OBJECTIVES: In the 1-year, double-blind, placebo-controlled ATTEST trial, efficacy of abatacept or infliximab vs. placebo was reported in patients with rheumatoid arthritis (RA) and inadequate response to methotrexate. We estimated trial-based and real life costs of abatacept and infliximab for achieving pre-defined remission or low disease activity state (LDAS) as recommended by the European League Against Rheumatism (EULAR). METHODS: Quantity of drug, serious adverse event (SAE) rates and time (months) in remission or LDAS were taken from ATTEST for the trial-based calculation to derive a cost per remitting/LDAS patient and cost per patient-month in remission/LDAS. We used list prices for drugs and public tariffs for infusion and hospitalization due to SAEs. Trial-based analyses were made for the full year, and the first and subsequent 6 months (initiation & maintenance).  Maintenance costs were extrapolated to real life, taking into account dose escalation and shortening of infusion intervals with infliximab. SAE rates from a Cochrane network meta-analysis were considered in the real-life analyses. All analyses were conducted from a health care system perspective for Italy. RESULTS: In Italy, the annual trial-based costs per remitting/LDAS patient were €70,259/€37,219 for abatacept vs. €85,547/€46,592 for infliximab. In the initiation phase, costs per patient-month in remission/LDAS were €11,028/€6,020 for abatacept vs. €8,347/€4,173 for infliximab. Abatacept showed lower costs per patient-month in remission/LDAS in the maintenance phase €5,046/€2,673 vs. €5,500/€2,996 for infliximab. Real-life maintenance costs per month in remission/LDAS were: €5,347/€2,832 for abatacept vs. €7,210/€3,927 for infliximab. Higher initiation cost for abatacept to achieve remission/LDAS would be offset at 14.6/16.1 months during real life. CONCLUSIONS: Our findings suggest a lower cost-consequence for abatacept during the maintenance phase and its real-life extrapolation. Abatacept is a sustainable, safe, and economically attractive biologic for the long-term treatment of RA when compared to infliximab.