A Study to Evaluate the Optimization of the Cytokine Release Syndrome Profile for Glofitamab in Combination With Gemcitabine Plus Oxaliplatin in Participants With Relapsed/Refractory Aggressive B-Cell Non-Hodgkin's Lymphoma

Inclusion Criteria: * Histologically confirmed large B-cell lymphoma (de novo or transformed from FL) with one of the following diagnoses according to World Health Organization, fifth edition: DLBCL Not Otherwise Specified (NOS); High-Grade B-Cell Lymphoma (HGBL), NOS; DLBCL/HGBL with MYC and BCL2 rearrangements * R/R disease, defined as: relapsed = disease that has recurred following a response that lasted \>/= 6 months after completion of the last line of therapy; refractory = disease that did not respond to or that progressed \< 6 months after completion of the last line of therapy * At least one line of prior systemic therapy * Participants who have failed only one prior line of therapy must not be a candidate for high-dose chemotherapy followed by autologous stem cell transplant (ASCT) * At least one bi-dimensionally measurable (\> 1.5 cm) nodal lesion, or one bi-dimensionally measurable (\> 1 cm) extranodal lesion, as measured on CT scan * Eastern Cooperative Oncology Group (ECOG) status of 0, 1, or 2 * According to the investigator's judgment, participants should be able to receive the step-up dose regimen in an outpatient setting * Adequate hematologic and renal function Exclusion Criteria: * Prior enrollment in Studies GO41943 (NCT04313608), GO41944 (STARGLO; NCT04408638), or Study GO44900 (NCT06624085) * Participant has failed only one prior line of therapy and is a candidate for stem cell transplantation * Any history of Waldenstrom's macroglobulinemia * Primary…