Interim phase 1 part A results for ALN‐APP, the first investigational RNAi therapeutic in development for Alzheimer’s disease
Sharon Cohen, Simon Ducharme, Jared R. Brosch, Everard G.B. Vijverberg, Liana G. Apostolova, Alexandre Sostelly, S Goteti, Nune Makarova, Andreja Avberšek, Weinong Guo, Bret L. Bostwick, Catherine J. Mummery
Abstract
BACKGROUND: . ALN-APP is an investigational intrathecally (IT) administered RNAi therapeutic designed to reduce upstream intracellular and extracellular amyloid precursor protein (APP) levels by lowering APP mRNA. As a result, we hypothesize that ALN-APP may alter the cascade of events that result in neurodegeneration, potentially slowing, halting, or reversing Alzheimer's disease progression. METHOD: ALN-APP-001 (NCT05231785) Part A is an ongoing randomized, double-blind, placebo-controlled, Phase 1 single-ascending dose study in patients with EOAD. Patients are required to have disease onset at age <65 years, Clinical Dementia Rating® global score of 0.5 or 1.0, and Mini Mental State Examination score >20. Patients are being evaluated over 6 months, with further follow-up of up to 6 months as needed. The primary endpoint is the safety and tolerability of ALN-APP. Secondary objectives include the evaluation of pharmacokinetics and pharmacodynamic effects of ALN-APP. RESULT: 12 patients were enrolled and randomized 2:1 to receive ALN-APP or placebo in 25mg and 75mg dose cohorts. Baseline characteristics are shown in Table 1. Mean (SD) duration on study was 6.7 (1.7) months for cohort 1 (25mg) and 2.0 (1.0) months for cohort 2 (75mg). Dose-dependent reductions of soluble APPα and APPβ (sAPPα and sAPPβ) levels in cerebrospinal fluid (CSF) at day 15 were observed following a single dose of ALN-APP, with mean reductions from baseline of 55% (sAPPα) and 69% (sAPPβ), and maximum reductions of 71% (sAPPα) and 83% (sAPPβ) in the 75mg cohort (n = 4) (Table 2). All adverse events (AEs) by data cut-off on 01/17/2023 were mild or moderate (Table 3), with no AEs deemed related to study drug by the investigators. Additional cohort data will be presented at the meeting. CONCLUSION: This first clinical study of a CNS-administered RNAi therapeutic demonstrates target engagement of APP, with reductions in CSF sAPPα and sAPPβ. To date, ALN-APP remains generally well tolerated with all reported AEs mild or moderate. These interim results support further evaluation of ALN-APP in patients with EOAD. Reference: 1. Hampel H et al. Molecular Psychiatry (2021). 26:5481-5503.