UB-311, a novel UBITh ^® amyloid β peptide vaccine for mild Alzheimer's disease

Abstract

Introduction

A novel amyloid β (Aβ) synthetic peptide vaccine (UB-311) has been evaluated in a first-in-human trial with patients of mild-to-moderate Alzheimer's disease. We describe translational research covering vaccine design, preclinical characterization, and phase-I clinical trial with supportive outcome that advances UB-311 into an ongoing phase-II trial.

Methods

UB-311 is constructed with two synthetic Aβ _1–14–targeting peptides (B-cell epitope), each linked to different helper T-cell peptide epitopes (UBITh ^®) and formulated in a Th2-biased delivery system. The hAPP751 transgenic mouse model was used to perform the proof-of-concept study. Baboons and macaques were used for preclinical safety, tolerability, and immunogenicity evaluation. Patients with mild-to-moderate Alzheimer's disease (AD) were immunized by intramuscular route with 3 doses of UB-311 at weeks 0, 4, and 12, and monitored until week 48. Safety and immunogenicity were assessed per protocol, and preliminary efficacy was analyzed by Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS-Cog), Mini–Mental State Examination (MMSE), and Alzheimer's Disease Cooperative Study–Clinician's Global Impression of Change (ADCS-CGIC).

Results

UB-311 covers a diverse genetic background and facilitates strong immune response with high responder rate. UB-311 reduced the levels of Aβ _1–42 oligomers, protofibrils, and plaque load in hAPP751 transgenic mice. Safe and well-tolerated UB-311 generated considerable site-specific (Aβ _1–10) antibodies across all animal species examined. In AD patients, UB-311 induced a 100% responder rate; injection site swelling and agitation were the most common adverse events (4/19 each). A slower rate of increase in ADAS-Cog from baseline to week 48 was observed in the subgroup of mild AD patients (MMSE ≥ 20) compared with the moderate AD subgroup, suggesting that UB-311 may have a potential of cognition improvement in patients with early stage of Alzheimer's dementia.

Discussion

The UBITh ^® platform can generate a high-precision molecular vaccine with high responder rate, strong on-target immunogenicity, and a potential of cognition improvement, which support UB-311 for active immunotherapy in early-to-mild AD patients currently enrolled in a phase-II trial (NCT02551809).