Sunitinib in combination with paclitaxel plus carboplatin in patients with advanced solid tumors: phase I study results

A Review of CYP3A Drug-Drug Interaction Studies: Practical Guidelines for Patients Using Targeted Oral Anticancer Drugs

Many oral anticancer drugs are metabolized by CYP3A. Clinical drug-drug interaction (DDI) studies often only examine the effect of strong CYP3A inhibitors and inducers. The effect of moderate or weak inhibitors or inducers can be examined using physiologically based pharmacokinetic simulations, but data from these simulations are not always available early after approval of a drug. In this review we provide recommendations for clinical practice on how to deal with DDIs of oral anticancer drugs if only data from strong CYP3A inhibitors or inducers is available. These recommendations were based on reviewed data of oral anticancer drugs primarily metabolized by CYP3A and approved for the treatment of solid tumors from January 1st, 2013 to December 31st, 2015. In addition, three drugs that were registered before the new EMA guideline was issued (i.e., everolimus, imatinib, and sunitinib), were reviewed. DDIs are often complex, but if no data is available from moderate CYP3A inhibitors/inducers, a change in exposure of 50% compared with strong inhibitors/inducers can be assumed. No a priori dose adaptations are indicated for weak inhibitors/inducers, because their interacting effect is small. In case pharmacologically active metabolites are involved, the metabolic pathway, the ratio of the parent to the metabolites, and the potency of the metabolites should be taken into account.

A Phase I, Dose-Escalation Trial of Pazopanib in Combination with Cisplatin in Patients with Advanced Solid Tumors: A UNICANCER Study

Introduction

To determine the feasibility, maximum-tolerated dose (MTD), and dose-limiting toxicities (DLT) of pazopanib in combination with cisplatin.

Methods

Patients with advanced malignancies were included in a 3 + 3 dose-escalation phase I study. Pazopanib administration started 8 days before the first infusion of cisplatin; some patients were treated according to a reverse sequence (cisplatin first). Five dose levels (DLs) were planned. MTD was based on DLT observed during cycles 1 and 2.

Results

Thirty-five patients were enrolled. The MTD was reached at the first DL, (pazopanib 400 mg daily + cisplatin 75 mg/m² every 21 days). Main DLTs were pulmonary embolism, neutropenia, thrombocytopenia, and elevation of liver enzymes. Overall, most common adverse events were anemia (83%), fatigue (80%), thrombocytopenia (80%), neutropenia (73%), hypertension (59%), neurotoxicity (56%), and anorexia (53%). Sixteen patients (46%) discontinued the study due to toxicity. One patient (sarcoma) had a complete response, and three patients (one with breast cancer and two with ovarian cancers) had a partial response. Pharmacokinetic (PK) analyses showed interactions with aprepitant, resulting in increased exposure to pazopanib, which might explain partly the poor tolerance of the combination.

Conclusion

Cisplatin and pazopanib could not be administered at their single agent full doses, partly due to a PK interaction between pazopanib and aprepitant.

Funding

This work was funded by GlaxoSmithKline and by the charity Ligue Nationale de Lutte Contre le Cancer.

Trial registered

ClinicalTrials.gov identifier, NCT01165385.

Phase I/II trial of neoadjuvant sunitinib administered with weekly paclitaxel/carboplatin in patients with locally advanced triple-negative breast cancer

The purpose of the study is to evaluate the feasibility and efficacy of adding sunitinib to paclitaxel/carboplatin in the neoadjuvant therapy of patients with triple-negative breast cancer (TNBC). Patients had histologically proven, previously untreated, triple-negative adenocarcinoma, with disease limited to the breast and axilla (clinical T1-T3, N0-N2, M0; T1N1M0 excluded). Following determination of the maximum tolerated doses in the phase I portion, patients in the phase II study received paclitaxel 70 mg/m(2) IV days 1, 8, and 15; carboplatin AUC 5.0 IV day 1; sunitinib 25 mg orally daily; treatment was administered for six 28-day cycles followed by definitive surgery. Sunitinib was resumed postoperatively to complete a 52-week course. Pathologic complete response (pCR) rate was the primary endpoint. Fifty-four patients enrolled; 41 received treatment in the phase II study. Sixteen patients (39 %) were able to complete six cycles of neoadjuvant therapy; 18 additional patients had surgery after completing 2-5 cycles of treatment. The pCR rate in these 34 evaluable patients was 35 %. The toxicity of the regimen was considerable, with myelosuppression resulting in numerous dose reductions and/or omissions of paclitaxel and carboplatin. Eleven patients (27 %) discontinued sunitinib during neoadjuvant therapy, and six patients (14 %) completed 52 weeks of single-agent sunitinib. In the neoadjuvant treatment of patients with TNBC, the combination of paclitaxel, carboplatin, and sunitinib was difficult to administer, and produced a pCR rate comparable to other less toxic regimens. This combination is not recommended for further evaluation. At present, sunitinib has no defined role in the treatment of breast cancer.

Drug interactions with sunitinib

PURPOSE

Sunitinib is a tyrosine kinase inhibitor indicated for the treatment of gastrointestinal stromal tumor, advanced renal cell carcinoma, and pancreatic neuroendocrine tumors. The aim of this article is to describe the pharmacological interactions between sunitinib and commonly prescribed drugs.

METHOD

We reviewed available information on pharmacological interactions between sunitinib and concomitantly prescribed drugs. Drugs were grouped into different therapeutic groups according to the Anatomical Therapeutic Chemical (ATC) classification.

RESULTS

Sunitinib interacts with CYP3A4 inducers or inhibitors and with P-glycoprotein and ABCG2 substrates. Pharmacodynamic interactions with drugs have also been found.

CONCLUSION

Current information on drug interactions between sunitinib and other drugs is scarce and most of the times it is difficult to apply to clinical practice. Even so, this difficulty in managing drug interactions should not be a reason to ignore them as they can help to explain intolerances and treatment failures.

The potential of sunitinib as a therapy in ovarian cancer

INTRODUCTION

Sunitinib malate (SU11248; Sutent®; Pfizer, Inc., New York) is a multi-kinase inhibitor currently approved for use in advanced renal cell carcinoma (RCC), imatinib-resistant/-intolerant gastrointestinal stromal tumours and progressive, well-differentiated pancreatic neuroendocrine tumours in patients with unresectable, locally advanced or metastatic disease.

AREAS COVERED

This article describes the mechanism of action and of the pharmacokinetics of sunitinib; further, it summarizes Phase I and II trials on the clinical efficacy, tolerability and safety of this agent in the setting of ovarian cancer (OC) treatment.

EXPERT OPINION

On the basis of the current literature, sunitinib has shown modest antitumour activity and acceptable toxicity. Studies investigating the impact of horizontal and vertical combinations should represent a priority of future research. Although clinical Phase II trials on the use of sunitinib in the treatment of OC demonstrated an acceptable profile of AEs, a greater comprehension of the toxicity of this compound is recommended.

Drug interactions with solid tumour-targeted therapies

Drug interactions are an on-going concern in the treatment of cancer, especially when targeted therapies, such as tyrosine kinase inhibitors (TKI) or mammalian target of rapamycin (mTOR) inhibitors, are being used. The emergence of elderly patients and/or patients with both cancer and other chronic co-morbidities leads to polypharmacy. Therefore, the risk of drug-drug interactions (DDI) becomes a clinically relevant issue, all the more so as TKIs and mTOR inhibitors are essentially metabolised by cytochrome P450 enzymes. These DDIs can result in variability in anticancer drug exposure, thus favouring the selection of resistant cellular clones or the occurrence of toxicity. This review provides a comprehensive overview of DDIs that involve targeted therapies approved by the FDA for the treatment of solid tumours for more than 3 years (sorafenib, sunitinib, erlotinib, gefitinib, imatinib, lapatinib, everolimus, temsirolimus) and medicinal herb or drugs. This review also provides some guidelines to help oncologists and pharmacists in their clinical practice.

Controlling escape from angiogenesis inhibitors

Selective inhibition of vascular endothelial growth factor (VEGF) increases the efficacy of chemotherapy and has beneficial effects on multiple advanced cancers, but response is often limited and the disease eventually progresses. Changes in the tumour microenvironment--hypoxia among them--that result from vascular pruning, suppressed angiogenesis and other consequences of VEGF inhibition can promote escape and tumour progression. New therapeutic approaches that target pathways that are involved in the escape mechanisms add the benefits of blocking tumour progression to those of slowing tumour growth by inhibiting angiogenesis.

Open-label feasibility study of pazopanib, carboplatin, and paclitaxel in women with newly diagnosed, untreated, gynaecologic tumours: a phase I/II trial of the AGO study group

Introduction:

Although most patients with advanced gynaecologic malignancies respond to first-line treatment with platinum-taxane doublets, a significant proportion of patients relapse. Combining targeted agents that have non-overlapping mechanisms of action with chemotherapy may potentially increase the disease-free interval. Accordingly, this study evaluated the feasibility of combining pazopanib, an oral angiogenesis inhibitor, with paclitaxel and carboplatin.

Methods:

This open-label, phase I/II study planned to evaluate the safety and efficacy of paclitaxel 175 mg m^–2 plus carboplatin (AUC5 (Arm A) or AUC6 (Arm B)) once in every 3 weeks for up to six cycles with either 800 or 400 mg per day pazopanib.

Results:

Dose-limiting toxicities (DLTs) were observed in two of the first six patients enrolled at pazopanib 800 mg plus paclitaxel 175 mg m^–2 plus carboplatin AUC5. Of the six patients enrolled in the next and lowest dosing level planned in the study, pazopanib 400 mg plus paclitaxel 175 mg m^–2 plus carboplatin AUC5, two patients also experienced DLTs and the study was terminated. Two of the 4 DLTs observed overall were gastrointestinal perforations. Severe myelotoxicity was reported in 6 of 12 patients.

Conclusion:

Combining either 800 or 400 mg per day pazopanib with standard carboplatin/paclitaxel chemotherapy is not a feasible treatment option.

Decreased exposure to sunitinib due to concomitant administration of ifosfamide: results of a phase I and pharmacokinetic study on the combination of sunitinib and ifosfamide in patients with advanced solid malignancies

BACKGROUND

This study aimed to define the maximally tolerated dose (MTD) of sunitinib combined with two different infusion schedules of ifosfamide.

METHODS

Patients with advanced solid tumours, good performance score, good organ function, and no standard therapy available were eligible. Continuous once daily sunitinib, in escalating doses per cohort, was combined with ifosfamide, 9 g m(-2) for 3 days or 6 g m(-2) for 5 days, administered every 3 weeks. Pharmacokinetic (PK) and pharmacodynamic (PD) assessments were performed.

RESULTS

With growth-factor support, the MTD of sunitinib combined with either ifosfamide schedule was 12.5 mg in 32 patients enrolled. Neutropenia-related adverse events were dose-limiting toxicities. Sunitinib did not affect ifosfamide PK. Ifosfamide significantly decreased exposure to sunitinib and increased exposure to its metabolite, SU12662. No consistent changes in PD parameters were observed.

CONCLUSION

With growth-factor support, the MTD of sunitinib with both ifosfamide schedules was 12.5 mg. Ifosfamide produced decreased sunitinib blood levels because of CYP3A induction. As PK interactions cannot explain the relatively low sunitinib doses that can be combined with ifosfamide, synergy in toxicity is likely. Whether this also holds true for anti-tumour activity needs to be further explored.