Update on the TOGETHER study: a patient‐ and investigator‐blind, randomized, placebo‐controlled study evaluating the efficacy, safety and tolerability of bepranemab, UCB0107, in prodromal‐to‐mild Alzheimer’s disease

Abstract

AbstractBackgroundBepranemab is a recombinant, humanized, full‐length IgG4 monoclonal antibody that binds to a central tau epitope (amino acids 235‐250). Here, we update on the progress of the TOGETHER study (AH0003; NCT04867616) with bepranemab in early Alzheimer’s disease (AD).MethodTOGETHER is a global, multicenter, double‐blind, placebo‐controlled, parallel‐group study investigating the efficacy, safety and tolerability of bepranemab versus placebo. Patients with prodromal (National Institute on Aging‐Alzheimer’s Association [NIA‐AA] Stage 3) or mild (NIA‐AA Stage 4) AD (target N = 450) will be randomized (1:1:1) to receive one of two doses of bepranemab or placebo (intravenous, every 4 weeks), over an 80‐week treatment period, followed by an optional 48‐week open‐label‐extension period. Participants will have a global Clinical Dementia Rating (CDR) score of 0.5 (prodromal AD) or 0.5–1.0 (mild AD) and a CDR‐Memory Box score ≥0.5 at screening and baseline, a score of ≤85 for the delayed recall domain of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), mini‐mental state examination (MMSE) ≥20 at screening and must meet the NIA‐AA 2018 definition of cerebral beta‐amyloid (Aβ) accumulation, by either a positive centrally read positron emission tomography (PET) scan or a positive cerebrospinal fluid (CSF) pTau181/Aβ1‐42 ratio. The primary endpoint is change from baseline to Week 80 in CDR scale Sum of Boxes total score. Secondary endpoints include: pharmacokinetics; safety and tolerability; tau PET imaging and change from baseline in AD Assessment Scale‐Cognitive Subscale 14, Amsterdam Instrumental Activities of Daily Living questionnaire and MMSE at Weeks 56 and 80.ResultAs of March 1, 2022, 56/125 planned centers have enrolled participants across 8 countries: Belgium, Canada, France, Netherlands, Poland, Spain, UK and USA. Of the 538 participants who entered screening, 62 have been randomized so far and 334 failed screening. Predominant reasons for screen failure include not meeting RBANS, MMSE or Aβ positivity (CSF or PET) criteria.ConclusionThis proof‐of‐concept study employs clinical outcome measures, imaging, pharmacokinetics, and biomarkers to assess the ability of bepranemab to slow progression of AD when administered in the early stages of disease. Enrollment and randomization are underway with nearly half of the study centers active.