A phase I study of docetaxel and 5-fluorouracil in patients with advanced solid malignancies

Docetaxel in the management of advanced pancreatic cancer

The poor outcome of pancreatic cancer with conventional treatment options emphasizes the need for continued research. The benefits of gemcitabine in improving quality of life and survival have been established in patients with advanced pancreatic cancer. Randomized clinical trials studying the addition of a second drug to gemcitabine, either a classic cytotoxic (5-fluorouracil, cisplatin, irinotecan, pemetrexed, oxaliplatin, or exatecan) or targeted agents (ie, the farnesyl transferase inhibitor R115777 or the metalloproteinase inhibitor marimastat) have not resulted in improvement in survival compared with gemcitabine alone. Although limited activity of docetaxel in patients with pancreatic adenocarcinoma has been reported in single-agent studies, attractive efficacy results have been documented with docetaxel in combination with other chemotherapeutic agents for the management of advanced pancreatic cancer. Phase I and II trials of docetaxel in combination with gemcitabine, irinotecan, 5-fluorouracil, or thalidomide, as well as trials of docetaxel and radiotherapy, suggest that docetaxel combinations in pancreatic cancer should be further studied in randomized trials.

Timed flat infusion of 5-fluorouracil increases the tolerability of 5-fluorouracil/docetaxel regimen in metastatic breast cancer: a dose-finding study

A dose-finding study was undertaken to determine the maximum-tolerated dose, and the recommended dose of docetaxel in combination with 12-h timed (22:00–10:00) flat infusion of 5-fluorouracil (5-FU) in metastatic breast cancer patients. This schedule seems to reduce the occurrence of stomatitis of the docetaxel and infusional 5-FU regimen.

Phase II multicentre study of docetaxel plus 5-fluorouracil in patients with anthracycline-pretreated metastatic breast cancer

The purpose of the study was to determine the efficacy and safety of docetaxel plus continuous infusion of 5-fluorouracil (5-FU) in patients with metastatic breast cancer previously treated with anthracyclines. A total of 41 patients with histologically proven metastatic breast cancer and performance status 0-2, who had received at least one anthracycline-containing regimen, received docetaxel 85 mg m(-2) followed by continuous infusion of 5-FU 750 mg m(-2) day(-1) for 5 days every 3 weeks for up to eight cycles. All patients received corticosteroid premedication, but there was no prophylactic colony-stimulating factor support. The most frequent metastatic sites were the liver (61%), bone (29%), and lung (29%). All 41 patients were assessable for toxicity and 30 were eligible and assessable for efficacy. The objective response rate was 70.0% (95% CI: 53.6-86.4%) for the per protocol group and 53.7% (95% CI: 38.4-68.9%) for the intent-to-treat (ITT) population. For the ITT population, median duration of response was 8.4 months (95% CI: 6.7-12.2 months), median time to progression was 6.7 months (95% CI 5.5-8.6 months), and median survival was 17 months (95% CI: 12.3-not recorded months). Grade 3/4 neutropenia occurred in 54% of patients, with febrile neutropenia in 24% of patients and 5% of cycles, but infections were rare. Stomatitis was frequent, grade 3 in 24% of patients and grade 4 in one patient (2%), but manageable. Diarrhoea was rare, grade 3 in 7% of patients and 1% of cycles. Other grade 3/4 nonhaematological toxicities were infrequent. In conclusion, this docetaxel/5-FU regimen is highly active and well tolerated in patients with anthracycline-pretreated metastatic breast cancer. The efficacy is particularly promising, as one-third of patients were either second-line and/or anthracycline-resistant/refractory.

Phase I-II parallel study of docetaxel on a bimonthly schedule in refractory metastatic breast carcinoma

BACKGROUND

The 3-week schedule with docetaxel (DTC) 75-100 mg/2 is associated with severe neutropenia, gastro-intestinal side-effects and fluid retention in a significant proportion of patients, which may be of concern in more elderly or poor performance status patients. A phase I-II trial was carried out to test the feasibility and the activity of a new bimonthly schedule of DCT.

PATIENTS AND METHODS

The trial included a phase I study which aimed at the identification of dose-limiting toxicity (DLT) and maximal tolerated dose (MTD) of DCT on a bimonthly schedule. The first group of three patients received DCT 40 mg/m2, and in absence of DLT, DCT dosage was escalated by 10 mg/m2/cycle until DLT was reached. In the phase II study, patients were randomized to receive: (a) standard 3-weekly DCT at the dose of 75 mg/m2 (calibration arm); or (b) bimonthly schedule with DCT at the dose recommended in the phase I study. All patients were pretreated with chemotherapy, mostly anthracycline-based regimens, for advanced/metastatic disease. Analysis of response rates, toxicity, and dose-intensity were the main aims of the study.

RESULTS

The DLT was represented by severe myelosuppression which was recorded in all patients treated at 70 mg/m2 dose level. Therefore, the MTD was 60 mg/m2 on a bimonthly schedule. However, the dose recommended for the phase II trial was 50 mg/m2, because no difference in delivered dose-intesity was seen between the 50 and 60 mg/m2 dose levels, and the latter dosage was still associated with grade 3 neutropenia in most patients. The parallel phase II study showed that the bimonthly schedule of DCT (50 mg/m2) allows to deliver the same dose-intensity of DCT 75 mg/m2 every 3 weeks. Grade 3-4 side-effects were rather infrequent in patients treated with the bimonthly schedule. Overall response rate (ORR) was 41 and 44% for the DCT 50 mg/m2 bimonthly and the DCT 75 mg/m2 every 3 weeks, respectively.

CONCLUSIONS

Data achieved in the phase I part of the study showed that DCT 50 mg/m2 every 15 days is the recommended dose for phase II studies, while results achieved in the phase II trial suggest that DCT 50 mg/m2 in a bimonthly schedule is active as second-line chemotherapy for MBC being able to induce an ORR in the range reported for DCT 75-100 mg/m2 every 3 weeks. The bimonthly schedule is, however, associated with relatively low toxicity. This characteristic may render the bimonthly schedule particularly attractive for future phase II trials of DCT in combination with other antineoplastic agents.

Phase I study of eniluracil and oral 5-fluorouracil in combination with docetaxel in the treatment of patients with metastatic breast carcinoma

PURPOSE

The authors conducted a single-institution Phase I clinical trial to determine the maximum tolerated doses and to define the toxic effects of oral eniluracil and oral 5-fluorouracil (5-FU) combined with docetaxel in patients with metastatic breast carcinoma.

PATIENTS AND METHODS

Patients with metastatic breast carcinoma were eligible if they had disease progression after anthracycline-based therapy and had never been exposed to taxanes. The starting doses of oral eniluracil and oral 5-FU were 11.5 mg/m(2) and 1.15 mg/m(2), respectively, twice daily on Days 1-14. Docetaxel was given intravenously at a starting dose of 50 mg/m(2) on Day 1 only. The dose of docetaxel was escalated among cohorts until a maximum tolerated dose was reached. Courses were repeated every 21 days.

RESULTS

The authors treated 19 patients with Stage IV breast carcinoma, of whom 5 had received prior chemotherapy for their metastatic disease. Fifty-three percent had a performance status of 1, and 53% had bone or soft tissue involvement as the dominant site of disease. All patients had received prior therapy with doxorubicin. The dose-limiting toxicity was neutropenic fever. No episodes of sepsis were observed. Significant antitumor activity was observed with a total of two complete and nine partial responses. The recommended doses for Phase II studies are 72 mg/m(2) docetaxel on Day 1 and 10.0/1.0 mg/m(2) oral eniluracil/5-FU twice daily for a total of 14 days, with courses being repeated every 21 days.

CONCLUSIONS

The combination of oral eniluracil/5-FU and intravenous docetaxel is a safe and well tolerated regimen. Significant antitumor activity is associated with this combination.

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.

Docetaxel alone or orally combined with 5-fluorouracil and its derivatives: effects on mouse mammary tumor cell line MM2 in vitro and in vivo

Although docetaxel (Taxotere; TXT), a taxoid anticancer drug, is clinically and experimentally very effective against breast cancer, its antitumor effect is of very short duration. We addressed whether 5-fluorouracil (5-FU) and its derivatives can act synergistically with TXT against mammary tumors, with placing particular stress on their use by oral route. Mouse mammary tumor cell line, MM2, was propagated in culture and as ascites in mice. Carmofur (HCFU) and doxifluridine (5'-DFUR) were used as 5-FU derivatives. In vitro, the cytotoxic effects of antitumor drugs on MM2 cells were examined by MTS assay. In vivo, mice inoculated i.p. with MM2 cells were treated with i.p. injection of TXT and/or oral administration of 5-FU or its derivatives, and observed for curing tumor. In vitro, the synergistic effects were observed in the combination of TXT and 5-FU or HCFU, but not in that of TXT and 5'-DFUR. In vivo, all of these combinations cured tumors far more effectively than TXT alone. The discrepant result of the combination of TXT and 5'-DFUR between in vitro and in vivo was ascribed to up-regulation of pyrimidine phosphorylase in tumor cells in vivo by TXT. Thus, 5-FU, its masked compounds like HCFU and its prodrugs like 5'-DFUR can act synergistically with TXT in the therapy of cancer even when administered by the oral route.

Drug interactions with the taxanes: clinical implications

BACKGROUND

The taxanes paclitaxel and docetaxel are among the most active antitumor agents. Clinically important pharmacodynamic interactions have been reported to occur with these agents that are sequence or schedule dependent. Because the taxanes undergo hepatic oxidation via the cytochrome P450 system, pharmacokinetic interactions due to enzyme induction or inhibition can also occur.

METHODS

A comprehensive literature search was conducted using Medline to identify clinically important drug-interactions with the taxanes.

RESULTS

Clinically significant taxane interactions were identified for carboplatin, cisplatin, doxorubicin, docetaxel, epirubicin and anticonvulsants. Doxorubicin and epirubicin should be administered 24 h before paclitaxel, and the cumulative anthracycline dose limited to 360 mg/m(2). This will prevent the enhanced toxicities due to sequence and schedule dependent interactions between anthracyclines and paclitaxel. Conversely, paclitaxel should be administered at least 24 h before cisplatin to avoid a decrease in clearance and increase in myelosuppression. With concurrent anticonvulsant therapy, cytochrome p450 enzyme induction results in decreased paclitaxel plasma steady state concentrations, possibly requiring an increased dose of paclitaxel. A number of other drug interactions have been reported in preliminary studies for which clinical significance has yet to be established.

CONCLUSION

Clinically significant drug interactions have been reported to occur when paclitaxel is administered with doxorubicin, cisplatin, or anticonvulsants (phenytoin, carbamazepine, and phenobarbital).

Docetaxel in combination with 5-fluorouracil in patients with metastatic breast cancer previously treated with anthracycline-based chemotherapy: a phase I, dose-finding study

This phase I study evaluated the maximum tolerated dose, dose-limiting toxicity and recommended dose of docetaxel in combination with 5-fluorouracil (5-FU) in patients with metastatic breast cancer previously treated with anthracycline-based chemotherapy. 32 patients received docetaxel at 60, 75, 85 or 100 mg/m(2) by 1-h intravenous (i.v.) infusion, followed, after a 1-h interval, by 5-FU at 250, 350, 500 or 750 mg/m(2)/day by continuous infusion over 5 days every 3 weeks. Dose-limiting stomatitis defined the maximum tolerated dose at a docetaxel dose of 100 mg/m(2) with 5-FU 750 mg/m(2)/day. None of 5 patients treated at the previous dose level (docetaxel 85 mg/m(2) with 5-FU 750 mg/m(2)/day) had a dose-limiting toxicity in the first cycle, and this was, therefore, considered the recommended dose. The combination was generally well tolerated. Grade 4 neutropenia was common (29 patients; 91%), but no patient experienced febrile neutropenia of duration >3 days requiring i.v. antibiotics. An objective response was achieved by 18 patients overall (56%), and in 4 out of 5 patients treated with the determined recommended dose. No pharmacokinetic interaction between docetaxel and 5-fluorouracil was apparent. The activity of docetaxel 85 mg/m(2) with 5-fluorouracil 750 mg/m(2)/day will be explored more extensively in phase II studies of patients with metastatic breast cancer previously treated with anthracycline-based chemotherapy.

Role of taxoids in head and neck cancer

Docetaxel and paclitaxel represent a new class of cytotoxic agents having both a specific chemical structure and mechanism of action. They act to promote tubulin polymerization and the formation of stable microtubules. The microtubules produced in the presence of taxoids are resistant to disassembly by physiologic stimuli, and cells exposed to these agents exhibit an accumulation of disorganized microtubule arrays. This affects the normal mitotic process and eventually results in cell death. Both drugs are active as single agents in patients with head and neck cancer with response rates ranging from 20% to 40%. They may be combined with other cytotoxic agents, radiotherapy, or both. A review is given of the presently available data.