| 1. |
- Friberg, Lena E., et al.
(författare)
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Model of Chemotherapy-Induced Myelosuppression With Parameter Consistency Across Drugs
- 2002
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 20:24, s. 4713-4721
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To develop a semimechanistic pharmacokinetic-pharmacodynamic model describing chemotherapy-induced myelosuppression through drug-specific parameters and system-related parameters, which are common to all drugs. PATIENTS AND METHODS: Patient leukocyte and neutrophil data after administration of docetaxel, paclitaxel, and etoposide were used to develop the model, which was also applied to myelosuppression data from 2'-deoxy-2'-methylidenecytidine (DMDC), irinotecan (CPT-11), and vinflunine administrations. The model consisted of a proliferating compartment that was sensitive to drugs, three transit compartments that represented maturation, and a compartment of circulating blood cells. Three system-related parameters were estimated: baseline, mean transit time, and a feedback parameter. Drug concentration-time profiles affected the proliferation of sensitive cells by either an inhibitory linear model or an inhibitory E(max) model. To evaluate the model, system-related parameters were fixed to the same values for all drugs, which were based on the results from the estimations, and only drug-specific parameters were estimated. All modeling was performed using NONMEM software. RESULTS: For all investigated drugs, the model successfully described myelosuppression. Consecutive courses and different schedules of administration were also well characterized. Similar system-related parameter estimates were obtained for the different drugs and also for leukocytes compared with neutrophils. In addition, when system-related parameters were fixed, the model well characterized chemotherapy-induced myelosuppression for the different drugs. CONCLUSION: This model predicted myelosuppression after administration of one of several different chemotherapeutic drugs. In addition, with fixed system-related parameters to proposed values, and only drug-related parameters estimated, myelosuppression can be predicted. We propose that this model can be a useful tool in the development of anticancer drugs and therapies.
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| 3. |
- Henningsson, Anja, et al.
(författare)
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Mechanism-based pharmacokinetic model for paclitaxel
- 2001
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 19:20, s. 4065-4073
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE To create a model based on known mechanisms of paclitaxel distribution that could describe the pharmacokinetics (PK) of total and unbound plasma concentrations, as well as blood concentrations. In addition, to investigate the relationship between exposure, based on unbound and total concentrations, and neutropenia. PATIENTS AND METHODS Paclitaxel and Cremophor EL (CrEL) concentrations were obtained from 23 female and three male patients (50 courses in total) with different cancer types that received paclitaxel (Taxol; Bristol-Myers Squibb Co, Princeton, NJ) (135 to 225 mg/m(2)) as 3- or 24-hour intravenous infusions. Seven of the patients received combination therapy with doxorubicin or cisplatin. The population PK model was built to fit three types of data simultaneously: unbound, total plasma, and blood concentrations. The area under the curve, threshold, and general models were used to relate neutrophil survival fraction from 19 patients (29 courses in total) to exposure based on unbound and total plasma concentration, respectively. RESULTS The PK model included a linear three-compartment model for unbound concentration, binding directly proportional to CrEL, linear and nonlinear binding to plasma proteins, and linear and nonlinear binding to blood cells. The threshold model best described the PK/pharmacodynamic (PD) relationship for total concentration. No distinction could be made between the models for unbound drug. CONCLUSION Earlier PK models for paclitaxel have been empirical. This study shows that a mechanistic model can be used to describe the nonlinear PK of paclitaxel. There is an indication that the PK/PD relationship is not the same for unbound and total plasma concentrations.
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| 4. |
- Jansson, Agneta, 1973-, et al.
(författare)
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Bax expression decreases significantly from primary tumor to metastasis in colorectal cancer
- 2002
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 20:3, s. 811-816
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Bax is a proapoptotic member of the bcl-2 family. Previous studies about Bax have shown that the expression increases from normal to tumor tissue, but the clinical significance is contradictory. Our aims were to analyze the expression of Bax from normal mucosa to primary tumor and to metastases in colorectal cancer patient. We further investigated whether low Bax expression in the primary tumor or changed expression from normal mucosa to primary tumor and to metastases had biologic and clinical significance.PATIENTS AND METHODS: The study included 135 patients with primary colorectal adenocarcinoma, of whom 31 had metastases in the lymph nodes and 75 had normal mucosa. Immunohistochemistry, DNA sequencing, and microsatellite analysis were used to detect Bax expression, mutations, and microsatellite instability.RESULTS: The protein was observed in 132 of 135 tumors, all normal epithelial cells and metastases. The frequencies of weak expression were greater from well/moderately to poorly differentiated and to mucinous carcinomas. Bax expression was stronger from normal to tumor tissue, but subsequently decreased in metastases. The matched cases with lower expression in the metastases than in the primary tumor showed a more infiltrative growth pattern and more distal metastases.CONCLUSION: The association of Bax expression with tumor differentiation/histologic types and a decreased expression in the metastases, suggests that Bax expression may be involved in tumor differentiation/histologic types and metastatic progression. We also propose the novel notion that changed Bax expression in the metastases compared with the primary tumors might provide information to determine the clinicopathologic characteristics of the tumor.
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| 5. |
- Lens, MB, et al.
(författare)
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Effect of pregnancy on survival in women with cutaneous malignant melanoma
- 2004
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 22:21, s. 4369-4375
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Tidskriftsartikel (refereegranskat)abstract
- Purpose An adverse influence of pregnancy on the risk of death in women with cutaneous melanoma was suggested historically by anecdotal reports. Previous studies included small numbers of women observed for short periods. Methods Using data from the Swedish National and Regional Registries, we performed a retrospective cohort study of all Swedish women who were diagnosed with cutaneous melanoma during their reproductive period, from January 1, 1958, to December 31, 1999. The relationship between pregnancy status at the diagnosis of melanoma and overall survival was examined in multivariable proportional-hazards models. Results The cohort comprised 185 women (3.3%) diagnosed with melanoma during pregnancy and 5,348 (96.7%) women of the same childbearing age diagnosed with melanoma while not pregnant. There was no statistically significant difference in overall survival between pregnant and nonpregnant groups (log-rank chi(2)1 [r] = 0.84, P =.361). Pregnancy status at the time of diagnosis of melanoma was not related to survival in a multivariable Cox model in the 2,101 women (hazard ratio for death in the pregnant group was 1.08, 95% Cl, 0.60 to 1.93). In the multivariable analysis, pregnancy status after diagnosis of melanoma was not a significant predictor of survival (hazard ratio for death in women who had pregnancy subsequent to the diagnosis of melanoma was 0.58, 95% Cl, 0.32 to 1.05). Conclusion The survival of pregnant women with melanoma is not worse than the survival of nonpregnant women with melanoma. Pregnancy subsequent to the diagnosis of primary melanoma was not associated with an increased risk of death. (C) 2004 by American Society of Clinical Oncology.
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| 6. |
- Renkonen, E, et al.
(författare)
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Altered expression of MLH1, MSH2, and MSH6 in predisposition to hereditary nonpolyposis colorectal cancer
- 2003
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Ingår i: Journal of Clinical Oncology. - 1527-7755. ; 21:19, s. 3629-3637
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: A considerable fraction (30% to 70%) of families with verified or putative hereditary nonpolyposis colorectal cancer fails to show mutations in DNA mismatch repair (MMR) genes. Our purpose was to address the genetic etiology of such families. Materials and Methods: We scrutinized a population-based cohort of 26 families from Finland that had screened mutation-negative by previous techniques. Blood was tested for allelic messenger RNA (mRNA) expression of MLH1, MSH2, and MSH6 by single nucleotide primer extension (SNuPE), and tumor tissue for MMR protein expression by immunohistochemistry (IHC) as well as for microsatellite instability (MSI). Full-length cDNAs of genes implicated by SNuPE or IHC were cloned and sequenced. Results: Unbalanced mRNA expression of MLH1 alleles was evident in two families. An inherited nonsense mutation was subsequently identified in one family, and complete silencing of the mutated allele was identified in the other family. Extinct protein expression by IHC implicated MLH1 in these two and in four other families, MSH2 in four families, and MSH6 in one family. Although no unequivocal genomic mutations were detected in the latter families, haplotype and other findings provided support for heritable defects. With one exception, all tumors with IHC alterations showed MSI, in contrast to the remaining families, which showed neither IHC changes nor MSI. Conclusion: Our expression-based strategy stratified the present "mutation-negative" cohort into two discrete categories: families linked to the major MMR genes MLH1, MSH2, and MSH6 (11 [42%] of 26) and those likely to be associated with other, as yet unknown susceptibility genes (15 [58%] of 26). (C) 2003 by American Society of Clinical Oncology.
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