Drugs with a narrow therapeutic index (NTI) can cause mortality. For these drugs, small differences in concentrations may lead to serious toxicities or therapeutic failures. Consequently, in the setting of generic drug development, it is critical that NTI generic drugs achieve exposures similar to reference products. To enhance the therapeutic equivalence of drugs with NTI, the Food and Drug Administration has tightened their bioequivalence standards. However, broad implementation of these new standards is challenging because some drugs do not have an established NTI classification. This can be due to a lack in characterization of the drugs'therapeutic range or dose/concentration-response relationship. Therefore, there is an urgent and unmet need for a systematic approach to identify and classify drugs with a NTI. This proposal will use a unique infrastructure to integrate clinical practice data with statistical tools to characterize the drug dose/concentration- response relationship and classify drugs with NTI. The central hypothesis of this proposal is that the proposed systematic approach will result in successful classification of drugs with a NTI. Dr. Cohen-Wolkowiez will evaluate this hypothesis by performing a comprehensive search of publicly available data (literature and databases) to extract information and allow classification of drugs with NTI. Because the amount of detail included in publicly available databases is variable, Dr. Cohen-Wolkowiez will supplement this data with information extracted from medical records at the Duke University Medical Center. If sufficient data is available from these two sources, he will then characterize the concentration-response relationship of candidate drugs with NTI using population pharmacokinetics (PK)-pharmacodynamic (PD) methodologies. This project evaluates a novel, systematic approach to classify drugs with NTI. If the combination of publicly available data, supplemental data from medical records, and population PK-PD methodologies can classify drugs with NTI, this will substantially affect public health and streamline applicability of new FDA standards for bioequivalence of generic drugs with NTI.

Public Health Relevance

The proposed project will evaluate the use of clinical practice data to classify drugs with narrow therapeutic index. This goal will be accomplished using a comprehensive search of the medical literature, publicly available databases, and medical records in combination with statistical tools (population pharmacokinetic (PK)/pharmacodynamics (PD) models) that can characterize the drug concentration-response relationship to classify drugs with narrow therapeutic index. This classification will result in a drug list that will be used by the Food and Drug Administration to evaluate new bioequivalence standards of generic products with narrow therapeutic index.

National Institute of Health (NIH)
Food and Drug Administration (FDA)
Research Project--Cooperative Agreements (U01)
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Special Emphasis Panel (ZFD1)
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Duke University
Schools of Medicine
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Maharaj, Anil R; Gonzalez, Daniel; Cohen-Wolkowiez, Michael et al. (2018) Improving Pediatric Protein Binding Estimates: An Evaluation of ?1-Acid Glycoprotein Maturation in Healthy and Infected Subjects. Clin Pharmacokinet 57:577-589
Ge, Shufan; Beechinor, Ryan J; Hornik, Christoph P et al. (2018) External Evaluation of a Gentamicin Infant Population Pharmacokinetic Model Using Data from a National Electronic Health Record Database. Antimicrob Agents Chemother 62:
Hornik, Christoph P; Onufrak, Nikolas J; Smith, P Brian et al. (2018) Association between oral sildenafil dosing, predicted exposure, and systemic hypotension in hospitalised infants. Cardiol Young 28:85-92
Salerno, Sara; Hornik, Christoph P; Cohen-Wolkowiez, Michael et al. (2017) Use of Population Pharmacokinetics and Electronic Health Records to Assess Piperacillin-Tazobactam Safety in Infants. Pediatr Infect Dis J 36:855-859
Ericson, Jessica E; Zimmerman, Kanecia O; Gonzalez, Daniel et al. (2017) A Systematic Literature Review Approach to Estimate the Therapeutic Index of Selected Immunosuppressant Drugs After Renal Transplantation. Ther Drug Monit 39:13-20
Wang, Laura A; Gonzalez, Daniel; Leeder, J Steven et al. (2017) Metronidazole Metabolism in Neonates and the Interplay Between Ontogeny and Genetic Variation. J Clin Pharmacol 57:230-234
Watt, Kevin M; Cohen-Wolkowiez, Michael; Williams, Duane C et al. (2017) Antifungal Extraction by the Extracorporeal Membrane Oxygenation Circuit. J Extra Corpor Technol 49:150-159
Gonzalez, Daniel; Chamberlain, James M; Guptill, Jeffrey T et al. (2017) Population Pharmacokinetics and Exploratory Pharmacodynamics of Lorazepam in Pediatric Status Epilepticus. Clin Pharmacokinet 56:941-951
Thakkar, Nilay; Guptill, Jeffrey T; AleŇ°, Kathy et al. (2017) Population Pharmacokinetics/Pharmacodynamics of 3,4-Diaminopyridine Free Base in Patients With Lambert-Eaton Myasthenia. CPT Pharmacometrics Syst Pharmacol 6:625-634
Rivera-Chaparro, Nazario D; Cohen-Wolkowiez, Michael; Greenberg, Rachel G (2017) Dosing antibiotics in neonates: review of the pharmacokinetic data. Future Microbiol 12:1001-1016

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