Secondary loss of response (initial good response followed by loss of response and flare up) is a frequent event occurring during biological therapy. The aim of this study was to assess loss of efficacy in patients with Crohn's disease treated with infliximab or adalimumab for a year. Secondary goals were to identify clinical or laboratory predictors of loss of response and to evaluate whether the frequency of dose escalation differs in patients receiving infliximab or adalimumab. Data were provided by a computerized database.
Patients and methods: Sixty-one patients with Crohn's disease achieved remission after induction therapy and received regular maintenance treatment. 35 of them were on infliximab, and 26 on adalimumab therapy. None of the patients treated with infliximab received previous biological therapy, while 10 of the adalimumab-treated patients were naïve to biological therapy. Authors compared the data of patients who relapsed with those who remained in remission and also the characteristics of infliximab-treated patients with adalimumab-naïve patients. Data were analyzed using Chi-square test. Kaplan Meier curve was used to show the time of loss of efficacy.
Results: Remission was achieved in 70.5%, and response was achieved in 29.5% of the patients after induction. Loss of response occurred in 22 of the 61 patients after a year of therapy. The proportion of remission after induction was significantly lower in patients who lost response vs. those who remained in remission. More patients with sustained remission received immunosuppressive therapy before and during the biological therapy vs. those with loss of response. Loss of response was significantly more frequent and occurred earlier in adalimumab-naive patients vs. infliximab-treated patients.
Conclusion: The need for dose escalation should be calculated in the budget in the majority of patients, especially in adalimumab-treated patients.