Phase I and pharmacologic study of weekly gemcitabine and paclitaxel in chemo-naïve patients with advanced non-small-cell lung cancer

Preclinical evaluation of local prolonged release of paclitaxel from gelatin microspheres for the prevention of recurrence of peritoneal carcinomatosis in advanced ovarian cancer

Patients with advanced ovarian cancer develop recurrence despite initial treatment response to standard treatment of surgery and intravenous/intraperitoneal (IP) chemotherapy, partly due to a limited peritoneal exposure time of chemotherapeutics. Paclitaxel-loaded genipin-crosslinked gelatin microspheres (PTX-GP-MS) are evaluated for the treatment of microscopic peritoneal carcinomatosis and prevention of recurrent disease. The highest drug load (39.2 µg PTX/mg MS) was obtained by immersion of GP-MS in aqueous PTX nanosuspension (PTXnano-GP-MS) instead of ethanolic PTX solution (PTXEtOH-GP-MS). PTX release from PTX-GP-MS was prolonged. PTXnano-GP-MS displayed a more controlled release compared to a biphasic release from PTXEtOH-GP-MS. Anticancer efficacy of IP PTX-GP-MS (PTXEtOH-GP-MS, D = 7.5 mg PTX/kg; PTXnano-GP-MS D = 7.5 and 35 mg PTX/kg), IP nanoparticular albumin-bound PTX (D = 35 mg PTX/kg) and controls (0.9% NaCl, blank GP-MS) was evaluated in a microscopic peritoneal carcinomatosis xenograft mouse model. PTXnano-GP-MS showed superior anticancer efficacy with significant increased survival time, decreased peritoneal carcinomatosis index score and ascites incidence. However, prolonged PTX release over 14 days from PTXnano-GP-MS caused drug-related toxicity in 27% of high-dosed PTXnano-GP-MS-treated mice. Dose simulations for PTXnano-GP-MS demonstrated an optimal survival without drug-induced toxicity in a range of 7.5-15 mg PTX/kg. Low-dosed PTXnano-GP-MS can be a promising IP drug delivery system to prevent recurrent ovarian cancer.

Population Pharmacokinetics of Gemcitabine and dFdU in Pancreatic Cancer Patients Using an Optimal Design, Sparse Sampling Approach

BACKGROUND

Gemcitabine remains a pillar in pancreatic cancer treatment. However, toxicities are frequently observed. Dose adjustment based on therapeutic drug monitoring might help decrease the occurrence of toxicities. In this context, this work aims at describing the pharmacokinetics (PK) of gemcitabine and its metabolite dFdU in pancreatic cancer patients and at identifying the main sources of their PK variability using a population PK approach, despite a sparse sampled-population and heterogeneous administration and sampling protocols.

METHODS

Data from 38 patients were included in the analysis. The 3 optimal sampling times were determined using KineticPro and the population PK analysis was performed on Monolix. Available patient characteristics, including cytidine deaminase (CDA) status, were tested as covariates. Correlation between PK parameters and occurrence of severe hematological toxicities was also investigated.

RESULTS

A two-compartment model best fitted the gemcitabine and dFdU PK data (volume of distribution and clearance for gemcitabine: V1 = 45 L and CL1 = 4.03 L/min; for dFdU: V2 = 36 L and CL2 = 0.226 L/min). Renal function was found to influence gemcitabine clearance, and body surface area to impact the volume of distribution of dFdU. However, neither CDA status nor the occurrence of toxicities was correlated to PK parameters.

CONCLUSIONS

Despite sparse sampling and heterogeneous administration and sampling protocols, population and individual PK parameters of gemcitabine and dFdU were successfully estimated using Monolix population PK software. The estimated parameters were consistent with previously published results. Surprisingly, CDA activity did not influence gemcitabine PK, which was explained by the absence of CDA-deficient patients enrolled in the study. This work suggests that even sparse data are valuable to estimate population and individual PK parameters in patients, which will be usable to individualize the dose for an optimized benefit to risk ratio.

Role of cytidine deaminase in toxicity and efficacy of nucleosidic analogs

INTRODUCTION

Nucleosidic analogs such as pyrimidine and purine derivatives are mainstay in the field of treating cancers, both in adults and in children. All these drugs act as antimetabolite compounds, that is, they interfere with the ability of cancer cells to synthesize the nucleosides or the nucleotides necessary for proliferation and progression. As with most cytotoxics, maintaining patients in their therapeutic window is challenging, and predicting changes in drug exposure is critical to ensure an optimal efficacy/toxicity balance.

AREAS COVERED

Among the antimetabolites, a small but widely prescribed number of drugs (i.e., gemcitabine, capecitabine, cytarabine, azacytidine) share a same metabolic pattern driven by a liver enzyme, cytidine deaminase (CDA), coded by a gene displaying several genetic and epigenetic polymorphisms. Consequently, CDA activity is erratic, ranging from deficient to ultra-rapid deaminator patients, with subsequent impact on drug pharmacokinetics and pharmacodynamics eventually. This review provides an update on the variety of clinical studies and case-reports investigating on CDA status as a marker for clinical outcome in cancer patients treated with nucleosidic analogs.

EXPERT OPINION

Whereas sorting patients on the basis of their CDA genotype remains tricky because of unclear genotype-to-phenotype relationships, developing functional strategies (i.e., phenotype-based status determination) could help to use CDA status as a biomarker for developing adaptive dosing strategies with nucleosidic analogs.

An efficient and robust method for analyzing population pharmacokinetic data in genome-wide pharmacogenomic studies: a generalized estimating equation approach

Powerful array-based single-nucleotide polymorphism-typing platforms have recently heralded a new era in which genome-wide studies are conducted with increasing frequency. A genetic polymorphism associated with population pharmacokinetics (PK) is typically analyzed using nonlinear mixed-effect models (NLMM). Applying NLMM to large-scale data, such as those generated by genome-wide studies, raises several issues related to the assumption of random effects as follows: (i) computation time: it takes a long time to compute the marginal likelihood; (ii) convergence of iterative calculation: an adaptive Gauss-Hermite quadrature is generally used to estimate NLMM; however, iterative calculations may not converge in complex models; and (iii) random-effects misspecification leads to slightly inflated type-I error rates. As an alternative effective approach to resolving these issues, in this article, we propose a generalized estimating equation (GEE) approach for analyzing population PK data. In general, GEE analysis does not account for interindividual variability in PK parameters; therefore, the usual GEE estimators cannot be interpreted straightforwardly, and their validities have not been justified. Here, we propose valid inference methods for using GEE even under conditions of interindividual variability and provide theoretical justifications of the proposed GEE estimators for population PK data. In numerical evaluations by simulations, the proposed GEE approach exhibited high computational speed and stability relative to the NLMM approach. Furthermore, the NLMM analysis was sensitive to the misspecification of the random-effects distribution, and the proposed GEE inference is valid for any distributional form. We provided an illustration by using data from a genome-wide pharmacogenomic study of an anticancer drug.

Population pharmacokinetics of gemcitabine and its metabolite in Japanese cancer patients: impact of genetic polymorphisms

BACKGROUND AND OBJECTIVE

Gemcitabine (2',2'-difluorodeoxycytidine) is an anticancer drug, which is effective against solid tumours, including non-small-cell lung cancer and pancreatic cancer. After gemcitabine is transported into cells by equilibrative and concentrative nucleoside transporters, it is phosphorylated by deoxycytidine kinase (DCK) and further phosphorylated to its active diphosphorylated and triphosphorylated forms. Gemcitabine is rapidly metabolized by cytidine deaminase (CDA) to an inactive metabolite, 2',2'-difluorodeoxyuridine (dFdU), which is excreted into the urine. Toxicities of gemcitabine are generally mild, but unpredictable severe toxicities such as myelosuppression and interstitial pneumonia are occasionally encountered. The aim of this study was to determine the factors, including genetic polymorphisms of CDA, DCK and solute carrier family 29A1 (SLC29A1 [hENT1]), that alter the pharmacokinetics of gemcitabine in Japanese cancer patients.

PATIENTS AND METHODS

250 Japanese cancer patients who received 30-minute intravenous infusions of gemcitabine at 800 or 1000 mg/m2 in the period between September 2002 and July 2004 were recruited for this study. However, four patients were excluded from the final model built in this study because they showed bimodal concentration-time curves. Two patients who experienced gemcitabine-derived life-threatening toxicities in October 2006 and January 2008 were added to this analysis. One of these patients received 30-minute intravenous infusions of gemcitabine at 454 mg/m2 instead of the usual dose (1000 mg/m2). Plasma concentrations of gemcitabine and dFdU were measured by high-performance liquid chromatography-photodiode array/mass spectrometry. In total, 1973 and 1975 plasma concentrations of gemcitabine and dFdU, respectively, were used to build population pharmacokinetic models using nonlinear mixed-effects modelling software (NONMEM version V level 1.1).

RESULTS AND DISCUSSION

Two-compartment models fitted well to plasma concentration-time curves for both gemcitabine and dFdU. Major contributing factors for gemcitabine clearance were genetic polymorphisms of CDA, including homozygous CDA*3 [208G>A (Ala70Thr)] (64% decrease), heterozygous *3 (17% decrease) and CDA -31delC (an approximate 7% increase per deletion), which has a strong association with CDA*2 [79A>C (Lys27Gln)], and coadministered S-1, an oral, multicomponent anti-cancer drug mixture consisting of tegafur, gimeracil and oteracil (an approximate 19% increase). The estimated contribution of homozygous CDA*3 to gemcitabine clearance provides an explanation for the life-threatening severe adverse reactions, including grade 4 neutropenia observed in three Japanese patients with homozygous CDA*3. Genetic polymorphisms of DCK and SLC29A1 (hENT1) had no significant correlation with gemcitabine pharmacokinetic parameters. Aging and increased serum creatinine levels correlated with decreased dFdU clearance.

CONCLUSION

A population pharmacokinetic model that included CDA genotypes as a covariate for gemcitabine and dFdU in Japanese cancer patients was successfully constructed. The model confirms the clinical importance of the CDA*3 genotype.

A randomized phase II trial assessing in advanced non-small cell lung cancer patients with stable disease after two courses of cisplatin-gemcitabine an early modification of chemotherapy doublet with paclitaxel-gemcitabine versus continuation of cisplatin-gemcitabine chemotherapy (GFPC 03-01 Study)

BACKGROUND

There is no consensus on the optimal treatment for patients with advanced non-small cell lung cancer and stable disease after cisplatin-based chemotherapy. The objective of the trial was to evaluate a switch to a different dual-agent chemotherapy.

METHODS

Patients with stage IV non-small cell lung cancer and stable disease after two cycles of cisplatin (P) and gemcitabine (G) (P day1 (d(1)): 75 mg/m(2), G: 1250 mg/m(2) d(1) and d(8) every 3 weeks) were randomized to receive either two further cycles of PG (arm A) or paclitaxel (100 mg/m(2) d(1), d(8), d(15)) plus gemcitabine (1250 mg/m(2) d(1) and d(8), every 4 weeks) (arm B).

RESULTS

Two-hundred-twenty-eight patients were enrolled between October 2003 and August 2006. After two cycles of PG, 98 patients (43%) had stable disease; 87 were randomized: 45 to arm A and 42 to arm B. The objective response rates were 15.6% (6.5-29.4) and 21.4% (10.3-36.8) in arms A and B. Overall survival after randomization was 9.6 months (7.0-13.8) in arm A and 9.3 months (7.4-13.3) in arm B. Adverse events were similar in the two arms for hematological and non hematological toxicities.

CONCLUSIONS

Sequential first-line chemotherapy in these patients is feasible with no difference in response rates. These results do not warrant a phase III trial.

Phase I trial of nanoparticle albumin-bound paclitaxel in combination with gemcitabine in patients with thoracic malignancies

BACKGROUND

Nab-paclitaxel has a different toxicity profile than solvent-based paclitaxel including a lower rate of severe neutropenia. This trial was designed to determine the maximum tolerated dose and dose limiting toxicities (DLT) of nab-paclitaxel in combination with gemcitabine.

METHODS

Patients were required to have a performance status of 0 to 1, < or = three prior cytotoxic chemotherapy regimens, and preserved renal, hepatic, and bone marrow function. Patients received gemcitabine 1000 mg/m on days 1, 8 in all cohorts, and nab-paclitaxel at doses of 260, 300, 340 mg/m every 21 days depending on the treatment cohort (1 cycle = 21 days). DLT were assessed after the first cycle, and doses were escalated in cohorts of 3 to 6 patients.

RESULTS

Eighteen patients were consented and 15 patients are evaluable [median age 62 years (range, 35-75); median number of prior treatments 3 (range, 1-4); tumor types: non-small cell lung cancer (NSCLC) (n = 8), small cell lung cancer (SCLC) (n = 6), and esophageal cancer (n = 1)]. At a nab-paclitaxel dose of 300 mg/m, 1 of 6 pts experienced a DLT (omission of day 8 gemcitabine due to absolute neutrophil count < 500), and at an nab-paclitaxel dose of 340 mg/m 2 of 3 patients experienced a DLT (1 pt grade 3 rash and pruritus; 1 pt grade 3 fatigue and anorexia). Responses were observed in NSCLC and SCLC.

CONCLUSIONS

The maximum tolerated dose of nab-paclitaxel is 300 mg/m in combination with gemcitabine 1000 mg/m on days 1, 8 every 21 days. This combination demonstrated activity in previously treated NSCLC and SCLC patients.

Phase I and pharmacokinetic study of imatinib mesylate (Gleevec) and gemcitabine in patients with refractory solid tumors

PURPOSE

Preclinical data shows improvements in response for the combination of imatinib mesylate (IM, Gleevec) and gemcitabine (GEM) therapy compared with GEM alone. Our goals were to determine the maximum tolerated dose of GEM and IM in combination, the pharmacokinetics of GEM in the absence and in the presence of IM, and IM pharmacokinetics in this combination.

PATIENTS AND METHODS

Patients with refractory malignancy, intact intestinal absorption, measurable/evaluable disease, adequate organ function, Eastern Cooperative Oncology Group PS 0-2, and signed informed consent were eligible. Initially, treatment consisted of 600 mg/m2 of GEM (10 mg/m2/min) on days 1, 8, and 15, and 300 mg of IM daily every 28 days. Due to excessive toxicity, the schedule was altered to IM on days 1 to 5 and 8 to 12, and GEM on days 3 and 10 every 21 days. Two final cohorts received IM on days 1 to 5, 8 to 12, and 15 to 19.

RESULTS

Fifty-four patients were treated. IM and GEM given daily at 500 to 600 mg/m2 on days 1, 8, and 15 produced frequent dose-limiting toxicities. With the modified scheduling, GEM given at 1,500 mg/m2/150 min was deliverable, along with 400 mg of IM, without dose-limiting toxicities. Three partial (laryngeal, renal, and mesothelioma) and two minor (renal and pancreatic) responses were noted at GEM doses of 450 to 1,500 mg/m2. Stable disease >24 weeks was seen in 17 patients. CA19-9 in 7 of 10 patients with pancreatic cancer was reduced by approximately 90%. IM did not significantly alter GEM pharmacokinetics.

CONCLUSION

The addition of intermittently dosed IM to GEM at low to full dose was associated with broad antitumor activity and little increase in toxicity.

Mature results of a phase II trial of gemcitabine/paclitaxel given every 2 weeks in patients with advanced non-small-cell lung cancer

PURPOSE

This phase II study evaluated the efficacy and toxicity of gemcitabine/paclitaxel given every 2 weeks in patients with advanced-stage non-small-cell lung cancer. Treatment with 1 previous chemotherapy regimen was allowed. Patients received gemcitabine 3000 mg/m(2) intravenously over 30 minutes and paclitaxel 150 mg/m(2) over 3 hours every 2 weeks.

PATIENTS AND METHODS

Forty-five patients were enrolled: 31 patients were chemotherapy naive and 14 patients were previously treated. The median age was 61 years, and the majority of patients had adenocarcinoma and stage IV disease. The minimum follow-up was 4.5 years. The response rate was 27% for all 45 patients and 32% for the 38 patients who were response evaluable.

RESULTS

The response rate was 26% (31% response evaluable) for the patients who were chemotherapy-naive and 29% (33% response evaluable) for the patients who were previously treated. For the entire group, the median time to progression was 3.3 months; median overall survival was 9.4 months, and the 1-year and 2-year survival rates were 38% and 13%, respectively. The overall survival and time to progression durations were not significantly different between patients who were chemotherapy-naive and patients who were previously treated. The toxicities associated with treatment were minimal, with only 1 episode of grade 4 neutropenia and a low incidence of significant nonhematologic toxicity.

CONCLUSION

Gemcitabine/paclitaxel is active in the treatment of non-small-cell lung cancer. The every-2-week schedule is likely to be responsible for the low level of toxicity seen with this regimen and could be used as the basis for the addition of other agents in future clinical trials.

Intra-patient alternated dose escalation of paclitaxel and gemcitabine versus paclitaxel followed by fixed dose rate infusion of gemcitabine in fit elderly non-small cell lung cancer patients

PURPOSE

This study was undertaken to select the best schedule of administration for the paclitaxel plus gemcitabine combination in fit elderly patients affected by locally advanced or metastatic non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Ninety-eight patients in stage III or IV NSCLC, aged 70 years or more and in ECOG performance status (PS)<or=1, were randomly allocated to receive: paclitaxel 80 mg/m(2) plus gemcitabine 1000 mg/m(2) i.v. on days 1 and 8, with an intra-patient alternated dose escalation up to 100 and 1200 mg/m(2), respectively, over three cycles (arm A); or paclitaxel 80 mg/m(2) followed by gemcitabine 1000 mg/m(2) i.v. (100 min) on days 1 and 8 (arm B). Treatment was repeated in both arms every 3 weeks for a maximum of six cycles.

RESULTS

With a median of 3 (range, 1-6) delivered cycles, the two schedules yielded a similar response rate (25% versus 26%), failure-free survival (median, 3.3 months versus 3.2 months), progression-free survival (median, 5.1 months versus 5.2 months), and overall survival (median, 9.7 months versus 9.6 months). Survival was independently affected by the PS of patients and by the metastatic spread. Severe side effects were comparable and negligible in both arms.

CONCLUSION

A substantial difference between these two schedules in terms of efficacy and safety can be ruled-out. Paclitaxel plus gemcitabine is an advisable combination for treating fit elderly patients with advanced NSCLC.

Coadministration of oxaliplatin does not influence the pharmacokinetics of gemcitabine

We investigated the possible pharmacokinetic interactions of gemcitabine and oxaliplatin in patients with advanced solid tumors. Ten patients with advanced stage solid tumors were treated with gemcitabine (1500 mg/m) as a 30-min intravenous infusion on days 1 and 8, followed by oxaliplatin (130 mg/m) as a 4-h intravenous infusion, on day 8 every 21 days. Pharmacokinetic data for 24 h after dosing were obtained for both day 1 (gemcitabine without oxaliplatin coadministration) and day 8 (gemcitabine with oxaliplatin) during the first cycle of treatment. Gemcitabine levels in plasma were quantified using a reverse-phase high-performance liquid chromatography assay with ultraviolet detection, and total and ultrafiltrated platinum levels by flameless atomic absorption spectrophotometry with deuterium correction. All pharmacokinetic parameters of gemcitabine seemed to be unchanged when coadministered with oxaliplatin (day 8) compared with pharmacokinetic data of gemcitabine given as a single agent (day 1). The mean (maximum) concentration of gemcitabine on days 1 and 8 was 13.57 (+/-7.42) and 10.23 (+/-5.21) mg/l, respectively (P=0.28), and the mean half-life was 0.32 and 0.44 h, respectively (P=0.40). Similarly, the P-values for AUC0-24 and the observed clearance were 0.61 and 0.30, respectively. Plasma total and free platinum levels were in agreement with other published data. Gemcitabine disposition appeared to be unaffected by oxaliplatin coadministration because no significant changes in pharmacokinetics between day 1 (gemcitabine without oxaliplatin coadministration) and day 8 (gemcitabine with oxaliplatin) were observed.

Optimized sequence of drug administration and schedule leads to improved dose delivery for gemcitabine and paclitaxel in combination: a phase I trial in patients with recurrent ovarian cancer

We examined appropriate sequence, schedule, and doses of gemcitabine (G) and paclitaxel (T) in patients with persistent or recurrent epithelial ovarian cancer. Patients received a maximum of six cycles of gemcitabine on days 1 and 8 (starting 1000 mg/m(2)), and paclitaxel (starting 135 mg/m(2)) on day 8 (groups A and B) or day 1 (group C). Drug sequences (G-->T and T-->G) were tested in group A. In group A, changing sequences of gemcitabine and paclitaxel infusion were evaluated. Sequence G-->T raised grade 3 alanine transaminase in two of three patients leading to use of T-->G sequence for remainder of study. In group B, maximum tolerable dose was reached at gemcitabine 1000 mg/m(2) and paclitaxel 175 mg/m(2). Reducing paclitaxel to 150 mg/m(2) allowed escalation of gemcitabine to 1250 mg/m(2), but neutropenia-related treatment delays occurred. Giving paclitaxel on day 1 (group C) enabled administration of paclitaxel 175 mg/m(2) and gemcitabine 1250 mg/m(2) with minimal dose adjustments. The overall response rate was 41.0%, with 2 complete responses and 14 partial responses in 39 eligible patients. The schedule of paclitaxel 175 mg/m(2) (day 1) and gemcitabine 1250 mg/m(2) (days 1 and 8), with sequence of T-->G, appears most suitable with tolerable toxicity and promising activity.

A proper schedule of weekly paclitaxel and gemcitabine combination is highly active and very well tolerated in NSCLC patients

BACKGROUND

In a previous phase I dose-escalation study, we showed a weekly administration of paclitaxel (TAX) and gemcitabine (GEM) to be active and very well tolerated in non-small-cell lung cancer (NSCLC) patients, with the lack of interaction between drugs. The dose of GEM 1500 mg/m(2) and TAX 100 mg/m(2) was selected for phase II studies due to its predictable kinetic behaviour and less severe thrombocytopenia.

PATIENTS AND METHODS

Fifty-four chemo-naïve patients with advanced NSCLC (53 patients: stage IV) received TAX (100mg/m(2) i.v. infusion over 1h) followed by GEM 1500 mg/m(2) over 30 min) on days 1, 8, 15 and 21 of a 28-day cycle.

RESULTS

The objective response rate was 46% (95% CI 32-61), median OS of 10.4 ms (95% CI 6.5-4.3), and a 1-year survival rate of 53%. Grades 3 and 4 haematological toxicity consisted of non-febrile neutropenia and thrombocytopenia in 13 and 4% of the cycles, respectively. Grade 3 non-haematological toxicities were observed in three patients (asthenia, diarrhoea and neuropathy), and were always reversible.

CONCLUSIONS

This weekly schedule of TAX and GEM is highly active in chemo-naïve NSCLC patients and confirms the low toxicity profile already observed in a previous phase I study.

First-line therapy with gemcitabine and paclitaxel in locally, recurrent or metastatic breast cancer: a phase II study

Background

This phase II study evaluated the efficacy and safety of gemcitabine (G) plus paclitaxel (T) as first-line therapy in recurrent or metastatic breast cancer.

Methods

Patients with locally, recurrent or metastatic breast cancer and no prior chemotherapy for metastatic disease received G 1200 mg/m² on days 1 and 8, and T 175 mg/m² on day 1 (before G) every 21 days for a maximum of 10 cycles.

Results

Forty patients, 39 metastatic breast cancer and 1 locally-advanced disease, were enrolled. Their median age was 61.5 years, and 85% had a World Health Organization performance status (PS) of 0 or 1. Poor prognostic factors at baseline included visceral involvement (87.5%) and ≥2 metastatic sites (70%). Also, 27 (67.5%) patients had prior adjuvant chemotherapy, 25 of which had prior anthracyclines. A total of 220 cycles (median 6; range, 1–10) were administered. Of the 40 enrolled patients, 2 had complete response and 12 partial response, for an overall response rate of 35.0% for intent-to-treat population. Among 35 patients evaluable for efficacy the response rate was 40%. Additional 14 patients had stable disease, and 7 had progressive disease. The median duration of response was 12 months; median time to progression, 7.2 months; median survival, 25.7 months. Common grade 3/4 toxicities were neutropenia in 17 (42.5%) patients each, grade 3 leukopenia in 19 (47.5%), and grade 3 alopecia in 30 (75.0%) patients; 1 (2.5%) patient had grade 4 thrombocytopenia.

Conclusion

GT exhibited encouraging activity and tolerable toxicity as first-line therapy in metastatic breast cancer. Phase III trials for further evaluation are ongoing.

Prolonged fixed dose rate infusion of gemcitabine with autologous haemopoietic support in advanced pancreatic adenocarcinoma

This study aimed to define the maximum-tolerated dose (MTD) of fixed dose rate (FDR) of gemcitabine (2′-2′-difluorodeoxycitidine) infusion with circulating haemopoietic progenitor support and to evaluate the activity of the treatment. Secondary end points were pharmacokinetic of gemcitabine and difluorodeoxyuridina (dFdU) measured at first course and the activity andexpression profile of cytidine deaminase (CdA) on circulating mononuclear cells. Patients with advanced pancreatic carcinoma received escalating dose of gemcitabine 10 mg m⁻² min⁻¹ every 2 weeks with circulating haemopoietic progenitor support. First dose level was 3000 mg m⁻² and the doses were increased by 500 mg m⁻² until MTD. In all, 23 patients were enrolled. Toxicities were mild or moderate; the only patient treated at 7000 mg m⁻² died because of toxicity; therefore; the MTD was established at 6500 mg m⁻². The overall response rate was 22.2%. The AUC of gemcitabine showed a dose-dependent increase, while the AUC of dFdU reached a plateau at 4500 mg m⁻². A significant relationship was found between the AUC of dFdU and CdA expression and activity (P<0.05). Moreover, progression rate and survival were significantly related to CdA expression and activity levels. The activity of high-dose gemcitabine is not superior to that reported with less intensive FDR schedules. The predictive role of CdA expression and activity on outcome deserves further investigation.

Overexpression of neuropilin-1 promotes constitutive MAPK signalling and chemoresistance in pancreatic cancer cells

Neuropilin-1 (NRP-1) is a novel co-receptor for vascular endothelial growth factor (VEGF). Neuropilin-1 is expressed in pancreatic cancer, but not in nonmalignant pancreatic tissue. We hypothesised that NRP-1 expression by pancreatic cancer cells contributes to the malignant phenotype. To determine the role of NRP-1 in pancreatic cancer, NRP-1 was stably transfected into the human pancreatic cancer cell line FG. Signal transduction was assessed by Western blot analysis. Susceptibility to anoikis (detachment induced apoptosis) was evaluated by colony formation after growth in suspension. Chemosensitivity to gemcitabine or 5-fluorouracil (5-FU) was assessed by MTT assay in pancreatic cancer cells following NRP-1 overexpression or siRNA-induced downregulation of NRP-1. Differential expression of apoptosis-related genes was determined by gene array and further evaluated by Western blot analysis. Neuropilin-1 overexpression increased constitutive mitogen activated protein kinase (MAPK) signalling, possibly via an autocrine loop. Neuropilin-1 overexpression in FG cells enhanced anoikis resistance and increased survival of cells by >30% after exposure to clinically relevant levels of gemcitabine and 5-FU. In contrast, downregulation of NRP-1 expression in Panc-1 cells markedly increased chemosensitivity, inducing >50% more cell death at clinically relevant concentrations of gemcitabine. Neuropilin-1 overexpression also increased expression of the antiapoptotic regulator, MCL-1. Neuropilin-1 overexpression in pancreatic cancer cell lines is associated with (a) increased constitutive MAPK signalling, (b) inhibition of anoikis, and (c) chemoresistance. Targeting NRP-1 in pancreatic cancer cells may downregulate survival signalling pathways and increase sensitivity to chemotherapy.

Alternating weekly administration of paclitaxel and gemcitabine: a phase II study in patients with advanced non-small-cell lung cancer

BACKGROUND

We sought to evaluate toxicity and efficacy of an alternating week schedule of paclitaxel and gemcitabine in patients with advanced non-small-cell lung cancer (NSCLC).

METHODS

Patients (n=27, mean age 56 years, range 27-73 years) received paclitaxel (100 mg/m(2) i.v. infusion over 1 h) on days 1 and 15 alternating with gemcitabine (1000 mg/m(2)) on days 8 and 22 of a 36-day cycle. Responses were evaluated after three cycles, and after the proposed six cycles.

RESULTS

In total, 116 cycles were administered (mean 4.25 cycles per patient). Haematological toxicity was slight: febrile neutropenia (n=1) and neutropenia grade III-IV (n=5). Non-haematological toxicities included arthromyalgia grade II (n=6) and neurotoxicity grade III (n=1). Objective response was 29%, stable disease 25% and disease progression 46%. Median duration of response was 8 months (95% CI 5-11 months), median progression-free survival was 7 months (95% CI 4-11 months), median overall survival was 13 months (95% CI 7-17 months) and survival at 1 year was 52%.

CONCLUSIONS

A regimen of alternating weekly paclitaxel and gemcitabine is feasible in patients with advanced NSCLC, showing a lower toxicity profile compared with other platinum-based combinations, which makes this novel scheme attractive for these patients.

Gemcitabine, Paclitaxel, and piritrexim: a phase I study

Piritrexim is a new antifolate that has shown activity in methotrexate-resistant tumors. Gemcitabine is an antimetabolite similar in structure to cytosine arabinoside with early studies demonstrating activity in a variety of cancers. It also has apparent synergistic activity with antifolates from initial work in tumor models. Paclitaxel is an antimicrotubule agent that has a wide spectrum of activity against a variety of solid tumors. The combination of gemcitabine, paclitaxel, and piritrexim was assessed in this phase I trial. Thirty patients were enrolled. The starting doses were piritrexim 25 mg orally twice daily (days 1-4, 15-18), paclitaxel 75 mg/m2 (days 1, 15), and gemcitabine 750 mg/m2 (days 1, 15), which then was escalated in a stepwise fashion. Four patients achieved stable disease while on study, whereas one patient with a poorly differentiated neuroendocrine tumor achieved a partial response. The main toxicity was myelosuppression. The maximum tolerated dose was thought to be piritrexim 25 mg orally three times daily (days 1-4), paclitaxel 150 to 175 mg/m2 (days 1, 15), and gemcitabine 1,000 mg/m2 (days 1, 15). The combination of these new antifolates with paclitaxel and gemcitabine appears safe and should be considered for phase II trials in known responsive tumors such as transitional cell carcinomas.

Pharmacogenetics of anticancer drug sensitivity in non-small cell lung cancer

In mammalian cells, the process of malignant transformation is characterized by the loss or down-regulation of tumor-suppressor genes and/or the mutation or overexpression of proto-oncogenes, whose products promote dysregulated proliferation of cells and extend their life span. Deregulation in intracellular transduction pathways generates mitogenic signals that promote abnormal cell growth and the acquisition of an undifferentiated phenotype. Genetic abnormalities in cancer have been widely studied to identify those factors predictive of tumor progression, survival, and response to chemotherapeutic agents. Pharmacogenetics has been founded as a science to examine the genetic basis of interindividual variation in drug metabolism, drug targets, and transporters, which result in differences in the efficacy and safety of many therapeutic agents. The traditional pharmacogenetic approach relies on studying sequence variations in candidate genes suspected of affecting drug response. However, these studies have yielded contradictory results because of the small number of molecular determinants of drug response examined, and in several cases this approach was revealed to be reductionistic. This limitation is now being overcome by the use of novel techniques, i.e., high-density DNA and protein arrays, which allow genome- and proteome-wide tumor profiling. Pharmacogenomics represents the natural evolution of pharmacogenetics since it addresses, on a genome-wide basis, the effect of the sum of genetic variants on drug responses of individuals. Development of pharmacogenomics as a new field has accelerated the progress in drug discovery by the identification of novel therapeutic targets by expression profiling at the genomic or proteomic levels. In addition to this, pharmacogenetics and pharmacogenomics provide an important opportunity to select patients who may benefit from the administration of specific agents that best match the genetic profile of the disease, thus allowing maximum activity.

Phase I-II and pharmacokinetic study of gemcitabine combined with oxaliplatin in patients with advanced non-small-cell lung cancer and ovarian carcinoma

BACKGROUND

The aim of this study was to determine the toxicity profile, the recommended dose (RD) and the pharmacokinetic parameters, and to evaluate the antitumor activity of gemcitabine combined with oxaliplatin in patients with advanced non-small-cell lung cancer (NSCLC) and ovarian carcinoma (OC).

METHODS

Gemcitabine was administered as a 30-min infusion followed by a 2-h infusion of oxaliplatin, repeated every 2 weeks. Doses of gemcitabine and oxaliplatin ranged from 800 to 1500 and 70 to 100 mg/m(2), respectively.

RESULTS

Forty-four patients (26 males, 18 females; median age 55 years) including 35 NSCLC (five platinum pretreated) and nine OC patients (all platinum pretreated) received a total of 355 cycles. All patients were evaluable for toxicity. No dose-limiting toxicity at any dose level occurred during the first two cycles; therefore, the highest dose-level of gemcitabine (1500 mg/m(2)) and oxaliplatin (85 mg/m(2)) was considered as the RD. Hematological toxicity was moderate amongst the 22 patients treated (167 cycles) at that dose level. Thirteen cycles were associated with grade 3-4 non-febrile neutropenia in six patients, and eight cycles with grade 3-4 thrombocytopenia in two patients. Other toxicities were mild to moderate, consisting of asthenia and peripheral neurotoxicity. Four of the 35 patients treated with oxaliplatin 85 mg/m(2) experienced grade 3 neurotoxicity requiring treatment discontinuation at cycle 10. In the range of the doses used, gemcitabine and its main metabolite 2',2'-difluorodeoxyuridine appeared not to be affected by oxaliplatin 70-100 mg/m(2). Of the 44 patients evaluable for activity, 12 NSCLC patients experienced objective responses (one complete and 11 partial responses) and three OC patients showed tumor stabilization lasting for 6 months with a 50% decrease of CA 125 level. Two partial responses (NSCLC) and one tumor stabilization (OC) occurred in platinum-resistant patients.

CONCLUSIONS

The combination of gemcitabine and oxaliplatin could be safely administered on an out-patient schedule in patients with advanced NSCLC and OC. The RD was gemcitabine 1500 mg/m(2) and oxaliplatin 85 mg/m(2) every 2 weeks. Promising antitumor activity was reported in patients with NSCLC and platinum-pretreated OC, and thus, deserves further evaluation.

Combination chemotherapy of the taxanes and antimetabolites: its use and limitations

In an effort to improve response rates of chemotherapy, taxanes have been combined with other cytotoxic agents such as antimetabolites. However, the use of some of these combinations in patients has been restricted by severe toxicity. The significance of the sequence of drug administration in combining methotrexate (MTX) and taxanes was recognised in in vitro studies, showing synergistic effects for the sequence of MTX followed by paclitaxel, and antagonism for exposure in the reverse order. A possible explanation might be an MTX-induced synchronisation of cells in the S phase of the cell cycle, after which cells are more susceptible for the cytotoxic action of taxanes. Clinical studies using this sequence were hampered by severe neutropenia and mucositis at relatively low doses of both drugs. As no pharmacokinetic interactions were observed, the excess of toxicity may have been due to sequence-dependent synergistic actions on bone marrow and mucosa. In contrast, and confusingly, in vitro studies on 5-fluorouracil (5-FU) and taxanes indicate that 5-FU preceeding or simultaneously given to paclitaxel impairs cytotoxicity as compared with paclitaxel monotherapy, while the reverse sequence results in additive or synergistic cytotoxicity. While almost all clinical studies have used the sequence of a taxane followed by 5-FU, various schedules appeared feasible and effective. The combination of a 5-FU analogue, capecitabine and taxanes was supported by in vitro data. A large phase III trial confirmed the feasibility and superior efficacy of this combination in breast cancer patients relapsing after an anthracycline. Conflicting results exist on the benefit of combining gemcitabine and taxanes in tumour cell lines. Although the accumulation of gemcitabine triphosphate (dFdCTP) in mononuclear cells was significantly higher with an increasing dose of paclitaxel, no pharmacokinetic interactions for both agents were noticed. A pharmacokinetic analysis of the gemcitabine-docetaxel combination therapy has not been published in detail. Despite numerous trials, so far no optimum schedule has been established. Regarding data on actually delivered dose intensities, a 2- or 3-weekly cycle seems favourable and feasible. However, possible severe pulmonary toxicity warrants cautious monitoring of patients treated with this combination. Different outcomes of preclinical and clinical studies reveal that combining two chemotherapeutic agents is not simply a matter of putting antitumour activities together. Drug interaction may result in synergism, not only of efficacy but also of toxic side-effects. Adding two drugs may also implicate antagonism in drug efficacy due to unwanted interference in cytotoxicity or pharmacokinetics. For agents acting at a specific phase of the cell cycle, the sequence of administration may determine the efficacy and toxicity of a combination therapy. Because of an observed discrepancy between in vitro data and clinical studies, we would like to emphasise the need for adequate dose-finding clinical trials together with pharmacokinetic data analysis before examining any new combination chemotherapy in more detail in phase II studies.

Drug distribution and pharmacokinetic/pharmacodynamic relationship of paclitaxel and gemcitabine in patients with non-small-cell lung cancer

BACKGROUND

Gemcitabine and paclitaxel are two of the most active agents in non-small-cell lung cancer (NSCLC), and pharmacologic investigation of the combination regimens including these drugs may offer a valuable opportunity in treatment optimization. The present study investigates the pharmacokinetics and pharmacodynamics of paclitaxel and gemcitabine in chemotherapy-naive patients with advanced NSCLC within a phase I study.

PATIENTS AND METHODS

Patients were given i.v. paclitaxel 100 mg/m2 by one-hour infusion followed by gemcitabine 1,500, 1,750 and 2,000 mg/m2 by 30-min administration. Plasma levels of paclitaxel, gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) were determined by high-performance liquid chromatography (HPLC). Concentration-time curves were modeled by compartmental and non-compartmental methods and pharmacokinetic/pharmacodynamic (PK/PD) relationships were fitted according to a sigmoid maximum effect (Emax) model.

RESULTS

Paclitaxel pharmacokinetics did not change as a result of dosage escalation of gemcitabine from 1,500 to 2,000 mg/m2. A nonproportional increase in gemcitabine peak plasma levels (Cmax, from 18.56 +/- 4.94 to 40.85 +/- 14.85 microg/ml) and area under the plasma concentration-time curve (AUC, from 9.99 +/- 2.75 to 25.01 +/- 9.87 h x microg/ml) at 1,500 and 2,000 mg/m, respectively, was observed, suggesting the occurrence of saturation kinetics at higher doses. A significant relationship between neutropenia and time of paclitaxel plasma levels > or = 0.05 micromol/l was observed, with a predicted time of 10.4 h to decrease cell count by 50%. A correlation was also observed between percentage reduction of platelet count and gemcitabine Cmax, with a predicted effective concentration to induce a 50% decrease of 14.3 microg/ml.

CONCLUSION

This study demonstrates the lack of interaction between drugs, the nonproportional pharmacokinetics of gemcitabine at higher doses and the Emax relationship of paclitaxel and gemcitabine with neutrophil and platelet counts, respectively. In addition, gemcitabine 1,500 mg/m2 is the recommended dosage in combination with paclitaxel 100 mg/m2 for future phase II studies, due to its predictable kinetic behaviour and less severe thrombocytopenia than expected.

Phase II trial of paclitaxel plus gemcitabine in patients with locally advanced or metastatic non-small-cell lung cancer

PURPOSE

Given the cisplatin-related myelotoxicity and nonhematologic toxicities, we were prompted to undertake a study of the noncisplatin combination of paclitaxel plus gemcitabine to evaluate the efficacy, tolerance, and survival of this combination in patients with locally advanced and metastatic non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients received gemcitabine 2,000 mg/m(2) and paclitaxel 150 mg/m(2) on days 1 and 15 of a 28-day cycle, for a maximum of eight cycles.

RESULTS

Between December 1997 and June 1998, 89 untreated NSCLC patients were enrolled; 30 (34%) had stage IIIB disease (23 with malignant pleural effusion and seven without), and 59 (66%) had stage IV disease. Eighty-six percent of patients had a performance status of 0 or 1. The median number of cycles administered was four (range, one to eight cycles). The mean dose-intensity for both paclitaxel and gemcitabine was nearly 100%. Hematologic and nonhematologic toxicities were mild. Thirty-eight patients received second-line chemotherapy after completion of the study. The overall intent-to-treat response rate was 32.2%, with a higher response rate for stage IIIB patients (43.3%) than for stage IV patients (26.3%). Overall median survival was 9.9 months, and 1-year survival was 38.8% (14.2 months for stage IIIB and 7.7 months for stage IV; P =.007). Median survival was 10.2 months for patients with a performance status of 0 or 1 and 4.8 months for patients with a performance status of 2 (P =.007).

CONCLUSION

A biweekly paclitaxel/gemcitabine regimen was well tolerated, with an acceptable response rate and a reasonable median survival time, especially in patients with good performance status. It merits further exploration in future studies.