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Avatar universal

Interferon question, alpha 2A/2B

Does anyone know or can point me in the right direction as to what is the major difference between the two other than manufactures interferon’s and are there any major differences in the side effects of each.
Thanks
Jasper
39 Responses
148588 tn?1465782409
PegIntron shows greater up regulation of IFN alfa response genes. Pegasys has a longer half-life from being linked with a branched PEG molecule.

http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=16780997&dopt=AbstractPlus
362971 tn?1201990634
What does that really mean? Does it mean that alpha-2b is more effective.
148588 tn?1465782409
It means alpha-2b may do some things on a biochemical level more efficiently during the early part of treatment but since the drugs currently available have IFN alpha-2a linked to a better PEG molecule, the two products are equally "effective". You'll have to get HR or someone else to explain 'upregulation of genes'.
And don't ask why 'they' don't produce a Peg IFN with alpha-2b linked to branched PEG molecule, instead of fiddling around with protease and polymerase inhibitors I might start talking about international patent law and corporate greed.
Avatar universal
the wikipedia article on interferons might be a good starting point
http://en.wikipedia.org/wiki/Interferon

interferons are a class of proteins naturally produced in response to the detection of virus. They play a fundamental role in the immune response; though they don't directly interact with virus they trigger a wide-raging set  of changes that inhibit viral replication and kill infected cells. Injecting ifn amounts to supplementing the ifn naturally produced by your body with an external supply of synthetically manufactured but identical molecules (hence your body responds as if it's dealing with the mother-of-all-flus)

The body naturally breaks down and recycles its proteins. To keep the ifn "car-alarm" in circulation longer, synthetic ifn was modified by  addition of an extension (polyethylene glycol, PEG). Tethering this "canon-ball" like extension to the protein has no change on its signaling activity, but it does delay its break down. Hence peg-ifns only have to be injected once a week whereas non-peg ifn is injected a minimum of 3/week. There's a tendency to see ifn-based studies as "dated" relative to peg-ifn studies. Not so - addition of the peg is purely a patient-convenience factor (for example consensus ifn is not pegylated and is often injected daily).

Roche  claims one-size-fits all dosing (180 micrograms/week) for its product a claim that those weighing above a certain cutoff might want to question. Schering's product is weight based.  As best  I know this is the only significant difference between the two, though a  number of people on this board who have tried both have reported different side effects.
Avatar universal
"There's a tendency to see ifn-based studies as "dated" relative to peg-ifn studies. Not so - addition of the peg is purely a patient-convenience factor (for example consensus ifn is not pegylated and is often injected daily).
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Willing, wasn't clear if the above is from Wiki, or your commentary. In any event, this large review of randomized studies seems to suggest otherwise. I also thought that Peg had been proven superior in the initial Peg trials, but maybe that is covered below.

"Conclusion: Pegylated interferon plus ribavirin compared with interferon plus ribavirin increased the proportion of patients with sustained virological response, but at the cost of more adverse events."

http://www.medscape.com/viewarticle/557838 (Free Mescape Registration Required)

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Also, re another topic -- frequent VL testing, some interesting comments by "Susie" re a well-known clinician/researcher. While I can't see I'm in certain agreement with him in this case, his contention is that the lack of early and frequent VL testing will affect the accuracy of predicting SVR Telaprevir prospects. In any case, if not in this instance, I think the more data we accumulate in this respect can only be a plus -- it not for the first treatment, but for perhaps future tx scenarios as per example Dr. S.

http://www.medhelp.org/posts/show/407302
Avatar universal
"There's a tendency to see ifn-based studies as "dated" relative to peg-ifn studies. Not so - addition of the peg is purely a patient-convenience factor (for example consensus ifn is not pegylated and is often injected daily).
-----------------------------------------------
Willing, wasn't clear if the above is from Wiki, or your commentary. In any event, this large review of randomized studies seems to suggest otherwise. I also thought that Peg had been proven superior in the initial Peg trials, but maybe that is covered below.

"Conclusion: Pegylated interferon plus ribavirin compared with interferon plus ribavirin increased the proportion of patients with sustained virological response, but at the cost of more adverse events."

http://www.medscape.com/viewarticle/557838 (Free Mescape Registration Required)

----------
Also, re another topic -- frequent VL testing, some interesting comments by "Susie" re a well-known clinician/researcher. While I can't see I'm in certain agreement with him in this case, his contention is that the lack of early and frequent VL testing will affect the accuracy of predicting SVR Telaprevir prospects. In any case, if not in this instance, I think the more data we accumulate in this respect can only be a plus -- it not for the first treatment, but for perhaps future tx scenarios as per example Dr. S.

http://www.medhelp.org/posts/show/407302
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