Removing barriers to TDM
It’s not clear that proactive TDM will benefit treatment with all biologic disease-modifying antirheumatic drugs (bDMARDs), but the findings from Dr. Syversen and colleagues state the clear value of using drug monitoring to guide maintenance therapy with infliximab, Zachary S. Wallace, MD, and Jeffrey A. Sparks, MD, wrote in an accompanying editorial.
Dr. Jeffrey A. Sparks
“The relatively large sample size and rigorous study design ... helped to overcome some limitations of previous observational studies and small clinical trials that yielded conflicting results regarding TDM,” they added, noting that these findings contrasted somewhat with the NOR-DRUM A trial in which TDM did not improve remission induction in patients initiating infliximab therapy.
Along those lines, they recognized that TDM appears to have a greater effect in patients on maintenance infliximab, compared with those just starting the drug, surmising – among several explanations – that achieving remission in someone beginning treatment is a more difficult outcome to achieve than controlling disease in a patient already in remission.
Dr. Zachary Wallace
For now, more clinical trials assessing specific diseases and involving other bDMARDs are needed; Dr. Wallace and Dr. Sparks stated that it’s time to remove barriers to implementing TDM – including the need for medical insurance preauthorization before increasing drug doses – and potentially “introduce a new era in treatment approach to maintenance therapy for patients with immune-mediated inflammatory diseases.”
The authors acknowledged their study’s limitations, including disease worsening being measured in part by patient-physician consensus and thus potentially subject to bias. In addition, they did not have the statistical ability to test TDM effectiveness in each of the six disease groups, noting that “these diseases have inherent differences, and findings may not be completely generalizable across groups.”
The study was funded by grants from the Norwegian Regional Health Authorities and the South-Eastern Norway Regional Health Authorities. The authors reported numerous potential conflicts of interest, including receiving personal fees and grants from various pharmaceutical companies. Dr. Wallace and Dr. Sparks also reported receiving research support and fees from pharmaceutical companies. Dr. Vande Casteele reported receiving research grants and personal fees from multiple pharmaceutical companies, all outside of the reviewed work.
A version of this article first appeared on Medscape.com.