Rapamycin - a midlife longevity drug?

From the Nature 'Editor's Summary' of the paper by Harrison et al.

The antitumour drug rapamycin targets TOR, a kinase that is part of the PI3K–AKT–mTOR cascade, involved in regulating protein translation, cell growth and autophagy. Reducing TOR function is known to extend the life of yeast, worms and flies. Now experiments replicated in three different laboratories demonstrate that rapamycin, fed to male and female mice in a dose that substantially inhibits TOR signalling, can extend their median and maximal lifespan by up to 14%. This life extension was observed in mice fed rapamycin from 270 days of age and also at a late stage in their life, from age 600 days. These findings point to the TOR pathway as a critical point in the control of ageing in mammals and in the pathogenesis of late-life illnesses.