Not the same, but is it the same? Cycling of biologic agents in rheumatoid arthritis. Experience in the Instituto Mexicano del Seguro Social.

INTRODUCTION

Available data for biocomparable drugs are not enough to make clear decisions with respect to the potential consequences of a change for non-medical reasons in efficacy, security and inmunogenicity in patients. In the near future, options on biological treatments, biocomparable drugs, non biocomparable drugs and new chemical synthesis options will grow. Therefore, it is important to know how patients behave in persistence of treatment after a change for non- medical reasons, which already happens on a regular basis in social security institutions in Mexico. This information will help us to better understand the standard of treatment for patients with chronic immunomediated conditions.

OBJECTIVE

The primary objective was to measure the impact of change for non-medical reasons in patients with rheumatoid arthritis (RA) treated with an innovative biological on persistence of treatment after changing to a biocomparable drug or a non-biocomparable drug, compared with those patients staying with the innovative biological.

STUDY DESIGN

This is an observational study (non-interventionist) of paired cohorts, where an historic cohort obtained by review of clinical records of stable patients in which no modifications to treatment were made for at least six months is compared with two cohorts of patients whose treatments were switched to another treatment with the same therapeutic mechanism for-non-medical reasons (cycling).

RESULTS

We included 264 RA patients (ACR/EULAR, 2010); 132 were switched for non-medical reasons, and 132 were not switched. Two-hundred and thirty (87.1%) were female. Average age was 53.9 years, ranging from 16 to 84 years. Two-hundred and sixty-three patients were Latino (99.6%); one was Caucasian. Persistence of treatment 12 months after the change was 84.8% (85.8% in Enbrel/Infinitam, 78.9% for Remicade/Remsima). No statistical difference was found with respect to RA clinical activity measured by DAS28 12 months after the switch (P > .05). In the 134 switched patients, 20 discontinued the new treatment due to lack of efficacy of the new drug and were changed to a different drug with a different biologic target. Although no differences were found in the cohorts of switched patients with respect to DAS 28 after 12 months of use, we did find differences in the frequency of adverse events. Forty-two patients had an adverse event in the drug switch cohorts: 33 in the Enbrel-Infinitam group and 9 in the Remicade-Remsima group.

CONCLUSIONS

The persistence of treatment after switching from an innovative drug to a biocomparable or a non- biocomparable in RA patients did not show statistically significative differences in our cohorts, but we did find a higher number of adverse events when comparing those who were changed with those who continued on an innovative drug. Twenty patients in the switch groups had to receive a new drug with a different biological target due to lack of efficacy of the switched drug.