Aβ42 vaccine on the Tg2576 Alzheimer model mice

In 1999, Schenk et al. [Nature 400 (1999) 173] reported remarkable improvement of Aβ amyloid burden in the transgenic mice brain by immunization with Aβ42 peptides. Soon after, four independent institutes showed the same findings on senile plaque amyloid and improvement of memory disturbance confirming the effect of Aβ vaccine on brain Aβ amyloidosis. In July 2001, Elan Corporation started cooperative Phase I study of AN-1792, synthetic Aβ42 peptide. In September, Phase II study of 375 Alzheimer patients began in Europe. Because of 15 cases of encephalitis in March 2002, this drug trial was suspended. This is serious accident for patients, family and specialists, who hope for a curative therapy for Alzheimer's disease (AD). However, this result provided new insight that brain amyloidosis is reversible. Prompt evaluation of candidate drugs such as anti-Aβ antibody, β-secretase inhibitor or anti-Aβ aggregation should be necessary in the near future.