A Study of Lifileucel (Tumor-infiltrating Lymphocytes) in Adults With Advanced Soft Tissue Sarcoma

The purpose of this study is to investigate the efficacy and safety of the lifileucel regimen in participants with previously treated soft tissue sarcoma. The length of the study for each participant may be up to 5 calendar years after receiving lifileucel. After Screening, each participant will have surgery to remove some tumor pieces that will be used to make the lifileucel, followed by a baseline visit prior to study treatment. Participants will then receive the lifileucel treatment regimen. This includes 2 drugs (cyclophosphamide and fludarabine) for up to 5 days to decrease lymphocytes in the body, the lifileucel infusion (1 day), and up to 4 days of aldesleukin to boost the activity of the lifileucel. Study visits will be every 6 weeks for 6 months, then every 3 months until 5 calendar years after the lifileucel infusion.