Below is a link to the research paper covering the results in his lab’s last mouse study, where a 3 month high dose of rapamycin at late middle age resulted in a 61% increase in remaining life expectancy (so, if done on a 50 year old human who today has a 30 year remaining life expectancy (i.e. 80 yrs total), you would expect to get 18 or so years.
This is based on the dosing / interval studies that have been done on mice so far. With a more rigorous effort related to dosing / interval optimization clinical studies in humans it may not be unreasonable to see upwards of 30 years life expectancy improvement with rapamycin (see tweet here explaining this).
Update: On Nov. 24th Matt Kaeberlein posted a more in-depth series of tweets explaining why 30 years life extension with rapamycin might be possible - see tweet series starting here.
Part of the rationale for this possibility of 30+ years increase is that rapamycin has shown surprising benefits in this area even in short term testing (see below for a 6 week test).
The key point is rapamycin in anti-aging is very compelling but that much more clinical research needs to be done to determine optimal dosing levels and frequency (and potential side effects longterm), but rapamycin is without question the drug that has the best evidence behind it by far, for any drugs in the anti-aging field.