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Sanghavi K, Ribbing J, Rogers JA, Ahmed MA, Karlsson MO, Holford N, Chasseloup E, Ahamadi M, Kowalski KG, Cole S, Kerwash E, Wade JR, Liu C, Wang Y, Trame MN, Zhu H, Wilkins JJ. Covariate modeling in pharmacometrics: General points for consideration. CPT Pharmacometrics Syst Pharmacol 2024; 13:710-728. [PMID: 38566433 PMCID: PMC11098153 DOI: 10.1002/psp4.13115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 01/15/2024] [Accepted: 02/05/2024] [Indexed: 04/04/2024] Open
Abstract
Modeling the relationships between covariates and pharmacometric model parameters is a central feature of pharmacometric analyses. The information obtained from covariate modeling may be used for dose selection, dose individualization, or the planning of clinical studies in different population subgroups. The pharmacometric literature has amassed a diverse, complex, and evolving collection of methodologies and interpretive guidance related to covariate modeling. With the number and complexity of technologies increasing, a need for an overview of the state of the art has emerged. In this article the International Society of Pharmacometrics (ISoP) Standards and Best Practices Committee presents perspectives on best practices for planning, executing, reporting, and interpreting covariate analyses to guide pharmacometrics decision making in academic, industry, and regulatory settings.
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Affiliation(s)
| | | | | | - Mariam A. Ahmed
- Quantitative Clinical Pharmacology, Takeda PharmaceuticalCambridgeMassachusettsUSA
| | | | - Nick Holford
- Department of Pharmacology & Clinical PharmacologyUniversity of AucklandAucklandNew Zealand
| | | | | | | | - Susan Cole
- Medical and Healthcare product Regulatory Agency (MHRA)LondonUK
| | - Essam Kerwash
- Medical and Healthcare product Regulatory Agency (MHRA)LondonUK
| | | | - Chao Liu
- Applied Innovation Quantitative Solutions, BeiGeneWashingtonDCUSA
| | - Yaning Wang
- Createrna Science and TechnologyClarksburgMarylandUSA
| | - Mirjam N. Trame
- Integrated Drug Development Northeast Regional LeadCertaraMassachusettsUSA
| | - Hao Zhu
- Division of Pharmacometrics, Office of Clinical PharmacologyCenter for Drug Evaluation and Research, Food and Drug AdministrationSilver SpringsMarylandUSA
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Briggs WA, Gao ZH, Scheel PJ, Burdick JF, Gimenez LF, Choi MJ. Differential Glucocorticoid Responsiveness of Dialysis Patients’ Lymphocytes. Perit Dial Int 2020. [DOI: 10.1177/089686089601600415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Objectives To evaluate in vitro glucocorticoid responsiveness of phytohemagglutinin (PHA)-stimulated lymphocytes from peritoneal dialysis (PO) patients compared to hemodialysis (HO) patients. Design Cross-sectional study of prevalent PO and HO patients and concurrent control subjects. Setting Urban outpatient dialysis unit. Patients 20 HO, 14 PO, and 20 control subjects. Measurements Using standard lymphocyte culture techniques, the concentration of prednisolone (P) and methylprednisolone (MP) required to cause 50% inhibition (ICso) of the proliferative response to phytohemagglutinin (PHA) was determined from dose-response curves. Results There was considerable heterogeneity in the sensitivities of individual patients’ PBMC to glucocorticoid inhibition, especially those of HO patients’ cells to P. The mean: i: SO ICso for MP was significantly (p ≤ 0.001) lower than that for P in each cohort: PO 11 ± 5 vs. 34 ± 18 ng/mL; HO 22 ± 14 vs. 89 ± 43 ng/mL; control subjects 14 ± 11 vs. 55 ± 56 ng/mL. Interestingly, the ICSO for both P and MP was significantly higher in HO than in either PO or controls (ANOVA, P: F = 6.56, p = 0.003; MP: F = 3.77, p = 0.03), indicating decreased sensitivity of HO lymphocytes to both drugs. There were no significant differences in mean ICSO values for either P or MP between PO and controls. No correlations were found between ICSO for either P or MP and patient age, gender, duration of dialysis, serum creatinine, serum albumin, or parathyroid hormone level. Conclusions In vitro glucocorticoid responsiveness of dialysis patients’ lymphocytes appears to be influenced by dialysis modality, butthefactor(s) involved remains to be determined. Thegreater sensitivity of PO lymphocytes to both P and MP might result in better immunosuppression and less severe rejection after renal transplantation. MP may be particularly advantageous following renal transplantation for any patient manifesting relative or absolute in vitro resistance to P.
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Affiliation(s)
- William A. Briggs
- Departments of Medicine, The Johns Hopkins University, School of Medicine Baltimore, Maryland
| | - Zu-Hua Gao
- Departments of Medicine, The Johns Hopkins University, School of Medicine Baltimore, Maryland
| | - Paul J. Scheel
- Departments of Medicine, The Johns Hopkins University, School of Medicine Baltimore, Maryland
| | - James F. Burdick
- Surgery, The Johns Hopkins University, School of Medicine Baltimore, Maryland
| | - Luis F. Gimenez
- Departments of Medicine, The Johns Hopkins University, School of Medicine Baltimore, Maryland
| | - Michael J. Choi
- Departments of Medicine, The Johns Hopkins University, School of Medicine Baltimore, Maryland
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Luo JC, Chang FY, Chen TS, Ng YY, Lin HC, Lu CL, Chen CY, Lin HY, Lee SD. Gastric mucosal injury in systemic lupus erythematosus patients receiving pulse methylprednisolone therapy. Br J Clin Pharmacol 2010; 68:252-9. [PMID: 19694746 DOI: 10.1111/j.1365-2125.2009.03445.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIMS Whether glucocorticoids induce gastric mucosal injury remains uncertain. We investigated whether very high-dose steroids caused gastric mucosal injury in systemic lupus erythematous (SLE) patients and evaluated the possible risk factors for mucosal injury. METHODS In this prospective paired study, 67 SLE patients who had received pulse methylprednisolone therapy were enrolled. Each patient underwent endoscopic examination and tissue and blood sampling before and after pulse steroid therapy. Mucosal injury was diagnosed if the follow-up injury scale was higher than the initial scale. Examined parameters included Helicobacter pylori infection, cyclooxygenase (COX)-1 and COX-2 activity, and current nonsteroidal anti-inflammatory drug (NSAID) usage including aspirin. RESULTS Eleven (16.4%) of 67 cases who developed gastric mucosal injury after pulse therapy had significantly higher rates of peptic ulcer history, NSAID/aspirin use, lower gastric thromboxane B(2) and prostaglandin E(2) levels when compared with cases without gastric mucosal injury (P < 0.05). Infection by H. pylori was not a risk factor for gastric mucosal injury. Multivariate logistic regression analysis showed that NSAID/aspirin use was the only risk factor for gastric mucosal injury in these patients (odds ratio 26.99, 95% confidence interval 4.91, 148.57, P < 0.0001). Pulse steroid therapy alone did not induce gastric mucosal injury in fifty SLE patients without taking any NSAID/aspirin. CONCLUSIONS Use of NSAIDs/aspirin, but not H. pylori infection, increases gastric mucosal injury in SLE patients receiving pulse methylprednisolone therapy. Very high-dose steroids de novo seem not to induce gastric mucosal injury in these patients. A larger case-controlled study enrolling a heterogeneous population is needed to clarify the role of glucocorticoids in gastric mucosal injury.
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Affiliation(s)
- Jiing-Chyuan Luo
- Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan
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Wählby U, Thomson AH, Milligan PA, Karlsson MO. Models for time-varying covariates in population pharmacokinetic-pharmacodynamic analysis. Br J Clin Pharmacol 2005; 58:367-77. [PMID: 15373929 PMCID: PMC1884602 DOI: 10.1111/j.1365-2125.2004.02170.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM If appropriately accounted for in a pharmacokinetic (PK)-pharmacodynamic (PD) model, time-varying covariates can provide additional information to that obtained from time-constant covariates. The aim was to present and apply two models applicable to time-varying covariates that capture such additional information. METHODS The first model estimates different covariate-parameter relationships for within- and between-individual variation in covariate values, by splitting the standard covariate model into a baseline covariate (BCOV) effect and a difference from baseline covariate (DCOV) effect. The second model allows the magnitude of the covariate effect to vary between individuals, by inclusion of interindividual variability in the covariate effect. The models were applied to four previously analysed data sets. RESULTS The models were applied to 10 covariate-parameter relationships and for three of these the first extended model resulted in a significant improvement of the fit. Even when this model did not improve the fit significantly, it provided useful information because the standard covariate model, which assumes within- and between-patient covariate relationships of the same magnitude, was only supported by the data in four cases. The inclusion of BCOV was not supported in two cases and DCOV was unnecessary in three cases. In one case, significantly different, nonzero, relationships were found for DCOV and BCOV. The second extended model was found to be significant for four of the 10 covariate-parameter relationships. CONCLUSIONS On the basis of the examples presented, traditionally made simplifications of covariate-parameter relationships are often inadequate. Extensions to the covariate-parameter relationships that include time-varying covariates have been developed, and their appropriateness and benefits have been described.
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Affiliation(s)
- Ulrika Wählby
- Division of Pharmacokinetics and Drug Therapy, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
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Kasiske BL, Vazquez MA, Harmon WE, Brown RS, Danovitch GM, Gaston RS, Roth D, Scandling JD, Singer GG. Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation. J Am Soc Nephrol 2001. [PMID: 11044969 DOI: 10.1681/asn.v11suppl_1s1] [Citation(s) in RCA: 394] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.
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Affiliation(s)
- B L Kasiske
- Division of Nephrology, Hennepin County Medical Center, University of Minnesota, Minneapolis 55415, USA.
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REPLY: CLINICAL RELEVANCE OF GLUCOCORTICOID PHARMACODYNAMICS IN KIDNEY TRANSPLANTATION. Transplantation 1997. [DOI: 10.1097/00007890-199709150-00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Girardin C, St-Louis G. Methylprednisolone pharmacodynamics assessed by antilymphocyte action in kidney transplantation: clinical relevance and utility. Transplantation 1996; 62:1377. [PMID: 8932294 DOI: 10.1097/00007890-199611150-00041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Briggs WA, Gao ZH, Xing JJ, Gimenez LF, Samaniego MD, Scheel PJ, Choi MJ, Burdick JF. Suppression of lymphocyte interleukin-2 receptor expression by glucocorticoids, cyclosporine, or both. J Clin Pharmacol 1996; 36:931-7. [PMID: 8930780 DOI: 10.1002/j.1552-4604.1996.tb04760.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Although glucocorticoids and cyclosporine are frequently used to treat patients with various types of glomerulopathy, clinical responses to treatment vary considerably. Considerable interindividual heterogeneity in the suppressive effects of glucocorticoids on lymphocyte proliferation in vitro has been previously reported, suggesting that differences in the pharmacodynamic responsiveness of the immune system to these agents might be an important determinant of how well an individual patient responds to treatment. It also has been shown that methylprednisolone is significantly more suppressive than prednisolone. To identify cellular mechanisms by which these drugs act, a study of the suppressive effects of prednisolone, methylprednisolone, and cyclosporine on lymphocyte proliferation and the expression of the cell surface receptor for interleukin-2 (IL-2R) was conducted using phytohemagglutin-stimulated peripheral blood mononuclear cells (PBMCs) from 13 patients with glomerulopathy and 12 control subjects. Heterogeneity among individuals in both parameters of lymphocyte responsiveness to these drugs was again found, and the significantly greater suppressive effect of methylprednisolone was confirmed for both proliferation and IL-2R expression in patients and control subjects. Cyclosporine alone was moderately suppressive. For most individuals, the greatest degree of suppression occurred when cells were exposed to both cyclosporine and glucocorticoid. Further studies are being conducted to determine whether pretreatment assessment of in vitro lymphocyte responsiveness has any predictive value regarding therapeutic efficacy of each drug in individual patients and to identify of those patients likely to require a more intensive or multidrug immunosuppressive regimen.
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Affiliation(s)
- W A Briggs
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Briggs WA, Gao ZH, Gimenez LF, Scheel PJ, Choi MJ, Burdick JF. Lymphocyte responsiveness to glucocorticoids, cyclosporine, or both. J Clin Pharmacol 1996; 36:707-14. [PMID: 8877674 DOI: 10.1002/j.1552-4604.1996.tb04239.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The reason why some patients with glomerular diseases respond to steroid treatment and others do not remains obscure, and it is not possible to prospectively evaluate the probability of response in individual patients. One factor that might contribute to the clinical response to treatment could be the relative sensitivity of a patient's immune system to the suppressive effects of steroids or other immunosuppressive agents. To evaluate this possibility, phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) from 16 patients with various biopsy-proven glomerulopathies were cultured with prednisolone or methylprednisolone in final concentrations of 10(-5) to 10(-8) mol/L. From the dose-response curves, the concentration of steroid required to cause 50% inhibition (IC50) of the PHA-induced proliferative response was determined. The PBMC from 10 patients also were cultured with 400 ng/mL cyclosporine both alone and with 10(-7) mol/L steroid, and the inhibitory effects were calculated. There was considerable heterogeneity in the sensitivities of individual patients to steroid inhibition, and the mean +/- SEM IC50 was significantly lower for methylprednisolone than for prednisolone. Cyclosporine caused 50% or greater inhibition in 6 of the 10 patients but had < 10% inhibitory effect in 2 patients. In most patients studied, cyclosporine plus steroid was significantly more inhibitory than cyclosporine alone, but the combination was usually no more effective than 10(-7) mol/L methylprednisolone alone. These results are consistent with the hypothesis that differences in the sensitivity of individual patient's immune systems to the immunosuppressive effects of steroids and cyclosporine might contribute to differences in their clinical responsiveness to treatment.
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Affiliation(s)
- W A Briggs
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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