Sirtris Pharmaceuticals, Inc. (NASDAQ: SIRT), a biopharmaceutical company focused on discovering and developing small molecule drugs to treat diseases of aging such as Type 2 Diabetes, announced positive top-line data from its twice-daily dosing study of SRT501, the company's proprietary formulation of resveratrol. The Phase 1b clinical trial, which tested either 1.25 or 2.5 grams of SRT501 given twice daily to Type 2 Diabetic patients, found that the patient group receiving 2.5 grams twice a day had significantly lower blood glucose levels as determined through an oral glucose tolerance test (OGTT) at the test's two-hour time point, as compared with the placebo group.

At 2.5 grams twice daily, the study also found that SRT501 had a statistically significant lowering of both fasting blood glucose and glucose levels after meals, known as the postprandial period, an important timeframe for Type 2 Diabetics who need better control of blood sugar levels after eating. While not at the level of statistical significance, this dose level also showed a strong trend in lowering postprandial insulin levels.

At 1.25 grams given twice daily, SRT501 also showed strong trends. While not at statistical significance, SRT501 at 1.25 grams given twice per day lowered fasting and postprandial glucose, and glucose when challenged with an OGTT at the two-hour time point on day 27 of the trial as compared to the placebo group. The data suggest a dose response.

The company plans to present the full data at the American Diabetes Association annual meeting in June.

"With this study, and the Phase 1b once daily dosing study data that we announced in January of this year, we have now observed a lowering of glucose in Type 2 Diabetic patients in two clinical trials with SRT501," says Peter Elliott, Ph.D., Senior Vice President of Development at Sirtris. "The two Phase 1b clinical trials tested SRT501 at different dosage levels and dose time points. While the primary focus of each study was safety and blood levels of SRT501, by developing the studies as we did, we are also able to see signs of efficacy and dose response."

"Our clinical trial program with SRT501 further validates our approach in targeting the SIRT1 enzyme for the development of a potential new treatment for Type 2 Diabetes," says Christoph Westphal, M.D., Ph.D., CEO and Vice Chair of Sirtris. "Today's Phase 1b announcement is the second time we've seen a translation of the positive results from preclinical studies carry over to humans."

The current multi-center, blinded and randomized Phase 1b study included approximately 100 Type 2 Diabetic patients divided into three groups. The first patient group received 1.25 grams of SRT501 twice daily for a total daily-dose level of 2.5 grams. The second patient group received 2.5 grams twice daily for a total daily-dose level of 5.0 grams. The third group received placebo twice daily.

The study was designed to assess the safety, tolerability and pharmacokinetics of twice-daily, orally administered dosing of SRT501 at 2.5 and 5.0 total grams. In both patient cohorts receiving SRT501, the drug was found to be safe and well-tolerated, with no evidence of drug accumulation. The study also indicates that suitable pharmacokinetics, a measure of drug levels in the blood, was achieved.

In January of this year, Sirtris announced positive Phase 1b trial results of its once-daily dosing of SRT501 at 2.5 and 5.0 grams. In that study, SRT501 was also found to be safe and well-tolerated and to significantly lower glucose as compared to the placebo group in an OGTT at the two-hour time point as part of the 28 day trial of patients with Type 2 Diabetes.

SRT501 is currently being tested in patients with Type 2 Diabetes in a Phase 2a study in combination with metformin, the current first-line therapy for Type 2 Diabetes. Results from this trial are expected in the second-half of this year.

Sirtris has also identified new chemical entities (NCEs) that are chemically distinct from resveratrol, and in in-vitro tests are up to 1,000 times more potent. In preclinical models of Type 2 Diabetes, Sirtris' NCEs have lowered glucose and improved sensitivity.

About Sirtris Pharmaceuticals

Sirtris Pharmaceuticals is a biopharmaceutical company focused on discovering and developing proprietary, orally available, small molecule drugs with the potential to treat diseases associated with aging, including metabolic diseases, such as Type 2 Diabetes. Our drug candidates are designed to mimic certain beneficial health effects of calorie restriction, without requiring a change in eating habits, by activation of sirtuins, a recently discovered class of enzymes that control the aging process. The company's headquarters are in Cambridge, Massachusetts.

http://www.sirtrispharma.com

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, the potential therapeutic effects of SIRT1 activators including SRT501 for diseases of aging, such as Type 2 Diabetes, the progress and results of pre-clinical and clinical studies of SIRT1 activators, the potential therapeutic effects of SRT501 and other SIRT1 activators, and the potential of sirtuin modulators and activators to receive regulatory approval. These forward-looking statements about future expectations, plans and prospects of Sirtris Pharmaceuticals involve significant risks, uncertainties and assumptions, including risks related to the lack of results that would provide a basis for predicting whether any of the Company's product candidates will be safe or effective, or receive regulatory approval, the possibility that results of pre-clinical studies are not necessarily predictive of clinical trial results, the Company's potential inability to initiate and complete pre-clinical studies and clinical trials for its product candidates, the fact that none of the Company's product candidates has received regulatory approvals, the potential inability of the Company to gain market acceptance of the Company's product candidates, and those other risks factors that can be found in the Company's filings with the Securities and Exchange Commission. Actual results may differ materially from those Sirtris Pharmaceuticals contemplated by these forward-looking statements. Sirtris Pharmaceuticals does not undertake to update any of these forward-looking statements to reflect a change in its views or events or circumstances that occur after the date of this release.

Sirtris Pharmaceuticals