concentration controlled ribavirin dosing

I am in a trial that will be comparing ribavirin dosing, weight based compared to concentration controlled based on AUC 0-12 after first dose.

http://clinicaltrials.gov/ct2/show/NCT01097395?term=hepatitis+c+AND+colorado&rank=1

Primary Outcome Measures:
•ribavirin AUC-12 variability [ Time Frame: steady state (~weeks 9-10) ] [ Designated as safety issue: No ]
Demonstrate that concentration-controlled ribavirin dosing can achieve a targeted level of plasma exposure with reduced variability in the steady-state area-under-the-concentration-time curve (AUC0-12) compared with standard weight-based ribavirin dosing



Secondary Outcome Measures:
•safety - absolute hemoglobin declines [ Time Frame: end of treatment ] [ Designated as safety issue: Yes ]

•efficacy - early and sustained virologic response [ Time Frame: EVR (12 weeks) and SVR (24 wks after cessation of treatment) ] [ Designated as safety issue: No ]
Compare proportions with EVR and SVR in standard weight-based vs. concentration-guided ribavirin dosing groups

I start tommorow morning, arms will be decided in week 2, I will keep everyone interested posted on my numbers as much as possible.

Keith

[it'sallgood]

In the ribavirin concentration controlled arm those with an AUC0-12h > 7000 or < 3000 ng*hr/mL will have their doses adjusted to a target AUC0-12h of approximately 5000 ng*hr/mL.  i agree that the concentration controlled arm is the place to be. but should you end up in the SOC arm and get either 1000mg or 1,200mg ribavirin per day your chances of SVR will be equivalent to anyone following the label.  you will also have the opportunity to use rescue drugs, if you can figure out how to pay for them.

[nygirl7]

Why are they doing this this was already proven a few years ago that weight based is imperative?

[hrsepwrguy]

Not sure but this one includes incivek

[nygirl7]

I wouldn't let anyone under dose me I dont care what, since the drugs do not work stand alone it seems awful risky.  If anything make sure you are getting extra.....

[hrsepwrguy]

Actually I'm hoping for the controll arm but it is not just dose decrease but increase as well depending on plasma exposer. I am not sure exactly what number they are looking for yet but will keep everyone posted as I go.

[it'sallgood]

In the ribavirin concentration controlled arm those with an AUC0-12h > 7000 or < 3000 ng*hr/mL will have their doses adjusted to a target AUC0-12h of approximately 5000 ng*hr/mL.  i agree that the concentration controlled arm is the place to be. but should you end up in the SOC arm and get either 1000mg or 1,200mg ribavirin per day your chances of SVR will be equivalent to anyone following the label.  you will also have the opportunity to use rescue drugs, if you can figure out how to pay for them.

[it'sallgood]

here is another ribavirin concentration study published in 2008 and the forum's comments on the study. this study did not include telaprivir.
http://www.medhelp.org/posts/Hepatitis-C/-can-anyone-explain-this/show/566352
looks to me like if they get close to 5000ng you will have an excellent chance at SVR, assuming you are in the the concentration controlled arm.  i think this is far superior to weight based ribavirin. good luck and keep us informed.

[dointime]

I'd be really interested to know how they measure the concentration and - more specifically - what in the devil is so difficult about it that we cannot get this test from Quest / Labcorp as part of our routine tx monitoring?  Would you be able to ask about that?

Good luck to you,
dointime  

[hrsepwrguy]

Thanks for informative and encourging post, makes me feel alot better about what I am doing.

dointime-I will definitly try to find out the answers to the questions you have and relate that info back to you if possible.

[it'sallgood]

no worries my friend, you will be in good hands.

dointime - i agree with you. wouldn't it be nice be be able to titrate dose based upon serum concentration?  Unfortunately it's all about economics.   Routine tests would need government approval.  government approval requires studies.

[Trish77]

At least this is a step in the right direction, to be doing a clinical trial measuring the effectiveness of serum concentration, which is reputed to be a more effective measure of appropriate ribavirin dosage than weight-based.  Exciting to see this.

hrsepwrguy - I note you're allowed rescue drugs like neupogen and procrit so that's a good thing also. Good luck with your trial!

Trish