Selinexor Plus Gemcitabine in Selected Advanced Soft-tissue Sarcoma (SeliSarc)

This study tests a combination of selinexor (a targeted cancer drug) and gemcitabine (a chemotherapy) in patients with advanced soft-tissue sarcoma — cancers that develop in fat, muscle, tendons, or other soft tissues. The goal is to find out if this combination is effective and safe. **You may be eligible if:** - You are 18 or older - You have a diagnosis of advanced soft-tissue sarcoma of a specific subtype included in this study - You have received at least one prior line of chemotherapy that didn't work or stopped working - You are in generally good health (ECOG performance status 0-1) **You may NOT be eligible if:** - You have bone sarcoma (osteosarcoma or chondrosarcoma) - You have received prior gemcitabine treatment - You have poor organ function (heart, kidney, liver) - You have active brain metastases - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.