The
therapy of metastatic
malignant melanoma is limited by poor responses and short overall survival. Thus it remains an important issue to identify and test potential new drugs in this disease. This study was performed to examine the effects of the bifunctional alkylating
cytostatic treosulfan in vitro. Using an in vitro microplate
ATP bioluminescence tumour chemosensitivity assay (
ATP-TCA) five highly chemoresistant
melanoma cell lines and
melanoma cells freshly isolated from
metastases surgically resected from stage IV
melanoma patients (n = 10) were incubated with
treosulfan. Three cell lines and eight of the 10 tested tumour cells isolated from
melanoma metasteses showed tumour growth inhibition >50% after incubation with
treosulfan. Therefore, 14 patients with rapidly progressing stage IV
malignant melanoma who had been pretreated with at least one standard
chemotherapy regimen received
treosulfan. In this population of patients with highly refractory advanced
melanoma, one complete remission (7.1%), two partial remissions (14.3%) and three cases of stable disease (21.4%) were observed. The median survival time for all the patients measured from the beginning of
treosulfan treatment was 9 months, and the median overall survival was 17 months. Except for two patients who developed grade 3 leucopenia, only moderate side effects were observed. Therefore, we conclude that
treosulfan was well tolerated in this small series of patients and seems to be a promising alkylating
cytostatic for the treatment of metastatic
melanoma. Further studies are warranted to test these findings.