A Retrospective Claims Database Study on Drug Utilization in Japanese Patients with Crohn's Disease Treated with Adalimumab or Infliximab.

INTRODUCTION: Crohn's disease (CD) is a chronic and progressive disease in which the long-term management is important. This study sought to assess treatment persistence and dose escalation in the maintenance phase with adalimumab (ADA) or infliximab (IFX) in a Japanese real-world setting.

METHODS: A retrospective analysis was conducted using the Japan Medical Data Center database. CD patients with either ADA or IFX prescriptions between January 2012 and February 2015 were included. Outcomes of interest were (1) failure in the induction phase (defined as switch or discontinuation) and (2) persistence in the maintenance phase (defined as the absence of switch or discontinuation over 12 months since maintenance initiation).

RESULTS: Overall, 133 patients (53 ADA; 80 IFX) were included. Of them, treatment failed in 26 patients (19.6%) in the induction phase. During the induction phase, there was a trend towards fewer treatment failures with ADA than IFX (88.7% vs. 75.0%; p = 0.051). Of those who completed induction, 64 patients (33 ADA; 31 IFX) had at least 12 months of valid insurance enrolment after the initiation of maintenance and 13 (5 ADA; 8 IFX) had either switch or discontinuation within 12 months after the initiation of maintenance. Probabilities of switch or discontinuation over 12 months after the maintenance date were 15.2% and 20.9% for ADA and IFX groups, respectively (p-log rank = 0.7764).

CONCLUSION: Japanese patients have a high primary response to anti-tumor necrosis factor therapy in the real-world setting, in line with the results of clinical trials. This initial therapeutic advantage can be lost during the maintenance phase, leading to dose escalation, treatment switch, or discontinuation. This study suggests that those events occurred in comparable proportions of patients treated with either ADA or IFX. However, these findings should be considered with caution given the retrospective nature and small size of the study.

FUNDING: Abbvie GK, Tokyo, Japan.