Proactively Versus Reactively Measuring CT-P13 Trough Levels Did Not Improve 1-Year Outcomes in IBD

In therapeutic drug monitoring (TDM), measurements of trough levels can be used to guide adjustments of treatment intensity as a way to minimize the risk of treatment failure. In some cases, patients are monitored proactively; in other cases, patients are monitored reactively, or only when they report signs or symptoms that may point to a loss of response to a drug. As yet, there exists no consensus as to whether proactive or reactive TDM is the most appropriate approach in patients with inflammatory bowel disease (IBD) who receive infliximab therapy.

Some research has pointed to the superiority of proactive TDM; one recent study from Portugal in 205 patients with IBD, 56 of whom received proactive monitoring, showed that those who were proactively monitored received more treatment escalation, needed fewer surgeries, and had higher rates of mucosal healing than their counterparts who received reactive monitoring.¹

However, in somewhat contrasting findings, researchers from Spain reported in a new study that in the first year of treatment with biosimilar infliximab CT-P13 (Inflectra, Remsima), patients with IBD did not have improved response or remission rates with the use of proactive monitoring versus reactive monitoring.²

In the study, 77 patients with IBD, 23 of whom had ulcerative colitis and 54 of whom had Crohn disease, received either proactive monitoring (n = 41) or reactive monitoring (n = 36). All of these patients were starting treatment with CT-P13.

The proactive monitoring group had levels of infliximab and antidrug antibodies measured at week 14, and those patients whose drug levels were too low received intensification, regardless of their clinical response to infliximab.

At week 14, 58.5% of the proactive monitoring group and 63.9% of the reactive monitoring group had achieved clinical remission. In the 2 groups respectively, 80.5% and 80.6%, respectively, had at least a partial response. At week 54, 61.0% of the proactive monitoring group and 77.8% of the reactively monitoring group were in clinical remission, and 73.2% and 80.6%, respectively, had at least a partial response.

Of the 13 patients in the proactive group who had their treatment intensified, there were no significant differences observed versus the reactive monitoring group in terms of secondary loss of response to infliximab.

According to the authors, proactive management does not improve response or remission rates for patients receiving CT-P13 in the first year versus reactive monitoring, and treatment intensification does not appear to prevent secondary loss of response in the first year of therapy.

References

1. Fernandes SR, Bernardo S, Simões C, et al. Proactive infliximab drug monitoring is superior to conventional management in inflammatory bowel disease [published online June 27, 2019]. Inflamm Bowel Dis. doi: 10.1093/ibd/izz131.

2. González AE, Segura PS, Lara DO, et al. Clinical value of CT-P13 trough levels, an infliximab biosimilar, in the management of inflammatory bowel disease [published online November 27, 2019]. Med Clin (Barc). doi: 10.1016/j.medcli.2019.07.025.