Actually, Betaseron has the highest incidence of NAbs (and the Tysabri product spec say 6% had NAbs to Tysabri), but I'm not sure what danger you are alluding to. NAbs *neutralize* the drug in question - making it ineffective. It's like not taking the drug. Nobody has reported a danger from this (other than financial).
Yes, Betaseron does give high NABs but its use is slowly diminishing. The original data on Tysabri showed 6% got NABs but the webcase stated 9%.NABs can do a lot of damage to you other than just make your MS medication useless. They can wreck havoc with your immune system if left untreated. Many patients on the CRABs experience elevated NABs but most patients have the NABs return to normal after a period of time. Some people, however, have to be treated if they don't go down on their own.
With Tysabri they seem to know how to detect them and when they are likely to occur, so you can be taken off the drug and not waste your time/money using it if you are in the unlucky group.
That's because the docs were keeping a very close eye on them knowing that they could become elevated with the drug. I can't count the number of times I read about CRAB users whose docs never bothered to check them for NABs and would ask on the net what they were!!
As to the combination being worse, I'm having a hard time imagining how NAbs to one drug would have anything to do with the other given how utterly and completely different their structures are and how specific antibodies are.
That's the problem...very little is known about combining the drugs.
Can you illucidate how your fears might manifest themselves? I can understand a general "this is a new compound, I wouldn't stick it in my body until more is known" (I'm sort of in that camp) but you seem to be hinting at something more specific.
My additional concerns come from speaking with some knowledgeable people in MS medicine...docs, nurses and researchers. Some of these people are very uncomfortable with the speed that Tysabri got approved, especially using only one year data from the Phase III trial. These medical people are used to having a lot more data available for a new drug and so far that data simply isn't available. Everything that we have heard has come from Biogen and they don't have the greatest reputation in providing information to the medical community. I have heard that comment on more than one occasion. Who knows, maybe when all the data from the Phase III trials becomes published and then peer reviewed, these attitudes may change.
I don't think we've seen any vendor specific drug interactions with the interferons so far. The NAbs differences seem to be due to route of administration and production quality, not dose level.
Perhaps but there has to be a lot more research done in this area.
EDIT: I just checked - Tysabri NAbs appeared in 10% of subjects at least once with 6% having persistent NAbs.
Geez. it just went up 1% while reading your message
You know, 6% is kind of a high level for persistency in one year data. It will interesting to see what the two year data gives us.