Abstract OT3-3-05: Neurotoxicity characterization phase II randomized study of nab-paclitaxel versus conventional paclitaxel as first-line therapy of metastatic HER2-negative breast cancer. An ONSOCUR Study Group.
Authors: Ciruelos E , Bueno C , Cantos B , Carrión R , Echarri M , Enrech S , García Saenz JA , Guerra JA , Lara MA , Martínez N , Rodríguez-Antona C , Domínguez-González C , Sanz JL , Baquero J , Cortés-Funes H , Sepúlveda JM 
Published: August 2014

Background: Nab-paclitaxel (Nab-P) is a nanoparticle albumin-bound form of paclitaxel that is thought to exploit natural albumin pathways to enhance the selective uptake and accumulation of paclitaxel at the site of the tumour, thus reducing its diffusion to normal tissues. Nab-P has been approved for the treatment of metastatic breast cancer patients who have failed first-line treatment for metastatic disease and for whom standard, anthracycline-containing therapy is not indicated. Toxicity profile of Nab-P is well characterized with significantly less haematological toxicities compared with conventional paclitaxel (P). Nab-P derived grade III neuropathy is short-lasting and more reversible than conventional P-derived neuropathy, probably due to absence of Cremophor solvent, or due to P itself. However there is still a lack of clinical and physiological characterisation of Nab-P induced neuropathy. The Current used tools for early detection and continuous evaluation of neurotoxicity are not optimal. Most used toxicity scales are limited, as they do not provide a detailed information of the severity of the neuropathy, its impact on quality of life, or physiopathology mechanisms. In addition, an inter-individual variability exists in terms of neurotoxicity predisposition when taxanes are used; it seems to be related to polymorphic differences in genes implicated in transport and metabolism of these drugs.

Specific aims: Primary objective is to characterize neurotoxicity according to Total Neuropathy Score (TNS) and electromyographic changes. Secondary endpoints are determine the rate of neuropathy chemo-induced, the predictive value of some genetic variants (SNPs) for the development of neuropathy, clinical activity, toxicity profile and safety of treatments and quality of life (EORTC QLQ-C30 and CIPN20).

Trial design: Phase II open-label randomised clinical trial with four parallel arms: a) conventional paclitaxel 80 mg/m2 on days 1, 8 and 15; b) Nab-P 100 mg/m2 on days 1, 8 and 15; c) Nab-P 150 mg/m2 on days 1, 8 and 15; d) Nab-P 150 mg/m2 on days 1 and 15. Study treatments will be administered in a 28-day cycle until progression disease, intolerable toxicity or investigator's decision.

Eligibility criteria: Women &gt;18 years, with cytological or histological confirmation of HER2-negative breast cancer, metastatic disease, not prior chemotherapy for advanced disease, no prior grade &gt; 1 neuropathy from any cause, measurable or evaluable disease, ECOG &gt;2 and adequate bone marrow, renal and hepatic functions. No Relevant comorbidities.

Statistical methods: This is an exploratory safety study to better characterize neurotoxicity in patients treated with Nab-P compared toP. Therefore no formal sample size or power calculations will be performed. We expect to recruit 60 patients, 15 in each treatment arm, in 18 months. Recruitment will start on October 2012.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT3-3-05.