Granulocyte colony-stimulating factors used in clinical practice: PoloNord Registry-Based Cohort Italian Study.

AIMS AND BACKGROUND: Granulocyte colony-stimulating factors are widely used to reduce myelotoxicity of chemotherapy and to allow its regular administration. National and international guidelines regulate their use. The aim of the study was to evaluate the use of pegfilgrastim and filgrastim/lenograstim in clinical practice, adherence to ASCO and ESMO guidelines, chemotherapy-related complications and adverse reactions. MATERIALS AND METHODS: Data from 645 consecutive patients and 3,150 chemotherapy administrations, receiving granulocyte colony-stimulating factors, as primary/secondary prophylaxis or therapeutic use, for the first time during a line of chemotherapy, were recorded from 08/2008 to 08/2011, in 10 Lombardy Italian cancer centers. Patients and chemotherapy administrations data were examined in a multiple logistic regression analysis model. RESULTS: Adherence to guidelines: primary prophylaxis, pegfilgrastim and filgrastim/ lenograstim 66%/47% (P = 0.002); secondary prophylaxis, 19.0%/26.8%; but 56.8%/ 53.6% including patients at high risk of febrile neutropenia with grade 3-4 neutropenia. Correct timing start (administration 24-72 h after chemotherapy): pegfilgrastim and filgrastim/lenograstim, 93.2%/61.5% (P <0.0001). CONCLUSIONS: Results suggest the more correct administration of pegfilgrastim as primary prophylaxis and timing start, compared to filgrastim/lenograstim. In secondary prophylaxis, the use of granulocyte colony-stimulating factors is extended beyond guideline recommendations to support patients at high risk of febrile neutropenia and to guarantee dose intensity. These outcomes suggest both the need of educational activities and the development of predictive tools to better define high risk patients and the use of granulocyte colony-stimulating factors.

D-dimer before chemotherapy might predict venous thromboembolism.

To see whether D-Dimer levels can identifying patients at high risk of venous thrombotic events and establish the best benefit/risk-of-bleeding ratio. Current guidelines do not recommend routine prophylaxis against venous thromboembolism (VTE) in cancer patients receiving chemotherapy, but the risk increases about 6.5-fold because of this treatment. D-dimer was measured at baseline in 124 cancer patients scheduled for their first chemotherapy. VTE events, including symptomatic episodes of deep vein thrombosis or pulmonary embolism or both, were recorded during the first 6 months of therapy, and asymptomatic deep vein thrombosis was revealed by compression ultrasonography at baseline and after 90 and 180 days. During follow-up, there were 11 episodes of VTE (8.9%). Mean D-dimer values were higher in patients with VTE (2195 +/- 1382 vs. 695 +/- 1039 ng/ml, (P < 0.001). On grouping D-dimer values in tertiles, only 2.4% (confidence interval, 0.9-5.7%) in the first (<262 ng/ml) and second tertiles (262-650 ng/ml) suffered a deep vein thrombosis/pulmonary embolism event as compared with 22% (confidence interval, 9-34%) in the third (>650 ng/dl) (P = 0.003). The VTE-free interval was significantly shorter in the third tertile than in the first (P = 0.0218, log-rank test; relative risk for third vs. first tertile, 11.0; 95% confidence interval, 1.4-81.3; P = 0.0033). Multivariate analysis found that only baseline D-dimer concentrations were correlated with the subsequent development of VTE. Baseline D-dimer values in cancer patients scheduled for chemotherapy might be used to select those at low risk of VTE, most likely to be safe without prophylaxis.

Alpha1 acid glycoprotein binds to imatinib (STI571) and substantially alters its pharmacokinetics in chronic myeloid leukemia patients.

PURPOSE: Imatinib (Glivec) is a potent inhibitor of bcr/abl, an oncogenic fusion protein that causes chronic myelogenous leukemia (CML). alpha1 acid glycoprotein (AGP) binds to imatinib with high affinity and inhibits imatinib activity in vitro and in vivo in an animal model. A pharmacokinetics analysis of imatinib was undertaken in CML patients. EXPERIMENTAL DESIGN: Imatinib plasma concentrations were measured in 19 CML patients treated with imatinib (400 or 600 mg/day). Five patients received a concomitant short-term course of clindamycin (CLI). RESULTS: A positive correlation between AGP and imatinib plasma levels was observed. CLI administration decreased imatinib plasma concentrations, evaluated as area under the curve (AUC) and peak concentrations (C(max)). The effects of a bolus of CLI was studied in three patients on imatinib 23 h after the last imatinib dose. Within 5-10 min in three of three cases, CLI caused a decrease in imatinib plasma concentrations of 2.6-, 2.7-, and 4.7-fold, respectively. In vitro experiments using fresh blasts from CML patients showed that AGP, at concentrations observed in the patients, decreased imatinib intracellular concentrations up to 10 times and blocked imatinib activity. The incubation with CLI restored imatinib intracellular concentrations and biological activity. CONCLUSION: AGP exerts significant effects of the pharmacokinetics, plasma concentrations, and intracellular distribution of imatinib in CML patients; these data indicate that plasma imatinib levels represent unreliable indicators of the cellular concentrations of this molecule.

Differences between in vivo and in vitro sensitivity to imatinib of Bcr/Abl+ cells obtained from leukemic patients.

Imatinib mesylate (imatinib) inhibits Bcr/Abl, an oncogenic fusion protein. The in vitro effects of imatinib on BCR/ABL+ leukemic cells include inhibition of Bcr/Abl tyrosine phosphorylation, block of proliferation, and induction of apoptosis. The in vivo effects of imatinib were evaluated in 12 CML (chronic myeloid leukemia) patients in blast crisis or accelerated phase who were treated with imatinib. Treatment caused a decrease in spontaneous proliferation of leukemic cells in 10 of 12 evaluable patients and the development of apoptosis in 9 of 11 cases. Imatinib also caused an inhibition of Bcr/Abl autophosphorylation; however, the degree of inhibition obtained in vivo was substantially lower than that achieved in vitro with similar concentrations of imatinib. In seven patients cells could be evaluated at relapse: spontaneous proliferation was no longer inhibited and Bcr/Abl phosphorylation was comparable or superior to that present at the beginning of treatment, before imatinib administration. Plasma imatinib concentrations were not reduced. Leukemic cells obtained at relapse maintained in vitro sensitivity (Bcr/Abl autophosphorylation and proliferation inhibition) to imatinib concentration measured in vivo (3 microM or higher), although a partial resistance to the antiproliferative effects of imatinib was present at low (0.01-0.3 microM) concentrations. In four patients, addition of erythromycin to blood samples obtained at relapse restored imatinib sensitivity in terms of phosphorylation inhibition, indicating that the majority of plasma imatinib was not available to cells and probably bound to alpha1 acid glycoprotein. These data suggest that measurements of Bcr/Abl kinase activity in peripheral blood samples may represent a more reliable indicator of active concentrations than the measurement of imatinib plasma levels.