A sequence-dependent combination of docetaxel and vinorelbine: pharmacokinetic interactions

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.

Gemcitabine and vinorelbine in recurrent advanced non-small cell lung cancer: sequence does matter

PURPOSE

Gemcitabine and vinorelbine have demonstrated clinical efficacy both as single agents and in combination in patients with metastatic non-small cell lung cancer (NSCLC). This phase II trial evaluated biweekly gemcitabine and vinorelbine in NSCLC patients who have had one prior chemotherapeutic regimen and have had disease progression.

METHODS

Gemcitabine (1,200 mg/m(2) IV over 30 min) was followed by vinorelbine (30 mg/m(2) IV over 6-10 min) on days 1 and 15 of each 28 day cycle. Chemotherapy was given for six cycles unless disease progression or unacceptable toxicity was seen.

RESULTS

From 11/1998 to 10/2000, 15 of 20 patients enrolled (6 males, 9 females) were evaluable for response and survival. Two patients had grade 4 neutropenia, and one patient had grade 4 thrombocytopenia. The only non-hematologic grade 3 toxicities were fatigue, phlebitis, and arthralgias. No objective responses were observed, but 11 patients had stable disease for a mean of 6 months. The median survival time was 9.4 months (95% CI = 4.2, 14.8), with a median time to progression of 4.2 months (95% CI = 1.9, 5.6). The 1 year survival was 47%.

CONCLUSIONS

While this schedule of gemcitabine and vinorelbine was well tolerated, it was felt to be inactive. In vitro and pharmacokinetic studies published after the completion of our trial, suggest gemcitabine followed by vinorelbine may have antagonistic effects leading to lower dose delivery of both drugs. Our study was the only study of gemcitabine and vinorelbine in second-line NSCLC in the literature without an objective response. Our study was the only second-line study that administered gemcitabine prior to vinorelbine. First-line studies in the literature that administered vinorelbine prior to gemcitabine had, on average, a 1.7 month higher median survival (10.0 vs. 8.3 mos; P value <0.001). Because of the lack of response, further studies using this drug sequence, dose, and schedule for gemcitabine and vinorelbine are not recommended.

Treatment of metastatic breast cancer with vinorelbine and docetaxel

OBJECTIVE

A phase II study was performed to evaluate efficacy and safety of the combination vinorelbine and docetaxel in patients with metastatic breast cancer previously treated with anthracycline-based regimens. Overall 41 patients were included in the study.

METHODS

Treatment consisted of vinorelbine 25 mg/m2 and docetaxel 75 mg/m2, both administered on day 1 every 3 weeks for a maximum of 9 cycles. Most patients (92%) were postmenopausal with a median age of 57 years, and median ECOG performance of 1. Sites of disease were viscera in 42% of patients, bones in 30%, soft-tissues in 32%. Sixty-five percent of patients had >2 metastatic sites. Previous treatments included neo-adjuvant chemotherapy in 7.3% of cases, adjuvant chemotherapy in 71%, and front-line chemotherapy for advanced disease in 50% of cases.

RESULTS

A total of 273 cycles of chemotherapy were delivered (mean 6 cycles/patient). All patients were assessable for toxicity: alopecia was recorded in all patients, grade 2-3 neutropenia in 34% and grade 4 in 9.7%; grade 2-3 nausea/vomiting in 29%, grade 2-3 mucositis in 24.3%. Out of 39 patients evaluable for response, 7 (18%) complete responses and 13 (33%) partial responses have been recorded with an overall response rate of 51%. Six patients (15%) experienced stable disease and 13 patients (33%) progressed. Mean duration of responses was 15.2 months. Median time to progression and median overall survival were 6.2 and 14 months, respectively.

CONCLUSION

In patients with metastatic breast cancer previously treated with anthracyclines the combination vinorelbine-docetaxel is very active and well tolerated representing a valid therapeutic option for the management of this patient population.

Preparation, characterization, cytotoxicity and pharmacokinetics of liposomes containing docetaxel

The taxanes, paclitaxel and docetaxel, are anticancer agents used in clinical trials against ovarian carcinoma, breast, lung and head/neck cancer. Paclitaxel, very insoluble in water, is generally formulated using Cremophor EL. Docetaxel, more soluble in water, is formulated using Tween 80 and ethanol. Tween 80, albeit less toxic than Cremophor EL, may be responsible of some toxic effects. To eliminate these vehicles and improve the drug's antitumor efficacy, taxanes have been incorporated in liposomes. We compared formulation, stability, biodistribution and pharmacokinetics of docetaxel in conventional and PEGylated liposomes. Of the several formulations examined, docetaxel-liposomes composed of ePC/PG/CHOL 9:1:2 and ePC/PG/DSPE-PEG2000/CHOL 9:1:2:0.7 were the most effective. Both conventional and PEGylated docetaxel-liposomes were stable at 4 degrees C after 15 days, whereas in the presence of serum at 37 degrees C they were less stable. The IC50 values of docetaxel-liposomes, evaluated on HT-29 and Igrov1 cell lines, remained very high. Pharmacokinetics and biodistribution were evaluated in Balb/c mice after i.v. injection of [14C]docetaxel, formulated in Tween 80 or in 3H-labeled conventional or PEGylated liposomes. The t(1/2)beta, which was low for docetaxel (52.3 min), rose to 260 min for conventional docetaxel-liposomes and to 665 min for PEGylated docetaxel liposomes. Biodistribution studies confirmed the pharmacokinetics.