SAT0196 Time to discontinuation of biologic therapy by mechanism of action in rheumatoid arthritis: results from the ontario best practice research initiative (OBRI) cohort

Background: Patients with rheumatoid arthritis (RA) may discontinue their biologic disease modifying antirheumatic drug (bDMARDs) due to non-response, loss of response or adverse events. However, time to discontinuation may be related to mechanism of action.

Objectives: We aimed to compare drug survival of tumor necrosis factor inhibitors (TNFi) versus non-TNFi in patients initiating bDMARD treatment in a Canadian (Ontario) observational cohort.

Methods: Patients enrolled in the Ontario Best Practice Research Initiative (OBRI) who started bDMARD therapy within 30 days before or any time after OBRI enrolment were included in the primary analysis. Patients were followed from bDMARD start until discontinuation/switching, death, lost to follow-up, or last visit, whichever came first. Time to discontinuation/switching of bDMARD due to (i) any reason, (ii) non-response or loss of response, and (iii) adverse events (AEs), were assessed using Kaplan-Meier survival analysis for TNFi versus non-TNFi users.

Results: Among the 943 patients included in the primary analysis, 187 (19.8%) received non-TNFi and 756 (80.2%) TNFi. Mean (SD) age and disease duration were 56.4 (12.7) years and 9.6 (9.8) years, respectively, and the majority were females (79.1%) and biologic naïve (84.4%). TNFi included Etanercept, Adalimumab, Certolizumab, Golimumab, and Infliximab; and non-TNFi inlcuded Abatacept, Rituximab, Tocilizumab, and Tofacitinib.

Over a mean (SD) follow-up of 2.4 (2.0) years, bDMARD discontinuation/switching was reported for 37.6% of patients, with significant difference in time to discontinuation between TNFi and non-TNFi users (Logrank p=0.01). However, there was no significant difference due to non-response or loss of response (Logrank p=0.67) between the two groups. At 2 years, more patients remained on TNFi (71.0%) compared to non-TNFi (57.0%). At 5 years, 51.0% and 44.0% of patients still remained on TNFi and non-TNFi, respectively.

Conclusions: The overall retention rate for biologics was comparable to finding in European registries. We found that patients stay on TNFi longer compared to non-TNFi. However, no significant difference was found between the two groups, for discontinuation or switching of bDMARDs due to non-response or loss of response. Further analyses are required to adjust for the effect of potential confounders (e.g. age, sex, disease activity, and other treatment regimens) on biologic discontinuation.

Reference [1]Alejandro Souto José Ramón Maneiro Juan J. Gómez-Reino. Rate of discontinuation and drug survival of biologic therapies in rheumatoid arthritis: a systematic review and meta-analysis of drug registries and health care databases. Rheumatology2016March 1;55(3):523–534.