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  1. FDA STEM Outreach, Education and Engagement

Analysis of Therapeutic Drug Monitoring in Drug Labels

Authors:
Poster Author(s)
Tran, Duy, FDA/CDER (student); Moore, Jason, FDA/CDER (Mentor)
Center:
Contributing Office
Center for Drug Evaluation and Research

Abstract

Poster Abstract

Introduction

Therapeutic drug monitoring (TDM) is a clinical practice that allows for measurement of drug concentration to maximize efficacy and safety. It is used to monitor pharmacokinetic (PK) variability in medications and adjust doses to target PK parameters. Appropriately targeting relevant parameters can allow for optimization of patient care to reduce toxicity while maximizing therapeutic effect.

Methods

Using an internal FDA labeling search tool, we searched for antibacterial and antifungal agents approved from 2016 to 2020 and determined which drug labels included TDM. Afterwards, we searched all Physician Labeling Rule labels for the term “therapeutic drug monitoring.” PK parameters for efficacy or safety, PK parameters for TDM, and dosage adjustments for organ impairment were collected for each drug with TDM mentioned in the labeling. Within the results, we compared the data collected from each search query to find any trends among drugs that describe TDM in their respective labeling.

Results

Thirteen antibacterial and antifungal agents have been approved from 2016 to 2020, with only plazomicin having TDM in its labeling. Within the second search query, 11 agents included the term “therapeutic drug monitoring” in labeling. In the group of 11 drugs, there were 4 drugs with instructions for renal impairment and 7 drugs with instructions for hepatic impairment. PK parameters associated with efficacy or safety were not mentioned for many of the drugs.

Conclusion

Overall, our analysis identified that there are 11 recent drugs that contain TDM in their labeling. Most of these drugs with TDM in labeling had dose instructions for hepatic or renal impairment, suggesting a defined relationship between PK and efficacy or safety even if a PK parameter for efficacy or safety was not listed in labeling. TDM was recommended to optimize efficacy, to reduce safety concerns, and/or to manage pharmacokinetic drug interactions with a victim drug. The CYP3A pathway played an important role for those drugs that use TDM to manage drug interactions. TDM studies can be costly and time-consuming but may be worthwhile to optimize therapy for patient care. A limitation of this analysis is that the search did not include drugs with labeling formats older than the Physician Labeling Rule and did not include drugs that lacked the specific term “therapeutic drug monitoring.” For example, carbamazepine was not captured in the search but has instructions to monitor serum concentrations in labeling. Disclaimer: The opinions contained herein are the private views of the authors and are not to be construed as reflecting true views of the US Food and Drug Administration.

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