Half-Life and Resistance
First of all, let me start with thaking you for the time you take to help in this forum. I have a question for you:
I am taking part in a study involving taking Truvada with either 400mg of Isentress twice daily or 800mg of Isentress once daily.
My question is as follows: Given the short half-life of isentress and as i did not have ANY side efects so far (I like my combo :-)), am I at risk of developing resistance to isentress IF I am in the group that takes the 800mg dosage ONCE a day?
I started getting worried as I LOVE my combo and I would like to stick with it for as LONG as i can.
Thank you. G, London, UK.
Dear G in London,
Thanks for your post and participation in clinical trials. I'm heartened to hear that you're not having any significant issues with side effects. It will be your viral load results that are the true measure of whether the regimen is working or not.
Raltegravir (Isentress) has shown very promising data in treatment naive persons (in combination with Truvada). There are recent in vitro (test-tube) studies that suggest that the drug binds very tightly to the viral integrase for many, many hours, far in excess of the plasma half-life of the medication in people. This suggests that once bound to the target, the effectiveness of the drug isn't really a function of the drug level in blood- hence, part of the story that fuels the basis of once-daily clinical trials.
Of course, this is all speculation until we see the data of the once-daily clinical trial-- I'm certainly not endorsing that patients or doctors take raltegravir once-daily (except in clinical studies) until we see the results of your study.
Happy holidays to you. From the other side of the pond,