IFN alfa-2b vs. alfa 2-a

This statement in an article recently brought up in another thread got my attention.
"..SVR rates have been improved...to ~40% of patients treated with the combination of IFN alfa-2b plus ribavirin, and 54-61% of patients treated with a pegylated IFN (I'm assuming 2-a here) and ribavirin, the current treatment of choice."  
http://jac.oxfordjournals.org/cgi/content/full/53/1/1.... dated 2004.  
  
Since my doctor has ordered IFN alfa 2-b for me, ready to start the end of this month, this poked me in the eye.  Then I found this:  http://www.natap.org/2008/EASL/EASL_19.htm.  Most of these numbers point to 2-a as a little bit more effective.
The only reason I see, according to this study, to use 2-b over 2-a is for HVL.  Everything else seems to point to 2-a as a little bit more effective. When my doctor decided on 2-b, my VL was ~600K... considered high, right?  But then dropped to 115K and hopefully holding.   Also, the drop-out rate and alopecia numbers seemed to be significantly higher for alpha 2-b.  People here have mentioned worse sides with Pegintron.

In the first article, it said, with IFN alpha 2-b, RNA levels would rebound within 48 to 72 hrs as serum levels declined, indicating some peaks and valleys, if I read it correctly.  Whereas 2-a maintained a more consistent initial suppression.  

I'm trying to wrap my brain around this, so I can tell my doctor why I want to switch to 2-a.  At this point, it seems to me for LVL alpha 2-a is the best choice.  

If I'm missing something or off the mark, I hope someone will let me know, because tonight I'm wanting the 2-a.  And, tomorrow, I'm about to tell an experienced doctor how to do his job.

[orleans]

be thankful you're no longer with dr. grumpy! hope you get some help as I know little on this subject. Let us know how it goes. Been there, done that. jerry

[desrt]

The reason Peg-Intron has more 'peaks and valleys' in most patients serum IFN levels has more to do with Pegasys being made with a better (branched) PEG molecule that allows for more even release. The only time a study shows that much of a difference in response rates between the two products is when you take patient compliance into account - in other words, Pegasys seems to have easier side effects, so easier to stay on full dose. If everything else were equal and 2b and 2a were both bonded to a branched PEG molecule, I'm guessing 2b might actually come out a little better SVR, but that's just a guess. Tell your doctor you're a 'Pegasyssy' and want the easy stuff.

[fretboard]

I'm thinking this must be the first time you've tx'ed so naturally you want the best drugs.  Excuse the wording there.lol  Here's another study and it looks like there really isn't much difference at least in the first 12wks between the two.  I read part of it, but that's all I needed to decide that this study was acceptable to me.  There are more studies on pubmed if you want to check them out.  Just type in "pegasys vs pegintron"  in the search bar without the quotes.  Also, there may be differences in the amount of sx's reported, but really that isn't a very good measuring stick as you don't know how you will respond to the one you' will get.  Anyways, "ask for what you want".    good luck


Early virologic response after peginterferon alpha-2a plus ribavirin or peginterferon alpha-2b plus ribavirin treatment in patients with chronic hepatitis C.

Di Bisceglie AM, Ghalib RH, Hamzeh FM, Rustgi VK.
Division of Gastroenterology and Hepatology, Saint Louis University School of Medicine, St Louis, MO 63110, USA. ***@****

Patients infected with hepatitis C virus (HCV) genotype 1 and with serum HCV RNA concentrations over 800 000 IU/mL have relatively low rates of virologic response to pegylated interferons. The 2 forms of pegylated interferon have different pharmacokinetic profiles, and pilot studies comparing them have yielded varying results. We compared the virologic response to 12 weeks of treatment with peginterferon alpha-2a plus ribavirin vs peginterferon alpha-2b plus ribavirin in 380 patients who were infected with HCV genotype 1 and had high viral loads. We observed no between-group differences in viral load reduction over time and no differences in the percentage of patients treated with peginterferon alpha-2a or peginterferon alpha-2b plus ribavirin who achieved early virologic response (EVR), defined as >/=2-log reduction in HCV RNA concentration or undetectable HCV RNA at 12 weeks (66%vs 63%). Serum levels of interferon were more frequently below the level of quantitation in patients treated with peginterferon alpha-2b plus ribavirin (58-68%) than in those treated with peginterferon alpha-2a plus ribavirin (1-2%). Patients treated with peginterferon alpha-2b plus ribavirin had higher rates of discontinuation for safety reasons (6%vs 1%). In conclusion, a substantial percentage of patients infected with HCV genotype 1 and high viral load can achieve EVR when treated with peginterferon and ribavirin. The 2 pegylated interferons showed comparable anti-HCV activity during the first 12 weeks of treatment when combined with the same doses of ribavirin (1000-1200 mg/day), but discontinuations for safety reasons were higher in the patients treated with peginterferon alpha-2b plus ribavirin.

PMID: 17875007 [PubMed - indexed for MEDLINE

[nygirl7]

This subject has been debated time and time again and honestly what I've observed the most is different peg's affect different people different.  Most doctors order whichever med company their hospital is affiliated with - that's how they do it believe it or not, they don't read studies and things like that nope that would be too sensible!

"really that isn't a very good measuring stick as you don't know how you will respond to the one you' will get.  Anyways, "ask for what you want".    good luck "

Yup - some people think Intron is harder and some people think Pegasys is harder.  Go figure but none of them are what I"d consider easy. I really don't think it makes that big a difference as much as making sure you are being correctly dosed with riba.

I started with a VL of only 568k - had a hell of a time getting them all and had to do 72 weeks.  Sometimes having a low side starting VL is a disadvantage believe it or not - again it just depends on your individual body.

[springfever]

Orleans - He's only grumpy if you don't accept one of his offers. My new doctor is not so obvious, but he'd rather just do this himself without me second guessing him.  We played tug of war over my lab reports.

desrt - lol, thanks for the laugh.  Looking at the Italian study, I see ETR rates (I'm assuming that's EVR) - 2a 78% and 2b 50% for geno 1.  I'm thinking this is because of the pharmokinetics, or whatever.  Throughout a 48 wk therapy, 2-b may hold better for those with high vl.  But, what if, big if, you have a low vl and are hoping, and wishing, and praying for the opportunity to reduce your treatment length due to rapid response detected in the first few days.  Looks to me like 2-a would be best in that hopeful situation.  

fretboard - yes, my first time and trying really hard to do all I can.  I have two family members who are losing this battle.  I'm in it to win.  Thanks for the study.  I'm reading all I can get my hands on.

nygirl - Dr. affiliation with one drug company over the other is what I think too.  This needs to change along with the rest of our health care system.  So sorry you had such a difficult time.  72 wk club members are true warriors.  I know it won't be easy no matter what.  Just doing the pre-tx jitter-bug. walking on hot coals, they're pushing me out of the plane and I'm afraid my chute's not quite ready.

Thanks to all for responding.