Pharmacokinetics of ifosfamide are changed by combination with docetaxel: results of a phase I pharmacologic study

Drug-Drug Interactions in Prostate Cancer Treatment

Polypharmacy is associated with an increased risk of drug-drug interactions (DDIs), which can cause serious and debilitating drug-induced adverse events. With a steadily aging population and associated increasing multimorbidity and polypharmacy, the potential for DDIs becomes considerably important. Prostate cancer (PCa) is the most common cancer in men and occurs mostly in elderly men in the Western world. Therefore, the aim of this review is to give an overview of DDIs in PCa therapy to better understand pharmacodynamic and pharm kinetic side effects as well as their interactions with other medications. Last, we explore potential future strategies, which might help to optimize treatment and reduce adverse events patients with polypharmacy and PCa.

Standardization of the infusion sequence of antineoplastic drugs used in the treatment of breast and colorectal cancers

The definition of antineoplastic administration sequences can help planning of therapeutic regimens in a more rational way, and thus optimize chemotherapy effects on patients, increasing efficacy and reducing toxic effects. In this way, this study aimed to evaluate the infusion order of antineoplastic agents of the main therapeutic protocols used in the treatment of colorectal and breast cancer which are used in a tertiary hospital, identifying possible interactions dependent on the infusion sequence. For the definition of protocols adopted in the hospital, medical prescriptions were used in the period of January to March 2016 and a literature review was conducted to search for studies assessing the sequence of administering the selected regimens. The databases used were SciELO, LILACS and MEDLINE, in addition to Micromedex Solutions® and UpToDate®. A total of 19 protocols were identified for antineoplastic therapy, 11 for colorectal cancer and 8 for breast cancer. The selected articles provided evidence for administration order of 19 protocols, and three protocols did no report relevance of infusion sequence. Sequence-dependent interactions were mainly related to toxicity, pharmacokinetics and efficacy of the drug combination. The definition of the infusion sequence has a great impact on the optimization of therapy, increasing efficacy and safety of the protocols containing combined antineoplastic therapies.

Docetaxel for the treatment of bladder cancer

INTRODUCTION

Docetaxel has had a significant impact on the management of urothelial carcinoma (UC). Multiple phase II trials have been conducted to evaluate the efficacy of docetaxel in the treatment of metastatic UC. Docetaxel is an accepted community standard for the therapy of platinum-treated patients with metastatic UC.

AREAS COVERED

This review focuses on the data supporting a role for docetaxel in the therapy of advanced UC. It also explores the future development of docetaxel and describes the ongoing clinical trials in the treatment of UC.

EXPERT OPINION

Docetaxel plays an important role as one of the standard agents used in the comparator arms of randomized trials evaluating new agents as salvage therapy for metastatic UC. Furthermore, biologic agents are being developed in chemo-biologic regimens using docetaxel as the platform. In the context of emerging novel agents such as T-cell checkpoint inhibitors, docetaxel may continue to play a role as a salvage therapy in select patients ineligible for immunotherapy or following checkpoint inhibitors.

Inter-patient variability in docetaxel pharmacokinetics: A review

Docetaxel is a frequently used chemotherapeutic agent in the treatment of solid cancers. Because of the large inter-individual variability (IIV) in the pharmacokinetics (PK) of docetaxel, it is challenging to determine the optimal dose in individual patients in order to achieve optimal efficacy and acceptable toxicity. Despite the established correlation between systemic docetaxel exposure and efficacy, the precise factors influencing docetaxel PK are not yet completely understood. This review article highlights currently known factors that influence docetaxel PK, and focusses on those that are clinically relevant. For example, liver impairment should be taken into account when calculating docetaxel dosages as this may decrease docetaxel clearance. In addition, drug-drug interactions may be of distinct clinical importance when using docetaxel. Particularly, drugs strongly inhibiting CYP3A4 such as ketoconazole should not be concurrently administered without dose modification, as they may decrease the clearance of docetaxel. Gender, castration status, and menopausal status might be of importance as potential factors influencing docetaxel PK. The role of pharmacogenetics in predicting docetaxel PK is still limited, since no polymorphisms of clinical importance have yet been established.

Docetaxel-Ifosfamide Combination in Patients with Advanced Breast Cancer Failing Prior Anthracycline- Based Regimens: Results of a Phase I-II Study

The established clinical activity of docetaxel and ifosfamide as single agents in anthracycline pre-treated breast cancer, led us to conduct a phase I-II study to define the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and clinical activity of the docetaxel+ifosfamide combination in this setting. Patients with histologically confirmed metastatic breast cancer, after failure on prior anthracycline-based chemotherapy, were treated at successive dose levels (DLs) in cohorts of 3-6 with escalated doses of docetaxel 70-100 mg/m(2) over 1 h on day 1 followed by ifosfamide 5-6 g/m(2) divided over days 1+2 (2.5-3.0 g/m(2)/day over 1 h), every 21 days. G-CSF was added once dose-limiting neutropenia was encountered at a certain DL and planned to be incorporated prophylactically in subsequent higher DLs. Between March 1997 and December 2002, 65 patients with a median age of 57 years (range, 32-72) and performance status (WHO) of 1 (range, 0-2) were treated at 5 DLs as follows; 21 in phase I DLs (DL1: 3, DL2: 6, DL3: 3, DL4: 6, and DL5: 3) and the remaining 44 were treated at DL4 (total of 50 patients at DL4), which was defined as the level for phase II testing. All patients were assessable for toxicity and 62 for response. DLT (with the addition of G-CSF after DL2) was reached at DL5 with 2/3 initial patients developing febrile neutropenia. Clinical response rates (RRs), on an intention-to-treat basis, in phase II were: 56%; (95% CI, 42.2-69.7%); 4 CRs, 24 PRs, 10 SD and 12 PD. The median response duration was 7 mo (3-24 mo), median TTP 6.5 mo (0.1-26 mo), and median OS 13 mo (0.1-33 mo). Grade 3/4 toxicities included: neutropenia in 72% of patients, with 60% developing grade 4 neutropenia (<or=7 days) and in 10% of these febrile neutropenia, while no grade 3/4 thrombocytopenia was observed. Other toxicities included peripheral neuropathy grade 2 only in 10%, grade 1/2 reversible CNS toxicity in 16%, no renal toxicity, grade 2 myalgias in 8%, grade 3 diarrhea in 8%, skin/nail toxicity in 14%, and grade 2 fluid retention in 2% of patients. One patient in the study treated at phase II died as a result of acute liver failure after the first cycle. The present phase I-II study has determined the feasibility, defined the MTD and demonstrated the encouraging activity of the docetaxel-ifosfamide combination in the phase II part of the study. Therefore, future randomized phase III studies versus single-agent docetaxel or combinations of the latter with other active agents are warranted.

Docetaxel, ifosfamide and cisplatin in solid tumour treatment: a phase I study

Docetaxel, ifosfamide and cisplatin have proven activity in a broad range of solid tumours and interfere with different phases of the cell cycle. We performed a phase I study with the aim to determine the maximum tolerated dose (MTD) of docetaxel, ifosfamide and cisplatin in patients with solid tumours and to define the safety, dose-limiting toxicity (DLT) and the recommended dose and administration schedule of docetaxel, ifosfamide and cisplatin for further phase II testing. Docetaxel was given by 1-h infusion on day 1, followed by ifosfamide 1000 mg/m(2)/day as a continuous infusion for 5 days. Mesna was added at the same doses to the same infusion bag and was continued for 12 h after the end of ifosfamide. Cisplatin was administered as a 24-h infusion concomitantly with ifosfamide, but in separate infusion bags, either on day 5 (schedule A) or on day 1 (schedule B). Escalation steps were planned only for docetaxel (60, 75, 85 mg/m(2)) and cisplatin (50, 75, 100 mg/m(2)). No intrapatient dose escalation was permitted. Prophylactic ciprofloxacin was used after a protocol amendment was implemented. No prophylactic haematopoietic growth factors were used. Cycles of docetaxel, ifosfamide and cisplatin were given at 3-week intervals. Toxicity was scored according to National Cancer Institute Canada-Common Toxicity Criteria 2. The MTD was defined as the dose at which a DLT was observed in fewer than two of six patients during the first treatment cycle. In total, 85 patients received 309 cycles. Only three escalation steps could be explored and DLTs were observed at each dose level. In total, 32 patients and 49 cycles showed DLTs. Febrile neutropenia occurred in 20 patients (24%). Only two DLTs were nonhaematological (one cerebral infarction and one encephalopathy grade 4). Neutropenia grade 4 lasted for greater than 7 days and/or thrombocytopenia grade 4 was dose limiting in 10 patients. Febrile neutropenia occurred in five of 41 patients (12%) who received prophylactic ciprofloxacin and in 15 of 44 patients (34%) who did not. MTD was reached at level 3 (docetaxel, 75 mg/m(2) and cisplatin, 75 mg/m(2)). With a lower dose of docetaxel (60 mg/m(2)) both schedules A and B were feasible, although, overall, schedule A seemed to be better tolerated. On the basis of this phase I study, the recommended docetaxel, ifosfamide and cisplatin regimen is docetaxel (60 mg/m(2)) on day 1, ifosfamide (1000 mg/m(2)/day) on days 1-5 and cisplatin (75 mg/m(2)) given on day 5. It is associated with substantial haematological toxicity, but this is feasible provided prophylactic antibiotics are used.

Docetaxel–ifosfamide combination in patients with HER2-non-overexpressing advanced breast cancer failing prior anthracyclines

The feasibility of the docetaxel-ifosfamide combination, as well as the definition of maximum tolerated doses (MTD) in a previous phase I study, led us to continue evaluating the regimen in an extended phase II study in patients with HER2-non-overexpressing, anthracycline pre-treated advanced breast cancer. Patients with histologically confirmed metastatic breast cancer failing prior anthracycline-based chemotherapy were treated with docetaxel 100 mg/m2 over 1 h on day 1 followed by ifosfamide 5 g/m2 divided over days 1 and 2 (2.5 g/m2/day over 1 h), and recycled every 21 days with prophylactic granulocyte-colony stimulating factor (G-CSF) administration from day 3-until a neutrophil count >10,000/microl. Between March 1999 and June 2002, 71 patients with a median age of 55 years (range, 28-72) and performance status (World Health Organization; WHO) of 1 (range, 0-2) were treated; all were assessable for toxicity and 70 patients for response. Clinical response rates (RRs), on an intention-to-treat basis were: 41/71 [58%; 95% CI, 46.5-69.5%]; 7 complete remissions (CRs), 34 partial remissions (PRs), 15 stable disease (SD) and 15 progressive disease (PD). The median response duration was 7.5 months (2-28 months), median time-to-progression (TTP) 6 months (0.1-30 months), and median overall survival (OS) 12 months (0.1-36 months). Grade 3/4 toxicities included; neutropenia in 63% of patients-with 52% developing grade 4 neutropenia (>or=7 days) and in 11% of these febrile neutropenia (FN), while no grade 3/4 thrombocytopenia was observed. Other toxicities included; peripheral neuropathy grade 2 only in 7%, grade 1/2 reversible central nervous system (CNS) toxicity in 11%, no renal toxicity, grade 2 myalgias in 7%, grade 3 diarrhea in 4%, skin/nail toxicity in 11%, and grade 1/2 fluid retention in 28% of patients. The present report has demonstrated encouraging activity of the docetaxel-ifosfamide combination in anthracycline-pretreated, HER2-negative advanced breast cancer. Therefore, future randomized phase III studies versus single-agent docetaxel or currently established combinations of the latter with other agents in this setting with established clinical activity, such as capecitabine or gemcitabine, will be warranted.

Clinical pharmacokinetics of docetaxel : recent developments

Docetaxel belongs to the class of taxane antineoplastic agents that act by inducing microtubular stability and disrupting the dynamics of the microtubular network. The drug has shown a broad spectrum of antitumour activity in preclinical models as well as clinically, with responses observed in various disease types, including advanced breast cancer and non-small cell lung cancer. The pharmacokinetics and metabolism of docetaxel are extremely complex and have been the subject of intensive investigation in recent years. Docetaxel is subject to extensive metabolic conversion by the cytochrome P450 (CYP) 3A isoenzymes, which results in several pharmacologically inactive oxidation products. Elimination routes of docetaxel are also dependent on the presence of drug-transporting proteins, notably P-glycoprotein, present on the bile canalicular membrane. The various processes mediating drug elimination, either through metabolic breakdown or excretion, impact substantially on interindividual variability in drug handling. Strategies to individualise docetaxel administration schedules based on phenotypic or genotype-dependent differences in CYP3A expression are underway and may ultimately lead to more selective chemotherapeutic use of this agent.

Docetaxel in the treatment of breast cancer: current experience and future prospects

It has become clear over the past 10 years that docetaxel, a semisynthetic taxoid antineoplastic agent, is among the most promising compounds to have been developed in the 1990s for the treatment of breast cancer. Data indicate that this drug became standard therapy in the treatment of patients with metastatic disease who have failed anthracycline treatment, and secondarily showed very encouraging results in the first-line metastatic setting either in monochemotherapy or when docetaxel was combined with an anthracycline. More recently, docetaxel also became one of the standard therapies in the adjuvant and neoadjuvant settings, and a promising partner for novel biologic therapies. Current research is further exploring the effect of docetaxel on outcome of early breast cancer in order to fully determine the extent that this chemotherapeutic agent will change the natural history of breast cancer.

Pharmacology of Ifosfamide

Ifosfamide is a bifunctional alkylating agent, used as a racemic mixture by intravenous route in the treatment of various tumors. It is an oxazaphosphorine derivative with a structural formula similar to that of cyclophosphamide. As a prodrug it requires activation in the liver by a cytochrome mixed-function oxidase system. Among various metabolites, ifosforamide mustard probably represents the most important cytotoxic compound able to produce irreparable cross-links between DNA strands. Resistance is due to the ability of neoplastic cells to repair DNA damages. Acrolein may induce hemorrhagic cystitis, whereas chloroacetaldehyde may be responsible both for nephro- and neurotoxicity. A thiol donor (mesna) can prevent urotoxic effects but not nephro- and neurotoxicity. Pharmacokinetics is markedly influenced by route of administration and duration of treatment, age, co-medication, liver and renal function.

Side Effects of Ifosfamide

Ifosfamide is relatively well tolerated but it can be associated occasionally with life-threatening complications such as arrhythmias and heart failure, severe encephalopathy and hemorrhagic cystitis. Mesna administration can control the urothelial toxicity of ifosfamide, but it is without effect on the other complications. Other preventive measures, such as amifostine or methylene blue administration, have not yet been adequately evaluated in a sufficient number of patients. Clinicians prescribing ifosfamide, especially in high doses, should be watchful for early signs of toxicity in order to discontinue ifosfamide administration soon enough to avoid development of major toxicity.

Phase I-II study of docetaxel and ifosfamide combination in patients with anthracycline pretreated advanced breast cancer

Given the established individual activity of docetaxel and ifosfamide in anthracycline pretreated advanced breast cancer, the present phase I-II study aimed to define the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), and activity of the docetaxel-ifosfamide combination in this setting. Cohorts of three to six patients with histologically confirmed metastatic breast cancer after prior anthracycline-based chemotherapy were treated at successive dose levels (DLs) with escalated doses of docetaxel 70-100 mg x m(-2) over 1 h on day 1 followed by ifosfamide 5-6 g x m(-2) divided over days 1 and 2 (2.5-3.0 g x m(-2) day(-1) over 1 h), and recycled every 21 days. G-CSF was added once dose-limiting neutropenia was encountered at a certain DL and planned to be incorporated prophylactically in subsequent higher DLs. In total, 56 patients with a median age of 54.5 (range, 32-72) years and performance status (WHO) of 1 (range, 0-2) were treated at five DLs as follows: 21 in phase I DLs (DL1: 3, DL2: 6, DL3: 3, DL4: 6, and DL5: 3) and the remaining 35 were treated at DL4 (total of 41 patients at DL4), which was defined as the level for phase II testing. All patients were assessable for toxicity and 53 for response. Dose-limiting toxicity (with the addition of G-CSF after DL2) was reached at DL5 with two out of three initial patients developing febrile neutropenia (FN). Clinical response rates, on an intention-to-treat basis, in phase II were: 53.6% (95% CI, 38.3-68.9%); three complete remissions, 19 partial remissions, seven stable disease, and 12 progressive disease. The median response duration was 7 months (3-24 months), median time to progression 6.5 month (0.1-26 month), and median overall survival 13 months (0.1-33 months). Grade 3/4 toxicities included time to progression neutropenia in 78% of patients-with 63% developing grade 4 neutropenia (<or=7 days) and in 12% of these FN, while no grade 3/4 thrombocytopenia was observed. Other toxicities included peripheral neuropathy grade 2 only in 12%, grade 1/2 reversible CNS toxicity in 17%, no renal toxicity, grade 2 myalgias in 10%, grade 3 diarrhoea in 10%, skin/nail toxicity in 17%, and grade 2 fluid retention in 2% of patients. One patient in the study treated at phase II died as a result of acute liver failure after the first cycle. In conclusion, the present phase I-II study determined the feasibility of the docetaxel-ifosfamide combination, defined the MTD and demonstrated the encouraging activity of the regimen in phase II, thus warranting further randomised phase III comparisons to single-agent docetaxel or combinations of the latter with other active agents.

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).