The objective of this study is to evaluate the activity of 2 oral doses of AB1010 in subjects suffering from active RA who have shown an inadequate response to one DMARD including MTX or anti-TNF, after 3 months (12 weeks) of treatment.

The safety and efficacy will be evaluated on:

Rate of patients achieving ACR 20, 50, 70 and 90 DAS (disease activity score) after 3 months treatment ACRn after 3 months treatment Therapeutic maintenance of AB1010 at 3 months Quality of Life assessed by SF12 Health Assessment Questionnaire (HAQ) Clinical and biological safety Pharmacokinetic profile of AB1010

Inclusion Criteria:

1. Meet American College of Rheumatology (ACR) criteria for RA
2. Have active RA
3. ACR functional class I-III
4. Disease onset at > 16 years of age
5. Disease duration of at least 6 months
6. Failure to one DMARD including methotrexate and anti-TNF alpha

Exclusion Criteria:

1. Pregnant or breastfeeding women
2. Inadequate bone marrow function
3. Current use of a DMARD within 4 weeks (or 5 half-lives, whichever is longer) of screening except for leflunomide which requires a specific wash-out
4. Any previous use of recombinant IL1-Ra
5. Current use of more than 1 non steroidal anti-inflammatory drug (NSAID) or change of dose of the NSAID within 4 weeks of baseline or NSAID use greater than the maximum recommended dose
6. Within 4 weeks before baseline, use of more than 10 mg/day of prednisone or equivalent or change in the dose of prednisone or equivalent, or having intra-articular corticosteroid injection or bolus intramuscular or intravenous treatment with corticosteroids (>20 mg prednisone or equivalent