Study to Investigate Lifileucel Regimen Plus Pembrolizumab Compared With Pembrolizumab Alone in Participants With Untreated Advanced Melanoma.

This study is looking for adults aged between 18 and 70 who have advanced melanoma that has spread or can't be removed by surgery, and who haven't had previous treatment specifically for their advanced melanoma. You might be eligible if you're generally well and active, with an estimated good life expectancy. Your medical team will also need to be able to take a sample of your tumour for the lifileucel treatment.

There are certain conditions that would mean you couldn't join the study. For example, if your melanoma started in the eye, or if you have active, untreated spread of the cancer to the brain causing symptoms. You also wouldn't be able to join if you've already had many previous cancer treatments, have certain severe medical conditions, or have a significant problem with your immune system.

If you're a woman who could become pregnant, or a man with a partner who could become pregnant, you would need to agree to use effective contraception during the study. If you are over 70, you might still be able to join after a discussion between your doctor and the study team.

If you decide to take part, you'll be randomly assigned to one of two treatment groups – either the combination of lifileucel and pembrolizumab or pembrolizumab alone. The exact schedule of visits and assessments will depend on which group you're in. Lifileucel involves a process where some of your immune cells are taken out, sent to a lab to be grown, and then given back to you. This process would involve hospital visits for cell collection and later for infusion. Pembrolizumab is given as an infusion, typically every few weeks.

You'll have regular medical check-ups, scans, and blood tests throughout the study to monitor your health and how the treatment is working. The study also includes follow-up visits after your main treatment period has ended to keep track of your long-term health. If you're in the group receiving pembrolizumab alone and your cancer progresses, you might have the option to switch to receive lifileucel. The total duration of your active participation, including treatment and follow-up, will be discussed by the study team, but typically these trials involve ongoing monitoring for a number of years.