P884 Patient satisfaction and experience after a switch to an adalimumab biosimilar with high concentration and citrate-free: results from a multicentric prospective real-life study

Abstract Background Switching from a reference product (RP) to a biosimilar (BS) aims at generating cost savings. Patient adherence after a switch is linked to overall experience that can be impacted by patient or treatment characteristics. This study aimed to analyse patient-experience after a switch from an adalimumab (ADA) to CT-P171 (ADA BS high concentration, HC, citrate-free). Methods YU-MATTER (NCT05427942), a multicentric prospective observational study included patients with inflammatory bowel disease (IBD) or chronic inflammatory rheumatic disease (CIR), treated with ADA: either the RP (HC: 100mg/ml) or a BS with low concentration (LC: 50 mg/ml). Patients were switched to CT-P17 and followed-up for 3 months (M). Clinical characteristics were collected at M0, including beliefs (BMQ questionnaire2), patient-experience via 5 self-questionnaires designed in collaboration with patient associations to explore satisfaction regarding the injection (Likert 7), discomfort (pain [NRS 0-10], redness [Likert 4], itching [NRS 0-10], and haematoma [Likert 3]). Satisfaction and overall injection tolerance (pain < 4 AND absence of redness AND itching < 4 AND absence of haematoma) were assessed between M0 (just before switch) and M3 (3 months after switch). Factors associated with satisfaction improvement (Likert) were explored through multivariable logistic regression. Results Of the 232 patients analysed, 167 had IBD (CD =136); mean age 44±15 years; median IBD duration 9 years ([Q1; Q3]: [5; 15]) and 50.9% were men. The median differential score necessity-concern was of 5 [3; 7] suggesting that the perceived necessity of the treatment was higher than its concerns. 119 (51.2 %) patients were switched from a BS (45 with citrate) and 113 (48.7%) from the RP. At M3, 175 patients (75.4%) were satisfied with the injection and 145 (62.5%) had a stable or improved satisfaction versus the previous ADA. Among patients receiving a BS, the presence of citrate was significantly associated with an improvement of satisfaction after switching to CT-P17 (58.3% vs. 30.0%, p=0.006). Overall injection tolerance significantly improved after switching from 28.9 % at M0 to 57.7 % at M3 (p