Hi there, I have faced the same predicament you describe. I have A.S, which stands for ankylosing spondylitis. It's an autoimmune arthritis very similar to R.A in respects. I also now have full body sfn sadly! Biologic treatments such as etanercept and humira are brilliant for A S. I think they have been used with R A with some success. I understand they are not the main drug of use for R A ( I think!)and other disease modifying drugs such as methotrexate and even thalidomide are used. I know this from a friend with R A. The biologics are powerful and effective to a great extent BUT, there are reports that these drugs have caused neuropathy. There are a few good reports online about this.
This wasnt the cause in my case. Mine came on alongside the A S of its own free will. I did try a biologic for a short while after the sfn had started. I am sure it helped some even with the sfn. I stopped taking it though. Options are a bit limited unfortunately. The two conditions do co exist sometimes. I have read a few online about R A and neuropathy. I have been researching online for over a year so have read loads. Still no clear answers unfortunately. Maybe control of the R A will help the neuropathy in your case. I'd get onto the rheumy about trying some o the disease modifying drug options.