peginterferon ALFA-2a

Could someone help me understand the difference amount the following  

Infergen:
Interferon:
PEG-IFN Alpha2a:
Pegylated Interferon-Alpha-2a
PEG-IFN Alpha2b:
Pegylated Interferon-Alpha-2b
PI:

I am using peginterferon Alpha-2a
How is this different from interferon?
Daniel

[Bill1954]

Hi Daniel,

There are essentially two naturally occurring interferon’s currently available for HCV treatment;

1) Pegylated interferon alpha 2a by Roche Pharmaceuticals (Pegasys)
2) Pegylated interferon alpha 2b by Schering-Plough. (PEG-Interferon)

These were superseded by
1) Roferon (a non-pegylated version of Pegasys by Roche)
2) Intron A (a non-pegylated version by  PEG-Intron by Schering-Plough
These versions are rarely in use by developing nations now.

Pegylation is a process of bonding of Poly Ethylene Glycol and interferon that produces a longer lasting/more efficacious product.

A third interferon that is labeled for use for non-responders is known as Infergen by brand name; also generically known as Consensus Interferon, or CIFN. This is a bio-engineered drug that has purportedly been designed using the optimal proteins from alpha 2a and 2b, however it’s not available in pegylated form

That’s a nutshell description; others will hopefully chime in with any needed corrections.

The efficacy of Pegasys ( Interferon alpha 2a is currently thought to be equivalent to the competition from Schering-Plough; here is a discussion from a very competent hepatologist that discusses some of the results from the recent IDEAL study that compared the two compounds:

http://www.hivandhepatitis.com/hep_c/news/2008/011808_a.html

Best,

Bill

[meki]

Dang Bill...

That was pretty good for an answer!

[Bill1954]

Oops, I said superseded above, and meant preceded. Bad spelling too :o).

Bill

[Bill1954]

LOL, I figure I'm safe as long as I can sound authoritative enough that no one checks my post :o). How are ya?

[daniel2u]

So Peginterferon alfa-2a is the good stuff?  

[Bill1954]

Peg interferon alfa-2a is compared in a number studies; current thought suggests it is very similar in efficacy to the competition. Whether it is “the good stuff” is a rather subjective question, and needs to be analyzed by experts. Some suggest the IDEAL study was less than ideal, and failed to provide a fair comparison.

For further research, try:

http://tinyurl.com/5glcsz

This is a sizable collection of expert analysis on the subject. What reasons (if any) did your doctor offer for using Pegasys this time, vs. Schering-Ploughs PEG-Intron?

Bill

[Bill1954]

Daniel,

Of particular interest, and very much on point:

http://www.hivandhepatitis.com/2006roberts/hcv/080906_c.html

P L M Jansen and H W Reesink. Antiviral effect of peginterferon alfa-2b and alfa-2a compared. Journal of Hepatology 45(2): 172-173. August 2006.

“In view of the more than 175 million patients who are infected with HCV, the stakes for the industry are high,” the authors concluded. “We as hepatologists should not be too naïve in thinking that these comparison trials are designed and conducted by the industry for purely scientific reasons. For the industry these trials are, economically speaking, life or death. We should continue to make sense of the data and we should not decide too quickly that one drug is better than the other.”

Bill

[DragonSlayer45]

I agree with the explanations above.

I would just add that the main difference between 2a and 2b (other than the drug companies that make them) are the molecule sizes of the drug. I believe 2a is a larger molecule size than 2b. Some people claim the sides are not as bad with pegasys. I am not sure if it is true or not but I am going to be taking pegasys so that would be OK with me LOL.

I would also like to just add that they are synthetic interferons that they use for treatment not naturally occurring interferons.

[Bill1954]

I tend to disagree with your statement:

“I would also like to just add that they are synthetic interferons that they use for treatment not naturally occurring interferons.”

I believe that Pegasys and PEG-Intron are considered naturally-occuring IFN. The exception might be Infergen (CIFN, Alphacon-1, Consensus IFN).

Please review this excerpt from the Cleveland Clinic Journal of Medicine:

http://www.ccjm.org/hepatitis/text21.htm

“Interferons. Alpha interferons are a family of naturally occurring proteins that are secreted by many mammalian cells”.

There is often confusion because these proteins are “cultured” from bacteria (in the case of PEG-Intron, ‘eschererichia coli’), but I think the protein is still a naturally occurring molecule.


Bill

[daniel2u]

Thanks all for the information.  There is so much to learn.  I feel that I am becoming anemic as I did last time so right now I struggle to stay focused.  I see the doctor on Tuesday for my first blood analyst since I started treatment.  I would assume that she will give me procrit then all should be well.  I know last time I handled the treatment very will.  
I would like to close in saying I sure can't wait until this is over.  

Thanks again

Daniel

[merryBe]

the simple answer is, peg/pegalated means it is time released. It dissolves slowly into your tissue which is why one shot a week is enough....it contains a seven day dose that will break down slowly and give a fairly even supply to the body.

for some people it works better, certainly less hassle. Other say daily shots helped them get clear when Peg did not....but most of the research does not bear out better results from the daily form....it does bear out worse side effects.

The peg form is easier on patients and also on those who must go somewhere and have help injecting. For this and many reasons it has become the preferred tx and SOC.

[DragonSlayer45]

I read the article you referred to and yes alpha-interferon is naturally occuring but it does not say that is what our drugs are.  I was always told by my doctor that it is synthetic or man made. While Interferon is naturally made in the body as part of our immune system the drug we take pegasys or peg-intron are not naturally occurring they are genetically engineered.

Here is an excerpt from the online publication "Choices" which is produced by the Caring Ambassadors Program (great resource). The chapter this came from was written by a doctor.

Natural Versus Manufactured Drugs
Western doctors consider any compound that is ingested to improve health or fight disease to be a drug. The distinction between so-called natural compounds and those that are manufactured is often an artificial one. Many manufactured drugs are derived from natural sources by taking extracts from plants, living organisms, or other naturally occurring materials. Other manufactured drugs are exact copies of naturally occurring compounds. For example, the drug alpha interferon, the basis of all current western therapies for HCV, is a copy of the alpha interferon the human body manufactures to combat viruses. The flu-like side effects of interferon therapy are not surprising when you realize that the same symptoms occur when the body releases its own interferons to combat a viral infection.

below are a couple of other links I saw as well.

http://www.hepatitisweek.org/members/Managing/interferon.htm

http://www.cancerhelp.org.uk/help/default.asp?page=4009

http://www.atdn.org/simple/pifn.htm

I am not trying to argue by the way just being factual and to understand all of this like the rest of us. I have nothing but the deepest respect for you as you do battle with this disease. I also am in awe of the fact that you are doing 96 weeks of treatment. All of that after doing 56 weeks prior. God Bless you Bill. You are a strong man and I only pray that I have the strength to handle this as you have.

Be well my friend and beat this beast!