A Study of Experimental Tabelecleucel in Subjects with Epstein-Barr Virus-associated Diseases (Mono)

• Diagnosis of EBV+ disorder
• Eastern Cooperative Oncology Group performance status <= 3 for participants aged >= 16 years; Lansky score >= 20 for participants from 1 year to < 16 years
• Adequate organ function test results, unless organ dysfunction is considered to be due to the underlying EBV-associated disease by the investigator

Cohort-specific Inclusion Criteria:

• For participants with PID LPD:
• Newly diagnosed or relapsed/refractory LPD confirmed by biopsy-proven EBV+ LPD or positive cerebrospinal fluid (CSF) cytology with or without radiographically measurable intracranial disease with EBV detected in CSF
• Participant must have systemic measurable disease and/ or CNS measurable disease
• Definitive therapy (eg, allogeneic HCT, gene therapy) for the underlying PID is planned
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with AID LPD:
• Newly diagnosed or relapsed/refractory LPD confirmed by biopsy-proven EBV+ LPD or positive CSF cytology, with or without radiographically measurable intracranial disease, with EBV detected in CSF
• Participant must have systemic measurable disease and/ or CNS measurable disease
• Participants who are human immunodeficiency virus positive (HIV+) must meet both of the following criteria: Have an HIV viral load assessed by reverse transcription-polymerase chain reaction (RT-PCR) below the lower limit of detection and CD4 >= 50 cells/μL within 6 months prior to the first dose of tabelecleucel
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with CNS PTLD:
• Newly diagnosed or relapsed/refractory EBV+ CNS PTLD histologically confirmed by biopsy-proven EBV+ CNS PTLD or positive CSF cytology with or without radiographically measurable intracranial disease with EBV detected in CSF
• Participant may have systemic and CNS disease or CNS disease only
• Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ LPD, as determined by the investigator
• For participants with EBV+ PTLD, where standard first line therapy (rituximab and/or chemotherapy) is not appropriate, including CD20-negative disease:
• Newly diagnosed, biopsy-proven EBV+ PTLD
• Ineligible for standard first-line therapy for EBV+ PTLD, as determined by the investigator
• Participants must have systemic disease measurable per Lugano Classification criteria, except when contraindicated or mandated by local practice, then MRI may be used.
• For participants with sarcoma, including LMS:
• Newly diagnosed or failed systemic first-line therapy for EBV+ sarcoma. Participants with newly diagnosed disease should be ineligible for standard first-line therapy for EBV+ sarcoma, as determined by the investigator.
• Biopsy-proven EBV+ sarcoma
• Measurable disease using diagnostic PET/CT and/or MRI following RECIST 1.1 criteria
• For participants with CAEBV:
• Newly diagnosed or previously treated CAEBV
• Detectable EBV viremia on at least 2 occasions at a minimum of 90 days apart

• At least 3 active clinical findings (per Kimura H, et al. Front Immunol. 2017;8:1867) as: Fever >= 38.5°C; splenomegaly, lymphadenopathy, and/or hepatomegaly; cytopenia affecting at least 2 or 3 lineages in the peripheral blood (hemoglobin < 9 g/dL, platelets < 100 × 10³/mL, neutrophils < 1 × 10³/mL); hypogammaglobulinemia; hemophagocytosis; hepatitis; neuropathy; rash; and hydroa vacciniforme

• For participants with EBV+ viremia with HLH:
• Newly diagnosed or previously treated EBV+ viremia with HLH
• A molecular diagnosis consistent with HLH-2004 trial (per Henter JI, et al.

Pediatr Blood Cancer. 2007;48:124-31) OR 5 or more of the clinical symptoms (per

Jordan MB, et al. Blood. 2011;118:4041-4052): Fever >= 38.5°C; splenomegaly; cytopenia affecting at least 2 or 3 lineages in the peripheral blood (hemoglobin < 9 g/dL, platelets < 100 × 10³/mL, neutrophils < 1 × 10³/mL); hypertriglyceridemia (fasting >= 265 mg/dL) and/or hypofibrinogenemia (<= 150 mg/dL); hemophagocytosis in bone marrow, spleen, lymph nodes, or liver; low or absent natural killer cell (NK-cell) activity; ferritin >= 500 ng/mL; and elevated soluble CD25

• Burkitt, T-cell (except in the setting of HLH), natural killer/T-cell lymphoma/LPD, Hodgkin, or transformed lymphoma
• Serious known active infections, defined as ongoing uncontrolled adenovirus infection or infections requiring systemic therapy at the time of enrollment
• Suspected or confirmed Grade >= 2 acute graft-versus-host disease (GvHD) per the Center for International Blood and Marrow Transplant Research (CIBMTR) consensus grading system or extensive chronic GvHD per National Institutes of Health (NIH) consensus criteria at the time of the enrollment
• Need for vasopressor or ventilatory support
• Prior therapy (in order of increasing washout period) prior to enrollment as:
• Within 4 weeks or 5 half-lives (whichever is shorter) for any investigational product and/ or any chemotherapy (systemic or intrathecal), targeted small molecule therapy, or antibody/biologic therapy. Note: prior anti-CD20 antibody use is permitted within the washout period if a subsequent disease response assessment indicates disease progression
• Within <= 8 weeks for cellular therapies (EBV-CTLs, chimeric antigen receptor therapies directed at T cells or T-cell subsets, donor lymphocyte infusion, other CTLs); and/or therapies which could impact tabelecleucel function (anti-thymocyte globulin, alemtuzumab)
• Unwilling to use protocol specified contraceptive methods
• Women who are pregnant or breastfeeding
• Ongoing need for daily steroids of > 0.5 mg/kg prednisone or glucocorticoid equivalent, ongoing methotrexate, or extracorporeal photopheresis (protocol-specified dexamethasone is permitted and concludes by the time of enrollment)
• For participants with PID LPD or AID LPD: history of prior allogeneic HCT or solid organ transplant