Population pharmacokinetics/pharmacodynamics of docetaxel in phase II studies in patients with cancer

Liquid chromatographic analysis and preliminary pharmacokinetics of methotrexate in cancer patients co-treated with docetaxel

A new HPLC method has been developed for the quantitative determination of methotrexate (MTX) and its 7-hydroxyl metabolite in human plasma. Samples were purified by protein precipitation with acetone and methanol, and a sample clean-up with a mixture of n-butanol and diethyl ether. The analytes were separated on an RP Inertsil ODS-80A column and eluted in a solvent system containing 5% (v/v) tetrahydrofuran in water (pH 2.0). UV absorption measurement was performed at 313 nm, and the detector response was linear in a concentration range of 10-10,000 ng/ml. The lower limit of quantitation of MTX was 10 ng/ml using 1 ml sample aliquots. Values for accuracy and (within-run and between-run) precision were between 95.5-111% and 3.69-11.0%, respectively, at four concentrations analyzed in quintuplicate on four separate occasions. The assay was applied to study the effects of docetaxel co-administration on the pharmacokinetics and metabolism of MTX in cancer patients.

Efficacy and safety of docetaxel (Taxotere) in heavily pretreated advanced breast cancer patients: the French compassionate use programme experience

The aim of this investigation was to assess retrospectively docetaxel safety and efficacy in advanced breast cancer patients in a French compassionate use programme. Patients had received > 1 prior chemotherapy regimen for advanced disease, were either anthracycline-resistant (that is progressed within 6 months after anthracycline-based chemotherapy) or had received the maximum cumulative dose. The recommended docetaxel dose was 100 mg/m2/cycle (75 mg/m2 in case of liver function impairment: transaminases > 1.5 x upper limit of normal (ULN), alkaline phosphatases > 3 x ULN). Between August 1993 and December 1995, 889 patients were treated in 67 French centres, of whom 870 were evaluable for safety and 825 were evaluable for patient and treatment characteristics and efficacy. 20.5% (of the 825 patients evaluable for baseline characteristics) had poor performance status (PS > or = 2), 49.3% liver metastasis and 9.6% biological liver dysfunction. 98.4% had been previously treated by anthracyclines, 50.8% had resistant disease and 37.1% had received > 2 prior palliative chemotherapy lines. The most frequent severe toxicity, febrile neutropenia (reported in 223/870 (25.6%) patients evaluable for safety), caused 10 deaths, 6 of these being patients with severe liver impairment before inclusion. Fluid retention syndrome and other common non-haematological toxicities were well tolerated. 3.1% (28/889) of all patients and 11.4% of those with liver dysfunction, died from treatment-related causes. The overall response rate in 825 assessable patients was 22.9% (95% confidence interval (CI): 20.2-26.2%). Median time to treatment failure was 4 months (95% CI: 3.6-4.3) and median survival was 9.8 months (95% CI: 8.8-10.7). This report on the largest series of unselected advanced breast cancer patients treated with docetaxel, supports previous phase II studies, confirming docetaxel's utility in patients relapsing after failing anthracycline-containing palliative chemotherapy.

A phase II study of docetaxel in patients with metastatic squamous cell carcinoma of the head and neck

This study was designed to evaluate the activity, safety and tolerance of docetaxel (D) in a selected population with metastatic squamous cell carcinoma of the head and neck (SCCHN). Twenty-four patients with no prior palliative therapy were enrolled and received D 100 mg m(-2) by 1 h of infusion, every 3 weeks. All but two patients had been evaluated for efficacy on lung metastatic sites. No prophylactic administration of anti-emetics or growth factors was given. A pharmacokinetic study was performed in 22 patients. Twenty-one patients were assessable for response and 24 for toxicity. One hundred and four cycles were administered with a median of 4.5 (range 1-9) per patient. The median cumulative dose was 449 mg m(-2). Partial responses were achieved in five patients with a median duration of 18.7 weeks (range 13.1-50.3). The overall response rate was 20.8% with a median duration of 11.0 weeks (range 2.4-52.6). The most frequent side-effect was neutropenia (79.2% grade IV) but with a short duration (median 4 days) and no febrile neutropenia. The incidence of moderate/severe fluid retention was 29.2% with one treatment discontinuation. Other toxicities (all grades) were common (skin 75%, asthenia 50%, infection 29.2%, nausea 16.7%, diarrhoea 12.5%, stomatitis 16.7%, vomiting 8.3% and HSR 8.3%). A mean clearance of 19.6 l h(-1) m(-2) and an area under the curve of 6.00 microg ml(-1) h(-1) was found in the pharmacokinetic analysis. Docetaxel is active in this selected population with metastatic SCCHN, with a good tolerance.

Docetaxel compared with sequential methotrexate and 5-fluorouracil in patients with advanced breast cancer after anthracycline failure: a randomised phase III study with crossover on progression by the Scandinavian Breast Group

The aim of this study was to compare the efficacy and tolerability of docetaxel to methotrexate and 5-fluorouracil in advanced breast cancer after anthracycline failure. A randomised multicentre trial was conducted in 283 patients with advanced breast cancer who had failed previous anthracycline treatment. Docetaxel at a dose of 100 mg/m2 every 3 weeks (n = 143) was compared with sequential methotrexate and 5-fluorouracil (MF; n = 139) given at day 1 and 8 every 3 weeks at dosages of 200 mg/ m2 and 600 mg/m2, respectively. After progression, crossover to the alternative treatment group was recommended. There was a significantly higher overall response rate in the docetaxel 42% (CR 8% + PR 34%) than in the MF arm 21% (CR 3% + PR 18%) (P < 0.001). The median time to progression (TTP) was 6.3 months in the docetaxel arm and 3.0 months in the MF arm (P < 0.001). Docetaxel also had a significantly higher response rate of 27% following crossover compared with MF (12%). Significantly more side-effects (leucopenia, infections, neuropathy, oedema, asthenia, skin, nail changes, alopecia) were seen in the docetaxel than in the MF group. However, grade 3 and 4 side-effects were infrequent with both drugs, with the exception of fatigue, alopecia and infections. Median overall survival (OS) including crossover phase was 10.4 months in the docetaxel and 11.1 months in the MF arm (P = 0.79). Based on the response rate and the primary endpoint of TTP, docetaxel is superior to sequential methotrexate and 5-fluorouracil in advanced breast cancer after anthracycline failure.

Weekly docetaxel in minimally pretreated cancer patients: a dose-escalation study focused on feasibility and cumulative toxicity of long-term administration

BACKGROUND

Docetaxel is an agent with impressive clinical activity but a rather poor profile of toxicity when given every three weeks. Therefore, optimisation of its clinical use is highly warranted. This is a dose-escalation study of weekly docetaxel particularly focused on the feasibility of long-term administration and characterisation of cumulative toxicity.

PATIENTS AND METHODS

Twenty-six patients (11 female/15 male, median age 56, range 23-73) were treated over the range of 25-50 mg/m2/week. Dose-limiting toxicity for this schedule was defined as any grade > 2 antiproliferative toxic effect resulting in a > 2-week delay for re-administration of the drug, or any grade > 2 organ-specific toxicity. Patients were monitored clinically and electrophysiologically for neurotoxicity. No prolonged corticosteroid co-medication or prophylactic haematopoietic growth factors were given.

RESULTS

A median/mean number of 8.5/8.7 consecutive weekly courses were given per patient. The maximum tolerated dose that prevented on-schedule administration of the drug was 50 mg/m2. The main cumulative toxicities were a mild fluid retention and dacryorrhea which became evident as the number of treatment courses increased. Grade 2 alopecia and fatigue were observed only at 45 mg/m2 and higher. Activity was seen at all of the dose levels studied.

CONCLUSIONS

Long-term weekly administration of docetaxel is feasible at doses up to 45 mg/m2/week with acceptable toxicity. Further clinical evaluation is justified at this schedule and 40 mg/m2/week of docetaxel is proposed for phase II studies as an active dose with minimal toxicity.

Comparative effects of paclitaxel and docetaxel on the metabolism and pharmacokinetics of epirubicin in breast cancer patients

PURPOSE

To investigate whether paclitaxel and docetaxel influence the pharmacokinetics and metabolism of epirubicin.

PATIENTS AND METHODS

We studied the pharmacokinetics and biotransformation patterns of epirubicin in 27 cycles and 20 breast cancer patients. Four patients received epirubicin alone 90 mg/m(2) by intravenous (IV) bolus; eight patients received the same dose of epirubicin followed immediately by paclitaxel 175 mg/m(2) in a 3-hour infusion; the other eight patients received epirubicin 90 mg/m(2) followed immediately by docetaxel 70 mg/m(2) in a 1-hour infusion. Epirubicin and its metabolites, epirubicinol (EOL) and 7-deoxydoxorubicinone (7d-Aone), were identified by high-pressure liquid chromatography.

RESULTS

No pharmacokinetic interaction between the parent compound epirubicin and taxanes was detected. Conversely, a significant effect on epirubicin metabolism by both paclitaxel and docetaxel was found. Epirubicin given with paclitaxel or docetaxel yielded areas under the plasma concentration-time curves (AUC) for 7d-Aone 1. 7-fold and 1.9-fold higher (P <.05), respectively, than epirubicin alone. The appearance of two polar metabolites sensitive to glucuronidase was also significantly greater in both taxane groups. Quantitatively different metabolic rates and patterns for EOL were observed in the paclitaxel and docetaxel combinations. The EOL AUC after paclitaxel treatment (1,521 +/- 150 ng/mL*h) was significantly higher (P <.01) than the corresponding values after epirubicin administered either as a single agent (692 +/- 46 ng/mL*h) or in combination with docetaxel (848 +/- 237 ng/mL*h).

CONCLUSION

There is no apparent pharmacokinetic interaction between the parent compound epirubicin and paclitaxel or docetaxel. A different pattern of interaction between these taxanes and epirubicin metabolism is clearly evident.

Docetaxel: standard recommended dose of 100 mg/m(2) is effective but not feasible for some metastatic breast cancer patients heavily pretreated with chemotherapy-A phase II single-center study

PURPOSE

Patients with metastatic breast cancer, especially those with progression after several prior chemotherapy treatments, need efficient chemotherapy. This study investigates the efficacy and toxicity of docetaxel in metastatic breast cancer patients with previous chemotherapy for metastatic disease.

PATIENTS AND METHODS

Thirty-one women (median age, 52 years; range, 40 to 65 years) treated for metastatic breast cancer with docetaxel were included. Eleven patients had one metastatic site, 10 patients had two, and 10 patients had three or more. The planned dose of docetaxel per course was the standard treatment of 100 mg/m(2) (or 75 mg/m(2) if liver enzyme levels were abnormal) every 3 weeks, given for six or eight cycles.

RESULTS

The overall response rate was 48% (three complete responses [CR] and 11 partial responses [PR] ), and the median duration of response was 7 months (range, 2 to 16 months). Twenty patients (65%) experienced fatigue, and 27 patients (87%) had alopecia. Fifteen cases (48%) of grade 4 leukopenia were observed. Edema with a weight gain of 2 to 15 kg was seen in 12 patients (39%), and mucositis occurred in 20 patients (65%). Twenty-three patients (74%) interrupted treatment before reaching the planned number of courses, nine patients owing to progression of cancer and 14 owing to toxicity. Dose reduction was required in 18 (61%) of the patients. Only two patients were able to receive the planned eight courses without dose reduction.

CONCLUSION

Docetaxel is highly active in metastatic breast cancer, even as a third-line treatment, and can be considered as an efficient standard option in second-line treatment. The standard recommended dose level of 100 mg/m(2) is not feasible in heavily pretreated patients; therefore, for such patients, an initial dose level not exceeding 75 mg/m(2) is recommended.

Phase I trial of docetaxel with estramustine in androgen-independent prostate cancer

PURPOSE

To evaluate the toxicity, efficacy, and pharmacokinetics of docetaxel when combined with oral estramustine and dexamethasone in a phase I study in patients with progressive metastatic androgen-independent prostate cancer.

PATIENTS AND METHODS

Thirty-four men were stratified into minimally pretreated (MPT) and extensively pretreated (EPT) groups. Estramustine 280 mg PO tid was administered 1 hour before or 2 hours after meals on days 1 through 5, with escalated doses of docetaxel from 40 to 80 mg/m2 on day 2. Treatment was repeated every 21 days.

RESULTS

Thirty-four patients were assessable for toxicity and 33 for response. In the MPT patients, dose-limiting myelosuppression was reached at 80 mg/m2, with six patients experiencing grade 3/4 granulocytopenia. In EPT patients, escalation above 70 mg/m2 was not attempted. Fourteen MPT (70%) and six EPT (50%) patients had a > or = 50% decline in serum PSA on two consecutive measurements taken at least 2 weeks apart. The overall 50% PSA response rate was 63% (95% confidence interval [CI], 28% to 81%). Of the 18 patients with bidimensionally measurable disease, five (28%; 95% CI, 11% to 54%) achieved a partial response. At the time of entry onto the study, 15 patients required narcotic analgesics for bone pain; after treatment, eight (53%) discontinued their pain medications. The area under the curve for docetaxel increased linearly from 40 to 70 mg/m2. At 80 mg/m2, the measured area under the curve was 8.37 (standard deviation, 0.724), which was significantly higher than the previously reported values.

CONCLUSION

The recommended phase II dose of docetaxel combined with estramustine is 70 mg/m2 in MPT patients and 60 mg/m2 in EPT patients. This combination is active in men with androgen-independent prostate cancer.

Clinical pharmacokinetics of docetaxel

Docetaxel (Taxotere), a semi-synthetic analog of paclitaxel (Taxol), is a promoter of microtubule polymerization leading to cell cycle arrest at G2/M, apoptosis and cytotoxicity. Docetaxel has significant activity in breast, non-small-cell lung, ovarian and head and neck cancers. Docetaxel has undergone phase I study in a number of schedules, including different infusion durations and various treatment cycles. Doses studied in adults have ranged from 5 to 145 mg/m2 and those in children from 55 to 235 mg/m2. The most frequently used regimen in adults is 100 mg/m2 every 3 weeks. A 1-hour infusion every 3 weeks has been favoured in phase II and III studies, and the disposition of docetaxel after such treatment is best described by a 3 compartment model with alpha, beta and gamma half-lives of 4.5 minutes, 38.3 minutes and 12.2 hours, respectively. The disposition of docetaxel appears to be linear, the area under the plasma concentration-time curve (AUC) increasing proportionately with dose. Docetaxel is widely distributed in tissues with a mean volume of distribution of 74 L/m2 after 100 mg/m2, every 3 weeks. The mean total body clearance after this schedule is approximately 22 L/h/m2, principally because of hepatic metabolism by the cytochrome P450 (CYP)3A4 system and biliary excretion into the faeces. Renal excretion is minimal (< 5%). Docetaxel is > 90% bound in plasma. Population pharmacokinetic studies of docetaxel have demonstrated that clearance is significantly decreased with age, decreased body surface area, increased concentrations of alpha 1-acid glycoproteinand albumin. Importantly, patients with elevated plasma levels of bilirubin and/or transaminases have a 12 to 27% decrease in docetaxel clearance and should receive reduced doses. Although docetaxel is metabolised by CYP3A4, phase I combination studies have not shown major evidence of significant interaction between docetaxel and other drugs metabolised by the same pathway. Nevertheless, care should be taken with the use of known CYP3A4 inhibitors such as erythromycin, ketoconazole and cyclosporin. Conversely, increased doses may be required for patients receiving therapy known to induce this cytochrome (e.g. anticonvulsants). Perliminary data suggest the erythromycin breath test, an indicator of CYP3A4 function, is a predictor of toxicity after treatment with docetaxel. Such methodologies may eventually enable clinicians to individualise doses of docetaxel for patients with cancer.

Benefits of pharmacological knowledge in the design and monitoring of cancer chemotherapy

Prescribing chemotherapy is a difficult task, because of drug resistance, which prevents all tumors to respond to a given protocol and because of drug toxicity, which is generally unavoidable but which must be limited to acceptable levels. The therapeutic window of anticancer drugs is very narrow and clinicians have to try to optimize the individual doses and schedules of the drugs to be administered. They can rely upon simple anthropometric features, such as body weight or surface area; they can also take into account the physiological status of the patient: age, liver and kidney function, genetic characteristics of drug metabolism, etc. The best way for dose adaptation lies in the establishment of pharmacokinetic/pharmacodynamic relationships, i.e., between the behavior of a drug in the body and its efficacy and toxicity. When it is established that the optimal effect of a drug is related to a given parameter, such as the area under the curve plotting plasma concentration vs. time (AUC), it becomes possible to administer the drug with the dose allowing to obtain the target parameter value. Individual dose adaptation can be achieved thanks to the study of the pharmacokinetics of a test dose preceding that of the therapeutic dose, or by the measure of drug plasma levels, either at steady state during a protracted infusion, or from cycle to cycle during repetitive protocols. Population analysis now allows the adaptation of anticancer drug dosing from a minimum knowledge of individual pharmacokinetic features, together with other characteristics of the patients such as age, gender or physiological functions.