Background Treatment of patients with rheumatoid arthritis (RA) must be directed to remission, and in some patients minimum activity, can be an option. The strategy most studied is the early and intensive treatment, associated with a strict monitoring. Half of these patients respond to initial monotherapy with methotrexate (MTX), and in non-responders, additive treatments with other synthetic DMARDs are an option. The utility of the combined and additive strategy (Step-up) of MTX and Leflunomide (LEF) is not well defined in early RA.

Objectives The objectives of this study was to estimate theproportion of clinical remission achieve by the Step-up strategy with LEF in patients with early RA that did not respond to initial monotherapy with MTX, the time to achieve remission, and estimate the state of remission in the last follow-up evaluation.

Methods An observational study of consecutive case series was performed by including a cohort of patients from Early Arthritis Argentine Consortium (CONAART) with RA of less than 2 years of disease duration, with no response to MTX in monotherapy according to medical judgment, and in whom treatment was additive with LEF. Assessment and data collection was performed every 3 months. Sociodemographic characteristics, functional status, disease activity and treatment were included. “Time to result” was assessed since the date of the beginning with the combination of MTX plus LEF to remission or last control. The state of remission was evaluated by DAS28. The Kaplan-Meier method was used to estimate the probability of each outcome.

Results A total of 106 patients were included. The mean duration of the disease at the time of inclusion was 4 months (IQR 2–8). The average age was 50±12 years and 83% were women. 68% were positive for RF and 65% for CCP. Median follow-up was 34±18 months (300 patient-years). After addition of LEF, 95 (90%) patients weren't in remission. The mean DAS28 was 4.61 (±1.61), HAQ =0.9 (±0.76), dose of prednisone =7.31 (±4.25). The median time in months of use of MTX was 6.7 (IQR 3.4–14.4), and 64% had doses greater than 20 mg of MTX during follow-up, 47 (50%) of patients achieved clinical remission in an average time of 8 months. The remaining patients did not achieve remission. The overall probability of remission for patients-month follow-up was 0.49. Twenty-seven of the 47 patients (58%) were still in remission at the last visit. Median follow-up after achieving remission was 20 months (IQR 3–29).

Conclusions In this early RA cohort study, 50% of patients with lack of response to MTX who added LEF achieved remission assessed by DAS28 at a median time of 8 months. 6 out of 10 of these patients were in remission at 2 years of follow-up.

Disclosure of Interest None declared