Evaluation of Foquest in Adults 65 Years and Older With ADHD

This is a prospective, open-label, within-subject (pre-post), investigator-initiated Phase IV trial evaluating the safety and efficacy of Foquest (multilayer-release methylphenidate hydrochloride; MLR-MPH) in adults aged 65 years and older with a DSM-5 diagnosis of ADHD.

Background: Foquest is a once-daily oral stimulant consisting of a 20% immediate-release outer layer and an 80% delayed-release core, with onset of effect within approximately 1 hour and duration of up to 16 hours. It is approved by Health Canada for ADHD in adults up to age 65. The product monograph acknowledges that data are lacking for individuals above this age. Pharmacoepidemiologic evidence (Tadrous et al., 2021) suggests a transient increase in cardiovascular risk during the first 30 days of stimulant initiation in adults aged 66 and older, underscoring the need for careful cardiac screening and monitoring in this population.

Study Design: Each participant will be involved for approximately 10 weeks, comprising a 6-week dose titration phase, a 2-week maintenance phase, and a 2-week follow-up period. Participants will attend 5 in-person visits and 4 phone visits. Foquest will be initiated at 25 mg daily (or an investigator-selected dose based on prior medication history) and titrated weekly to a maximum of 100 mg daily based on efficacy and tolerability.

Cardiovascular Safety Monitoring: Enhanced cardiovascular monitoring is incorporated based on published evidence of early cardiovascular risk with stimulant initiation in older adults. Blood pressure and heart rate are measured in triplicate at screening and assessed at all in-person visits. Twelve-lead ECGs are performed at screening, baseline, Week 3, Week 5, and end of treatment (Week 8). Predefined criteria for treatment interruption include sustained resting heart rate greater than 100 bpm, systolic blood pressure greater than 180 mmHg, or diastolic blood pressure greater than 110 mmHg. Immediate discontinuation criteria include blood pressure at or above 180/120 mmHg, new arrhythmia, or symptoms suggestive of acute cardiovascular or cerebrovascular events.

Primary Endpoint: Mean change from baseline (Week 1) to end of treatment (Week 8) in AISRS total score, analyzed using a paired t-test in the modified intention-to-treat population.

Secondary Endpoints: Change from baseline to Week 8 in ASRS-5 total score, CGI-S score, BRIEF-A Global Executive Composite T-score, and distribution of CGI-I scores at Week 8. Cardiovascular parameters (systolic and diastolic blood pressure, heart rate, QTcF interval) and adverse events will be analyzed as safety endpoints.

Sample Size: 36 participants are planned, allowing for up to 15% attrition to ensure 30 completers, providing 80% power to detect a within-subject effect size of Cohen's d of 0.53 or greater.

This study addresses a critical evidence gap regarding the pharmacological treatment of ADHD in older adults and aims to inform evidence-based prescribing decisions for this underserved population.

Inclusion criteria

• Male or female aged 65 years or older at the time of consent.
• Mentally and physically competent to provide informed consent and willing to comply with the study protocol
• Meets DSM-5 criteria for ADHD combined presentation, inattentive presentation, or hyperactive/impulsive presentation based on clinical history
• SRS-5 score of 14 or greater at screening
• AISRS total score of 24 or greater at baseline
• Montreal Cognitive Assessment (MoCA) score of 26 or greater

Exclusion criteria

• Satisfied with current ADHD treatment
• History of myocardial infarction, arrhythmia, or congenital heart disease
• Mean systolic blood pressure greater than 160 mmHg or diastolic blood pressure greater than 100 mmHg measured in triplicate at screening despite treatment
• Treated hypertension not stable on medication or with dose changes in the last 30 days
• History of transient ischemic attack or stroke
• Current or lifetime DSM-5 diagnosis of bipolar I or II disorder, cyclothymic disorder, or bipolar disorder not otherwise specified
• Clinical history strongly suggestive of undiagnosed bipolar spectrum disorder
• Active suicidal ideation or behavior per C-SSRS at screening
• Current substance use disorder
• History of drug or alcohol abuse in the last 10 years as defined by DSM-5 criteria for substance use disorder (moderate or severe)
• True allergy to methylphenidate, history of serious adverse reactions to methylphenidate, or known non-response to methylphenidate
• History of seizure disorder other than a single childhood febrile seizure before age 3
• History of glaucoma, hyperthyroidism, thyrotoxicosis, advanced arteriosclerosis, or severe renal insufficiency (eGFR less than 30 mL/min/1.73 m²)
• Use of a monoamine oxidase inhibitor currently or within the past 14 days
• Abnormal baseline ECG including left ventricular hypertrophy or QTc greater than 450 ms (males) or greater than 470 ms (females)
• History of heart failure, unexplained dyspnea on exertion, or newly identified murmur
• MoCA score less than 26 or evidence of cognitive impairment
• Currently considered a suicide risk in the opinion of the investigator