Annals of Oncology Advance Access published online on April 23, 2008
Annals of Oncology, doi:10.1093/annonc/mdn171
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A multicenter phase II study of XRP6258 administered as a 1-h i.v. infusion every 3 weeks in taxane-resistant metastatic breast cancer patients
1 Department of Medical Oncology, University Hospital Jean Minjoz, Besançon; Institut National de la Santé et de la Recherche Médicale, Unit 645, Besançon, France
2 Rydygier Memorial Hospital, 31-826 Krakow, os. Zlotej Jesieni 1, Poland
3 Clinical Oncology Institution and Research, Mendoza, Argentina
4 Department of Medical Oncology, Mount Hospital, Perth, Australia
5 Department of Medical Oncology, Institut Paoli Calmettes, UMR599 Inserm, Université de la Méditerranée Marseille, France
6 Department of Medical Oncology, Federal Univ, Porto Alegre, Brazil
7 Department of Oncology development, Sanofi-Aventis, Antony
8 Department of Medical Oncology, Hopital Tenon, Paris, France
* Correspondence to: Prof. X. Pivot, Service d'Oncologie Médicale, Centre Hospitalier Universitaire de Besançon, 25030 BESANCON cedex, France. Tel: +33-3-81-66-88-58; Fax: +33-2-81-66-88-58; E-mail: Xavier.pivot{at}univ-fcomte.fr
Background: XRP6258 is a novel taxoid with a low affinity for P-glycoprotein. This multicenter phase II study assessed the activity of XRP6258 in the treatment of taxane-resistant metastatic breast cancer (MBC).
Patients and methods: XRP6258 was administered as a 1-h i.v. infusion every 3 weeks at 20 mg/m2 (then, in the absence of severe toxicity, at 25 mg/m2 from cycle 2). The primary end point was the objective response rate (ORR) assessed according to response evaluation criteria in solid tumours (RECIST) guidelines.
Results: Seventy-one patients were enrolled. The median relative dose intensity was 0.98. The ORR was 14% (two complete, eight partial responses). Eighteen patients (25%) had stable disease of >3 months duration. At a median follow-up of 20.0 months, the median time to progression was 2.7 months, and the median overall survival 12.3 months. The most common grade 3/4 adverse events (AEs) were neutropenia (73%) and leucopenia (55%), with a low febrile neutropenia rate (3%) and infrequent grade 3/4, treatment-related, non-hematological AEs (<5% patients for any AE). Two deaths were reported, one related to study drug and one to unknown cause.
Conclusions: XRP6258 was active and well tolerated in this group of MBC patients with taxane-resistant disease. These results support the further clinical development of this agent.
chemotherapy, metastatic breast cancer, resistance, taxane, taxoid, XRP6258
Received for publication February 14, 2008. Revision received March 19, 2008. Accepted for publication March 20, 2008.