These medications are powerful, and they do carry risks. However, reding the warnings, one must look at the trade-offs. You know for certain that untreated AS will almost certainly cause difficulty for your body. Once that damage happens, it will not usually be possible to undo it.
Measure against the most uncertain possible side effects. You will want to speak directly to your doctor about your concerns. I can tell you that Cimzia is well generally a well-toleated medication.
As a matter of fact, I used it and liked it a great deal. I know many people who have used this medication, and I have not heard of any undue consequences. Is that a guarantee that nothing will happen? No, of course not. But if you look at almost every biologic medication on the market, you will find exactly the same warnings.
Again I suggest you talk frankly about your concerns with your rheumatologist and then make an informed decision. But you must compare your current situation of pain and the high possibility of future joint damage with the relatively low incidence of the negative aspects you suggest.
I wish you well. I know it is a big decision. It is one I made over 20 years ago, and I a, delighted I did.
rick - moderator