Phase I trial of fixed dose-rate gemcitabine in combination with carboplatin in chemonaive advanced non-small-cell lung cancer: a Cancer Therapeutics Research Group study

Rapid Homogeneous Immunoassay to Quantify Gemcitabine in Plasma for Therapeutic Drug Monitoring

BACKGROUND

Gemcitabine (2',2'-difluoro-2'-deoxycytidine) is a nucleoside analog used as a single agent and in combination regimens for the treatment of a variety of solid tumors. Several studies have shown a relationship between gemcitabine peak plasma concentration (Cmax) and hematological toxicity. An immunoassay for gemcitabine in plasma was developed and validated to facilitate therapeutic drug monitoring (TDM) by providing an economical, robust method for automated chemistry analyzers.

METHODS

A monoclonal antibody was coated on nanoparticles to develop a homogenous agglutination inhibition assay. To prevent ex vivo degradation of gemcitabine in blood, tetrahydrouridine was used as a sample stabilizer. Validation was conducted for precision, recovery, cross-reactivity, and linearity on a Beckman Coulter AU480. Verification was performed on an AU5800 in a hospital laboratory. A method comparison was performed with (LC-MS/MS) liquid chromatography tandem mass spectrometry using clinical samples. Selectivity was demonstrated by testing cross-reactivity of the major metabolite, 2',2'-difluorodeoxyuridine.

RESULTS

Coefficients of variation for repeatability and within-laboratory precision were <8%. The deviation between measured and assigned values was <3%. Linear range was from 0.40 to 33.02 μ/mL (1.5-125.5 μM). Correlation with validated LC-MS/MS methods was R = 0.977. The assay was specific for gemcitabine: there was no cross-reactivity to 2',2'-difluorodeoxyuridine, chemotherapeutics, concomitant, or common medications tested. Tetrahydrouridine was packaged in single-use syringes. Gemcitabine stability in whole blood was extended to 8 hours (at room temperature) and in plasma to 8 days (2-8°C).

CONCLUSIONS

The assay demonstrated the selectivity, test range, precision, and linearity to perform reliable measurements of gemcitabine in plasma. The addition of stabilizer improved the sample handling. Using general clinical chemistry analyzers, gemcitabine could be measured for TDM.

A sequential temperature cycling study for the investigation of carboplatin infusion stability to facilitate `dose-banding'

Study objective. To determine the physical and chemical stability of carboplatin infusion for dosebanding, with cycling between refrigerated storage and room temperature in-use conditions.

Design. A sequential study design was selected to closely simulate the temperatures and conditions experienced by drug infusions in pharmaceutical storage and in clinical use. Carboplatin infusions, 0.70 and 2.15 mg/mL, were stored refrigerated for up to 84 days, followed by incubation at 258C for 24 h. The infusions were also returned to refrigerated storage for 3 and 7 days, to replicate a situation in which returned, unused infusions are kept for re-issuing. On pre-determined time-points, infusion chemical and physical stability were determined by HLPC, sub-visual particulatecounts, pH-measurement, and weighing of infusions.

Results. Light protected carboplatin infusions at both study concentrations were chemically and physically stable following refrigerated storage for 84 days, followed by a further 24 h under ‘in-use’ conditions at 258C. Additionally, the infusions were stable following return to refrigerated storage again for at least 7 days.

Conclusion. This study has demonstrated extended stability of carboplatin infusions which enables batch-scale preparation of standard infusions for dose- J Oncol Pharm Practice (2007) 13: 119–126.

SLC28A3 genotype and gemcitabine rate of infusion affect dFdCTP metabolite disposition in patients with solid tumours

Background:

Gemcitabine is used for the treatment of several solid tumours and exhibits high inter-individual pharmacokinetic variability. In this study, we explore possible predictive covariates on drug and metabolite disposition.

Methods:

Forty patients were enrolled. Gemcitabine and dFdU concentrations in the plasma and dFdCTP concentrations in peripheral blood mononuclear cell were measured to 72 h post infusion, and pharmacokinetic parameters were estimated by nonlinear mixed-effects modelling. Patient-specific covariates were tested in model development.

Results:

The pharmacokinetics of gemcitabine was best described by a two-compartment model with body surface area, age and NT5C2 genotype as significant covariates. The pharmacokinetics of dFdU and dFdCTP were adequately described by three-compartment models. Creatinine clearance and cytidine deaminase genotype were significant covariates for dFdU pharmacokinetics. Rate of infusion of <25 mg m⁻² min⁻¹ and the presence of homozygous major allele for SLC28A3 (CC genotype) were each associated with an almost two-fold increase in the formation clearance of dFdCTP.

Conclusion:

Prolonged dFdCTP systemic exposures (⩾72 h) were commonly observed. Infusion rate <25 mg m⁻² min⁻¹ and carriers for SLC28A3 variant were each associated with about two-fold higher dFdCTP formation clearance. The impacts of these covariates on treatment-related toxicity in more selected patient populations (that is, first-line treatment, single disease state and so on) are not yet clear.

Phase I dose-escalation study and population pharmacokinetic analysis of fixed dose rate gemcitabine plus carboplatin as second-line therapy in patients with ovarian cancer

OBJECTIVE

This phase I study of fixed dose rate (FDR) gemcitabine and carboplatin assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, pharmacokinetic (PK)/pharmacodynamic (PD) profile and preliminary anti-tumor activity in patients with recurrent ovarian cancer (OC).

METHODS

Patients with recurrent OC after first line treatment were treated with carboplatin and FDR gemcitabine (infusion speed 10mg/m(2)/min) on days 1, 8 and 15, every 28 days. Pharmacokinetics included measurement of platinum concentrations in plasma ultrafiltrate (pUF) and plasma concentrations of gemcitabine (dFdC) and metabolite dFdU. Intracellular levels of dFdC triphosphate (dFdC-TP), the most active metabolite of gemcitabine, were determined in peripheral blood mononuclear cells (PBMCs). Population pharmacokinetic modeling and simulation were performed to further investigate the optimal schedule.

RESULTS

Twenty three patients were enrolled. Initial dose escalation was performed using FDR gemcitabine 300 mg/m(2) (administered at infusion speed of 10 mg/m(2)/min) combined with carboplatin AUC 2.5 and 3. Excessive bone marrow toxicity led to a modified dose escalation schedule: carboplatin AUC 2 and dose escalation of FDR gemcitabine (300 mg/m(2), 450 mg/m(2), 600 mg/m(2) and 800 mg/m(2)). DLT criteria as defined per protocol prior to the study were not met with carboplatin AUC 2 in combination with FDR gemcitabine 300-800 mg/m(2) because of myelosuppressive dose-holds (especially thrombocytopenia and neutropenia).

CONCLUSIONS

FDR gemcitabine in combination with carboplatin administered in this 28 days schedule resulted in increased grade 3/4 toxicity compared to conventional 30-minute infused gemcitabine. A two weekly schedule (chemotherapy on days 1 and 8) would be more appropriate.

Pharmacologic modulation strategies to reduce dose requirements of anticancer therapy while preserving clinical efficacy

Drug interactions may be exploited to overcome pharmacokinetic issues in order to improve the therapeutic index of a drug, with clinical goals of reducing the dose of the active drug while preserving efficacy or reducing toxicity. This strategy has been used in infectious disease and transplant medicine, and, more recently, in oncology. Pharmacologic modulation strategies range from coadministration of either a drug that inhibits a metabolizing enzyme that would inactivate the drug of interest, a drug that induces an enzyme that activates the drug of interest or a drug that inhibits transporters that affect the uptake or elimination of the drug of interest. This review will discuss pharmacologic modulation strategies that have been tested clinically in order to increase systemic drug exposure. Important examples include ketoconazole inhibition of hepatic CYP3A4 in order to increase systemic exposure to docetaxel, irinotecan and etoposide, and cyclosporine inhibition of intestinal ATP-binding cassette transporters in order to decrease the toxicity of irinotecan and increase the bioavailability of oral docetaxel, paclitaxel and topotecan.

Prolonged versus standard gemcitabine infusion: translation of molecular pharmacology to new treatment strategy

Gemcitabine is frequently used in the treatment of patients with solid tumors. Gemcitabine is taken up into the cell via human nucleoside transporters (hNTs) and is intracellularly phosphorylated by deoxycytidine kinase (dCK) to its monophosphate and subsequently into its main active triphosphate metabolite 2',2'-difluorodeoxycytidine triphosphate (dFdCTP), which is incorporated into DNA and inhibits DNA synthesis. In addition, gemcitabine is extensively deaminated to 2',2'-difluorodeoxyuridine, which is largely excreted into the urine. High expression levels of human equilibrative nucleoside transporter type 1 were associated with a significantly longer overall survival duration after gemcitabine treatment in patients with pancreatic cancer. Clinical studies in blood mononuclear and leukemic cells demonstrated that a lower infusion rate of gemcitabine was associated with higher intracellular dFdCTP levels. Prolonged infusion of gemcitabine at a fixed dose rate (FDR) of 10 mg/m2 per minute was associated with a higher intracellular accumulation of dFdCTP, greater toxicity, and a higher response rate than with the standard 30-minute infusion of gemcitabine in patients with pancreatic cancer. In the current review, we discuss the molecular pharmacology of nucleoside analogues and the influence of hNTs and dCK on the activity and toxicity of gemcitabine, which is the basis for clinical studies on FDR administration, and the results of FDR gemcitabine administration in patients. These findings might aid optimal clinical application of gemcitabine in the future.

Phase II study of gemcitabine and carboplatin in patients with advanced non-small-cell lung cancer

PURPOSE

To evaluate the efficacy and safety of gemcitabine in combination with carboplatin at standard rate or fixed dose rate infusion in patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

In this prospective study, patients with chemonaive advanced NSCLC were randomized to receive gemcitabine at a standard rate (gemcitabine 1,200 mg/m2 over 30 min, the standard arm) or a fixed dose rate (gemcitabine 1,200 mg/m2 over 120 min, the FDR arm) on days 1 and 8 every 3 week cycle. In both treatment arms, carboplatin at AUC of 5 was administered over 4 h following gemcitabine on day 1 of each cycle.

RESULTS

From November 2003 to June 2005, a total of 42 patients, in which 7 (17%) patients had stage III(B) disease and 35 (83%) had stage IV disease, were enrolled into this study. All patients were included in efficacy and toxicity assessment. No patient had a complete response. Seven (33%) patients in the standard arm and 10 (48%) in the FDR arm had a partial response. The median time to progression and median overall survival time in the standard arm was 5.4 months (95% CI, 3.8-7 months) and 11.5 months (95% CI, 8.2-14.8 months), respectively, while in the FDR arm was 6.5 (95% CI, 4.4-8.6 months) months, 12.0 months (95% CI, 11.3-12.7 months), respectively. The most frequently reported grade 3 or 4 hematological toxicities were thrombocytopenia (38% patients in the standard arm and 43% in the FDR arm) and neutropenia (24% in the standard arm and 33% in the FDR arm). Although hematological toxicity occurred in a little higher percent of patients in the FDR arm than in the standard arm, there were no discernible differences by statistical analysis in both treatment arms (P > 0.05). And significant nonhematologic toxicities were infrequent and tolerable in both arms. No significant difference existed also (P > 0.05).

CONCLUSION

In this phase II study, gemcitabine in combination with carboplatin either at standard rate or fixed dose rate infusion was clinically effective and well tolerated in patients with advanced NSCLC.

A multicentre randomised phase II study of carboplatin in combination with gemcitabine at standard rate or fixed dose rate infusion in patients with advanced stage non-small-cell lung cancer

BACKGROUND

Intracellular gemcitabine triphosphate (dFdCTP) levels can be optimised by administering gemcitabine at a fixed dose rate infusion.

PATIENTS AND METHODS

Patients with chemonaive advanced non-small cell lung cancer (NSCLC) were randomised to receive gemcitabine at a fixed dose rate gemcitabine 750 mg/m(2) over 75 min (arm A) or gemcitabine 1000 mg/m(2) over 30 min (arm B) on days 1 and 8 every three week cycle. Carboplatin at AUC of 5 was administered in both treatment arms on day 1 of each cycle. End points were activity, tolerability and pharmacokinetics of plasma and intracellular gemcitabine.

RESULTS

76 patients were randomised. Response rate was 34% in arm A and 42% in arm B. Toxicity and quality of life scores were similar for both treatment arms. Mean plasma Cmax(gemcitabine) and mean dFdCTP AUC in arm A was 20.8 microM +/- 17.2 microM and 35,079 +/- 18,216 microM*min respectively and in arm B, 41.2 +/- 13.9 microM and 32 249 +/- 11 267 microM*min respectively. dFdCTP saturation was reached in Arm B but not in Arm A.

CONCLUSION

The saturability of dFdCTP accumulation in Arm A suggests optimal delivery of gemcitabine is achieved using fixed rate infusion compared to 30-min infusion. Fixed dose rate gemcitabine is active and feasible, supporting the concept of fixed dosing rate of gemcitabine in advanced NSCLC. However, this entails a longer infusion time with associated higher costs involved.

Phase II trial of a 2-h infusion of gemcitabine plus carboplatin as first-line chemotherapy for advanced non-small-cell lung cancer

PURPOSE

To evaluate the efficacy and safety of the combination of using gemcitabine as a rate infusion of 10 mg/m(2) per min with carboplatin in front-line chemonaive patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-four chemonaive patients with stage IIIB or IV NSCLC have been included, 44 males and 10 females, with a median age 63 years (range 19-75). Thirty-two (59%) patients had adenocarcinoma, 13 (24%) squamous cell, 1 (2%) large cell carcinoma and 8 (15%) others. Eight (15%) had stage IIIB and 46 (85%) stage IV. Treatment was consisted of 1,200 mg/m(2) gemcitabine given as a 2-h continuous infusion (10 mg/m(2) per min) on days 1 and 8 of each cycle an AUC 5 carboplatin as on day 1, repeating each cycle for every 21 days. A total of 223 chemotherapy cycles were administered, with a median of four cycles per patient (range 1-6), and 15 (28%) patients received all six cycles.

RESULTS

Of the 54 patients enrolled, all were evaluated for toxicity and 51 assessed for response. The overall response rate was 41% (95% confidence interval, 28-57%) with complete and partial responses of 4 and 37%, respectively. The median time to disease progression was 5.0 months (95% CI, 3.7-6.3 months), and median overall survival time was 11.5 months (95% CI, 9.9-13.1 months). One-year survival was 42%. The main grade 3-4 toxicity (according to the WHO scale) consisted of neutropenia (56%) and thrombocytopenia (57%). Patients were required platelet transfusion in 27 cycles (12%) and hematopoietic growth factors support care in 56 (25%) cycles. No bleeding episodes were recorded. Grade 3 nausea/vomiting occurred in 6% and grade 1-2 skin rash occurred in 43%.

CONCLUSIONS

Prolonged gemcitabine infusion combined with carboplatin is manageable and tolerated, and its efficacy is similar to that of other chemotherapeutic schemes used for NSCLC treatment.

In vitro procoagulant activity induced in endothelial cells by chemotherapy and antiangiogenic drug combinations: modulation by lower-dose chemotherapy

One of the emerging problems concerning the use of antiangiogenic drugs, when used in combination with certain chemotherapy regimens, is enhanced rates and severity of adverse clotting events. For as yet unknown reasons, certain drugs and particular combinations can induce an elevated incidence of thromboembolic events in treated cancer patients [e.g., SU5416, a vascular endothelial cell growth factor receptor-2 (VEGFR-2) antagonist, when combined with gemcitabine and cisplatin (CDDP)]. Such results highlight the need to develop assays capturing the essence of enhanced clot formation under such combination treatment and which may have predictive potential as well. Here, we report the possibility of such an assay (i.e., the ratio of tissue factor over tissue factor pathway inhibitor expression or activity in cultured human endothelial cells calculated as a coagulation index). A marked increase in coagulation index was observed after exposure to SU5416 and the CDDP/gemcitabine chemotherapy combination in contrast to either of these treatments used alone. Substitution of SU5416 with any one of ZD6474, SU6668, IMC-1121, a monoclonal antibody to VEGFR-2, or an antibody to VEGF (bevacizumab) did not cause a marked increase in the coagulation index, nor did the combination of SU5416 with 5-fluorouracil and leucovorin. Finally, we noted that reducing the concentrations of gemcitabine and CDDP (i.e., use of "metronomic dosing" in vitro) significantly attenuated the coagulation index increase induced by these drugs, suggesting that use of low-dose chemotherapy regimens might be an approach to consider for reducing the incidence of adverse clotting events associated with chemotherapy alone or in conjunction with antiangiogenic drug combination therapies.