In a recent New York Times article, the reporter described two new drugs inclinical trials for Type 2 diabetes, both of which seem to have a remarkable and unexpected side effect, at least in animals – they extend the normal lifespan. These drugs activate sirtuin, an enzyme that behaves like a calorically restricted diet which has been shown to increase longevity. Theoretically, if one can create a true longevity drug, its use might avert degenerative diseases of aging such as diabetes, heart disease, cancer and Alzheimer’s. There is no Food and Drug Administration category for longevity drugs so if the pharmaceutical company plans to submit the drug for approval,it needs to be for a specific disease.

Researchers around the world have been searching for the key to longevity for decades now.Some are looking for a specific gene for aging; some, like longevity guru Roy Wolford at UCLA have successfully demonstrated that severely restricted calorie diets can extend life; while others, like the folks at GlaxoSmithKline are looking for a longevity elixir. That’s why the pharamceutical giant just spent $720 million to buy Sirtris, a small company whose founder is testing these two new sirtuin activators. It is uncharted waters to be sure, but the potential to extend life is makes the drugs potentially a mega money maker.

The basic theory behind sirtuin activators is that all or most species have an ancient strategy for riding out famines: switch resources from reproduction to tissue maintenance. Reducing a healthy diet by 30 percent fewer calories has been shown to trigger this rection in mice and is the one intervention that consistently increases their life span. The mice apparently live longer because they are somehow protected from the usual diseases that kill them.

For humans, such a severe restriction of calories is nearly impossible. That’s why a drug that could activate the famine reflex is so appealing. So far the most potent activator that has been found is resveratrol, a natural substance found in low amounts in redwine. The Sirtris drug being tested in diabetic patients is a special formulation of resveratrol that delivers a bloodstream dose five times as highas the chemical alone. This drug, called SRT501, has passed safety tests and,at least in small-scale trials, has reduced the patients’ glucose levels.

The impact of Sirtris’s drugs, if successful, could extend beyond the drug industry. A company spokesman believes that many people would start taking themin middle age, though after having started a family because they may suppress fertility.

Mice on the drugs generally remain healthy right until the end of their lives and then just drop dead. “If they work in people that way, one would look to an extension of health span, with an extension of life as a possible side effect,” the spokesman said. “It would necessitate changing ideas about when people retire and when they stop paying into the system.”

GlaxoSmithKlinecould put SRT501, its resveratrol formulation, on the market right away,selling it as a natural compound and nutritional pharmaceutical that does notrequire approval by the F.D.A. Hopefully, they wll not go that route, but instead set up clinical trials to show that resveratrol is safe in the large doses required for efficacy. Because it seems to exert many influences on the body, some not exerted through sirtuin, there could be dangerous side effects.

Most potential drugs fail to make it past clinical trials, and the same may prove true for Sirtris’s candidates. But what this does show is that the idea of extending the human lifespan even 10% is one that ignites enthusiasm among scientists and lay people alike.

In our novel, Rabbit in the Moon, Dr. Ni-Fu Cheng, like the researchers at Sirtris is obsessed with finding the key to longevity. After 40 years he discovers that the solution to the puzzle puts himself, his granddaughter Lili Quan and the entire world in jeopardy. We started with a “what if” premise: what if someone did come up with a longevity elixir? From there we developed two questions: who would want it? and what might they do to obtain it?

Our story is certainly not science fiction. We just didn’t think science was that close to finding a way to actually extend the human lifespan. Perhaps we’re almost there now. And if so, we need to think about the pros and cons of such a discovery.

What do you think?