptoms in individuals with Alzheimer disease, is associated with significant caregiver burden, excess disability, increased medical costs, and mortality.

Objective

To measure whether methylphenidate compared with placebo decreases the severity of apathy in individuals with Alzheimer disease.

Design, Setting, and participants

This multicenter randomized placebo-controlled clinical trial was conducted from August 2016 to July 2020 in 9 US clinics and 1 Canadian clinic specializing in dementia care. A total of 307 potential participants were screened. Of those, 52 did not pass screening and 55 were not eligible. Participants with Alzheimer disease, mild to moderate cognitive impairment, and frequent and/or severe apathy as measured by the Neuropsychiatric Inventory (NPI) were included.

Interventions

Ten milligrams of methylphenidate, twice daily, vs matching placebo.

Main Outcomes and Measures

The coprimary outcomes included (1) change from baseline to 6 months in the NPI apathy subscale or (2) improved rating on the Alzheimer's Disease Cooperative Study Clinical Global Impression of Change. Other outcomes include safety, change in cognition, and quality of life.

Results

Of 200 participants, 99 were assigned to methylphenidate and 101 to placebo. The median (interquartile range) age of study participants was 76 (71-81) years; 68 (34%) were female and 131 (66%) were male. A larger decrease was found from baseline to 6 months in the NPI apathy score in those receiving methylphenidate compared with placebo (mean difference, -1.25; 95% CI, -2.03 to -0.47; P = .002). The largest decrease in the NPI apathy score was observed in the first 100 days, with a significant hazard ratio for the proportion of participants with no apathy symptoms receiving methylphenidate compared with placebo (hazard ratio, 2.16; 95% CI, 1.19-3.91; P = .01). At 6 months, the odds ratio of having an improved rating on the Alzheimer's Disease Cooperative Study Clinical Global Impression of Change for methylphenidate compared with placebo was 1.90 (95% CI, 0.95-3.84; P = .07). The difference in mean change from baseline to 6 months estimated using a longitudinal model was 1.43 (95% CI, 1.00-2.04; P = .048). Cognitive measures and quality of life were not significantly different between groups. Of the 17 serious adverse events that occurred during the study, none were related to the study drug. No significant differences in the safety profile were noted between treatment groups.

Conclusions and Relevance

This study found methylphenidate to be a safe and efficacious medication to use in the treatment of apathy in Alzheimer disease.

Trial Registration

ClinicalTrials.gov Identifier: NCT02346201.

Neuropsychiatric Aspects of Alzheimer Dementia: From Mechanism to Treatment

Developing disease-modifying treatments for Alzheimer dementia requires innovative approaches to identify novel biological targets during the course of the disease. Treatment development for the neuropsychiatric symptoms of Alzheimer may benefit from a mechanistic approach to treatment. There has been progress in identifying mild forms of behavioral impairment along the Alzheimer spectrum that may lead to additional insights into progression to dementia as well as the fundamental mechanisms of the symptoms. Developing therapies for complex neurobehavioral syndromes may require the translation of mechanistic insights into therapy, which may both improve the symptoms and delay progression to dementia in certain patients.

Behavioral and psychological symptoms in Alzheimer's dementia and vascular dementia

Behavioral and psychological symptoms of dementia (BPSD) are highly prevalent and represent a significant burden for patients and their caregivers. Early recognition and management of these symptoms is crucial as they are associated with increased risk of institutionalization, impairments in daily functioning, reduced quality of life, and more rapid progression to severe dementia. This chapter will discuss the pathophysiology, proposed diagnostic criteria, clinical features, and management of BPSD, including apathy, depression, agitation/aggression, psychosis, and sleep disturbances. Apathy and depression are the most common overall, and apathy is associated with high symptom severity likely because of its greater persistence. Symptoms such as agitation, aggression, hallucinations, and delusions may be especially distressing and dangerous to patients and caregivers. Nonpharmacologic management should be considered first-line therapy in most cases due to the modest and inconsistent evidence base for pharmacologic agents and greater risk of harm. However, the judicious use of pharmacologic agents may be warranted when symptoms are dangerous and/or severely distressing.

Symptomatic Treatment of Vascular Cognitive Impairment (STREAM-VCI): Protocol for a Cross-Over Trial

Background

People with vascular cognitive impairment (VCI) constitute a clinically heterogeneous group, but previous symptomatic drug trials in VCI did not take this clinical heterogeneity into account. Executive dysfunction and memory impairment are the cognitive domains that are most frequently impaired in VCI, and these impairments are likely to reflect vascular damage to specific neurotransmitter systems, which opens the possibility for targeted symptomatic treatment directed at specific neurotransmitters.

Objective

Here we describe the design of the “Symptomatic Treatment of Vascular Cognitive Impairment” (STREAM-VCI) trial. In this proof-of-concept study, we investigate whether people with VCI with executive dysfunction due to vascular damage to the monoaminergic neurotransmitter system differentially respond to a monoaminergic challenge, whereas people with VCI with memory dysfunction associated with vascular damage to the cholinergic system will in turn respond to a cholinergic challenge.

Methods

The STREAM-VCI is a single center, double blind, three-way cross-over trial among 30 people with VCI, in which subjects received a single dose of galantamine, methylphenidate, or placebo on separate occasions. The most important inclusion criteria were a diagnosis of VCI with a Mini-Mental State Examination score of ≥16 and a Clinical Dementia Rating of 0.5-1.0. For each person, the challenges consisted of a single 16 mg dose of galantamine, 10 mg of methylphenidate, and placebo, in random order on three separate visits. Change in performance in executive functioning and memory was assessed directly after the challenge using standardized neuropsychological tests. We will correlate a positive response to the cholinergic and monoaminergic treatment with differences in structural and functional connectivity at baseline using structural magnetic resonance imaging (MRI), diffusion tension MRI, and resting-state functional MRI.

Results

The protocol of this study is approved by the Medical Ethics Committee of VU University Medical Center and the competent authority. The first participant was enrolled in April 2014. In September 2017, enrolment for the study was completed. We expect to publish the results in 2018.

Conclusions

STREAM-VCI is the first study to investigate the association of a response to a cholinergic and monoaminergic treatment with structural and functional connectivity of the monoaminergic and/or cholinergic systems on MRI. We aim to predict on an individual basis which individuals show a positive response to a cholinergic and/or monoaminergic challenge in people with VCI. This may be instrumental in moving in the direction of individually-tailored pharmacological interventions based on MRI measures in people with VCI.

Trial Registration

ClinicalTrials.gov NCT02098824; https://clinicaltrials.gov/ct2/show/NCT02098824 (Archived by WebCite at http://www.webcitation.org/6xhO7Ya1q)

The Apathy in Dementia Methylphenidate Trial 2 (ADMET 2): study protocol for a randomized controlled trial

BACKGROUND

Alzheimer's disease (AD) is characterized not only by cognitive and functional decline, but also often by the presence of neuropsychiatric symptoms. Apathy, which can be defined as a lack of motivation, is one of the most prevalent neuropsychiatric symptoms in AD and typically leads to a worse quality of life and greater burden for caregivers. Treatment options for apathy in AD are limited, but studies have examined the use of the amphetamine, methylphenidate. The Apathy in Dementia Methylphenidate Trial (ADMET) found that treatment of apathy in AD with methylphenidate was associated with significant improvement in apathy in two of three outcome measures, some evidence of improvement in global cognition, and minimal adverse events. However, the trial only enrolled 60 participants who were followed for only 6 weeks. A larger, longer-lasting trial is required to confirm these promising findings.

METHODS

The Apathy in Dementia Methylphenidate Trial 2 (ADMET 2) is a phase III, placebo-controlled, masked, 6-month, multi-center, randomized clinical trial targeted to enroll 200 participants with AD and apathy. Participants are randomly assigned 1:1 to 20 mg methylphenidate per day prepared as four over-encapsulated tablets or to matching placebo. The primary outcomes include (1) the mean difference in the Neuropsychiatric Inventory Apathy subscale scores measured as change from baseline to 6 months, and (2) the odds of having a given rating or better on the modified AD Cooperative Study Clinical Global Impression of Change ratings at month 6 compared with the baseline rating. Other outcomes include change in cognition, safety, and cost-effectiveness measured at monthly follow-up visits up to 6 months.

DISCUSSION

Given the prevalence of apathy in AD and its impact on both patients and caregivers, an intervention to alleviate apathy would be of great benefit to society. ADMET 2 follows on the promising results from the original ADMET to evaluate the efficacy of methylphenidate as a treatment for apathy in AD. With a larger sample size and longer follow up, ADMET 2 is poised to confirm or refute the original ADMET findings.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02346201 . Registered on 26 January 2015.

Apathy in Neurodegenerative Diseases: Recommendations on the Design of Clinical Trials

Apathy is a common feature of neurodegenerative disorders but is difficult to study in a clinical trial setting due to practical and conceptual barriers. Principal challenges include a paucity of data regarding apathy in these disorders, an absence of established diagnostic criteria, the presence of confounding factors (eg, coexisting depression), use of concomitant medications, and an absence of a gold-standard apathy assessment scale. Based on a literature search and ongoing collaboration among the authors, we present recommendations for the design of future clinical trials of apathy, suggesting Alzheimer disease and Parkinson disease as models with relevance across a wider array of neuropsychiatric disorders. Recommendations address clarification of the targeted study population (apathy diagnosis and severity at baseline), confounding factors (mood/cognition, behavior, and treatment), outcome measures, study duration, use of comparators and considerations around environment, and the role of the caregiver and patient assent. This review contributes to the search for an optimal approach to study treatment of apathy in neuropsychiatric disorders.

Quantifying motivational deficits and apathy: a review of the literature

Varying definitions of apathy in the published literature and a lack of a consensus regarding diagnostic criteria make the identification and quantification of apathy difficult in both clinical trials and clinical practice. The Apathy Evaluation Scale was developed specifically to assess apathy, but variations in the threshold values defined for clinically significant apathy diminish its use as a screening tool in clinical trials, although it has demonstrated sensitivity to changes in treatment in a number of studies. The Neuropsychiatric Inventory contains an Apathy subscale, which has been used to identify clinical trial populations (with a consistent threshold value) and measure changes following treatment. Few of the other assessment tools currently used in patients with neuropsychiatric disorders are specific for apathy or explore it in any depth, most have not been validated in the general population, do not have cut-off points representing clinically significant apathy, and its changes over time and in response to treatment. Further research is required to address these issues in order to facilitate the quantification of apathy and its natural history. Such research should be conducted with the aim of developing new, specific tools for use across neuropsychiatric disorders.

Assessment of potential cardiovascular risks of methylphenidate in comparison with sibutramine: do we need a SCOUT (trial)?

With the recent approval of methylphenidate (MPH) for treating attention-deficit/hyperactivity disorder (ADHD) in adults, the number of patients exposed will increase tremendously. The ongoing debate on the cardiovascular safety of MPH has triggered two large retrospective cohort studies in children and adolescents as well as in young to middle-aged adults. These studies looked into serious cardiovascular events (sudden cardiac death, acute myocardial infarction and stroke) as primary endpoints and concluded that MPH was safe after a mean duration of 2.1 years of follow-up in children and adolescents and mean duration of 0.33 years of current use in adults. The results are encouraging with respect to the short- and medium-term use of MPH. Without the inherent limitations of retrospective cohort studies, a prospective randomized, double-blind, placebo-controlled, multicenter trial in individuals stratified for cardiovascular risk factors would allow for an optimized risk assessment. With many millions of patients treated per year and drawing parallels to the lately discovered risks of sibutramine, another sympathomimetic with an overlapping mode of action and similar side effects on heart rate and blood pressure, we hypothesize that such a trial might be a dedicated risk mitigation strategy for public health. A critical assessment of cardiovascular side effects of MPH appears particularly warranted, because ADHD is associated with obesity, smoking and poor health in general. We summarize recent findings with the focus on cardiovascular risks of MPH in humans; we additionally analyze the limited number of rodent studies that have addressed cardiovascular risks of MPH.

Molecular imaging of neuropsychiatric symptoms in Alzheimer's and Parkinson's disease

Neuropsychiatric symptoms (NPS) are very common in neurodegenerative diseases and are a major contributor to disability and caregiver burden. There is accumulating evidence that NPS may be a prodrome and/or a "risk factor" of neurodegenerative diseases. The medications used to treat these symptoms in younger patients are not very effective in patients with neurodegenerative disease and may have serious side effects. An understanding of the neurobiology of NPS is critical for the development of more effective intervention strategies. Targeting these symptoms may also have implications for prevention of cognitive or motor decline. Molecular brain imaging represents a bridge between basic and clinical observations and provides many opportunities for translation from animal models and human post-mortem studies to in vivo human studies. Molecular brain imaging studies in Alzheimer's disease (AD) and Parkinson's disease (PD) are reviewed with a primary focus on positron emission tomography studies of NPS. Future directions for the field of molecular imaging in AD and PD to understand the neurobiology of NPS will be discussed.

Principles and management of neuropsychiatric symptoms in Alzheimer's dementia

Neuropsychiatric symptoms of Alzheimer's disease (NPS-AD) are highly prevalent and lead to poor medical and functional outcomes. In spite of the burdensome nature of NPS-AD, we are continuing to refine the nosology and only beginning to understand the underlying pathophysiology. Cluster analyses have frequently identified three to five subsyndromes of NPS-AD: behavioral dysfunction (for example, agitation/aggressiveness), psychosis (for example, delusions and hallucinations), and mood disturbance (for example, depression or apathy). Recent neurobiological studies have used new neuroimaging techniques to elucidate behaviorally relevant circuits and networks associated with these subsyndromes. Several fronto-subcortical circuits, cortico-cortical networks, and neurotransmitter systems have been proposed as regions and mechanisms underlying NPS-AD. Common to most of these subsyndromes is the broad overlap of regions associated with the salience network (anterior cingulate and insula), mood regulation (amygdala), and motivated behavior (frontal cortex). Treatment strategies for dysregulated mood syndromes (depression and apathy) have primarily targeted serotonergic mechanisms with antidepressants or dopaminergic mechanisms with psychostimulants. Psychotic symptoms have largely been targeted with anti-psychotic medications despite controversial risk/benefit tradeoffs. Management of behavioral dyscontrol, including agitation and aggression in AD, has encompassed a wide range of psychoactive medications as well as non-pharmacological approaches. Developing rational therapeutic approaches for NPS-AD will require a firmer understanding of the underlying etiology in order to improve nosology as well as provide the empirical evidence necessary to overcome regulatory and funding challenges to further study these debilitating symptoms.

Brain apoptosis signaling pathways are regulated by methylphenidate treatment in young and adult rats

Methylphenidate (MPH) is commonly prescribed for children who have been diagnosed with attention deficit hyperactivity disorder (ADHD); however, the action mechanisms of methylphenidate have not been fully elucidated. Studies have shown a relationship between apoptosis signaling pathways and psychiatric disorders, as well as in therapeutic targets for such disorders. So, we investigated if chronic treatment with MPH at doses of 1, 2 and 10mg/kg could alter the levels of pro-apoptotic protein, Bax, anti-apoptotic protein, Bcl-2, caspase-3 and cytochrome c in the brain of young and adult Wistar rats. Our results showed that MPH at all doses increased Bax in the cortex; the Bcl-2 and caspase-3 were increased with MPH (1mg/kg) and were reduced with MPH (2 and 10mg/kg); the cytochrome c was reduced in the cortex after treatment with MPH at all doses; in the cerebellum there was an increase of Bax with MPH at all doses, however, there was a reduction of Bcl-2, caspase-3, and cytochrome c with MPH (2 and 10mg/kg); in the striatum the treatment with MPH (10mg/kg) decreased caspase-3 and cytochrome c; treatment with MPH (2 and 10mg/kg) increased Bax and decreased Bcl-2 in the hippocampus; and the caspase-3 and cytochrome c were reduced in the hippocampus with MPH (10mg/kg). In conclusion, our results suggest that MPH influences plasticity in the brain of young and adult rats; however, the effects were dependent of age and brain area, on the one hand activating the initial cascade of apoptosis, increasing Bax and reducing Bcl-2, but otherwise inhibiting apoptosis by reduction of caspase-3 and cytochrome c.

Effect of methylphenidate on attention in apathetic AD patients in a randomized, placebo-controlled trial

BACKGROUND

Little is known about the effect of methylphenidate (MPH) on attention in Alzheimer's disease (AD). MPH has shown to improve apathy in AD, and both apathy and attention have been related to dopaminergic function. The goal was to investigate MPH effects on attention in AD and assess the relationship between attention and apathy responses.

METHODS

MPH (10 mg PO twice daily) or placebo was administered for six weeks in a randomized, double-blind trial in mild-to-moderate AD outpatients with apathy (Neuropsychiatric Inventory (NPI) Apathy ≥ 4). Attention was measured with the Wechsler Adult Intelligence Scale--Digit Span (DS) subtest (DS forward, selective attention) and apathy with the Apathy Evaluation Scale (AES). A mixed effects linear regression estimated the difference in change from baseline between treatment groups, defined as δ (MPH (DS week 6-DS baseline)) - (placebo (DS week 6-DS baseline)).

RESULTS

In 60 patients (37 females, age = 76 ± 8, Mini-Mental State Examination (MMSE) = 20 ± 5, NPI Apathy = 7 ± 2), the change in DS forward (δ = 0.87 (95% CI: 0.06-1.68), p = 0.03) and DS total (δ = 1.01 (95% CI: 0.09-1.93), p = 0.03) favored MPH over placebo. Of 57 completers, 17 patients had improved apathy (≥3.3 points on the AES from baseline to end point) and 40 did not. There were no significant associations between AES and NPI Apathy with DS change scores in the MPH, placebo, AES responder, or non-responder groups. DS scores did not predict apathy response to MPH treatment.

CONCLUSION

These results suggest MPH can improve attention and apathy in AD; however, the effects appear independent in this population.

Safety and efficacy of methylphenidate for apathy in Alzheimer's disease: a randomized, placebo-controlled trial

OBJECTIVE

In a recent crossover trial, methylphenidate treatment decreased apathy in Alzheimer's disease. We further assessed this finding in the Apathy in Dementia Methylphenidate Trial (ADMET).

METHOD

Six-week, randomized, double-blind, placebo-controlled multicenter trial enrolling Alzheimer's disease participants (NINCDS-ADRDA criteria) with apathy assigned to methylphenidate 20 mg daily or placebo, conducted from June 2010 to December 2011. Primary outcomes were change in Apathy Evaluation Scale (AES) score and modified Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGI-C). Secondary outcomes included change in Neuropsychiatric Inventory (NPI) apathy score, Mini-Mental State Examination (MMSE) score, and safety.

RESULTS

60 participants were randomly assigned (29 methylphenidate, 31 placebo). At baseline, mean (SD) age = 76 (8) years, MMSE score = 20 (5), AES score = 51 (12), NPI total score = 16 (8), and 62% of the participants (n = 37) were female. After 6 weeks' treatment, mean (SD) change in AES score was -1.9 (1.5) for methylphenidate and 0.6 (1.4) for placebo (P = .23). Odds ratio for improvement in ADCS-CGI-C was 3.7 (95% CI, 1.3 to 10.8) (P = .02), with 21% of methylphenidate versus 3% of placebo rated as moderately or markedly improved. NPI apathy score improvement was 1.8 points (95% CI, 0.3 to 3.4) greater on methylphenidate than on placebo (P = .02). MMSE trended toward improvement on methylphenidate (P = .06). There were trends toward greater anxiety and weight loss > 2% in the methylphenidate-treated group.

CONCLUSIONS

Methylphenidate treatment of apathy in Alzheimer's disease was associated with significant improvement in 2 of 3 efficacy outcomes and a trend toward improved global cognition with minimal adverse events, supporting the safety and efficacy of methylphenidate treatment for apathy in Alzheimer's disease.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01117181.