Summary

This phase II trial tests how mosunetuzumab with or without polatuzumab vedotin works in treating patients undergoing chemotherapy followed by chimeric antigen receptor (CAR) T-cell therapy for diffuse large B-cell lymphoma that has come back (recurrent) or does not respond to treatment (refractory) or in patients with grade IIIB follicular lymphoma. Mosunetuzumab is a monoclonal antibody that binds to a protein called CD3, which is found on T cells (a type of white blood cell). It also binds to a protein called CD20, which is found on B cells (another type of white blood cell) and some lymphoma cells. This may help the immune system kill cancer cells. Polatuzumab vedotin is a monoclonal antibody called polatuzumab, linked to an anticancer drug called vedotin. Polatuzumab vedotin attaches to specific molecules (receptors) called CD79B, which is found on B cells and some lymphoma cells and delivers vedotin to kill them. It is a form of targeted therapy and a type of antibody-drug conjugate. Fludarabine is in a class of medications called purine analogs. It stops cells from making DNA and may kill cancer cells. It is a type of antimetabolite. Cyclophosphamide is in a class of medications called alkylating agents. It works by damaging the cell’s DNA and may kill cancer cells. It may also lower the body’s immune response. CAR T-cell therapy is a type of treatment in which a patient's T cells are changed in the laboratory so they will attack cancer cells. T cells are taken from a patient’s blood. Then the gene for a special receptor that binds to a certain protein on the patient’s cancer cells is added to the T cells in the laboratory. The special receptor is called a chimeric antigen receptor. Large numbers of the CAR T cells are grown in the laboratory and given to the patient by infusion for treatment of certain cancers. Giving mosunetuzumab with or without polatuzumab vedotin after chemotherapy and CAR T-cell therapy may be more effective at controlling or shrinking relapsed/refractory diffuse large B-cell lymphoma or grade IIIB follicular lymphoma than not giving them.

Objectives

PRIMARY OBJECTIVES:
I. To compare the progression-free survival in participants with relapsed/refractory large B-cell lymphoma or follicular lymphoma grade 3B with stable disease (SD) or partial remission (PR) on first imaging response by central review (day +30 positron emission tomography [PET]/computed tomography [CT] scan) after commercial CD19 CAR T-cell therapy who are randomized to receive each consolidation therapy versus those that receive no consolidation therapy (i.e. control).
Ia. To compare the progression free survival (PFS) of 1) mosunetuzumab consolidation to no consolidation, 2) polatuzumab vedotin consolidation to no consolidation, 3) mosunetuzumab + polatuzumab vedotin to no consolidation.

SECONDARY OBJECTIVES:
I. To compare overall survival (OS) in participants randomized to each consolidation treatment arm versus control.
II. To compare the complete remission (CR) conversion rate up to one year in participants randomized to each consolidation arm versus control.
III. To evaluate the treatment-related adverse events in participants randomized to each consolidation arm.
IV. To evaluate the association between total metabolic tumor volume (TMTV), standardized uptake value (SUV) max, and sum product (SPD) of diameters by PET-CT at first imaging response with complete remission conversion up to one year in participants randomized to each consolidation arm as well as those randomized to control.
V. To evaluate the overall response rate (ORR), CR rate, PFS, and OS of participants randomized to Arm 4 (observation) who have lymphoma progression within 12 months of CAR T-cell infusion and subsequently ‘cross-over' to receive treatment with mosunetuzumab + polatuzumab vedotin.
VI. To estimate overall survival for all patients registered to this study.
VII. To assess the difference in overall survival between participants who achieved CR at first imaging (day +30) versus those who did not achieve CR at first imaging.

BANKING OBJECTIVES:
I. To bank specimens for future correlative studies.
II. To bank PET-CT images for future correlative studies.

OUTLINE:

STEP I: Patients receive lymphodepleting chemotherapy consisting of fludarabine intravenously (IV) and cyclophosphamide IV on days 1-3. Patients then receive tisagenlecleucel IV between days 6-15, axicabtagene ciloleucel IV on day 6 or lisocabtagene maraleucel IV between days 6-11. Patients also undergo PET-CT imaging.

STEP II: Patients are randomized to 1 of 4 arms.

ARM I: Patients receive mosunetuzumab IV over 4 hours on days 1, 8, and 15 of cycle 1, followed by day 1 of each subsequent cycle. Cycles repeat every 21 days for up to 8 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo PET-CT or CT imaging and collection of blood and tissue samples throughout the study.

ARM II: Patients receive polatuzumab vedotin IV per institutional guidelines on day 1 of each cycle. Cycles repeat every 21 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo PET-CT or CT imaging and collection of blood and tissue samples throughout the study.

ARM III: Patients receive polatuzumab vedotin IV per institutional guidelines on day 1 of cycles 2-7 and mosunetuzumab IV over 4 hours on days 1, 8, and 15 of cycle 1, followed by day 1 of each subsequent cycle. Cycles repeat every 21 days in the absence of disease progression or unacceptable toxicity. Patients also undergo PET-CT or CT imaging and collection of blood and tissue samples throughout the study.

ARM IV: Patients undergo observation over 90 minutes. Patients also undergo PET-CT or CT imaging and collection of blood and tissue samples throughout the study. Patients with subsequent progression within 12 months of CAR T-cell therapy may crossover to Arm III.

After completion of study treatment, patients who receive CAR T-cell infusion and who are ineligible for Step 2 randomization will be followed every 3 months for 2 years, then every 6 months until 5 years after Step 1 registration, or progression, or death, whichever occurs first.

Eligibility

1. STEP 1: REGISTRATION: Participants must have a histologically confirmed diagnosis of diffuse large B-cell lymphoma or follicular lymphoma grade 3b or primary mediastinal large B-cell lymphoma (PMBCL)
2. STEP 1: REGISTRATION: Participants with transformed DLBCL must have transformed DLBCL from follicular or marginal zone lymphoma
3. STEP 1: REGISTRATION: Participant must have bi-dimensionally measurable systemic disease (at least one lesion with longest diameter > 1.5 cm)
4. STEP 1: REGISTRATION: Participants with secondary central nervous system (CNS) lymphoma (parenchymal, spinal cord, meningeal, cerebrospinal fluid involvement) must be asymptomatic from their CNS disease
5. STEP 1: REGISTRATION: Participants must be registered for step 1 after they have signed institutional consent for CAR T-cell leukapheresis but prior to the start of lymphodepleting (LD) chemotherapy for commercial CAR T-cell product
6. STEP 1: REGISTRATION: In the opinion of the enrolling physician, participants must be felt to be a candidate for CAR T-cell therapy with plans to be treated with Food and Drug Administration (FDA) approved commercially available CD19 CAR T-cell construct. * Participants must qualify for commercially approved CD19 CAR T-cell therapy per FDA package insert. * If the CAR T-cell product does not meet parameters to be given as an FDA approved product (i.e. does not meet specification criteria mandated by FDA and is infused under an expanded access protocol [EAP] or single participant investigational new drug [IND]) the participant will be taken off of study and no longer be eligible for step 2 randomization
7. STEP 1: REGISTRATION: Participants are permitted to receive or have received ‘bridging therapy’ after CAR T-cell leukapheresis. However, participants must not receive polatuzumab vedotin, and/or mosunetuzumab as part of bridging therapy. * Bridging therapy is defined as lymphoma directed therapy administered between leukapheresis and the start of LD chemotherapy. This includes cytotoxic chemotherapy (e.g.: bendamustine and rituximab [BR], rituximab, gemcitabine and oxaliplatin [R-gem/ox]), radiation, corticosteroids, as well as novel therapies such as BTK inhibitors (e.g.: Ibrutinib), immunomodulators (e.g.: lenalidomide), monoclonal antibodies (e.g.: rituximab, obinutuzumab, tafasitamab) antibody drug conjugates (e.g: loncastuximab), checkpoint inhibitors (e.g.: pembrolizumab, nivolumab), clinical trial treatments, etc. * If a participant receives polatuzumab vedotin or mosunetuzumab as bridging they will ineligible to continue on step 1 registration portion of the study and be ineligible for step 2 randomization
8. STEP 1: REGISTRATION: PET-CT scan must be planned for completion within 60 days prior to the start of LD chemotherapy. * All pre-CAR T-cell therapy disease must be assessed and documented on the baseline/pre-registration tumor assessment form. * If receiving bridging therapy, participants must have a PET-CT scan upon completion of all planned bridging therapy. If the PET-CT scan after completion of bridging therapy is consistent with complete remission per Lugano criteria as determined by enrolling physician, that participant will be ineligible for step 2 randomization. * Participants are permitted to receive corticosteroids after leukapheresis without the need to repeat a PET-CT scan. If steroids are used, they must be planned to stop no later than 3 days before CAR -T cell infusion. Recommend dose no greater than dexamethasone 40 mg (or equivalent) for < 7 days. * If response assessment by central review cannot be completed (I.e., poor quality of PET-CT scan, PET-CT performed out of window, etc.) this would be recorded as 'inadequate assessment’ and patient would not be eligible for randomization
9. STEP 1: REGISTRATION: Participants that have previously been treated with polatuzumab vedotin or mosunetuzumab prior to CAR T-cell leukapheresis for either indolent or aggressive NHL are eligible as long as the participant did not have refractory disease or progression/relapse within 6 months of the last infusion with either agent
10. STEP 1: REGISTRATION: Participants must be planning to receive CAR T-cell infusion no earlier than 2 days and no later than 14 days after completion of the last day of lymphodepleting chemotherapy. Any participant receiving CAR T-cell infusion outside of this window will be ineligible for step 2 randomization
11. STEP 1: REGISTRATION: LD chemotherapy prior to CAR T-cell infusion must be planned to start within 60 days after step 1 registration
12. STEP 1: REGISTRATION: Participants must be >= 18 years of age at the time of registration
13. STEP 1: REGISTRATION: Participants must have Zubrod performance score (PS) of 0, 1, or 2
14. STEP 1: REGISTRATION: Total bilirubin =< 1.5 x institutional upper limit of normal (ULN) (within 14 days prior to registration) * Unless due to Gilbert's disease or lymphomatous involvement of liver
15. STEP 1: REGISTRATION: Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =< 3 x institutional ULN (within 14 days prior to registration)
16. STEP 1: REGISTRATION: Creatinine clearance >= 40 mL/min, as estimated by the Cockcroft and Gault formula. The creatinine value used in the calculation must have been obtained within 14 days prior to registration. Estimated creatinine clearance is based on actual body weight
17. STEP 1: REGISTRATION: Participants must have an echocardiogram (ECHO) or multigated acquisition scan (MUGA) within 60 days prior to registration with a cardiac ejection fraction >= 40%. * Participants with current symptoms of cardiac disease must have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, participants must be class 2B or better. * Participants must not have documented myocardial infarction and percutaneous coronary intervention (PCI) within 6 months prior to registration or myocardial infarction without PCI within 3 months of registration, or unstable angina
18. STEP 1: REGISTRATION: Participants with peripheral neuropathy must have < grade 2
19. STEP 1: REGISTRATION: Participants with hepatitis B virus infection must have undetectable viral load within 14 days prior to registration, be on suppressive therapy and have no evidence of hepatitis B virus (HBV) related hepatic damage
20. STEP 1: REGISTRATION: Participants with hepatitis C infection must have eradication therapy completed, have no evidence of hepatitis C infection (HCV) related damage and have undetectable viral load within 14 days prior to registration
21. STEP 1: REGISTRATION: Participants with known human immunodeficiency virus (HIV)-infection must be on effective anti-retroviral therapy at time of registration and have undetectable viral load test on the most recent test results obtained within 6 months prior to registration
22. STEP 1: REGISTRATION: Participants must be offered the opportunity to participate in banking for planned translational medicine and future research. With participant consent, any residuals from the mandatory tissue submission will also be banked for future research. * Note: Streck tubes must be ordered in advance. Please allow 5-7 days for shipment of the collection kits
23. STEP 1: REGISTRATION: NOTE: As a part of the OPEN registration process the treating institution's identity is provided in order to ensure that the current (within 365 days) date of institutional review board approval for this study has been entered in the system. * Participants must be informed of the investigational nature of this study and must sign and give informed consent in accordance with institutional and federal guidelines. ** For participants with impaired decision-making capabilities, legally authorized representatives may sign and give informed consent on behalf of study participants in accordance with applicable federal, local, and Central Institutional Review Board (CIRB) regulations
24. STEP 2: RANDOMIZATION: Participants must have met all eligibility criteria for step 1 registration
25. STEP 2: RANDOMIZATION: Participant’s CAR T-cell product must have met specification parameters to be given as an FDA approved commercial product
26. STEP 2: RANDOMIZATION: Participants must have a PET-CT scan between days 25-40 after CAR T-cell infusion and determined to have a response consistent with stable disease or partial remission by central review compared to most recent pre-LD chemo/CAR T-cell PET-CT scan. * Note: Patients with delayed enrollment > 21 days after ‘day +30’ PET-CT scan will necessitate a repeat PET-CT scan if concerning signs or symptoms of lymphoma progression develop. * Note: If response assessment by central review cannot be completed (I.e., poor quality of PET-CT scan, PET-CT performed out of window, etc.) this would be recorded as 'inadequate assessment’ and patient would not be eligible for randomization
27. STEP 2: RANDOMIZATION: Eligible participants must be randomized no later than 60 days after CAR -T infusion
28. STEP 2: RANDOMIZATION: Participants must have started LD chemotherapy within 60 days of signing consent for step 1 registration
29. STEP 2: RANDOMIZATION: Participants must have S2114 CAR T-cell therapy form submitted to Southwest Oncology Group (SWOG) prior to step 2 randomization
30. STEP 2: RANDOMIZATION: Participants must have had a PET-CT scan upon completion of all planned bridging therapy if received, with the exception of up to 7 days of corticosteroids. If the PET-CT scan after completion of bridging therapy was consistent with complete remission per Lugano criteria as determined by enrolling physician, that participant will be ineligible for step 2 randomization. * If response assessment by central review cannot be completed (I.e., poor quality of PET-CT scan, PET-CT performed out of window, etc.) this would be recorded as 'inadequate assessment’ and patient would not be eligible for randomization
31. STEP 2: RANDOMIZATION: Participants must have Zubrod PS of 0, 1, or 2
32. STEP 2: RANDOMIZATION: Absolute neutrophil count (ANC) >= 1.0 x 10^3/uL and participants must not have received myeloid growth factor within 72 hours prior to this lab being drawn (within 7 days prior to step 2 randomization)
33. STEP 2: RANDOMIZATION: Platelets >= 75 x 10^3/uL and participants must not have received platelet transfusion within 72 hours prior to this lab being drawn (within 7 days prior to step 2 randomization)
34. STEP 2: RANDOMIZATION: Total bilirubin =< 1.5 x institutional ULN (within 7 days prior to step 2 randomization) * Unless due to Gilbert's disease or lymphomatous involvement of liver
35. STEP 2: RANDOMIZATION: AST and ALT =< 3 x institutional ULN (within 7 days prior to step 2 randomization)
36. STEP 2: RANDOMIZATION: Creatinine clearance >= 40 mL/min, as estimated by the Cockcroft and Gault formula. The creatinine value used in the calculation must have been obtained within 7 days prior to step 2 randomization. Estimated creatinine clearance is based on actual body weight (within 7 days prior to step 2 randomization)
37. STEP 2: RANDOMIZATION: Participants with peripheral neuropathy must have < grade 2
38. STEP 2: RANDOMIZATION: Participants with current symptoms of cardiac disease must have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, participants must be class 2B or better
39. STEP 2: RANDOMIZATION: Participants with history of hepatitis B viral infection must have undetectable viral load within 14 days prior to step 2 randomization and on suppressive therapy
40. STEP 2: RANDOMIZATION: Participants with history of hepatitis C viral infection must have undetectable viral load within 14 days prior to step 2 randomization
41. STEP 2: RANDOMIZATION: Participants with known human immunodeficiency virus (HIV)-infection must be continuing to receive anti-retroviral therapy and have an undetectable viral load test within 14 days prior to step 2 randomization
42. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants must have documented disease progression while on Arm 4 (observation) on this protocol. The follow-up tumor assessment form documenting disease progression must be submitted to SWOG prior to step 3 crossover registration
43. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants must be registered within 28 days of the date of progression
44. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants must have imaging that clearly demonstrates progression compared to day +30 PET-CT scan * Note: These scans should be performed as standard of care and only performed between scheduled response assessments required for study if symptoms arise that are concerning for progression
45. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants must have Zubrod PS of 0, 1, or 2
46. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): ANC >= 1.0 x 10^3/uL and participants must not have received myeloid growth factor within 72 hours prior to this lab being drawn (within 14 days prior to step 3 crossover registration)
47. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Platelets >= 75 x 10^3/uL and participants must not have received platelet transfusion within 72 hours prior to this lab being drawn (within 14 days prior to step 3 crossover registration)
48. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Total bilirubin =< 1.5 x institutional ULN (within 14 days prior to step 3 crossover registration) * Unless due to Gilbert's disease or lymphomatous involvement of liver
49. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): AST and ALT =< 3 x institutional ULN
50. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Creatinine clearance >= 40 mL/min, as estimated by the Cockcroft and Gault formula. The creatinine value used in the calculation must have been obtained within days prior to step 3 crossover registration. Estimated creatinine clearance is based on actual body weight (within 14 days prior to step 3 crossover registration)
51. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants with peripheral neuropathy must have < grade 2
52. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants with current symptoms of cardiac disease must have a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, participants must be class 2B or better
53. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants with history of hepatitis B viral infection must have undetectable viral load within 14 days prior to step 3 crossover registration and on suppressive therapy
54. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants with history of hepatitis C viral infection must have undetectable viral load within 14 days prior to step 3 crossover registration
55. STEP 3: CROSSOVER REGISTRATION (ARM 4 ONLY): Participants with known human immunodeficiency virus (HIV)-infection must be continuing to receive anti-retroviral therapy and have an undetectable viral load test within 14 days prior to step 3 crossover registration

Treatment Sites in Georgia