Testing the Addition of an Anti-cancer Drug, Hu5F9-G4 (Magrolimab), to the Usual Chemotherapy Treatment (Mogamulizumab) in T-Cell (a Type of Immune Cell) Lymphoma That Has Returned After Treatment or Does Not Respond to Treatment

This phase Ib/II trial identifies the best dose and possible benefits and/or side effects of magrolimab when given in combination with mogamulizumab in treating patients with stage IB-IV mycosis fungoides or Sezary syndrome types of T-cell lymphoma that has come back (relapsed) or does not respond to treatment (refractory). Magrolimab and mogamulizumab are monoclonal antibodies that may interfere with the ability of cancer cells to grow and spread. Treatment with magrolimab in combination with mogamulizumab may stabilize cancer for longer period than the usual treatment in patients with relapsed/refractory T-cell lymphoma who have been previously treated.

PRIMARY OBJECTIVES: I. To characterize the safety and toxicity profile and to determine a safe recommended phase 2 dose (RP2D) of Hu5F9-G4 (magrolimab) when given in combination with mogamulizumab. (Phase I) II. To compare the proportion of patients who achieve a partial or complete response lasting at least 6 months (ORR6) of the combination of Hu5F9-G4 (magrolimab) and mogamulizumab versus mogamulizumab alone. (Phase II) SECONDARY OBJECTIVES: I. To observe and record anti-tumor activity. (Phase I) II. To compare the efficacy of the combination of Hu5F9-G4 (magrolimab) and mogamulizumab versus mogamulizumab alone with respect to the following endpoints (Phase II): IIa. Overall response rate (ORR); overall response rate lasting at least 4 months (ORR4); overall response rate lasting at least 12 months (ORR12). IIb. Duration of response (DOR). IIc. Progression-free survival (PFS). IId. Time to next treatment (TTNT). EXPLORATORY OBJECTIVES: I. To identify potential biomarkers that correlate with response to mogamulizumab and Hu5F9-G4 (magrolimab) including (Phase I and II): Ia. Expression of CCR4. Ib. Somatic mutations and germline polymorphisms. Ic. Phenotyping of lymphoma and immune microenvironment. Id. Functional assay of phagocytosis. OUTLINE: This is a phase Ib, dose de-escalation study of magrolimab followed by a phase II study. Patients in the phase Ib study receive treatment as in Arm I. Patients in the phase II study are randomized to Arm I or Arm II. ARM I: Patients receive magrolimab intravenously (IV) over 2-3 hours weekly during cycles 1-2, then every 2 weeks (Q2W) during cycles 3-12. Patients also receive mogamulizumab IV over at least 60 minutes weekly during cycle 1, then Q2W during cycles 2-12. Cycles repeat every 28 days for up to 12 cycles in the absence of disease progression or unacceptable toxicity. Patients undergo positron emission tomography (PET)/computed tomography (CT) or diagnostic CT, blood sample collection, and may undergo a skin punch biopsy during screening and on study. ARM II: Patients receive mogamulizumab IV over at least 60 minutes weekly during cycle 1, then Q2W during cycles 2-12. Cycles repeat every 28 days for up to 12 cycles in the absence of disease progression or unacceptable toxicity. Patients who have received at least 2 full treatment cycles and have progressive disease (PD) or have received at least 6 full treatment cycles and have stable disease (SD) may crossover to Arm I. Patients undergo PET/CT or diagnostic CT, blood sample collection, and may undergo a skin punch biopsy during screening and on study. After completion of study treatment, patients are followed up every 3 months for 2 years.