Randomized double blind (DB) placebo (Plcb) controlled phase III study assessing the efficacy of xaliproden (X) in reducing the cumulative peripheral sensory neuropathy (PSN) induced by the oxaliplatin (Ox) and 5-FU/LV combination (FOLFOX4) in first-line treatment of patients (pts) with metastatic colorectal cancer (MCRC)

Abstract

3507 Background: X, an orally administered non-peptide neurotrophic agent developed by sanofi-aventis, was shown in vitro to minimize neuritic damage induced by Ox (co-culture of Schwann cells and dorsal roots ganglia explant). The probability of occurrence of Grade (Gr) 3–4 PSN at a cumulative dose of Ox of 1000 mg/m2, was consistently reported to be of 18–20%. Methods: First line MCRC pts were randomized to receive, in a DB fashion, FOLFOX4 and either Plcb or X 1mg daily. X was administered from the 1st day of chemotherapy till 15 days post last Ox cycle. Co-primary objectives were reduction in the risk of occurrence of Gr 3–4 PSN relative to cumulative dose of Ox (Kaplan-Meier method) and non-inferiority in response rate (RR). Secondary endpoints included evaluation of sensory action potential (SAP) and safety. Results: From July 2002 to May 2004, 649 pts were randomized (324 Plcb, 325 X). Pts characteristics were well balanced across arms, median number of Ox cycles was 12 in both arms, median relative dose intensity (%) was 83.8 (Plcb) and 85.2 (X). A significant risk reduction of 39% in the probability of Grade 3–4 PSN in favor of X was reported (hazard ratio [95% CI] = 0.61 [0.40; 0.93], p= 0.0203). Overall RR [95 % CI] was: Plcb 42.6% [37.1; 48.2] and X 44.9% [39.4; 50.6]. As prospectively defined in the protocol, the lower bound of the CI of the RR ratio above 0.8 confirms noninferiority in RR (1.055 [0.88; 1.26]). In both arms the mean % of change in SAP worsens as a function of PSN severity. 17.3 (Plcb) and 13.5% (X) of the pts discontinued Ox because of PSN. Severe toxicities (% Gr 3–4), reported with a ≥2% difference between arms, were (plcb vs X): diarrhea 10.9 vs 13.0, pulmonary embolism 0.9 vs 3.1, fatigue 3.7 vs 1.5, neutropenia 43.0 vs 37.8. Conclusion: X was shown to be efficient in reducing the risk of Grade 3–4 oxaliplatin-induced PSN without impacting FOLFOX4 antitumor activity. No significant financial relationships to disclose.