• Histologically confirmed diagnosis of PMBCL, EBV+ DLBCL or THRLBCL at one of the participating institutions.

• Availability of archival or freshly collected tumor tissue before study enrollment. If archival tissue is unavailable or is determined to be inadequate, tumor tissue must be obtained from a biopsy performed at screening, unless an exception is given after consultation with the sponsor-investigator.

• Eligible for standard of care CAR T-cell therapy with progression after at least two prior lines of therapy OR refractory to initial chemoimmunotherapy OR relapse within 12 months of front-line chemoimmunotherapy OR one prior line of therapy and not fit for HSCT.

• ECOG Performance Status of 0 or 1.

• Left ventricular ejection fraction (LVEF) ≥ 50% on cardiac multiple-gated acquisition (MUGA) scan or cardiac echocardiogram (ECHO).

• Adequate hematologic function (unless due to underlying disease, as established for example, by extensive bone marrow involvement or due to hypersplenism secondary to the involvement of the spleen by lymphoma per the investigator), defined as follows:

‣ ANC ≥ 1,000/μL

⁃ Hemoglobin ≥ 8 g/dL

⁃ Platelet count ≥ 50,000/μL

• Participants must have adequate organ as defined below:

‣ Total bilirubin ≤1.5 ×ULN OR direct bilirubin ≤ULN for participants with total bilirubin levels \>1.5 × ULN

⁃ AST(SGOT)/ALT(SGPT) ≤2.5 × ULN (≤5 × ULN for participants with liver involvement)

⁃ Adequate renal function defined by serum creatinine ≤1.5 x ULN or creatinine clearance (by Cockcroft-Gault) ≥ 40 ml/min for patients with serum creatinine \>1.5 x ULN

• At least one bi-dimensionally FDG-avid measurable lymphoma lesion on PET/CT scan, defined as ≥ 1.5 cm in its longest dimension on CT scan, or ≥ 1 cm if extranodal (and measurable).

• Women of childbearing potential (WOCBP) and men must agree to use effective contraception when sexually active. This applies for the time period between signing of the informed consent form and 6 months for WOCBP and for men after the last administration of study treatment. A woman is considered of childbearing potential, i.e. fertile, following menarche and until becoming post-menopausal unless permanently sterile. Permanent sterilization methods include but are not limited to hysterectomy, bilateral salpingectomy and bilateral oophorectomy. A postmenopausal state is defined as no menses for continuous 12 months without an alternative medical cause. A high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a post-menopausal state in women not using hormonal contraception or hormonal replacement therapy. The investigator or a designated associate is requested to advise the patient how to achieve highly effective birth control, e.g. intrauterine device (IUD), intrauterine hormone-releasing system (IUS), bilateral tubal occlusion, vasectomized partner, use of two forms of birth control, and sexual abstinence. The use of condoms by male patients is required unless the female partner is permanently sterile.

• Age ≥18 years.

• Ability to understand and the willingness to sign a written informed consent document.