Rapamycin, as I'm sure you're aware by now, is a drug that has been shown to extend life in mice via a mechanism that may stack with the beneficial effects of calorie restriction on longevity. Unfortunately, its primary effect, and the reason for its commercial development in the first place, is suppression of the immune system. Rapamycin has been used to help prevent rejection of organ transplants for quite a while. It's not the sort of thing you'd really want to take on a regular basis, given the choice.
Nonetheless, now that rapamycin has been shown to influence longevity strongly enough to be worth an entry into the Mprize, interest has been spurred amongst those researchers who aim to slow aging through drug-induced manipulation of metabolic processes. So expect to see a steady flow of papers, as various research communities try it out in their laboratories. For example:
Rapamycin, a drug that keeps the immune system from attacking transplanted organs, may have another exciting use: fighting Alzheimer's disease. Rapamycin rescued learning and memory deficits in a mouse model of Alzheimer's ... Rapamycin also reduced lesions in the brains of the mice, the team found. The lesions are similar to those seen in the brains of people who died with Alzheimer's.
"Our findings may have a profound clinical implication," said Dr. Oddo, who is a member of the university's Barshop Institute for Longevity and Aging Studies. "Because rapamycin is a U.S. Food and Drug Administration-approved drug, a clinical trial using it as an anti-Alzheimer's disease therapy could be started fairly quickly."
I'm of the opinion that the existence of the FDA creates a "looking for the keys under the lamppost" syndrome amongst researchers. The results we actually want - reversal of aging, bold new discoveries in biotechnology, and so forth - lie somewhere out there in the darkness, beyond what has been FDA approved, and in most cases beyond any framework the FDA has set in place to consider medical technologies. But how much easier it is to stick to the small circle of light and commercialize new uses for an already approved drug! The FDA's oppressive regulatory costs create a perverse incentive for researchers to focus their resources upon reuse of existing drugs, work that will never produce anywhere near the benefits that might be realized from completely new developments in medical technology. So we all suffer, and we cannot see the true cost, because that cost is measured in technologies and medicines that might have been brought into being by now, if not for the regulators.
But to return to the theme, I see that Ouroboros posted on the topic of rapamycin today as well:
This isn't exactly news, but it's news to me: Rapamycin has an orally administered derivative, Everolimus, already in use as an anti-cancer and anti-rejection drug. ... But the drug itself might be bad news, especially if it is taken over long periods of time: mTOR, the target of rapamycin, appears to be necessary for reconsolidation of long-term memory in mammals; inhibition of mTOR is efficacious enough at blocking fear memories that it's discussed as a strategy for treating PTSD. ... So, as I've commented before, I have this fear that rapamycin (or a derivative) will turn out to be a bona fide longevity enhancement drug, but one whose chronic use erodes long-term memory, which does defeat the purpose to some extent.