Sirtris Anti-Aging Drug Generates Buzz, But May Already Be Old News
Cambridge, MA-based Sirtris Pharmaceuticals (NASDAQ: SIRT) generated a flurry of media coverage, and a moderate stock gain, this week after announcing the first evidence that its formulation of resveratrol, a naturally occurring anti-aging substance found in red wine, helps to control symptoms of diabetes in humans. But it’s unclear that the study results—which were not reported in a peer-reviewed forum—will have much impact on the company’s future.
Sirtris reported at a JPMorgan health care conference in San Francisco yesterday that a preliminary “Phase 1b” safety trial, conducted on 98 Type 2 diabetes sufferers in India who had taken no previous drugs for diabetes, demonstrated that the company’s drug, called SRT501, had no serious side effects. After four weeks, the company said, patients who received the drug had an increased tolerance for glucose (that is, their bodies controlled glucose levels more effectively than before).
Phase 1 trials are not typically designed, however, to test how well a drug works. They’re usually conducted on healthy volunteers, and are merely intended to assess whether a drug is safe and well-tolerated at various doses, whether it accumulates in the bloodstream, and the like. Sirtris’s trial was somewhat unusual in that the participants were actual diabetes patients, but evidence of the drug’s effectiveness, at this stage, would have little effect on the drug’s chances for eventual regulatory approval—assuming that Sirtris intends to carry SRT501 through to commercialization, which it may not.
Sirtris designed SRT501 to be absorbed by the body more readily than pure resveratrol (which doesn’t show up at therapeutic levels in red wine, by the way, no matter how much you might attempt to drink). But as we reported in November, resveratrol derivatives are rapidly being overshadowed inside Sirtris by unrelated compounds with more power to activate SIRT1, the key gene that’s thought to be involved in the metabolic pathways that regulate aging and that seem to be out of whack in people with aging-related diseases such as diabetes and obesity. In a November Nature paper, Sirtris reported that three such compounds, called SRT1460, SRT1720, and SRT2183, are up to 1000 times as effective at activating SIRT1 as SRT501. CEO Christoph Westphal says the company plans to begin safety studies of the new compounds in the first half of this year.
Sirtris’s stock was hovering around $14.10 on the NASDAQ this morning, up roughly 7 percent over Monday’s price.
UPDATE 3:20 pm, 1/8/08: I spoke this afternoon with a Sirtris representative who emphasized that the company has never said that it will push aside testing and commercialization of SRT501. In fact, the company sees the compound as a potential treatment for MELAS (a rare mitochondrial disorder; the acronym stands for “mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes”) and for Type 2 diabetes when used in combination with metformin, a popular anti-diabetes drug. The company plans to publish the results of the recent Phase Ib trial in a peer-reviewed publication this spring.
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