peginterferon alfa-2b Vs. 2a

What is the difference between peginterferon alfa-2b
and 2a ? what are the advatages and disadvantages for each therapy ?

[GrandOak]

2a has a larger molecular structure than the other.  This is thought to also relate to a longer more steady dosage remaining in the body between injections.  I read a study which recommended smaller 2B injection dosages twice a week to maintain a more consistent level in the body.

2a is a single dosage amount, while 2b is weight based meaning it varies the amount based upon weight.

Some patients anedoctes which have done both say SX's are less harsh on 2A.

Some studies suggest 2b might be more effective in the long run.

These are just a few which come to mind of the top of my head.  I suggest perusing the archives for this forum as the question has arisen multiple times and many answers have been given.

[zazza]

Because of the smaller molecular size Pegintron (alfa 2b) is said to be able to penetrate even the smallest blood vessels and regions where HCV virus can be found, for example those in the lungs.

[FlGuy]

This question comes up every once in a while. 2A (Roche Pegasys) and 2B (Shering  Redidpen) , see their websites.  I have not been convinced that one is more effective than the other. As GO points out, the 2B is weight-based and if you weigh more than about 190 pounds you may get more interferon per lb with 2B than with Pegasys.  I've used both.  Currently, Pegasys pre-filled 2A.  The two treatments I've been on are not really comparable due to dose/duration, so I'll never be able to if one was more effective than another.  There are two minor reasons I prefer Pegasys over Schering's Redipen.  The first is the ease of the injector, I have a gimpy thumb.  The other is that I think that the sx's with Pegasys are milder - less rude.  But, people react to the same meds in different ways.

[FlGuy]

Looking at the prescribing info (see pegintron.com for full information) that seems to be the amount to use for combo (peg and riba being combo therapy) for a person who weighs in the range of 165-185.  Doc's prescibe.  If you read something that is amiss in the referenced material, call your doc for clarification.  When do you start?

[mari74]

My doctor uses Schering  2b.  
My treatment will start with Peg Intron 0.5ml sc qw dose 120mg...

Is this a lot?

[desrt]

Peg-IFN alfa 2a Pegasys : longer half-life from the branched PEG part of the molecule

Peg-IFN alfa 2b Peg-Intron : possibly better IFN portion of molecule


Now go ask someone why you can't attach a branched PEG molecule (Roche's product) onto an alfa 2b molecule (S-P's product) instead of fooling around with protease/polymerase inhibitors.

[madbrad]

I'm passing the halfway mark in my 48 wk tx...And I'm on Alfa 2a...I'm wondering if it wouldn't be prudent to change to Alfa 2b.To get the little critters hiding.....Hey I'm willing to go to 2 shots a week just to make SURE.....
   I'm thinking when I was twelve and half millions copies to start with and now less then 50...I figure it would be good to hunt down the rest with a little but just as powerful a gun......Thoughts????