APP and Alzheimer disease: If the iAβ depletion treatment were transient, the duration of its effect would be identical to the time interval required for the restoration of iAβ (produced at this point solely in the AβPP proteolytic pathway) to the T1 threshold levels, for the consequent re-activation of the AβPP-independent iAβ production pathway and the AD Engine, and for the recurrence of the disease.