t(1:14) and trisomy 4 in a patient with concomitant leukaemias.

Rheumatoid arthritis (RA) societal costs are high because the disease may cause not only restricted joint mobility, chronic pain, fatigue, and functional disability, but also psychological distress. Direct health care costs represent about one-fourth of all costs and are prevalently represented by in-patient care expenditures. The introduction of biologics disease-modifying anti-rheumatic drugs (B-DMARDs), has really changed the perspectives of the patients not fully responding to conventional DMARDs, but the direct costs for drugs has really modified the expenditure for this disease and many other diseases, i.e. psoriatic arthritis, spondyloarthropathies. Increasing pressure for lower cost versions of biological medicines, the scientific technology (particularly analytical technology) that continues to improve will lead to the introduction through reverse ingeneering of biosimilar drugs in rheumatology. The hope is to provide cost savings, which may broaden access to biopharmaceuticals and stimulate further research. The need for patients to have a biosimilar product, with comparable efficacy and safety, will be discussed in this paper along with all the possible issues that will govern the assessment of the bioequivalence and of the interchangeability.