SAT0503 DEVELOPMENT OF MALIGNANCIES IN JIA PATIENTS EXPOSED TO BIOLOGIC AGENTS:A SINGLE CENTRE RETROSPECTIVE STUDY

Abstract

Background: Over the last two decades, the usage of biological agents in the treatment of Juvenile Idiopathic Arthritis (JIA) has been a successful and promising approach in controlling the disease activity and preventing chronic sequelaes. However, since Food and Drug Administration (FDA) has drawn attention to the possible association between the use of biological agents and the development of malignancy in 2008, there are ongoing concerns about the long-term safety data and side effect profile of the drugs with the contradictory study results. Objectives: We aimed to present preliminary data on the incidence of malignancy in patients with JIA treated with biological agents versus the general population rates in Turkey. Methods: A retrospective single-center hospital-based cohort study was performed to analyse cancer occurrence among JIA patients treated with biologic agents over the observation period between January 2004 and January 2018. The medical patient records were reviewed to obtain information about the clinical follow-up. As reference data for direct standardization; age, sex and calendar-year-specific incidence rates from Turkish cancer registry were used. The standardized incidence ratio (SIR, ratio of cancers observed to expected) was generated, with 95% confidence intervals. Results: The study sample consisted of 504 JIA patients, who had been started their first biologic treatment between 2004 and 2018. Mean age was 17.1 years (SD 5.6) with 56% of female proportion. The mean disease duration was 10,3±5.1 years. Median time from baseline to start of the first biological was 17,5 (IQR:43) months. Mean age of initiation of biologic treatment was 9,8 ± 4,2 years. Etanercept was most commonly preferred drug to initiate as first-line biologic treatment (n=361,72%). 172 (34.1%) patients in the cohort required a switch to a second biologic agent. Main reason for switching to another biologic agent was due to lack of response (16.6%). Median duration of biologic use was 35 (IQR:41) months. One cancer occurred within observation period, compared with 0.095 expected (SIR:10.53, 95% CI 0.526 to 51.91). The patient was 18-year-old male, who had previously received etanercept and tocilizumab up until diagnosis of the hematological malignancy. Conclusion: In our JIA cohort, patients treated with biologic agents appeared to have an increased rate of incident malignancy compared to children of the same sex and age group in the general population in Turkey. However, before mentioning a clear causal relationship, other potential contributing factors such as inflammatory process of the underlying disease itself and the use of concomitant immunosuppressants should be taken into consideration. Additional long-term studies with larger populations are needed to be able to draw definite conclusions.