LONGECITY

I have been checking in and out of the Resv forum mainly looking for an update on the srt501 clinical trial. Anyone seen any results on efficacy? I thought the phase II results were supposed to be released a while ago.

Hope that I'm not asking an already answered question.

Sirtris's web site says:

• SRT501, a formulation of resveratrol with roughly five times higher bioavailability than the chemical alone
  
  • Two completed 28-day Phase IIa studies in Type 2 Diabetes show safety, lowering fasting plasma glucose and insulin, and a significant lowering of glucose in an oral glucose tolerance test at the two hour time point.
  • Completing a 3-month Phase IIa trial in patients with Type 2 Diabetes who remain uncontrolled despite metformin therapy
  • Currently under way with a Phase IIa trial in oncology
• SRT2104, a new chemical entity (NCE) that activates SIRT1 – structurally unrelated to and up to 1,000 times more potent than resveratrol
  
  • Completed a first-in-human Phase I trial to assess safety, tolerability, and pharmacokinetics
  • Will enter into a Phase IIa human trial in 2009

Remember that they have no trials to show that it makes healthy volunteers healthier or live longer, if only because that would not help them get FDA approval.

Thanks unglued,
I was slightly confused where as it seems that I had missed the press release following their phase IIb trial.

Here is what it said for anyone interested:

Sirtris issued positive results from a phase Ib study of SRT501 for the treatment of type II diabetes. This multi-center, blinded and randomized trial enrolled one hundred subjects who received one of three oral dose regimens: 1.25 grams of SRT501 twice daily, 2.5 grams twice daily or placebo twice daily. The group who received SRT501 2.5 grams twice a day had significantly lower blood glucose levels compared to placebo. This was determined through an oral glucose tolerance test (OGTT) at the test's two-hour time point. This arm also showed a statistically significant lowering of both fasting blood glucose and glucose levels after meals (the postprandial period). A strong trend in lowering postprandial insulin levels was also observed. While not reaching 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 twenty seven of the trial as compared to the placebo group. SRT501 was found to be safe and well tolerated, with no evidence of drug accumulation. A phase II trial of SRT501 is currently underway.

SRT501 is 5 times more bioavailable than resveratrol alone...It is my understanding that Resveratrol + Tween 80 is more bioavailable than SRT 501 and it is available today without a prescription? Am I correct? If so, is there a need for SRT 501?

SRT501 is 5 times more bioavailable than resveratrol alone...It is my understanding that Resveratrol + Tween 80 is more bioavailable than SRT 501 and it is available today without a prescription? Am I correct? If so, is there a need for SRT 501?

I was under the impression that Resveratrol + Tween 80 increased absorption, not bioavailability. What's important is the systemic effect on Sir2/SIRT1.

SRT501 is 5 times more bioavailable than resveratrol alone...It is my understanding that Resveratrol + Tween 80 is more bioavailable than SRT 501 and it is available today without a prescription? Am I correct? If so, is there a need for SRT 501?

I was under the impression that Resveratrol + Tween 80 increased absorption, not bioavailability. What's important is the systemic effect on Sir2/SIRT1.

The distinction may be somewhat moot; there is a limit to blood serum levels that can be attained from oral ingestion, unless resveratrol is micronized and delivered via a vehicle such as tween80 or HPMC, which increases the upper bound. If it doesn't get into the blood, it's not going to be available. "Five times" may be a somewhat optimistic number.

Enhancing the amount that is absorbed by cells once it gets into the blood is another matter; some seek to slow down its metabolization by blocking glucuronidation or sulfonation with piperine, quercetin or most effectively with luteolin. There is no definitive answer as to whether these strategies actually enhance resveratrol's effects. They might, but some people (I am one) report negative effects from combining these with resveratrol, possibly due to luteolin and quercetin being powerful anti-aromatases, and possibly being responsible for joint pain (which can be manifest as tendinitis) due to too little estrogen being produced from testosterone (see some of the other threads in this forum.) Resveratrol is a weaker anti-aromatase.

Another wrinkle: the glycon form of resveratrol, polydatin, is converted into resveratrol in the body, and may achieve higher blood levels than from taking resveratrol, probably by bypassing first-pass liver metabolization. Taking the two together may have an additive effect. Hedgehog was measuring this while he had use of a lab, but now has other responsibilities that preclude further research on his part. The preliminary measurements he made indicated much higher serum levels with polydatin.

If anyone wants to experiment with HPMC, luteolin or polydatin, like for a graduate thesis, PM me for information.

Sirtris's web site says:

• SRT501, a formulation of resveratrol with roughly five times higher bioavailability than the chemical alone
  • Two completed 28-day Phase IIa studies in Type 2 Diabetes show safety, lowering fasting plasma glucose and insulin, and a significant lowering of glucose in an oral glucose tolerance test at the two hour time point.
  • Completing a 3-month Phase IIa trial in patients with Type 2 Diabetes who remain uncontrolled despite metformin therapy
  • Currently under way with a Phase IIa trial in oncology
• SRT2104, a new chemical entity (NCE) that activates SIRT1 – structurally unrelated to and up to 1,000 times more potent than resveratrol
  • Completed a first-in-human Phase I trial to assess safety, tolerability, and pharmacokinetics
  • Will enter into a Phase IIa human trial in 2009

Remember that they have no trials to show that it makes healthy volunteers healthier or live longer, if only because that would not help them get FDA approval.

"While not reaching 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 twenty seven of the trial as compared to the placebo group. SRT501 was found to be safe and well tolerated, with no evidence of drug accumulation. A phase II trial of SRT501 is currently under."


Now this study could not reach statistical significance. that is bit disappointing. was it because low sample size ? and is there any study on increasing the cognitive ability of human beings ?

SRT501 is 5 times more bioavailable than resveratrol alone...It is my understanding that Resveratrol + Tween 80 is more bioavailable than SRT 501 and it is available today without a prescription? Am I correct? If so, is there a need for SRT 501?

I was under the impression that Resveratrol + Tween 80 increased absorption, not bioavailability. What's important is the systemic effect on Sir2/SIRT1.

Resveratrol is absorbed quite well, actually. The absorption of plain resveratrol is better than 50%, so it could not be improved by a factor of 5. The factor of 5 probably does refer to bioavailability, which for ordinary resveratrol is very low. Absorption is the fraction of the dose that gets into systemic circulation in any form, while bioavailability refers to the fraction that gets in in an unchanged form. Resveratrol is rapidly and efficiently sulfated and glucuronidated, so little of it remains in the native form. The various formulations may assist in temporarily swamping the conjugative enzymes in the liver by virtue of more rapid absorption, or, perhaps more likely, they may reduce the level of conjugation in the gut. At any rate, it's a straightforward experiment to draw aliquots of blood over some time interval after dosing, and analyze for free resveratrol. That would be the typical pharmacokinetic practice.

If one is worried about absorption, why not just inject it to bypass the gut?