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Keizer RJ, Jansen RS, Rosing H, Thijssen B, Beijnen JH, Schellens JHM, Huitema ADR. Incorporation of concentration data below the limit of quantification in population pharmacokinetic analyses. Pharmacol Res Perspect 2015; 3:e00131. [PMID: 26038706 PMCID: PMC4448983 DOI: 10.1002/prp2.131] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 11/30/2022] Open
Abstract
Handling of data below the lower limit of quantification (LLOQ), below the limit of quantification (BLOQ) in population pharmacokinetic (PopPK) analyses is important for reducing bias and imprecision in parameter estimation. We aimed to evaluate whether using the concentration data below the LLOQ has superior performance over several established methods. The performance of this approach (“All data”) was evaluated and compared to other methods: “Discard,” “LLOQ/2,” and “LIKE” (likelihood-based). An analytical and residual error model was constructed on the basis of in-house analytical method validations and analyses from literature, with additional included variability to account for model misspecification. Simulation analyses were performed for various levels of BLOQ, several structural PopPK models, and additional influences. Performance was evaluated by relative root mean squared error (RMSE), and run success for the various BLOQ approaches. Performance was also evaluated for a real PopPK data set. For all PopPK models and levels of censoring, RMSE values were lowest using “All data.” Performance of the “LIKE” method was better than the “LLOQ/2” or “Discard” method. Differences between all methods were small at the lowest level of BLOQ censoring. “LIKE” method resulted in low successful minimization (<50%) and covariance step success (<30%), although estimates were obtained in most runs (∼90%). For the real PK data set (7.4% BLOQ), similar parameter estimates were obtained using all methods. Incorporation of BLOQ concentrations showed superior performance in terms of bias and precision over established BLOQ methods, and shown to be feasible in a real PopPK analysis.
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Affiliation(s)
- Ron J Keizer
- Department of Bioengineering & Therapeutic Sciences, University of California San Francisco Box 2911, San Francisco, California, 94143 ; Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands
| | - Robert S Jansen
- Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands
| | - Hilde Rosing
- Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands
| | - Bas Thijssen
- Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands
| | - Jos H Beijnen
- Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands ; Division of Drug Toxicology, Section of Biomedical Analysis, Department of Pharmaceutical Sciences, Faculty of Science, Utrecht University Utrecht, The Netherlands
| | - Jan H M Schellens
- Division of Drug Toxicology, Section of Biomedical Analysis, Department of Pharmaceutical Sciences, Faculty of Science, Utrecht University Utrecht, The Netherlands ; Division of Clinical Pharmacology, Department of Medical Oncology, Antoni van Leeuwenhoek, Hospital/the Netherlands Cancer Institute Amsterdam, The Netherlands
| | - Alwin D R Huitema
- Department of Pharmacy & Pharmacology, Slotervaart Hospital/The Netherlands Cancer Institute Louwesweg 6, 1066 EC, Amsterdam, The Netherlands
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Wilson RH. Novel Therapeutic Developments Other Than EGFR and VEGF Inhibition in Colorectal Cancer. Oncologist 2006; 11:1018-24. [PMID: 17030644 DOI: 10.1634/theoncologist.11-9-1018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Developments that may improve existing cytotoxic therapy for colorectal cancer (CRC) include alternatives to 5-fluorouracil (5-FU) such as the liposomal Thymidylate Synthase inhibitor OSI-7904L and the multitargeted antifolate pemetrexed. Studies have explored means of reformulating irinotecan, modulating its pharmacokinetics, and enhancing its activity by maximizing DNA damage through poly(ADP-ribose) polymerase inhibition. Cell cycle inhibitors may offer an alternative to combination with 5-FU. However, as standard regimens become more complex, so do the clinical trials needed to develop new agents, and the path to registration becomes ever more tortuous. It is therefore likely that several drugs with promise in CRC will not be developed for this indication.
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Affiliation(s)
- Richard H Wilson
- Centre for Cancer Research and Cell Biology, Queen's University, Belfast, Northern Ireland, UK.
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