A Study Evaluating the Efficacy, Safety, and Pharmacokinetics of Glofitamab in Combination With Rituximab Plus Ifosfamide, Carboplatin Etoposide Phosphate in Participants With Relapsed/Refractory Transplant or CAR-T Therapy Eligible Diffuse B-Cell Lymphoma

Inclusion Criteria:

* Life expectancy ≥ 12 weeks
* Histologically confirmed B-cell lymphoma
* One line of prior systemic therapy including an anti-CD20 monoclonal antibody (i.e. rituximab) and an anthracycline
* Relapsed or refractory disease after first-line chemoimmunotherapy
* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
* Participant must be a candidate for high-dose chemotherapy followed by ASCT or CAR-T therapy

Exclusion Criteria:

* Treatment with more than one prior line of therapy for DLBCL
* Primary mediastinal B-cell lymphoma
* Prior treatment with glofitamab or other bispecific antibodies targeting both CD20 and CD3
* Peripheral neuropathy assessed to be Grade \> 1 according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0 at enrollment
* Treatment with radiotherapy, chemotherapy, immunotherapy, immunosuppressive therapy, or any investigational agent for the purposes of treating cancer within 2 weeks prior to first study treatment
* Treatment with monoclonal antibodies for the purposes of treating cancer within 4 weeks prior to first study treatment
* Primary or secondary CNS lymphoma at the time of enrollment or history of CNS lymphoma
* Current or history of CNS disease, such as stroke, epilepsy, CNS vasculitis, or neurodegenerative disease
* Known or suspected history of hemophagocytic lymphohistiocytosis (HLH)
* Known history of progressive multifocal leukoencephalopathy
* Adverse events from prior anti-cancer therapy that have not resolved to Grade 1 or better (with the exception of alopecia and anorexia, or as otherwise permitted by inclusion criteria)
* Prior solid organ transplantation
* Prior allogeneic stem cell transplant
* Prior ASCT for lymphoma
* Prior autologous stem cell transplant for any indication other than lymphoma, within 5 years from the start of study treatment
* Active autoimmune disease requiring treatment
* Prior treatment with systemic immunosuppressive medications (including, but not limited to, cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor necrosis factor agents), within 4 weeks prior to first dose of study treatment
* Ongoing corticosteroid use \> 30 mg/day of prednisone or equivalent. Participants who received corticosteroid treatment with ≤ 30 mg/day of prednisone or equivalent must be documented to be on a stable dose of at least 4 weeks' duration prior to Cycle 1 Day 1. Participants may have received a brief (≤ 7 days) course of systemic steroids (≤ 100 mg prednisone equivalent per day) prior to initiation of study therapy for control of lymphoma-related symptoms
* Recent major surgery (within 4 weeks before the first study treatment) other than for diagnosis
* Clinically significant history of cirrhotic liver disease