Trial in Patients With Metastatic or Locally Advanced Leiomyosarcoma

This study compares two chemotherapy drugs — gemcitabine and trabectedin — for people with leiomyosarcoma (a type of soft tissue cancer) that has spread or cannot be removed surgically, and who have already received anthracycline-based chemotherapy. The goal is to find which second-line treatment works best. **You may be eligible if...** - You are 18 or older - You have confirmed leiomyosarcoma that is unresectable or metastatic - You have already received at least one prior chemotherapy regimen that included an anthracycline (like doxorubicin) - Your cancer has progressed within the past 6 months (confirmed by standard imaging) - Your overall health allows you to receive either gemcitabine or trabectedin - Your blood counts, heart, liver, and kidney function are adequate **You may NOT be eligible if...** - You have previously received trabectedin or gemcitabine - Your cancer has spread to the brain or surrounding membranes - You have HIV, active viral hepatitis - You have had a blood clot (deep vein thrombosis or pulmonary embolism) in the last year - You have severe bleeding history or active infections - You are pregnant or breastfeeding - You are on certain medications that affect how trabectedin is broken down in the body Talk to your doctor to see if this trial is right for you.