Clinical Trial Shows Anti-pTau Alzheimer’s Vaccine Generates Potent Immune Response 

New interim phase 1b/2a (NCT04445831) data on a vaccine against phosphorylated tau (Ptau) (ACI-35.030; AC Immune SA, Lausanne, Switzerland and Janssen Pharmaceuticals, Titusville, NJ) show strong induction of antibodies specific for Ptau and its aggregated form, enriched paired helical filaments (ePHF). 

AntiPtau IgG titers increased by 2 orders of magnitude from baseline 2 weeks after the first vaccination at the middle dose of 3 being tested. Anti-ePHF IgG titers increased by 1 order of magnitude from baseline 2 weeks after the second injection also at the middose, which was given 8 weeks after the first injection. The anti-ePHF IgG response was boosted following additional vaccine doses at weeks 8 and 24, and the immune response lasted over an initial period of 26 weeks.  

“To see such a strong and lasting immune response against a self-protein in an elderly population is both an exceptional finding and an important step towards shifting the AD treatment paradigm towards earlier treatment and prevention,” said Andrea Pfeifer, chief executive officer, AC Immune SA. “Ptau is present in the cerebrospinal fluid as a precursor many years before tau accumulation is detectable in the brain with imaging techniques. By developing ACI-35.030 while leveraging cutting edge tau diagnostics, we aim to deliver on the significant promise this vaccine has shown as a potential early intervention for AD.”  

Interim safety data support the favorable safety and tolerability profile of the therapy, with no clinically relevant safety concerns observed to date. 
These data were presented at the 14th Clinical Trials on Alzheimer's Disease (CTAD) conference held in Boston, Massachusetts from November 9-12, 2021.