A Study to Evaluate Glofitamab as a Single Agent vs. Investigator's Choice in Participants With Relapsed/Refractory Mantle Cell Lymphoma

Inclusion Criteria: * Life expectancy at least 12 weeks * Histologically-confirmed MCL, with documentation of either overexpression of cyclin D1 or the presence of t(11:14) within 12 months of study entry * Relapsed (disease progression after the last treatment regimen) or refractory (failure to achieve a partial or complete response from the last treatment regimen) disease * At least 1 line of prior systemic therapy including a BTK inhibitor and additional systemic therapy option * Confirmed availability of tumor tissue, unless deemed unsafe per investigator assessment * At least one bi-dimensionally measurable (defined as at least 1.5 cm) nodal lesion, or one bi-dimensionally measurable (at least 1 cm) extranodal lesion, as measured on CT scan * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 * Negative HIV test at screening * Adequate hematological function Exclusion Criteria: * Pregnancy or breastfeeding, or intention of becoming pregnant during the study or within 3 months after the final dose of tocilizumab, 2 months after the final dose of glofitamab, whichever is longer * Leukemic, non-nodal MCL * History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies (or recombinant antibody-related fusion proteins) or known sensitivity or allergy to murine products * Contraindication to obinutuzumab or rituximab, and either bendamustine or lenalidomide * Prior treatment with glofitamab or other bispecific antib…