Study to Evaluate Safety and Antitumor Activity of Lete-Cel (GSK3377794) in HLA-A2+ Participants With NY-ESO-1 Positive Previously Treated Advanced (Metastatic or Unresectable) Synovial Sarcoma or Myxoid/Round Cell Liposarcoma

To join this study, you would need to meet certain requirements. Firstly, you must be at least 10 years old and weigh 40 kilograms (about 6 stone 4 pounds) or more. You need to have a confirmed diagnosis of synovial sarcoma or myxoid/round cell liposarcoma, and your cancer must be advanced, meaning it has spread or can't be removed by surgery without major health risks. Your medical team would also need to confirm that your cancer has certain specific genetic changes. This includes a particular genetic marker called HLA-A2 and another one called NY-ESO-1 on your cancer cells.

You would also need to have tried at least one standard treatment for your advanced cancer, such as certain types of chemotherapy like doxorubicin, which hasn't worked or you couldn't tolerate. Your doctor would assess your general health and confirm that you are expected to live for at least another 24 weeks. This study is open to both men and women, but if you are able to have children, specific contraception rules would apply during treatment.

If you decide to take part, the first step is called 'leukapheresis'. This is a procedure similar to donating blood, where some of your blood is taken, and your immune cells (T-cells) are separated out. These T-cells are then sent to a lab to be specially prepared and 'trained' to fight your cancer. While your cells are being prepared, you might receive some short courses of chemotherapy, such as Cyclophosphamide and Fludarabine, to help make space for the new, engineered T-cells in your body.

Once your T-cells are ready, they will be given back to you through an infusion, like a drip. After the treatment, you will have regular check-ups and tests with the study team to see how you are doing, how the treatment is affecting your cancer, and to monitor for any side effects. These check-ups will continue over time and could include blood tests, scans, and physical examinations. The total length of your participation would depend on your response to the treatment and the study plan, but you would be monitored closely for many months.