4CPS-126 A population pharmacokinetic model of adalimumab in a cohort of paediatric patients with inflammatory bowel disease: a preliminary analysis

Abstract

Background and importance The paradigm of patients with immune mediated autoimmune diseases has changed with the introduction of biological medicines. The correct use of these drugs is necessary to guarantee their effectiveness. Aim and objectives To analyse adherence in immune mediated diseases patients treated with selective immunosuppressive drugs (adalimumab or etanercept) and to establish a link with patient characteristics and treatment duration. Material and methods A retrospective study in a third level hospital was conducted in patients receiving treatment with adalimumab or etanercept from January to December 2018. Adherence was measured via the medication possession ratio (MPR) over 1 year. Variables recorded were sex, age, pathology, previously taken biological drug treatments, treatment duration in days and number of auto-injectors. Statistical analysis of the data was made with SPSS. Results The sample population was 146 patients, 55.5% (81) men, mean age 53.58±12.47 years, and 55.5% were treated with adalimumab, 39.7% with etanercept and 3.9% with the biosimilar etanercept. Medium treatment duration was 5.07 ±3.09 years. The main pathologies and frequency were: rheumatoid arthritis in 32.2% (47) of patients, spondyloarthropathy in 18.5% (27), psoriatic arthritis in 17.8% (26), psoriasis in 13.7% (20), Crohn's disease in 11% (16), ulcerative colitis in 4.8% (7) and other pathologies in 2.1% (3). Regarding adherence, the overall rate was 89.3%. For each patient group, adherence was 86.24% in patients with rheumatoid arthritis, 89.36% in patients with spondyloarthropathy, 94.5% in patients with psoriatic arthritis, 84.11% in patients with psoriasis, 94.63% in patients with Crohn's disease, 93.01% in patients with ulcerative colitis, 84.38% in patients with Verneuil's disease and 84.11% in patients with systemic lupus erythematosus. In total, 78.1% (114) of all patients were adherent (MPR !80%). We did not observe statistically relevant associations between any of variables except for lower adherence to treatment and longer treatment duration (p=0.038). Conclusion and relevance Patients had good adherence to selective immunosuppressant treatments according to the MPR method. Sex, pathology or drug type were not related to absence of adherence. However, lack of adherence was observed the longer treatment lasted, which implies that it would be useful to have closer pharmacotherapeutic monitoring of this kind to reinforce adherence in patients.