Background There are two approved biological drugs, infliximab and adalimumab, for the treatment of Crohn´s disease (CD). For patients who lose their initial response, consideration can be given to dose intensification (DI) to regain therapeutic benefit.

Purpose Evaluation of the occurrence and effectiveness of DI of infliximab and adalimumab in CD patients who were primary responders.

Material and methods Observational retrospective study in a second level hospital, which included patients with CD on treatment with infliximab or adalimumab, from January 2004 to December 2013, and who responded to an induction regimen of the anti-TNF-α drug.

The variables collected were: anti-TNF-α drug, patient’s response, requirement for DI and time of follow-up.

The effectiveness of DI was determined by the numbers of patients responding to anti-TNF-α drugs at an intensified dose. This variable and the numbers of DI were calculated as the percentage of patient-years of follow-up.

Results A total of 40 primary responders to infliximab and 15 to adalimumab were included, who provided 125.2 and 23.1 patient-years of follow-up, respectively.

The proportion of patients who required intensified infliximab treatment was 8.8% (11/125.2) per patient-year and for adalimumab 8.6% (2/23.1) per patient-year. The times with intensified treatment were 18.8% and 5.3% patient-years follow-up, for infliximab and adalimumab, respectively. The percentage of patients maintaining a response to intensified doses of the drugs was 16% (3/18.8) per patient-year for infliximab and 37.7% (2/5.3) per patient-year for adalimumab.

Conclusion The proportion of patients who required DI was similar for the two drugs and it was less than 10% per patient-year. The effectiveness of DI was relatively low, due to the fact that the proportion of patients maintaining a response to DI was less than 40% per patient-year.

In other studies (Gisbert and Billioud et al.), the proportion of patients who needed intensified infliximab was similar to our results (13% per patient-year) and the annual risk of DI for adalimumab was greater (24.8% per patient-year).

References and/or Acknowledgements No conflict of interest.