Simufilam 100 mg for Mild-to-Moderate Alzheimer's Disease (RETHINK-ALZ)

• ClinicalTrials.gov Identifier: NCT04994483
• Recruitment Status: Active, not recruiting
• First Posted: August 6, 2021
• Last Update Posted: January 26, 2024
• Sponsor: Cassava Sciences, Inc.
• Collaborator: Premier Research Group plc
• Information provided by (Responsible Party): Cassava Sciences, Inc.

Tracking Information

• First Submitted Date: July 29, 2021
• First Posted Date: August 6, 2021
• Last Update Posted Date: January 26, 2024
• Actual Study Start Date: November 3, 2021
• Estimated Primary Completion Date: October 2024 (Final data collection date for primary outcome measure)

Current Primary Outcome Measures (submitted: July 29, 2021)

• Change from baseline in the 12-item Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADAS-Cog12) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the ADAS-Cog12, a psychometrician-administered battery comprised of several cognitive domains including memory, comprehension, praxis, orientation, and spontaneous speech. Scores range from 0 (best) to 80 (worst).
• Change from baseline in the Alzheimer's Disease Cooperative Study - Activities of Daily Living (ADCS-ADL) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the ADCS-ADL, a 23-item study partner questionnaire that covers both basic activities of daily living (ADL) and more complex ADL or instrumental ADL. Scores range from 0 to 78, with a lower score indicating greater severity of functional loss.

• Original Primary Outcome Measures: Same as current

Current Secondary Outcome Measures (submitted: April 28, 2023)

• Change from baseline in the integrated Alzheimer's Disease Rating Scale (iADRS) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the iADRS, where scores range from 0 to 146 with lower scores indicating worse performance.
• Change from baseline in the Neuropsychiatric Inventory (NPI) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the NPI, a 12-item study partner interview, which records the frequency and severity of common neuropsychiatric symptoms in dementia, as well as the level of study partner distress due to each of the neuropsychiatric problems. Scores range from 0 to 144, with higher scores indicating more frequent and severe symptoms, and greater levels of partner distress.
• Change from baseline in the Mini-Mental State Exam (MMSE) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the MMSE, a set of standardized questions covering several target areas: orientation, registration, attention and calculation, short-term verbal recall, naming, repetition, 3-step command, reading, writing, and visuospatial cognitive assessment. Lower scores indicate more severe impairment.
• Change from baseline in the Clinical Dementia Rating Sum of Boxes (CDR-SB) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the CDR-SB, which characterizes 6 domains of cognitive and functional performance applicable to AD and related dementias: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. Higher scores indicate more severe impairment.
• Change from baseline in the Zarit Burden Interview (ZBI) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the ZBI, a 22-item study partner questionnaire designed to assess the stress or burden experienced by caregivers of people with dementia, with a higher score indicating greater stress or burden.
• Changes from baseline in plasma phospho-tau181 (P-tau181) and/or phospho-tau217 (P-tau217), and neurofilament light chain. [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  Change from baseline in plasma biomarkers of AD pathology, neurodegeneration, and neuroinflammation.
• Changes from baseline in the plasma SavaDx biomarker [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  Change from baseline in SavaDx, a novel plasma biomarker

Original Secondary Outcome Measures (submitted: July 29, 2021)

• Change from baseline in the integrated Alzheimer's Disease Rating Scale (iADRS) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the iADRS, where scores range from 0 to 146 with lower scores indicating worse performance.
• Change from baseline in the Neuropsychiatric Inventory (NPI) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the NPI, a 12-item study partner interview, which records the frequency and severity of common neuropsychiatric symptoms in dementia, as well as the level of study partner distress due to each of the neuropsychiatric problems. Scores range from 0 to 144, with higher scores indicating more frequent and severe symptoms, and greater levels of partner distress.
• Change from baseline in the Mini-Mental State Exam (MMSE) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the MMSE, a set of standardized questions covering several target areas: orientation, registration, attention and calculation, short-term verbal recall, naming, repetition, 3-step command, reading, writing, and visuospatial cognitive assessment. Lower sores indicate more severe impairment.
• Change from baseline in the Clinical Dementia Rating Sum of Boxes (CDR-SB) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the CDR-SB, which characterizes 6 domains of cognitive and functional performance applicable to AD and related dementias: memory, orientation, judgment and problem solving, community affairs, home and hobbies, and personal care. Higher scores indicate more severe impairment.
• Change from baseline in the Zarit Burden Interview (ZBI) [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  The change from baseline to Week 52 in the ZBI, a 22-item study partner questionnaire designed to assess the stress or burden experienced by caregivers of people with dementia, with a higher score indicating greater stress or burden.
• Changes from baseline in plasma biomarkers: P-tau181, SavaDx, and neurofilament light chain [ Time Frame: Baseline (Study Day 1) to Week 52 ]
  Change from baseline in plasma biomarkers of AD pathology, neurodegeneration, and neuroinflammation.

• Current Other Pre-specified Outcome Measures: Not Provided
• Original Other Pre-specified Outcome Measures: Not Provided

Descriptive Information

• Brief Title: Simufilam 100 mg for Mild-to-Moderate Alzheimer's Disease
• Official Title: A Phase 3, Randomized, Double-blind, Placebo-controlled, Parallel-group, 52-week Study Evaluating the Safety and Efficacy of Simufilam 100 mg Tablets in Subjects With Mild-to-Moderate Alzheimer's Disease
• Brief Summary: A 52-week safety and efficacy study of simufilam (PTI-125) given twice daily to participants with mild-to-moderate Alzheimer's disease (AD) for 52 weeks. Approximately 750 participants will be randomized (1:1) to receive either placebo or 100 mg tablets of simufilam, twice daily, for 52 weeks. Clinic visits will occur 4 weeks after the baseline visit, and then every 12 weeks until the end of the study. The safety of simufilam, and its efficacy in enhancing cognition and slowing cognitive and functional decline will be evaluated.

Detailed Description

The primary objective of this study is to investigate the safety and efficacy of simufilam (PTI-125) in enhancing cognition and slowing cognitive and functional decline following 52-week, repeat-dose oral administration in participants with mild-to-moderate AD. Secondary objectives include the assessment of simufilam's effect on neuropsychiatric symptoms and caregiver burden. A third objective is to investigate the effect of simufilam treatment on plasma biomarkers. A limited number of research sites will be invited to participate in the pharmacokinetic (PK) and plasma biomarker sub-study. Collection of PK samples will enable an exposure-response analysis. Approximately 100 subjects will participate (50 per group). Plasma samples will be collected during the Screening Visit and again at Weeks 28 and 52. Change from Baseline for plasma biomarkers represent additional secondary endpoints.

Safety will be evaluated by adverse event monitoring, vital signs, clinical labs, and the Columbia Suicide Severity Rating Scale at every visit. Subjects will undergo magnetic resonance imaging (MRI) during screening to ensure entry criteria are met (unless recent MRI confirms entry criteria). Resting electrocardiograms will be conducted at Baseline (Study Day 1) and Weeks 4, 28, and 52. A complete physical and neurological examination will be performed at screening, and brief examinations will be performed at all other visits. Weight will be measured during the Screening Period, at Baseline (Study Day 1), and at all other visits.

An independent Data Safety Monitoring Board (DSMB) will meet periodically to review subject safety assessments and determine if dosing may continue. A charter will be developed with specific guidance for the DSMB.

• Study Type: Interventional
• Study Phase: Phase 3

Study Design

Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description:

Approximately 750 patients will be enrolled into the study. All patients will be randomized (1:1) to receive either placebo or 100 mg tablets of simufilam, twice daily, for 52 weeks.

Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description:

Randomized treatments will be assigned by subject numbers in a randomly generated numeric sequence. Randomization (1:1) will be stratified by low or high Mini-Mental State Exam (MMSE; 16-20 and 21-27).

The randomization code will not be revealed to study subjects, Investigators, clinical staff, study monitors, or the Sponsor until all subjects have completed therapy and the database has been finalized and locked.

Primary Purpose: Treatment

• Condition: Alzheimer Disease

Intervention

• Drug: Simufilam
  Simufilam is a novel drug candidate designed to treat and slow the progression of AD. Simufilam binds with femtomolar affinity to an altered conformation of filamin A that is present in the brain of patients with AD and critical to the toxicity of Aβ42. In this study, simufilam will be given b.i.d. for 52 weeks at a dose of 100 mg.
  Other Name: PTI-125
• Drug: Placebo
  Matching placebo given b.i.d. for 52 weeks.

Study Arms

• Placebo Comparator: Placebo
  Matching placebo, supplied by Cassava as coated tablets, and taken twice daily (b.i.d.) for 52 weeks
  Intervention: Drug: Placebo
• Experimental: Simufilam 100 mg
  Simufilam 100 mg, supplied by Cassava as coated tablets, and taken b.i.d. for 52 weeks
  Intervention: Drug: Simufilam

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Active, not recruiting
• Estimated Enrollment (submitted: July 29, 2021): 750
• Original Estimated Enrollment: Same as current
• Estimated Study Completion Date: October 2024
• Estimated Primary Completion Date: October 2024 (Final data collection date for primary outcome measure)

Eligibility Criteria

Key Inclusion Criteria:

1. Meets National Institute on Aging and Alzheimer's Association Research Framework criteria for individuals in clinical Stage 4 or 5 of the Alzheimer's continuum.
2. Evidence for AD pathophysiology, confirmed either prior to or during screening.
3. MMSE score ≥ 16 and ≤ 27 at screening.
4. Clinical Dementia Rating - Global Score must be 0.5, 1 or 2.
5. If receiving background AD medications, the dosing regimen must be stable for at least 12 weeks prior to randomization. Chronic medications for conditions other than AD (such as depression) must be prescribed at a stable dose for at least 4 weeks prior to screening.
6. The subject has not been a cigarette smoker or chewed tobacco for at least 3 years.
7. Availability of a study partner.
8. Individuals who have participated in a clinical study with an investigational drug targeting the underlying AD process may be permitted to participate in this study.
9. Completed a COVID-19 vaccine primary series ("fully vaccinated") at least 2 weeks prior to randomization or had an unambiguous COVID-19 infection diagnosed more than 3 months before the start of the Screening Period.

Key Exclusion Criteria:

1. A neurologic condition other than AD that significantly contributes to the subject's dementia.
2. Any current primary psychiatric diagnosis other than AD if it is likely to confound cognitive assessment or ability to comply with study procedures.
3. Geriatric Depression Scale (15-item) score > 8. (Note - a subject with a score > 8 may continue in screening if, in the judgment of the Investigator, the elevated score is not attributed to a major depressive episode).
4. Suicidal ideation during the past 3 months or suicidal behavior during the past 12 months.
5. Alcohol or substance use disorder within 2 years of screening.
6. MRI presence of cerebral vascular or other significant pathology.
7. History of transient ischemic attack or stroke within 12 months of screening
8. Seizure within 12 months of screening.
9. Severe head trauma or head trauma considered likely to be contributing to the subject's cognitive impairment.
10. Sleep apnea that is considered likely to be contributing to the subject's cognitive impairment.
11. Insufficiently controlled diabetes mellitus or hypertension.
12. Body mass index < 18.5 or > 37.5.
13. History or diagnosis of clinically significant cardiac disease
14. Currently or previously prescribed/administered aducanumab, lecanemab, or any anti-amyloid monoclonal antibody, more than 2 doses.

Sex/Gender

• Sexes Eligible for Study: All

• Ages: 50 Years to 87 Years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: Australia, Canada, United States

Administrative Information

• NCT Number: NCT04994483
• Other Study ID Numbers: PTI-125-07
• Has Data Monitoring Committee: Yes

U.S. FDA-regulated Product

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No

IPD Sharing Statement

• Plan to Share IPD: No

• Current Responsible Party: Cassava Sciences, Inc.
• Original Responsible Party: Same as current
• Current Study Sponsor: Cassava Sciences, Inc.
• Original Study Sponsor: Same as current
• Collaborators: Premier Research Group plc

Investigators

• Study Chair: Jim Kupiec, MD; Cassava Sciences

• PRS Account: Cassava Sciences, Inc.
• Verification Date: January 2024