New therapies are needed to improve the prognosis of patients with metastatic melanoma. This study evaluates the safety and efficacy of weekly paclitaxel in patients with metastatic melanoma. Patients received paclitaxel at 80 mg/m over 1 h, weekly for 3 weeks, followed by a 1-week rest period. Disease status was assessed every other cycle. Treatment was continued until patients experienced either disease progression or unacceptable toxicity. Twenty-seven patients were enrolled in this phase II clinical trial. Of these patients, two were subsequently determined to be ineligible. All patients, however, were considered to be evaluable for toxicity and all patients were included for response assessment in an intention-to-treat analysis. Patients received paclitaxel for a median of two cycles (range, <1-8). None of the 27 patients showed a response to treatment. Eight patients had stable disease. The median progression-free survival was 1.8 months (95% confidence interval, 1.7-2.5 months) and the median survival was 7.6 months (95% confidence interval, 4.7-9.7 months). The most common grade 3 toxicity was neutropenia (four patients) and one patient had grade 4 neutropenia. Other treatment-related grade 3 toxicities included hypersensitivity reaction (one patient) and diarrhoea (one patient). Of note, five patients had peripheral neuropathy; however, in each case, the neuropathy was only grade 1. Weekly paclitaxel is relatively well tolerated and can maintain disease stability for some metastatic melanoma patients. Unfortunately, the anti-tumour activity of this single-agent therapy is low and additional treatment innovations are needed.
"Higher response rates (12–41%) were seen in these reports when taxanes were given in association with other anticancer agents, such as temozolomide, dacarbazine, cisplatin, carboplatin, or tamoxifen (Mohith et al., 1996; Nathan et al., 2000; Hodi et al., 2002; Bafaloukos et al., 2002a, b; Tas et al., 2003; Rao et al., 2006; Ugurel et al., 2006). However, there have been some pessimistic reports on the efficacy of taxane derivatives; the response rate of singleagent therapy appears quite low (Legha et al., 1990; Walker et al., 2005) and there were no differences in median survival time and median time to progression between paclitaxel with and without carboplatin (Zimpfer-Rechner et al., 2003). The efficacy of taxane derivatives is thus controversial in malignant melanomas and at best is limited to a subset of patients. "
[Show abstract][Hide abstract] ABSTRACT: Overexpression of class III beta-tubulin (TUBB3) is an important mechanism of taxane resistance. Using 7 melanoma cell lines, 2 normal neonatal human epidermal melanocyte (NHEM) cultures, and 49 primary melanomas, we investigated TUBB3 expression, its relationship to chemosensitivity to taxane derivatives, and the epigenetic mechanism controlling TUBB3 gene expression. Normal melanocytes in vitro and in vivo strongly expressed TUBB3 protein. NHEMs exhibited marked chemoresistance to paclitaxel-induced apoptosis. A subset (10 of 49, 20%) of primary malignant melanomas was TUBB3 negative. The incidence of TUBB3-negative melanomas increased with stage of progression. TUBB3 protein expression varied among cell lines; one (HMV-I) of the seven cell lines exhibited an extremely low endogenous level. TUBB3 protein expression correlated well with chemosensitivity to paclitaxel-induced apoptosis (P<0.05). Treatment with a histone deacetylase (HDAC) inhibitor restored TUBB3 expression in HMV-I. Chromatin immunoprecipitation assays revealed that histones H3 and H4 were hypoacetylated at the TUBB3 gene in HMV-I as compared with a TUBB3-overexpressing cell type (HMV-II). Treatment with the HDAC inhibitor induced gain of histone acetylation only in HMV-I. These results suggest that loss of TUBB3 protein may be induced by histone deacetylation in a subset of malignant melanomas, and may be associated with chemosensitivity to taxane.
Recent Advances in the Biology, Therapy and Management of Melanoma, Edited by Lester M. Davids, chapter Current Therapies and New Pharmacologic Targets for Metastatic Melanoma, pages 42; InTech., ISBN: 978-953-51-0976-1
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