Christian Dittrich

New prognostic factors and calculators for outcome prediction in patients with recurrent glioblastoma: A pooled analysis of EORTC Brain Tumour Group phase I and II clinical trials

BACKGROUNDnPrognostic models have been developed to predict survival of patients with newly diagnosed glioblastoma (GBM). To improve predictions, models should be updated with information at the recurrence. We performed a pooled analysis of European Organization for Research and Treatment of Cancer (EORTC) trials on recurrent glioblastoma to validate existing clinical prognostic factors, identify new markers, and derive new predictions for overall survival (OS) and progression free survival (PFS).nnnMETHODSnData from 300 patients with recurrent GBM recruited in eight phase I or II trials conducted by the EORTC Brain Tumour Group were used to evaluate patients age, sex, World Health Organisation (WHO) performance status (PS), presence of neurological deficits, disease history, use of steroids or anti-epileptics and disease characteristics to predict PFS and OS. Prognostic calculators were developed in patients initially treated by chemoradiation with temozolomide.nnnRESULTSnPoor PS and more than one target lesion had a significant negative prognostic impact for both PFS and OS. Patients with large tumours measured by the maximum diameter of the largest lesion (⩾42mm) and treated with steroids at baseline had shorter OS. Tumours with predominant frontal location had better survival. Age and sex did not show independent prognostic values for PFS or OS.nnnCONCLUSIONSnThis analysis confirms performance status but not age as a major prognostic factor for PFS and OS in recurrent GBM. Patients with multiple and large lesions have an increased risk of death. With these data prognostic calculators with confidence intervals for both medians and fixed time probabilities of survival were derived.

Population Pharmacokinetics and Pharmacodynamics of Paclitaxel and Carboplatin in Ovarian Cancer Patients: A Study by the European Organization for Research and Treatment of Cancer-Pharmacology and Molecular Mechanisms Group and New Drug Development Group

Purpose: Paclitaxel and carboplatin are frequently used in advanced ovarian cancer following cytoreductive surgery. Threshold models have been used to predict paclitaxel pharmacokinetic-pharmacodynamics, whereas the time above paclitaxel plasma concentration of 0.05 to 0.2 μmol/L (tC > 0.05−0.2) predicts neutropenia. The objective of this study was to build a population pharmacokinetic-pharmacodynamic model of paclitaxel/carboplatin in ovarian cancer patients. Experimental Design: One hundred thirty-nine ovarian cancer patients received paclitaxel (175 mg/m2) over 3 h followed by carboplatin area under the concentration-time curve 5 mg/mL*min over 30 min. Plasma concentration-time data were measured, and data were processed using nonlinear mixed-effect modeling. Semiphysiologic models with linear or sigmoidal maximum response and threshold models were adapted to the data. Results: One hundred five patients had complete pharmacokinetic and toxicity data. In 34 patients with measurable disease, objective response rate was 76%. Neutrophil and thrombocyte counts were adequately described by an inhibitory linear response model. Paclitaxel tC > 0.05 was significantly higher in patients with a complete (91.8 h) or partial (76.3 h) response compared with patients with progressive disease (31.5 h; P = 0.02 and 0.05, respectively). Patients with paclitaxel tC > 0.05 > 61.4 h (mean value) had a longer time to disease progression compared with patients with paclitaxel tC > 0.05 < 61.4 h (89.0 versus 61.9 weeks; P = 0.05). Paclitaxel tC > 0.05 was a good predictor for severe neutropenia (P = 0.01), whereas carboplatin exposure (Cmax and area under the concentration-time curve) was the best predictor for thrombocytopenia (P < 10−4). Conclusions: In this group of patients, paclitaxel tC > 0.05 is a good predictive marker for severe neutropenia and clinical outcome, whereas carboplatin exposure is a good predictive marker for thrombocytopenia.

Semi-physiological model describing the hematological toxicity of the anti-cancer agent indisulam

SummaryIndisulam (N-(3-chloro-7-indolyl)-1,4-benzenedisulfonamide, GOAL, E7070) is a novel anti-cancer drug currently in phase II clinical development for the treatment of solid tumors. Phase I dose-escalation studies were conducted comparing four treatment schedules. Neutropenia and thrombocytopenia were dose limiting in all schedules. The aim of this study was to describe the extent and the time course of the hematological toxicity and its possible schedule dependency using a semi-physiological model.Data from 142 patients were analyzed using NONMEM. The semi-physiological model comprised a progenitor blood cell compartment, linked to the central circulation compartment, through 3 transition compartments representing the maturation chain in the bone marrow. Plasma concentrations of the drug were assumed to reduce the proliferation rate in the progenitor compartment according to a linear function. A feedback mechanism was included in the model representing the rebound effect of endogenous growth factors. The model was validated using a posterior predictive check.The model adequately described the extent and time course of neutropenia and thrombocytopenia. The mean transition time (MTT, i.e. maturation time in bone marrow) of neutrophils was increased by 47% in patients who received indisulam as a weekly dose administered for four out of every six weeks. For platelets, MTT was increased by 33% in patients who received this schedule and also in patients who received a continuous 120-h infusion. The validation procedure indicated that the model adequately predicts the nadir value of neutrophils and platelets and the time to reach this nadir.A semi-physiological model was successfully applied to describe the time course and extent of the neutropenia and thrombocytopenia after indisulam administration for four treatment schedules.

Population Pharmacokinetics and Pharmacodynamics of Doxorubicin and Cyclophosphamide in Breast Cancer Patients : A Study by the EORTC-PAMM-NDDG

AimsTo investigate the population pharmacokinetics and pharmacodynamics of doxorubicin and cyclophosphamide in breast cancer patients.Patients and methodsSixty-five female patients with early or advanced breast cancer received doxorubicin 60 mg/m2 over 15 minutes followed by cyclophos-phamide 600 mg/m2 over 15 minutes. The plasma concentration-time data of both drugs were measured, and the relationship between drug pharmacokinetics and neutrophil counts was evaluated using nonlinear mixed-effect modelling. Relationships were explored between drug exposure (the area under the plasma concentration-time curve [AUC]), toxicity and tumour response.ResultsFifty-nine patients had complete pharmacokinetic and toxicity data. In 50 patients with measurable disease, the objective response rate was 60%, with complete responses in 6% of patients. Both doxorubicin and cyclophosphamide pharmacokinetics were associated with neutrophil toxicity. Cyclophosphamide exposure (the AUC) was significantly higher in patients with at least stable disease (n = 44) than in patients with progressive disease (n = 6; 945 μmol ∙ h/L [95% CI 889, 1001] vs 602 μmol ∙ h/L [95% CI 379, 825], p = 0.0002). No such correlation was found for doxorubicin. Body surface area was positively correlated with doxorubicin clearance; AST and patient age were negatively correlated with doxorubicin clearance; creatinine clearance was positively correlated with doxorubicinol clearance; and occasional concurrent use of carbamazepine was positively correlated with cyclophosphamide clearance.ConclusionsThe proposed inhibitory population pharmacokinetic-pharmacodynamic model adequately described individual neutrophil counts after administration of doxorubicin and cyclophosphamide. In this patient population, exposure to cyclophosphamide, as assessed by the AUC, might have been a predictor of the treatment response, whereas exposure to doxorubicin was not. A prospective study should validate cyclophosphamide exposure as a predictive marker for the treatment response and clinical outcome in this patient group.

Phase II study of XR 5000 (DACA), an inhibitor of topoisomerase I and II, administered as a 120-h infusion in patients with non-small cell lung cancer.

XR5000 is a tricyclic carboxamide-based cytotoxic agent that binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II. The aim of this study was to evaluate the antitumoral activity and safety profile of XR5000 given as second-line chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). Patients received XR5000 at the dose of 3010 mg/m(2) as a 120-h central venous infusion every 3 weeks. The 15 patients (median age 56 years, range 48-71 years) enrolled had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 (3 patients), 1 (11 patients) or 2 (1 patient). A total of 32 cycles of XR5000 (median 2, range 1-6) were given to 14 patients. No objective response (assessed according to World Health Organization (WHO) criteria) was documented in the 12 evaluable patients by an external review panel; in 4 out of the 12 patients disease stabilisation was recorded. The following toxicities graded according to the Common Toxicity Criteria (CTC) version 2.0. were observed: one grade 3 and two grade 4 granulocytopenia, one grade 3 and one grade 4 thrombocytopenia, one grade 3 deep venous thrombosis, one grade 3 fatigue, and grade 3 undocumented epileptic seizures which led to death in 2 patients. With only 4 out of 12 patients reaching stable disease when using this dose and regimen, further evaluation of XR5000 in advanced NSCLC is not justified.

Phase II study of XR 5000, an inhibitor of topoisomerases I and II, in advanced colorectal cancer

XR 5000 is one of a series of tricyclic carboxamide-based cytotoxic agents. It binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II, thus possibly overcoming the resistance resulting from downregulation of either enzyme. Twenty patients with advanced or metastatic colorectal cancer, unpretreated for metastatic disease, received XR 5000 at the dose of 3010 mg/m(2) in a 120-h central intravenous (i.v.) infusion every 3 weeks. Response was evaluated every two cycles. No complete (CR) or partial responses (PR) were observed in eligible patients (response rate, 0 of 19, 0%; 95% confidence interval (CI): 0-18%). 5 patients had stable disease, which lasted from 79 to 157 days. Haematological toxicity was low, since only one grade 4 neutropenia and two grade 3 anaemia were observed. Other treatment-related grade 3-4 toxicities were: deep venous thrombosis (2 cases), liver toxicity, diarrhoea, anorexia, dyspnoea, chest pain, infection (1 case each). Despite the good toxicity profile, these results do not support further trials with XR 5000 in metastatic colorectal cancer.

Phase II study of XR5000 (DACA), an inhibitor of topoisomerase I and II, administered as a 120-h infusion in patients with advanced ovarian cancer.

Background. XR5000 is a tricyclic carboxamide-based cytotoxic agent that binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II. The aim of the present study was to evaluate the antitumoral activity and safety profile of XR5000 given as second-line chemotherapy in patients with ovarian cancer who had relapsed within 1 year after first-line chemotherapy with taxanes and platinum for advanced disease. Patients and methods. Patients received XR5000 at the dose of 3010u2009mg/m2 through a 120-h central venous infusion every 3 weeks. Toxicity was graded according to the Common Toxicity Criteria (CTC), version 2.0. An independent panel assessed response every two cycles according to the World Health Organization (WHO) criteria. Gehans rule was used for sample size determination. Results. Sixteen patients were enrolled; one patient was ineligible because of prior melphalan single agent treatment. Eastern Cooperative Oncology Group (ECOG) performance status was 0 (eight patients), 1 (five patients), or 2 (two patients). The 15 eligible patients received 43 cycles of XR5000 (median 2, range 1–8). Hematological toxicity was mild with only one grade 3 anemia in one patient. Other drug-related toxicities never exceeded grade 3 and included fatigue (four patients), thrombosis (one patient), nausea (one patient), stomatitis (one patient) as well as dyspnea/cough (one patient). One patient who had refused further therapy and controls after the first cycle was not assessable for response evaluation. No objective responses were observed. Four patients experienced stable disease and 10 patients progressive disease. The median time to progression was 42 days (CI 95% 40; 54). Conclusions. The complete lack of any objective response does not justify further evaluation of XR5000 in patients with advanced ovarian cancer using this dose and schedule, although the therapy was generally well tolerated.

Population pharmacokinetic and pharmacodynamic analysis to support treatment optimization of combination chemotherapy with indisulam and carboplatin.

AIMSnIndisulam and carboplatin have shown synergistic activity in preclinical studies. In a dose escalation study of the combination, a treatment delay was frequently required in a 3-weekly regimen to allow recovery from myelosuppression from previous cycles. A 4-weekly regimen was better tolerated, but had a decreased dose-intensity which may compromise efficacy. The aims of this study were (i) to develop a pharmacokinetic-pharmacodynamic (PK-PD) model to describe the myelosuppressive effect of the combination, and (ii) to use this model to select a dosing regimen for Phase II evaluation.nnnMETHODSnSixteen patients were treated at four different dose levels of indisulam (1-h infusion on day 1) and carboplatin (30-min infusion on day 2). Pharmacokinetic data were analysed with nonlinear mixed effects modelling. A semiphysiological model describing chemotherapy-induced myelosuppression characterized the relationship between the pharmacokinetics and the haematological toxicity of indisulam and carboplatin. A simulation study was performed to evaluate the tolerability and dose-intensity for 3-weekly and 4-weekly treatment regimens.nnnRESULTSnThe PK-PD model described the pharmacokinetics and the myelosuppressive effect of indisulam and carboplatin. The risk of a treatment delay at cycle 2 due to myelosuppression was unacceptably high (34-65%) in a 3-weekly regimen for various dose levels (350-600 mg m(-2) indisulam in combination with carboplatin to achieve an AUC of 4-6 mg min(-1) ml(-1)). This risk was acceptable for a 4-weekly regimen (9-24%), which is in line with the clinical study results.nnnCONCLUSIONSnThis PK-PD study supports the selection of indisulam 500 mg m(-2) and a dose of carboplatin to achieve an AUC of 6 mg min(-1) ml(-1) in a 4-weekly regimen as the recommended dose for future studies.

Pharmacokinetics of Darbepoetin Alfa after Intravenous or Subcutaneous Administration in Patients with Non-myeloid Malignancies Undergoing Chemotherapy

Background and objectiveThe pharmacokinetics of darbepoetin alfa after intravenous (IV) administration in the oncology setting have not been previously reported. The objective of this study was to evaluate the pharmacokinetics of IV or subcutaneous (SC) darbepoetin alfa in patients with non-myeloid malignancies undergoing multicycle chemotherapy.MethodsFifty-six patients (haemoglobin <13.0 g/dL) received weekly darbepoetin alfa 2.25 µg/kg administered either IV (n = 27) or SC (n = 29) during up to three cycles of chemotherapy. Noncompartmental pharmacokinetic analysis was performed, including analysis of intensive pharmacokinetic profiles collected over 168 hours during week 1 of both the first and third cycles of chemotherapy.ResultsDarbepoetin alfa serum concentrations exhibited a biphasic profile (a rapid distributive phase followed by a slower terminal elimination phase) after IV administration, whereas darbepoetin alfa was slowly absorbed after SC administration. Darbepoetin alfa exhibited limited extravascular distribution after IV administration, with both initial and steady-state mean volumes of distribution (36.1 mL/kg and 55.2 mL/kg, respectively, after a single IV dose) approximating the plasma volume. After a single IV dose, darbepoetin alfa exhibited a mean clearance of 1.05 mL/h/kg, with a mean terminal half-life of 38.8 hours. Similar pharmacokinetic results were observed after single and multiple doses of darbepoetin alfa, for both SC and IV administration.ConclusionDarbepoetin alfa is cleared slowly after IV administration to patients with cancer receiving chemotherapy, resulting in a terminal half-life of 38.8 hours. No evidence of accumulation and no changes in pharmacokinetic profiles after repeated administration were observed in cancer patients undergoing cyclic chemotherapy, for both IV and SC dosing.