Sequence effect of epirubicin and paclitaxel treatment on pharmacokinetics and toxicity

Nicotinamide increases the sensitivity of chronic myeloid leukemia cells to doxorubicin via the inhibition of SIRT1

The NAD-dependent deacetylase Sirtuin 1 (SIRT1) plays a vital role in leukemogenesis. Nicotinamide (NAM) is the principal NAD⁺ precursor and a noncompetitive inhibitor of SIRT1. In our study, we showed that NAM enhanced the sensitivity of chronic myeloid leukemia (CML) to doxorubicin (DOX) via SIRT1. We found that SIRT1 high expression in CML patients was associated with disease progression and drug resistance. Exogenous NAM efficiently repressed the deacetylation activity of SIRT1 and induced the apoptosis of DOX-resistant K562 cells (K562R) in a dose-dependent manner. Notably, the combination of NAM and DOX significantly inhibited tumor cell proliferation and induced cell apoptosis. The knockdown of SIRT1 in K562R cells enhanced NAM+DOX-induced apoptosis. SIRT1 rescue in K562R reduced the NAM+DOX-induced apoptosis. Mechanistically, the combinatory treatment significantly increased the cleavage of caspase-3 and PARP in K562R in vitro and in vivo. These results suggest the potential role of NAM in increasing the sensitivity of CML to DOX via the inhibition of SIRT1.

A guide to clinically relevant drug interactions in oncology

This paper presents an overview of new information on clinically relevant drug-drug interactions, particular focuses on negative drug interactions in oncology. We have generated a concise table of drug-drug interactions that provides a synopsis of the clinical outcome of the interaction along with a recommendation for management. We have also generated other tables that describe specific interactions with methotrexate and dosing guidelines for cytotoxic drugs in the presence of renal or hepatic dysfunction. Since warfarin is one of the non-anticancer drugs that is commonly used in cancer patients for the treatment and prevention of venous thromboembolism, its interactions with other anticancer drugs that have been reported in literatures were also reviewed in this paper. In general, drug interactions observed in cancer patients may be categorized into pharmacokinetic, pharmacodynamic and pharmaceutic interactions. Pharmacokinetic interactions involve one drug altering the absorption, distribution, metabolism, or excretion of another drug. Interpatient variability in the pharmacokinetic profile of many anticancer agents often complicates the predictability of the antitumor response and toxicities. Among four pharmacokinetic characteristics, drug interactions involving hepatic metabolism is probably the most common and important mechanism responsible for oncologic drug interactions. For example, several anticancer drugs including taxanes, vinca alkaloids, and irinotecan are known to be metabolized by cytochrome CYP3A4. Enzyme-inducing anticonvulsants have been shown to significantly decrease the plasma levels of these anticancer drugs, thereby compromising the anti-tumor effects. N ephrotoxicity or changes in hepatic function caused by some anticancer drugs (e.g., cisplatin, asparaginase) may also have an impact on the pharmacokinetics of the interacting agents. Pharmacodynamic interactions may occur when two or more drugs acting at a common receptor-binding site impact on the pharmacologic action of the object drug, without influencing the pharmacokinetics of each interacting agent. In clinical setting, a decrease of antitumor efficacy was observed in breast cell lines when gemcitabine or vinorelbine were used in combination with paclitaxel. On the other hand, a decreased incidence of thrombocytopenia was seen in patients receiving combination of carboplatin and palcitaxel compared to those receiving carboplatin alone. The third type of drug-drug interaction is known as pharmaceutic interaction. When one drug may alter the physical or chemical compatibility of another drug that utlimately leads to a change in appearance of the solution or a decrease of effectiveness of the drug due to drug inactivation or degradation.

A comparative analysis on the efficacy and safety of intaxel® and taxol® in advanced metastatic breast cancer

BACKGROUND

Among the presently available cytotoxic drugs, paclitaxel, in combination with doxorubicin and carboplatin, come under the highly active therapy for metastatic breast cancer. Between the two brands of paclitaxel (Intaxel, which is marketed by Fresenius Kabi and Taxol, the original paclitaxel which is manufactured by BMS) the similarity has not been evaluated in clinical trial settings till date. This prospective, controlled, randomized, multicentre, open-label phase IV study was planned to compare the safety and efficacy of Intaxel with Taxol, when they were used in combination with carboplatin or doxorubicin, as a second line treatment for metastatic breast cancer.

METHODS

Fourty nine eligible patients were randomized to receive Intaxel or Taxol with either doxorubicin or carboplatin. The patients who had received a prior anthracycline based chemotherapy were randomized to the paclitaxel/carboplatin arm. The patients were evaluated in three phases i.e. at baseline, during the treatment and at follow up for the tumour response, the time period till the disease progression and the toxicity. The time till the disease progression was assessed by the Kaplan-Meier method. The continuous and categorical variables were assessed by using the ANOVA test and Fisher's exact test, respectively.

RESULTS

After 3 cycles, an objective response rate of 55.56% (CR = 3, PR = 7) was noted in the Intaxel group and that of 59.09% (CR = 1, PR = 12) was noted in the Taxol group. After 6 cycles, an objective response rate of 50% was noted in both the groups. No significant difference was observed in the response rate of the two groups after 3 cycles (p > 0.05) and at the end of the treatment (p > 0.05). The patients who received Intaxel had a lower incidence of thrombocytopaenia (p = 0.0146) and neurosensory loss (p = 0.008) as compared to those who received Taxol.

CONCLUSION

The results of this study demonstrated that the safety and efficacy of Intaxel and Taxol are equivalent when they are used in combination with other cytotoxic agents as the second line of treatment for metastatic stage IV breast cancer.

First-line treatment of advanced ovarian cancer with paclitaxel/carboplatin with or without epirubicin (TEC versus TC)--a gynecologic cancer intergroup study of the NSGO, EORTC GCG and NCIC CTG

BACKGROUND

The addition of anthracyclines to platinum-based chemotherapy may provide benefit in survival in ovarian cancer patients. We evaluated the effect on survival of adding epirubicin to standard carboplatin and paclitaxel.

PATIENTS AND METHODS

We carried out a prospectively randomized phase III study comparing carboplatin plus paclitaxel (TC; area under the curve 5 and 175 mg/m(2)) with the same combination and epirubicin (TEC; 75 mg/m(2) i.v.). Between March 1999 and August 2001, 887 patients with epithelial ovarian, tubal or peritoneal cancer International Federation of Gynecology and Obstetrics stages IIB-IV were randomized to receive either TC (442 patients) or TEC (445 patients).

RESULTS

Median time to progression was 16.4 months in the TEC arm and 16.0 months in the TC arm (hazard ratio 0.99; 95% confidence interval [CI]: 0.9-1.2). Median overall survival time was 42.4 months for the TEC arm and 40.2 for the TC arm (hazard ratio 0.96; 95% CI: 0.8-1.1). Grade 3/4 hematologic toxic effects and most grade 3/4 non-hematologic toxic effects were more frequent in the TEC arm. Accordingly, a quality-of-life analysis showed inferiority of TEC versus TC.

CONCLUSION

The addition of epirubicin to standard carboplatin and paclitaxel treatment did not improve survival in patients with advanced ovarian, tubal or peritoneal cancer.

Anti-apoptotic role of HIF-1 and AP-1 in paclitaxel exposed breast cancer cells under hypoxia

Background

Hypoxia is a hallmark of solid tumors and is associated with metastases, therapeutic resistance and poor patient survival.

Results

In this study, we showed that hypoxia protected MDA-MB-231 breast cancer cells against paclitaxel- but not epirubicin-induced apoptosis. The possible implication of HIF-1 and AP-1 in the hypoxia-induced anti-apoptotic pathway was investigated by the use of specific siRNA. Specific inhibition of the expression of these two transcription factors was shown to increase apoptosis induced by chemotherapeutic agents under hypoxia indicating an involvement of HIF-1 and AP-1 in the anti-apoptotic effect of hypoxia. After HIF-1 specific inhibition and using TaqMan Human Apoptosis Array, 8 potential HIF-1 target genes were identified which could take part in this protection. Furthermore, Mcl-1 was shown to be a potential AP-1 target gene which could also participate to the hypoxia-induced chemoresistance.

Conclusions

Altogether, these data highlight two mechanisms by which hypoxia could mediate its protective role via the activation of two transcription factors and, consecutively, changes in gene expression encoding different anti- and pro-apoptotic proteins.

A phase II randomised clinical trial comparing cisplatin, paclitaxel and ifosfamide with cisplatin, paclitaxel and epirubicin in newly diagnosed advanced epithelial ovarian cancer: long-term survival analysis

To test the feasibility and efficacy of epirubicin and ifosfamide added to first-line chemotherapy with cisplatin and paclitaxel in a phase II randomised clinical trial. Patients with histologically proven epithelial ovarian cancer were randomly assigned to receive first-line polychemotherapy with cisplatin/paclitaxel/epirubicin (CEP) or cisplatin/paclitaxel/ifosfamide (CIP) for six cycles every 21 days. Two hundred and eight patients were randomised between the two treatment arms and the median number of cycles per patient was six. Toxicity was predominantly haematological with both regimens; however, anaemia, leucopaenia, neutropaenic fever and use of granulocyte colony-stimulating factors and transfusion were significantly more frequent in the CIP treatment arm. Response rates were 85% (95% confidence interval (CI) 77–93%) in the CIP arm and 90% (95% CI 84–96%) in the CEP arm; complete response rates were 48 and 52%. After a median follow-up of 82 months, median overall survival (OS) was 51 and 65 months; 5-year survival rates were respectively 43 and 50%. In this clinical trial, both regimens showed good efficacy, but toxicity was heavier with the CIP regimen. Considering that more than 50% of patients were suboptimally debulked after the first surgery, OS seems to be longer than is commonly reported. This unexpected finding might be a consequence of the close surgical surveillance and aggressive chemotherapeutic approach.

Antiemetic care for patients with breast cancer: focus on drug interactions and safety concerns

PURPOSE

The drug interactions and adverse events that should be considered when individualizing antiemetic therapy for patients undergoing treatment for breast cancer are reviewed.

SUMMARY

A variety of antiemetic agents are available, including antihistamines, dopamine-receptor antagonists, serotonin-receptor antagonists, and neurokinin-receptor antagonists. To ensure optimal symptom control for each patient without unnecessarily prolonging treatment, patient- and treatment-specific risk factors must be considered. Neurokinin-receptor antagonists, the newest class of antiemetics, are effective in preventing acute and delayed chemotherapy-induced nausea and vomiting but must be used in combination with a serotonin-receptor antagonist and a corticosteroid. The serotonin-receptor antagonists have become the mainstay of antiemetic therapy, but current guidelines do not distinguish among the different agents in this class. However, there are distinct pharmacologic differences that may affect the potential for drug interactions and, ultimately, patient outcomes and the occurrence of adverse events. Therefore, the potential for drug interactions must be considered when selecting an antiemetic, particularly for patients who are taking multiple concomitant medications. Further, because a number of breast cancer therapies and some antiemetic agents carry cardiovascular warnings or precautions and since breast cancer patients may already be suffering from cardiovascular complications, the possible cardiotoxic effects of the antiemetic or chemotherapy agents or the combinations of these agents should be considered.

CONCLUSION

Antiemetic treatment is essential for patients with breast cancer who are undergoing moderately to highly emetogenic cytotoxic treatment. When selecting an antiemetic, clinicians must select an agent that provides optimal protection against nausea and vomiting while avoiding drug-drug interactions and additional adverse events.

Plasma and tissue pharmacokinetics of epirubicin and Paclitaxel in patients receiving neoadjuvant chemotherapy for locally advanced primary breast cancer

The objective of the study was to assess individual distribution of antineoplastic drugs into the tumor. Twelve advanced-stage primary breast cancer patients with neoadjuvant epirubicin+paclitaxel chemotherapy were studied. Plasma concentrations of epirubicin and paclitaxel were monitored for 24 h. Epirubicin concentrations in subcutaneous and tumor tissues were measured using microdialysis up to 12 h postdose. Epirubicin concentrations were described by a compartmental population pharmacokinetic model (NONMEM). Noncompartmental analysis was used for paclitaxel. Plasma pharmacokinetics corresponded to published data. Mean epirubicin exposure in the tumor and in subcutaneous tissue was very similar, but tissue Cmax and area under the curve values reached only (means) 1% and 11%, respectively, of plasma values. Epirubicin doses were significantly correlated to tumor exposure irrespective of body surface area. There is no specific barrier for epirubicin to reach primary breast cancer tumors.

Effect of Pregnancy on the Pharmacokinetics of Paclitaxel: A Case Report

Breast cancer during pregnancy is increasingly common as women delay childbearing until later in life. Safe administration of adjuvant chemotherapy during pregnancy has been reported. Physiologic and metabolic changes during pregnancy could alter the pharmacokinetics of these agents. This is a pilot study to prospectively study the pharmacokinetics of chemotherapeutic agents during pregnancy. Herein, we report the initial results with paclitaxel in the first patient.

Drug interactions in cancer therapy

Drug interactions in oncology are of particular importance owing to the narrow therapeutic index and the inherent toxicity of anticancer agents. Interactions with other medications can cause small changes in the pharmacokinetics or pharmacodynamics of a chemotherapy agent that could significantly alter its efficacy or toxicity. Improvements in in vitro methods and early clinical testing have made the prediction of potentially clinically significant drug interactions possible. We outline the types of drug interaction that occur in oncology, the mechanisms that underlie these interactions and describe select examples.

A phase I clinical and pharmacokinetic study of paclitaxel and docetaxel given in combination in patients with solid tumours

The aim of this study was to determine the safety and feasibility profile of paclitaxel (PTX) and docetaxel (DTX) in combination and the pharmacokinetic and pharmacodynamic interaction between these two drugs in two different alternated sequences of administration. The starting dose was PTX (100 mg/m(2)) as a 3-h IV infusion followed by DTX (50 mg/m(2)) as 1-h IV infusion or the alternative sequence in every other patient. The sequence was alternated in the second course in each patient treated. Cycle duration was 21 days. Twenty patients received 103 cycles of treatment through three dose levels. Febrile neutropenia and grade 4 neutropenia lasting longer than 7 days were dose-limiting and defined the toxic dose of DTX (50 mg/m(2)) and PTX (135 mg/m(2)) in patients with prior treatment and the recommended dose in patients without prior treatment. Non-hematological toxicities included asthenia, neuropathy, arthralgia/myalgia and stomatitis. Pharmacokinetics of DTX were significantly affected by the sequence. Nadir ANC was more profound when DTX was administered first (P=0.022). There were one complete response and six partial responses, giving an overall response rate of 35%. DTX (50 mg/m(2)) followed by PTX (135 mg/m(2)) can be administered safely and it is an active regimen. The pharmacokinetics of PTX are not influenced by DTX but DTX pharmacokinetics depend on the sequence of administration, which influences its haematological toxicity profile.

Drug–drug interactions in oncology: Why are they important and can they be minimized?

Adverse drug-drug interactions are a major cause of morbidity and mortality. Cancer patients are at particularly high risk of such interactions because they commonly receive multiple medications, including cytotoxic chemotherapy, hormonal agents and supportive care drugs. In addition, the majority of cancer patients are elderly, and so require medications for co-morbid conditions such as cardiovascular, gastrointestinal, and rheumatological diseases. Furthermore, the age-related decline in hepatic and renal function reduces their ability to metabolize and clear drugs and so increases the potential for toxicity. Not all drug-drug interactions can be predicted, and those that are predictable are not always avoidable. However, increased awareness of the potential for these interactions will allow healthcare providers to minimize the risk by choosing appropriate drugs and also by monitoring for signs of interaction. This review considers the basic principles of drug-drug interactions, and presents specific examples that are relevant to oncology.

Paclitaxel chemotherapy: from empiricism to a mechanism-based formulation strategy

Paclitaxel is an anticancer agent effective for the treatment of breast, ovarian, lung, and head and neck cancer. Because of water insolubility, paclitaxel is formulated with the micelle-forming vehicle Cremophor EL to enhance drug solubility. However, the addition of Cremophor EL results in hypersensitivity reactions, neurotoxicity, and altered pharmacokinetics of paclitaxel. To circumvent these unfavorable effects resulting from the addition of Cremophor EL, efforts have been made to develop new delivery systems for paclitaxel administration. For example, ABI-007 is a Cremophor-free, albumin-stabilized, nanoparticle paclitaxel formulation that was found to have significantly less toxicity than Cremophor-containing paclitaxel in mice. Pharmacokinetic studies indicate that in contrast to Cremophor-containing paclitaxel, ABI-007 displays linear pharmacokinetics over the clinically relevant dose range of 135-300 mg/m(2). In a phase III study conducted in patients with metastatic breast cancer, patients treated with ABI-007 achieved a significantly higher objective response rate and time to progression than those treated with Cremophor-containing paclitaxel. Together these findings suggest that nanoparticle albumin-bound paclitaxel may enable clinicians to administer paclitaxel at higher doses with less toxicity than is seen with Cremophor-containing paclitaxel. The role of this novel paclitaxel formulation in combination therapy with other antineoplastic agents needs to be determined.

Pharmacokinetic studies in children with cancer

We reviewed the current status of our knowledge of pharmacokinetics and pharmacodynamics of some anti-neoplastic drugs, used in the treatment of childhood cancer. Extrapolation of data from pharmacokinetic studies in adults to the paediatric population is often not feasible. Specific studies in children are needed. Of all reviewed anti-neoplastic drugs methotrexate appears to be most extensively studied. Methotrexate pharmacokinetics is correlated with toxicity and response to therapy, and it has been shown that individualized adaptive dosing of methotrexate is correlated with a better response to therapy without increasing toxicity in children with ALL and osteosarcoma. Of most of the other reviewed anti-neoplastic drugs it is demonstrated that pharmacokinetics is correlated with toxicity, and of some drugs a relationship of pharmacokinetics with response to therapy is demonstrated as well. In case of cytarabine, etoposide, and teniposide, individualized dosing also appears to be feasible. However, there is no evidence that this strategy improves response to therapy. Specifically data on pharmacokinetic and pharmacodynamic correlations and effect of pharmacokinetically guided, individualized dosing are important for the design of optimal cancer chemotherapy for individual patients. Unfortunately for a considerable number of anti-neoplastic drugs these specific data are lacking in children and future research is needed.

Pharmacokinetics of combined doxorubicin and paclitaxel in mice

Doxorubicin (DOX) has excellent antitumor activity when combined with paclitaxel (PTX) and this combination is used as first-line treatment for metastatic breast cancer. Results from clinical studies on pharmacokinetic interaction of these agents are not conclusive and pre-clinical studies are still needed. Pharmacokinetic studies were carried out in female Balb/c mice with combined DOX (6 mg/kg) and PTX (10 mg/kg) treatment. Combined treatment with PTX and DOX leads to alterations in the pharmacokinetics of both agents, with the predominant effect being elevated drug levels in liver and gut tissues. DOX levels in kidney and heart tissues were unaffected by concurrent PTX treatment. Further, plasma levels of DOX are not changed by concurrent PTX treatment suggesting that monitoring of plasma levels of DOX, when used in combination with another drug that is a P-glycoprotein (PGP) substrate, will not reflect actual pharmacokinetic changes occurring in other tissues.

Preclinical pharmacology of the taxanes: implications of the differences

Taxanes are one of the most powerful classes of compounds among all chemotherapeutic drugs. Only 30 years separate the isolation of the first taxane from the results of direct clinical comparisons in metastatic breast, ovarian, and lung cancer between the two taxanes available in routine clinical practice. These results suggest a more favorable benefit-to-risk ratio for docetaxel compared to paclitaxel when these drugs are used as single agents or in combination with other chemotherapeutic agents in an every-3-week dosing regimen. Pharmacological data support the difference between the taxanes, likely explaining the clinical results. Considering the molecular pharmacology of the two drugs, docetaxel appears to bind to beta-tubulin with greater affinity and has a wider cell cycle activity than paclitaxel. Docetaxel also appears to have direct antitumoral activity via an apoptotic effect mediated by bcl-2 phosphorylation. In addition, docetaxel has a longer retention time in tumor cells than paclitaxel because of greater uptake and slower efflux. Pharmacokinetics and pharmacodynamics of the taxanes show both agents to be extensively metabolized in the liver, and paclitaxel has a nonlinear pharmacokinetic behavior while docetaxel has linear pharmacokinetics. These differences explain the more simple treatment schedule and favorable results for docetaxel as a single agent and in combination therapy. Last, but not least, there is a pharmacokinetic interaction between paclitaxel and the anthracyclines, an active class of compounds commonly used in the treatment of breast cancer. This pharmacokinetic interaction is associated with greater cardio- and myelotoxicities, which are sequence dependent. These pharmacological data likely explain the different clinical development strategies for the two molecules as well as the different clinical results from individual trials and direct comparisons.

Pegylated liposomal doxorubicin hydrochloride (PLD) and paclitaxel in recurrent or metastatic head and neck carcinoma: a phase I/II study conducted by the Hellenic Cooperative Oncology Group (HeCOG)

A phase I pharmacokinetics and dose-finding study and a phase II study of the combination of pegylated liposomal doxorubicin HCl (PLD) and paclitaxel were conducted in patients with recurrent or metastatic head and neck cancer (HNC). Sixty patients with recurrent or metastatic disease were enrolled in the study: 11 patients in the phase I study and 49 patients in the phase II study. In the phase I study, the initial dose level of PLD was 35 mg/m as a 1-h infusion with escalating increments of 5 mg/m until the maximum tolerated dose (MTD) was reached. A fixed dose of paclitaxel (175 mg/m) was administered as a 3-h infusion. The combination was administered every 28 days. Pharmacokinetic studies performed on 10 patients indicated that the sequence of drug administration did not cause clinically significant modifications in the pharmacokinetics of either drug. The MTD for PLD was 45 mg/m (dose level 3) and the dose-limiting toxicity was febrile neutropenia, occurring in three of five patients. The phase II dose of PLD was 40 mg/m (dose level 2) and a total of 214 cycles were delivered. Grade 3 or 4 neutropenia was observed in 26% patients and febrile neutropenia occurred in 16% of patients. Grade 3 palmar-plantar erythrodysesthesia (PPE) was recorded in only one patient. The overall response rate was 28% for patients with non-nasopharyngeal tumors [95% confidence interval (CI) 15-45%] and 28.6% for the study population (95% CI 17-43%). The median survival for the study population was 9.7 months; 1-year survival was 38%. We conclude that the recommended dose for the combination of PLD and paclitaxel is 40 and 175 mg/m every 28 days, without granulocyte colony stimulating factor support. The combination of paclitaxel with PLD demonstrated activity in recurrent or metastatic HNC, a favorable toxicity profile and relative ease of administration.

Concomitant versus sequential administration of epirubicin and paclitaxel as first-line therapy in metastatic breast carcinoma

BACKGROUND

The authors performed a randomized trial comprising patients with metastatic breast carcinoma (MBC). They used a noninferiority design to evaluate whether the results of sequential administration of epirubicin and paclitaxel were not markedly worse than the concomitant administration in terms of objective response rates (ORRs). Toxicity profile, quality of life (QOL), and pharmacoeconomic evaluations were evaluated as well.

METHODS

In the current study, 202 patients with MBC were randomized to receive either the combination of epirubicin at a dose of 90 mg/m2 plus paclitaxel at a dose of 200 mg/m2 for 8 cycles (concomitant arm, n = 108) or epirubicin at a dose of 120 mg/m2 for 4 cycles followed by paclitaxel at a dose of 250 mg/m2 over 3 hours for 4 cycles every 21 days (sequential arm, n = 94).

RESULTS

The authors rejected the null hypothesis that the sequential treatment is less active than the standard concomitant regimen (ORRs: concomitant = 58.5%, sequential = 57.6%). The median progression-free and overall survival periods were 11.0 months (95% confidence interval [95% CI], 9.7-12.3) and 20.0 months (95% CI, 17.2-22.6), respectively, in the concomitant arm and 10.8 months (95% CI, 7.9-13.6) and 26 months (95% CI, 18.1-33.8), respectively, in the sequential arm (P = not significant). Patients who received the sequential regimen experienced a higher incidence of Grade 3/4 (according to the World Health Organization grading system) neutropenia (62.2% of courses vs. 50.62%; P = 0.003) and Grade > or = 2 neuropathy (45.5% vs. 30.4% of patients; P = 0.03), whereas 6 patients who received the concomitant regimen developed Grade II cardiotoxicity according to New York Heart Association criteria. QOL analyses failed to provide clear differences.

CONCLUSIONS

The sequential administration of epirubicin and paclitaxel at full doses was found to be as active as their association. Therefore, both the sequential and the combined administration were acceptable options.

Carboplatin plus paclitaxel combination chemotherapy: impact of sequence of drug administration on treatment-induced neutropenia

OBJECTIVE

While the importance of the sequence of administration of cisplatin and paclitaxel on the degree of observed neutropenia has been documented, there is limited information available in the oncology literature to determine whether there exists sequence-dependent toxicity for the combination of carboplatin plus paclitaxel.

METHODS

Patients with advanced gynecologic malignancies were randomized to receive either carboplatin (AUC 6), followed by paclitaxel (175 mg/m(2) over 3 h) (C-P), or the same doses of the agents delivered in the opposite sequence (P-C). The primary endpoint was the degree of neutropenia experienced during the initial treatment course.

RESULTS

A total of 40 patients (median age: 63) entered this trial, of whom 27 had complete pretreatment and nadir counts available for course 1 and 24 for both course 1 and course 2. By random chance, patients initially receiving P-C began therapy with a higher baseline ANC than those treated with C-P. During course 1, the P-C population was noted to have a greater reduction, from baseline, in ANC (P = 0.02), but no difference in absolute nadir counts (ignoring the baseline value) (P = 0.64). There was no difference between P-C, followed by C-P, versus C-P, followed by P-C in the severity of neutropenia experienced during course 2 (P = 0.38).

CONCLUSIONS

The sequence of carboplatin/paclitaxel administration does not exert a significant influence on the level of observed neutropenia. This finding leads to the suggestion that the sequence of drug delivery can be modified, as necessary, to satisfy unique requirements of individual patients and to establish the optimal drug delivery strategy of an innovative investigational treatment regimen.

First-line chemotherapy with epidoxorubicin, paclitaxel, and carboplatin for the treatment of advanced epithelial ovarian cancer patients

OBJECTIVE

A combination of carboplatin (CBDCA) and paclitaxel (TAX) is the standard treatment in advanced ovarian cancer (AOC) patients. Epidoxorubicin (EDX) is an active treatment in AOC and exhibits nonoverlapping toxicities with CBDCA and TAX; moreover, when added to platinum-based chemotherapy, it improves long-term survival. We have therefore conducted a phase II study to evaluate the tolerability and antitumor activity of an EDX/TAX/CBDCA (ETC) triplet in AOC patients.

METHODS

Patients with histologically confirmed suboptimal stage III-IV ovarian cancer who had not previously received cytotoxic drugs were treated with TAX (175 mg/m(2) in a 3-h iv infusion), CBDCA (AUC 6, Calvert formula), and EDX (75 mg/m(2) iv bolus) all given on day 1 every 28 days for a maximum of six courses on an outpatient basis. EDX dosage was chosen after a pilot phase I study.

RESULTS

Fifty-five patients were registered, of whom 5 were determined ineligible bacause of age. Forty-two of the 50 are evaluable for response; 27 (64%) achieved a clinical complete response (CR) and 9 (21%) a partial response (PR) for a response rate of 86% (95% CI 71-94%). Thirty-three patients underwent a secondary debulking procedure after a median of 6 courses (range 2-6). Pathological CR and PR were observed in 9 (27.3%) and 21 (63.6%), respectively; among patients with persistent disease a successful cytoreduction (<1 cm) was obtained in 53.8% of patients. At a median follow up of 35.6 months (range 0-55.5) median progression-free survival is 19.5 months and median overall survival is 36 months. The most common adverse effects were G3-4 leukopenia and thrombocytopenia which occurred in 59 and 37% of patients, respectively.

CONCLUSIONS

The ETC combination given according to the outlined doses and schedule is highly active in AOC patients with poor prognostic factors and deserves further study.

Docetaxel with epirubicin--investigations on cardiac safety

The aim was to evaluate clinical and subclinical cardiac toxicity of epirubicin-docetaxel (ET) combination. Breast cancer patients were given epirubicin (75 mg/m2 for 15 min), followed 1 h later by a 1-h infusion of docetaxel (75 mg/m2) q3w as first-line treatment. Cardiac function was monitored using a 24-h ambulatory electrocardiogram (ECG), left ventricular ejection fraction (LVEF), physical examination and chest radiography. The median LVEF did not decrease during the course of the treatment: median LVEF was 64% prior to treatment and 68% after cycle 8. The 24-h ECG did not reveal any significant changes in heart rate variability. The number of extrasystoles or cardiac arrhythmia did not increase with the ET treatment. No patient experienced congestive heart failure during treatment or the mean follow-up of 34 months. We conclude that first-line ET caused no major cardiac changes during 6 months of treatment (8 cycles) or during follow-up. Twenty-four-hour ECG, combined with echocardiography to measure LVEF, was a feasible method for the close monitoring of the cardiac effects during chemotherapy.

Phase I and pharmacokinetic study of docetaxel in combination with epirubicin and cyclophosphamide in advanced cancer: dose escalation possible with granulocyte colony-stimulating factor, but not with prophylactic antibiotics

BACKGROUND

The objective of this phase I trial was to determine the maximally tolerated doses of the combination of docetaxel, epirubicin and cyclophosphamide.

PATIENTS AND METHODS

Patients with advanced cancer, World Health Organization (WHO) performance status 0 to 2, who had received up to one prior chemotherapy regimen were treated with docetaxel, epirubicin and cyclophosphamide repeated every 21 days. The cyclophosphamide dose was fixed at 600 mg/m(2) and the dose levels studied were: docetaxel/epirubicin; 60/60, 75/60, 75/75, 75/90, 85/90 and 85/105 mg/m(2). There was provision for the addition of prophylactic ciprofloxacin and granulocyte colony-stimulating factor (G-CSF) in separate steps if dose-limiting toxicity (DLT) was neutropenia related.

RESULTS

Forty-three patients were entered and all were assessable for toxicity. Dose-limiting toxicity, predominantly febrile neutropenia, was surprisingly seen at the first dose level. The addition of prophylactic ciprofloxacin did not permit dose escalation, but dose escalation was possible with the addition of G-CSF. The highest administered dose level with G-CSF was docetaxel 85 mg/m(2) and epirubicin 105 mg/m(2) with DLTs in five of six patients. Treatment was well tolerated in 10 patients treated at the recommended dose level (85/90) with only one patient experiencing DLT. Responses were seen in a range of malignancies including breast and anaplastic thyroid cancers. No significant pharmacokinetic interaction was observed, but a transient increase in epirubicinol plasma concentration occurred during and after docetaxel infusion.

CONCLUSIONS

The recommended dose level of docetaxel 85 mg/m(2), epirubicin 90 mg/m(2) and cyclophosphamide 600 mg/m(2) with G-CSF support has a favorable toxicity profile and is suitable for further investigation in phase II and III trials.

Doxorubicin pharmacokinetics: Macromolecule binding, metabolism, and excretion in the context of a physiologic model

The studies described herein were designed to determine whether doxorubicin (DOX) pharmacokinetics (PKs) could be described by a physiologically based PK model that incorporated macromolecule-specific binding and organ-specific metabolism and excretion. Model parameters were determined experimentally, or were gathered from the literature, in a species-specific manner, and were incorporated into a physiologically based description of DOX blood and tissue distribution for mice, dogs, and humans. The resulting model simulation data were compared with experimentally determined data using PK parameters calculated using compartmental or noncompartmental analysis to assess the predictability of the models. The resulting physiologically based PK model that was developed could accurately predict blood and tissue PKs of DOX in mice. When this model was interspecies extrapolated to predict DOX levels in dogs and humans undergoing treatment for cancer, predictions in dog plasma or human serum were also consistent with the actual clinical data. This model has potential utility for predicting the magnitude of PK interactions of DOX with other drugs, and for predicting changes in DOX PKs in any number of clinical situations.

Gemcitabine, epirubicin and paclitaxel: pharmacokinetic and pharmacodynamic interactions in advanced breast cancer

BACKGROUND

The objectives of this study were to investigate the disposition of gemcitabine, epirubicin, paclitaxel, 2',2'-difluorodeoxyuridine and epirubicinol, and characterize the pharmacokinetic and pharmacodynamic profile of treatment in patients with breast cancer.

PATIENTS AND METHODS

The drug dispostion in 15 patients who received gemcitabine 1000 mg/m2, epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (GEP) on day 1 of a 21-day cycle, was compared with that of patients treated with epirubicin 90 mg/m2 and paclitaxel 175 mg/m2 (EP, n = 6) and epirubicin 90 mg/m2 alone (n = 6). Drug and metabolite levels in plasma and urine were assessed by high-performance liquid chromatography and parameters of drug exposure were related to hematological toxicity by a sigmoid-maximum effect (Emax) model.

RESULTS

Paclitaxel administration significantly increased the epirubicinol area under the concentration-time curve, from 357+/-146 (epirubicin) to 603+/-107 (EP) and 640+/-81 h x ng/ml (GEP), and reduced the renal clearance of epirubicin and epirubicinol by 38 and 52.2% and 34.5 and 53% in GEP- and EP-treated patients, respectively, compared with epirubicin alone. Gemcitabine had no apparent effect on paclitaxel and epirubicin pharmacokinetics, and renal clearance of epirubicin and epirubicinol. The only pharmacokinetic/pharmacodynamic relationship observed was between neutropenia and the time spent above the threshold plasma level of 0.1 micromol/l (tC0.1) of paclitaxel, with the time required to obtain a 50% decrease in neutrophil count (Et50) of GEP being 7.8 h, similar to that of EP.

CONCLUSIONS

Paclitaxel and/or its vehicle, Cremophor EL, interferes with the disposition and renal excretion of epirubicin and epirubicinol; gemcitabine has no affect on epirubicin and paclitaxel plasma pharmacokinetics and renal excretion of epirubicin, while neutropenia is not enhanced by gemcitabine.

Pharmacokinetics and pharmacodynamics of combination chemotherapy with paclitaxel and epirubicin in breast cancer patients

AIMS

To investigate the pharmacokinetics and pharmacodynamics of epirubicin and paclitaxel in combination, as well as the effects of paclitaxel and its vehicle Cremophor EL on epirubicin metabolism.

METHODS

Twenty-seven female patients with metastatic breast cancer received epirubicin 90 mg m-2 i.v. followed 15 min or 30 h later by a 3 h i.v. infusion of paclitaxel 175, 200 and 225 mg m-2. Plasma concentrations of paclitaxel, epirubicin and epirubicinol were measured and the relationship between neutropenia and drug pharmacokinetics was evaluated using a sigmoid maximum effect (Emax) model. Finally, the influence of paclitaxel and Cremophor EL on epirubicin metabolism by whole blood was examined.

RESULTS

An increase in epirubicinol plasma concentrations occurred after the start of the paclitaxel infusion, resulting in a significant increase in the area under the plasma concentration-time curve (AUC) of epirubicinol (+0.5 micromol l-1 h [95% CI for the difference: 0.29, 0.71],+0.66 micromol l-1 h [95% CI for the difference: 0.47, 0.85] and +0.82 micromol l-1 h [95% CI for the difference: 0.53, 1.11] at paclitaxel doses of 175, 200 and 225 mg m-2, respectively), compared with epirubicin followed by paclitaxel 30 h later (0.61+/-0.1 micromol l-1 h). A significant increase in epirubicin AUC (+0.74 micromol l-1 h [95% CI for the difference: 0.14, 1.34] and +1.09 micromol l-1 h [95% CI for the difference: 0.44, 1.74]) and decrease in drug clearance (CLTB) (-25.35 l h-1 m-2[95% CI for the difference: -50.18, -0.52] and -35.9 l h-1 m-2[95% CI for the difference -63,4,-8,36]) occurred in combination with paclitaxel 200 and 225 mg m-2 with respect to the AUC (3.16+/-0.6 micromol l-1 h) and CLTB (74.4+/-28.4 l h-1 m-2) of epirubicin followed by paclitaxel 30 h later. An Emax relationship was observed between neutropaenia and the time over which paclitaxel plasma concentrations were equal to or greater than 0.1 micromol l-1 (tC0.1). The tC0.1 value predicted to yield a 50% decrease in neutrophil count was 7.7 h. Finally, Cremophor EL markedly inhibited the metabolism of epirubicin to epirubicinol in whole blood.

CONCLUSIONS

Paclitaxel/Cremophor EL affects the disposition of epirubicinol and epirubicin. Furthermore, the slope factor of the Emax relationship between neutropenia and tC0.1 of paclitaxel suggests that the drugs might also interact at the pharmacodynamic level.

Influence of alternate sequences of epirubicin and docetaxel on the pharmacokinetic behaviour of both drugs in advanced breast cancer

BACKGROUND

Previously we observed a pharmacokinetic interference of epirubicin elimination when paclitaxel is given in combination in a sequence-dependent manner (i.e. when paclitaxel is administered as first drug). The aim of this study was to determine whether these sequence-dependent pharmacological effects were also evident when epirubicin was combined with docetaxel.

PATIENTS AND METHODS

Patients who received epirubicin 75 mg/m2 or 90 mg/m2 as an intravenous bolus followed immediately by docetaxel 70 mg/m2 or 80 mg/m2 over a 1-h infusion, or the opposite sequence, every 3 weeks were eligible for this study. The pharmacokinetics of docetaxel, epirubicin and its metabolites were studied at the first and second cycle of treatment. Pharmacokinetic data were normalised to the lower dose of each drug. Toxicity was recorded at nadir and graded according to National Cancer Institute Common Toxicity Criteria.

RESULTS

Twelve consecutive patients, each acting as their own control, entered the study. The sequence of drug administration of docetaxel and epirubicin did not affect the pharmacokinetics of the parent anthracycline. Statistically significant lower glucuronidation metabolism of epirubicin was observed in patients who received docetaxel before epirubicin. The pharmacokinetics of docetaxel were not influenced by the sequence of drug administration. No difference in haematological and non-haematological toxicity was observed in the two sequences of treatment.

CONCLUSIONS

The pharmacokinetics of the parent anthracycline and of docetaxel were similar between the two schemes of treatment. The metabolic variations observed, i.e. differences in the plasma levels of epirubicin glucuronides, seem not to have clinical relevance.

Systemic therapy

A large body of data on systemic therapy has been presented and published in the past year, including new information on primary risk reduction, patient selection for adjuvant systemic therapy, and anthracycline-analogs. New data on ongoing adjuvant trials (including taxane studies), unpublished updates from the fourth Oxford Overview in September 2000, and provocative data on ovarian ablation were important features of the November 2000 National Institutes of Health Consensus Development Conference on Adjuvant Therapy for Breast Cancer. Important new data on anti-estrogen therapy, including aromatase inhibitors and pure antiestrogens, further expand the role of the oldest targeted breast cancer therapy. Trastuzumab and other novel compounds are being investigated as single-agents and in combination with conventional systemic approaches. Discussions on the long-term effects of adjuvant therapy have taken center stage also. These and other important ongoing developments since 2000 are examined in this review article.

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).

A phase II study of sequential 5-fluorouracil, epirubicin and cyclophosphamide (FEC) and paclitaxel in advanced breast cancer (Protocol PV BC 97/01)

Sequential administration of the association of 5-fluorouracil, epirubicin and cyclophosphamide (FEC) and paclitaxel could be better tolerated than the association of an anthracycline and paclitaxel while having a similar antitumour effect. 69 patients with advanced breast cancer previously untreated with anthracyclines or paclitaxel entered a phase II multicentre study in which FEC was followed by paclitaxel. Both regimens were administered 4 times every 21 days. The median follow-up is 20 months and 38/69 patients have died. Grade III-IV toxicity was acceptable. Leukopenia occurred in 26% of patients, thrombocytopenia in 2% and anaemia in 4%. One patient had reversible heart failure during FEC therapy. Peripheral neuropathy and arthralgia-myalgia occurred in 9% and 4% of patients, respectively and one patient had respiratory hypersensitivity during paclitaxel treatment. 9 patients did not complete therapy because of: treatment refusal (n = 1), cardiac toxicity (n = 1), early death during FEC chemotherapy (n = 1), major protocol violations (n = 4), hypersensitivity reaction (n = 1) and early death during paclitaxel chemotherapy (n = 1). The overall response rate was 65% (95% CI = 53-76), and 7% of patients had stable disease. Therapy was defined as having failed in 28% of patients because they were not evaluable (13%) or had progressive disease (15%). The median time to progression and survival are 13.2 and 23.5 months, respectively. Sequential FEC-paclitaxel is a suitable strategy for patients with metastatic breast cancer who have not been previously treated with anthracyclines and/or taxanes. In fact, it avoids major haematologic toxicity and has a good antitumour effect.

Paclitaxel: epirubicin in metastatic breast cancer--a review

BACKGROUND

Treatment of metastatic breast cancer (MBC) with paclitaxel (T) and doxorubicin has yielded high response rates but the regimen is associated with significant cardiac toxicity. Epirubicin (E) is a less cardiotoxic anthracycline which has also been combined with paclitaxel in the treatment of MBC.

MATERIALS AND METHODS

This paper is a review of studies evaluating the pharmacokinetics, toxicity profile, and efficacy of the ET combination in MBC.

RESULTS

The ET combination has been studied extensively in Europe. The unique pharmacokinetics of the combination do not lead to the accumulation of cardiotoxic metabolites as in the case of the doxorubicin-paclitaxel combination. In terms of efficacy, the ET combination yields an overall response rate of 50%-70% and complete response rate (CR) 10%-15% in MBC in the same range as the more recent doxorubicin paclitaxel studies.

CONCLUSION

In summary the ET combination is safe and effective in MBC. It is less cardiotoxic than the doxorubicin paclitaxel combination. Further studies with ET in both the adjuvant setting and in MBC are in progress.

Clinical and pharmacologic study of the epirubicin and paclitaxel combination in women with metastatic breast cancer

PURPOSE

A pharmacokinetic interaction may cause increased cardiotoxicity of paclitaxel (PTX) and high cumulative dose of doxorubicin. We tested antitumor activity, tolerability, and pharmacokinetics of the lesser cardiotoxic epirubicin (EPI) and PTX (ET combination).

PATIENTS AND METHODS

Twenty-seven women with untreated metastatic breast cancer, median age of 56 years, and prominent visceral involvement (74%) were studied. Three-weekly EPI (90 mg/m(2)) and PTX (200 mg/m(2) over 3 hours) were given for a maximum nine cycles. EPI was administered 24 hours before PTX (E --> T) in cycle 1, and 15 minutes before PTX (ET) thereafter. EPI, epirubicinol (EOL), EPI-glucuronide (EPI-glu), EOL-glucuronide (EOL-glu), PTX, and 6alpha-OH-PTX were measured in plasma and urine in 14 women.

RESULTS

Patients received 205 cycles of ET and a median EPI dose of 720 mg/m(2). Grade 4 neutropenia (49% of cycles) was the most frequent toxicity. Cardiac contractility was decreased in five patients. Mild congestive heart failure occurred in two (7.4%). Response rate was 76% (28% complete). Median overall survival was 29 months. On the basis of intrapatient comparison in the first 24 hours of E --> T and ET cycles, PTX did not affect EPI disposition, but significantly increased plasma exposure to EOL (by 137%), EPI-glu (threefold) and EOL-glu (twofold). Urinary excretion of EPI dose went from 8.2% in E --> T to 11.8% in ET cycles. Clearance of PTX was 30% slower in ET than E --> T. ET cycles caused lower neutrophil nadir than E --> T (644 +/- 327 v 195 +/- 91, P <.05)

CONCLUSION

ET is feasible, devoid of excessive cardiac toxicity, and active. A reciprocal pharmacokinetic interference between the two drugs has pharmacodynamic consequences, and suggests a direct effect of PTX on EPI metabolism requiring ad hoc investigation.

The relevance of drug sequence in combination chemotherapy

The concept of combining chemotherapeutic agents to increase the cytotoxic efficacy has evolved greatly over the past several years. In the past, the rationale for combination chemotherapy centered on attacking different biochemical targets, overcoming drug resistance in heterogenous tumors, and increasing the dose-density of combination chemotherapy to take advantage of tumor growth kinetics. The overall goal was to improve clinical efficacy with acceptable clinical toxicity. It is now apparent that the sequence of drug administration can significantly enhance the therapeutic effect of chemotherapy. These sequence-dependent effects can be explained by chemotherapy-induced cell cycle perturbations, or by pharmacodynamic interactions between the agents in combination. In this review, we focus on drug combinations with taxanes and camptothecins, which we believe best illustrate the importance of the cell cycle and pharmacologic interactions in the sequential administration of chemotherapy. As our understanding of the cell cycle grows, our ability to appropriately sequence chemotherapy can have a great impact on the treatment of human cancers. Copyright 2000 Harcourt Publishers Ltd.