Effects of patupilone on the pharmacokinetics and pharmacodynamics of warfarin in patients with advanced malignancies: a phase I clinical trial

Patupilone is a novel microtubule-targeting cytotoxic agent, which exerts its antitumor effect through microtubule stabilization. Pharmacokinetics, pharmacodynamics, and safety of warfarin when administered concomitantly with patupilone were investigated, and antitumor activity was assessed. This was a phase I, two-center, drug-drug interaction study. In the core phase of the study, treatment consisted of warfarin 20 mg orally (days 1 and 29) and patupilone 10 mg/m(2) i.v. (days 8 and 29). Patients benefiting from patupilone treatment continued treatment every 3 weeks (extension phase) until progression of disease, death, or unacceptable toxicity. Seventeen patients were treated (core phase, 17; extension, 9). The geometric mean ratios (comedication/monotherapy) for C(max) and area under the curve(0-168) of warfarin were near unity and their 90% confidence intervals were within the equivalence limits of 0.80 and 1.25. The half-life, plasma clearance, and International Normalized Ratio (INR) of warfarin were not affected by patupilone coadministration. The most common adverse events were diarrhea, nausea, vomiting, abdominal pain, anorexia, dehydration, asthenia, and peripheral neuropathy. Five (29.4%) patients experienced grade 3 study drug-related adverse events (diarrhea, 17.6%; increased INR, 11.8%; dehydration, 5.9%; and neutropenia, 5.9%). One patient with triple-negative breast cancer (estrogen receptor, progesterone receptor, and HER2/neu negative) had a partial response (35% decrease in tumor measurements by Response Evaluation Criteria in Solid Tumors), and 11 had stable disease for 6 weeks or more (≥12 weeks, 6 patients). The pharmacokinetics and pharmacodynamics of warfarin were not affected by patupilone coadministration, suggesting that patupilone has no clinically relevant effect on CYP2C9 metabolism. Patupilone showed antitumor activity in triple-negative breast cancer.

Pharmacokinetics and antitumor activity of patupilone combined with midazolam or omeprazole in patients with advanced cancer

PURPOSE

Patupilone is a novel microtubule-targeting cytotoxic agent with potential interaction with CYP3A4/CYP2C19 enzymes. Midazolam and omeprazole are primarily metabolized by CYP3A4 and CYP2C19, respectively. We evaluated the inhibitory effects of patupilone on the CYP3A4/CYP2C19 pathways.

METHODS

This study had 2 parts: in an initial core phase, patients were randomly assigned to receive midazolam 4 mg or omeprazole 40 mg PO (days 1 and 29) and patupilone 10 mg/m(2) IV (days 8 and 29). Patients without progression continued patupilone every 3 weeks until disease progression or unacceptable toxicity (extension phase).

RESULTS

Forty-six patients were treated. The areas under the concentration-time curves (AUC)s of midazolam with or without patupilone co-administration were similar. The C (max) of midazolam when co-administered with patupilone was highly variable and was lower compared with midazolam alone; however, the oral clearance and terminal half-lives were similar. Both the C (max) and AUC of omeprazole when co-administered with patupilone were highly variable and lower than with omeprazole alone. However, the oral clearance and terminal half-lives were similar. The latter data suggest that patupilone decreased the absorption of omeprazole (by ~20%). The overall safety profile was consistent with that of previous single-agent patupilone studies; 2 partial responses (ovarian and pancreatic cancer) and 1 complete response (serous ovarian adenocarcinoma) were observed.

CONCLUSIONS

Patupilone was not a potent CYP3A4 or CYP2C19 inhibitor. No dose adjustment is required when omeprazole or midazolam is used in patients treated with patupilone. Patupilone exhibited promising antitumor activity in heavily pretreated patients with ovarian and pancreatic cancer.

Patupilone in cancer treatment

IMPORTANCE OF THE FIELD

Since the introduction of taxane-based chemotherapy for advanced solid tumors in the 1990s, the median overall survival of patients with metastatic breast cancer increased from 2 years to almost 5 years. Similarly, the 5-year overall survival for ovarian cancer has increased from 30% to more than 40%.

AREAS COVERED IN THIS REVIEW

Patupilone is a novel cytotoxic compound, with similar microtubule-binding and apoptotic properties of taxanes and is active in taxane-resistant cell lines. Over 1200 patients have been treated with patupilone in Phase I - III clinical trials and a wealth of knowledge has accumulated about this compound. This review discusses current pharmacology and data from clinical trials with patupilone from the last seven years.

WHAT THE READER WILL GAIN

We present a comprehensive summary of data from Phase II and III trials, as well as an overview of currently accruing trials.

TAKE HOME MESSAGE

Although patupilone has not demonstrated superiority over pegylated liposomal doxorubicin in a large Phase III trial in relapsed or refractory ovarian cancer, its evaluation is continuing in a range of other malignancies, especially in primary or secondary tumors of the CNS.

Safety and efficacy of patupilone in patients with advanced ovarian, primary fallopian, or primary peritoneal cancer: a phase I, open-label, dose-escalation study

PURPOSE To evaluate the safety, maximum tolerated dose (MTD), and pharmacokinetics of patupilone administered once every 3 weeks with proactive standardized diarrhea management in patients with resistant or refractory ovarian, fallopian, or peritoneal cancer. PATIENTS AND METHODS Patients received patupilone (6.5 to 11.0 mg/m(2)) every 3 weeks via 20-minute infusion. Adverse events, dose-limiting toxicities (DLT), MTD, and tumor response were determined. The tumor response was measured by Response Evaluation Criteria in Solid Tumors (RECIST) and cancer antigen 125 levels. Results Forty-five patients were enrolled. Adverse events were mild to moderate in intensity, and grade 3 diarrhea (13%) was the most commonly reported serious adverse event. Grade 3 peripheral neuropathy was noted in two patients (4%). Diarrhea, peripheral neuropathy, and fatigue were the most common DLTs; however, these were uncommon in the first cycle and the MTD was therefore not reached in this study. Overall response (OR; complete and partial responses; median cycles, 8) per RECIST in patients with measurable disease (n = 36) was 19.5%. Median duration of disease stabilization (complete and partial responses and stable disease) was 15.8 months. These results appear improved from a previous study in a similar patient population using a weekly schedule (2.5 mg/m(2)/week; N = 53; OR, 5.7%). CONCLUSION Patupilone once every 3 weeks was well-tolerated at doses up to 11.0 mg/m(2). Patupilone demonstrated promising antitumor activity in patients with drug-resistant/refractory disease. An ongoing phase III study in this patient population is testing the 10.0 mg/m(2) dose.

Potential clinical applications of epothilones: a review of phase II studies

BACKGROUND

Epothilones are cytotoxic macrolides that share a similar mechanism of action with the taxanes but demonstrate antitumor activity in taxane-resistant settings. Six epothilones are in early clinical trials for cancer treatment.

DESIGN

This review summarizes data from phase II clinical studies of the epothilones ixabepilone (BMS-247550), patupilone (EPO906), and KOS-862. Data were identified by searches of PubMed and of the proceedings of the American Society of Clinical Oncology annual meetings and the Federation of European Cancer Societies biennial conference for the period 2000-2006. Studies were included if safety and efficacy data were available for at least 10 patients with a given tumor type in a standard phase II design.

RESULTS

Epothilones have demonstrated activity in lung, ovarian, breast, prostate, and renal carcinomas and in non-Hodgkin's lymphoma in phase II studies. Little or no evidence of clinical activity has been reported in studies of epothilones in other tumor types. Preliminary data indicate that epothilones can be combined safely with other cytotoxic agents such as carboplatin.

CONCLUSIONS

The epothilones may play a role as an alternative to taxanes if activity in resistant settings can be confirmed together with an acceptable toxicity profile. Randomized studies are awaited to investigate the utility of epothilones in single-agent and combination regimens.

Novel tubulin-targeting agents: anticancer activity and pharmacologic profile of epothilones and related analogues

BACKGROUND

Epothilones are 16-member ring macrolides with antimicrotubule activity that share a similar mechanism of action to the taxanes but have demonstrated potent antiproliferative activity in several different multidrug-resistant and paclitaxel-resistant tumor cell lines in vitro and in vivo.

DESIGN

This review summarizes data from preclinical and phase I clinical studies of epothilone B (patupilone; EPO960) and epothilone D (KOS-862) and their second-generation (ixabepilone, BMS-310705, KOS-1584) and third-generation (ZK-EPO, ABJ-879) derivatives. Data were identified by searches of PubMed and the Proceedings of the American Society of Clinical Oncology annual meetings from 2000 to 2006.

RESULTS

Epothilones demonstrate a linear dose-dependent pharmacokinetic profile, are well tolerated, and exhibit antitumor activity in a variety of tumor types in phase I studies of patients with cancer. Although similar in chemical structure, the epothilones demonstrate a striking difference in toxicity profile in phase I studies. Diarrhea is the dose-limiting toxicity (DLT) associated with patupilone, whereas neurotoxicity and neutropenia are the DLTs most commonly encountered with other epothilones. Consistent with preclinical data, partial responses were observed with patupilone and ixabepilone in patients with breast cancer previously treated with taxanes.

CONCLUSION

The epothilones demonstrate promising antitumor activity in a broad spectrum of taxane-sensitive and -refractory tumors at doses and schedules associated with tolerable side-effects.