Background and objectives: Biosimilars are cost-effective alternatives to reference products for patients with inflammatory bowel diseases (IBD) and chronic inflammatory rheumatic diseases (CIRD), but patient beliefs can affect adherence to the transition. This study aimed to explore patient experience and satisfaction after switching to CT-P17, a high-concentration (100 mg/mL), citrate-free adalimumab biosimilar.Patients and methods: This observational, multicenter, prospective French study included adult patients with IBD or CIRD who switched to CT-P17 from reference adalimumab (R-ADA; 100 mg/mL) or a low-concentration adalimumab biosimilar (ADA-BioS; 50 mg/mL). Patients completed online questionnaires to assess treatment perceptions, satisfaction, and tolerance at study inclusion (under previous treatment) and over 3 months of CT-P17 treatment. The primary criterion was overall patient satisfaction, which was assessed with the question, \"What is your global satisfaction with the CT-P17 injection?\", using a 7-point Likert scale. Multivariate logistic regression analysis was performed to identify factors associated with increased treatment satisfaction after switching to CT-P17.Results: The total analysis population included 232 patients (IBD 72.0%, CIRD 28.0%). Median patient age was 57.0 years (interquartile range [IQR] 46.0-63.0), 50.4% were men, and median disease duration was 9 years (IQR 5-16). Approximately half of the cohort (51.2%) switched to CT-P17 from an ADA-BioS (including 19.4% from an ADA-BioS with citrate) and half (48.7%) from R-ADA. The proportion of patients who were satisfied with treatment was stable between baseline (under previous treatment) and 3 months (under CT-P17). More patients reported increased satisfaction after switching to CT-P17 from an ADA-BioS (22.7% vs 8.0% when switching from R-ADA; p = 0.002), or from an ADA-BioS containing citrate (28.9% vs 12.3% when switching from a citrate-free ADA-BioS; p = 0.008). Independent prognostic factors for increased satisfaction were previous treatment with an ADA-BioS (odds ratio [OR] 2.88 [95% confidence interval 1.17-7.08]; p = 0.021) and pain at the injection site under previous treatment (OR 1.26 [1.08-1.47]; p = 0.004). Significantly fewer patients reported pain, redness, itching, and hematoma after 3 months of CT-P17 treatment versus baseline (p < 0.001).Conclusions: The majority of patients had stable or increased treatment satisfaction after switching from R-ADA or an ADA-BioS to CT-P17. In particular, switching to CT-P17 from a low-concentration ADA-BioS or an ADA-BioS containing citrate was associated with increased patient satisfaction. An improvement in overall tolerance with CT-P17 versus previous adalimumab treatment was also reported.Trial registration: ClinicalTrials.gov identifier NCT05427942, registered June 22, 2022.http://clinicaltrials.gov/show/NCT05427942