Background Tocilizumab (TCZ) is a monoclonal antibody that binds to the interleukin 6 receptor and has shown efficacy in rheumatoid arthritis (RA) patients with different profiles (DMARD failure, monotherapy or anti-TNF failure). Although the efficacy and safety of TCZ in clinical trials has been demonstrated, it is also shown a maintained response with only few adverse events.
Objectives To analyze the efficacy and safety of TCZ treatment in RA patients with different profiles (monotherapy, DMARD failure or anti TNF failure) over a period of 4 years.
Methods We have performed a retrospective study by reviewing clinical data of RA patients who have been treated with TCZ, due to unsatisfactory response to DMARDs or other biological therapies, during the past 4 years. The DAS28 was used as a measure of disease activity and incidents that arose during treatment were collected. A mixed linear regression model was used for statistical analysis.
Results We included 58 RA patients treated with TCZ over a period of 4 years, with a mean age of 55 years (21-87) and 88% were women. The average DAS28 at different intervals is shown in the table below.
28 cases were treated with TCZ due to ineffectiveness after another biological treatment: 17 cases after one anti-TNF, 7 cases after two anti-TNFs, 3 cases after three anti-TNFs, 3 cases after one anti-TNF + abatacept and 2 cases after two anti-TNFs + abatacept. The most frequently administrated TCZ doses were: 8mg/kg in 78% of cases, 6mg/kg in 12% of cases and 4mg/kg in 10% of cases, and TCZ dosing has been reduced most frequently due to low disease activity and cytopenia. 90% of patients were treated with a synthetic DMARD, mainly methotrexate. There were a total of 53 adverse events in 50 patients (with infections in 27 of them, 14 cases of cytopenia and 2 neoplasias), although in only 22 cases was necessary to delay the TCZ intake. The most frequent infection was respiratory infection and the second most frequent was urinary tract infection. Hypercholesterolaemia is an adverse event characteristic of TCZ, and was found in 46 cases, but only in 11 of them appeared after the TCZ treatment. Discontinuing TCZ treatment was necessary in 14 patients, being the most frequent cause the treatment ineffectiveness (4 patients).
Biostatistical analysis shows that at the beginning of treatment, there is a very rapid clinical response (measured by das28 and reaching clinical remission in the sixth month) that is maintained over the time (p=0.0012). Furthermore, there is no influence based on the DMARD used, previous biologic therapy or the DAS28 result at the beginning and during treatment.
Conclusions Treatment with TCZ in RA patients is associated with a rapid clinical response evaluated by DAS28 appearing within the first 6 months. According to our analysis, this clinical response is maintained over time up to 4 years. Furthermore, the long-term safety profile is consistent with the data from previous studies.
Disclosure of Interest None declared