Sorry if im sounding thick but what is MTX and what does it do?
MTX is methotrexate which is a disease modifying anit rheumatic drub (DMARD). It is usually the first medication you are put on after a diagnosis of RA and barring side effects the medication you are likely to stay on even as you add other drugs. MTX is the "gold standard" medication. The effectiveness of all other drug are measured against it.