The purpose of this study is to compare the effectiveness of the investigational drug trabectedin (Yondelis) with that of dacarbazine in patients with advanced liposarcoma or leiomyosarcoma that has continued to grow or has returned despite therapy with an anthracycline (such as doxorubicin, also known as Adriamycin).
Trabectedin may stop cancer cells from growing by binding to DNA in cancer cells. Dacarbazine is commonly used to treat liposarcoma and leiomyosarcoma. In this study, patients will be randomly assigned to receive trabectedin or dacarbazine, but not both. Each patient has a two out of three chance of receiving trabectedin and a one in three chance of receiving dacarbazine.