Combined treatment with pemetrexed and vinflunine in patients with metastatic urothelial cell carcinoma after prior platinum-containing chemotherapy - results of an exploratory phase I study.

Vinflunine is to date the only registered agent for second-line treatment of metastatic urothelial cell carcinoma (UCC) in Europe. However, the effect is modest. Pemetrexed has demonstrated some single-agent activity in this disease entity. In order to improve treatment possibilities for UCC patients, a phase I trial (VINTREX) was undertaken to assess the safety of vinflunine and pemetrexed in metastatic UCC patients. A dose escalation design was planned to determine the dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) of a vinflunine/pemetrexed combination. Pemetrexed was added to vinflunine dosed at 280 mg/m2 on day 1 of a 21-day cycle. Three levels of pemetrexed were planned starting at 400 mg/m2. Four patients were enrolled with a mean age of 66 years and with a mean number of prior GC-cycles of 6,8. Two DLT's were observed at the lowest dose-level in cohort 1. One patient experienced grade 4 thrombocytopenia and a second demonstrated hepatobiliary toxicity grade 3 with an increase in alanine aminotransaminase. Most common grade 3 and 4 adverse events were anemia, thrombocytopenia and neutropenia. Three out of four patients received 3 cycles of pemetrexed and vinflunine, all had progressive disease. Based on these observations and due to protocol design, the study was interrupted at dose level 1 for safety reasons. The combined therapy of vinflunine (Javlor®, Pierre Fabre Pharma) and pemetrexed (Alimta®, Eli Lilly) is poorly tolerated in metastatic UCC patients. The combination cannot be recommended for further investigations in metastatic UCC.