Background: High placebo response in attention deficit hyperactivity disorder (ADHD) can reduce medication-placebo differences, jeopardizing the development of new medicines. This research aims to (1) determine placebo response in ADHD, (2) compare the accuracy of meta-regression and MetaForest in predicting placebo response, and (3) determine the covariates associated with placebo response.
Methods: A systematic review with meta-analysis of randomized, placebo-controlled clinical trial investigating pharmacological interventions for ADHD was performed. Placebo response was defined as the change from baseline in ADHD symptom severity assessed according to the 18-item, clinician-rated, DSM-based rating scale. The effect of study design-, intervention-, and patient-related covariates in predicting placebo response was studied by means of meta-regression and MetaForest.
Results: Ninety-four studies including 6614 patients randomized to placebo were analyzed. Overall, placebo response was -8.9 points, representing a 23.1% reduction in the severity of ADHD symptoms. Cross-validated accuracy metrics for meta-regression were R2 = 0.0012 and root mean squared error = 3.3219 for meta-regression and 0.0382 and 3.2599 for MetaForest. Placebo response among ADHD patients increased by 63% between 2001 and 2020 and was larger in the United States than in other regions of the world.
Conclusions: Strong placebo response was found in ADHD patients. Both meta-regression and MetaForest showed poor performance in predicting placebo response. ADHD symptom improvement with placebo has markedly increased over the last 2 decades and is greater in the United States than the rest of the world.
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http://dx.doi.org/10.1093/ijnp/pyab054 | DOI Listing |
Background: Phase 3 randomized clinical trials within Alzheimer's Disease (AD) typically last over 18 months. Post-baseline participants can use additional treatment for Alzheimer's disease, potentially impacting the cognitive ability as evaluated by the primary endpoint. Consequently, this could overestimate or underestimate the treatment effect, depending on the distribution of usage between treatment arms.
View Article and Find Full Text PDFBackground: While a number of recent anti-amyloid antibodies demonstrated a robust reduction of amyloid biomarkers in clinical trials, the impact on functional improvement is much more variable. We hypothesize that this larger variability is driven by comedications, common genotype variants and underlying tau pathology.
Method: In a previously calibrated computational neuroscience model of ADAS-Cog, we implemented the effect of soluble amyloid monomers and oligomers on glutamate and nicotinic AChR neurotransmission and the effect of intracellular tau oligomers on voltage-gated Na and K+ channels and synaptic density.
Background: Patients with Alzheimer's disease (AD) often experience burdensome neuropsychiatric symptoms, including agitation which occurs in both home and long-term care (LTC) facilities, and is associated with substantial increases in caregiver burden and LTC placements. AXS-05 (45-mg dextromethorphan/105-mg bupropion), a novel, oral NMDA receptor antagonist and sigma-1 receptor agonist, approved by the FDA for major depressive disorder, is being investigated for treatment of AD agitation (ADA). AXS-05 has been evaluated in 2 randomized, double-blind studies: Phase 2 ADVANCE-1 (NCT03226522); Phase 3 ACCORD (NCT04797715).
View Article and Find Full Text PDFBackground: Pivotal Alzheimer's Disease (AD) trials typically require thousands of participants, resulting in long enrollment timelines and substantial costs. We leverage deep learning predictive models to create prognostic scores (forecasted control outcome) of trial participants and in combination with a linear statistical model to increase statistical power in randomized clinical trials (RCT). This is a straightforward extension of the traditional RCT analysis, allowing for ease of use in any clinical program.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
School of Medicine, Johns Hopkins University, and Johns Hopkins Bayview Medical Center, Baltimore, MD, USA.
Background: Agitation is a common and disabling symptom of Alzheimer's dementia (AD). Pharmacological treatments are recommended if agitation is not responsive to psychosocial intervention. Citalopram was effective in treating agitation in AD but was associated with cognitive and cardiac risks linked to its R- but not S-enantiomer.
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