A Study of Lifileucel (Tumor-infiltrating Lymphocytes) in Adults With Advanced Endometrial Cancer.

Inclusion Criteria

1. Participants must have a histologically confirmed diagnosis of endometrial carcinoma. All histologies, including carcinosarcoma, will be allowed. Uterine sarcoma will not be allowed.

2. Participants who have received the following previous therapy:

   • Up to 3 lines of systemic therapy with no more than 1 line of chemotherapy for recurrent, metastatic, or primary unresectable disease. Prior hormonal therapy is allowed and do not count as prior lines of therapy.
   • Participants have progressed on or after platinum-based chemotherapy and anti-PD-1/PD-L1 therapy. Platinum-based chemotherapy and anti-PD-1/PD-L1 therapy may have been given together or in separate lines of therapy.
   • Participants must have documented radiographic disease progression during or after the last line of therapy.

3. Participants who have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and estimated life expectancy of >6 months.

4. Participants having at least one resectable lesion and at least one measurable lesion, following resection of the lesion for TIL generation.

5. Participants who have adequate organ function, including adequate cardiopulmonary function.

6. Participants of childbearing potential must be willing to practice an approved method of highly effective birth control during treatment and up to 12 months after the last dose of study intervention.

7. Participants who are >70 years of age may be allowed to enroll after the investigator discusses with the medical monitor.

Exclusion Criteria

1. Participants who have symptomatic untreated brain metastases.
2. Participants who have had a history of allogeneic organ transplant or any form of cell therapy involving prior conditioning chemotherapy within the past 20 years.
3. Participants who require systemic steroid therapy > 10 mg/day prednisone or another steroid equivalent dose.
4. Participants who have any form of primary immunodeficiency.
5. Participants who have another primary malignancy within the previous 3 years.
6. Participants who have received or will receive a live or attenuated vaccination within 28 days prior to the start of the NMALD.