Glofitamab as a Bridge to and/or Consolidation Post Autologous Stem Cell Transplant in Patients With Relapsed B Cell Lymphomas

Inclusion Criteria: \- To be eligible to participate in this trial, an individual must meet all of the following criteria: 1. Provision of signed and dated informed consent form (ICF) ) by the patient/impartial witness/legal representative before any trial related procedures. 2. Male or female aged between 18 and 65 years. 3. Ability and willingness to comply with the study protocol. 4. Histologically confirmed diagnosis of primary refractory or relapsed DLBCL (all subtypes including primary mediastinal B cell lymphoma, high grade B cell lymphoma, large B cell lymphoma etc) or transformed low grade B cell lymphoma planned for salvage Rituximab-chemotherapy regimens followed by ASCT. 5. Patients with a life expectancy of at least 6 months. 6. All patients must be stable without any signs of active infection, systemic (oral or parenteral) corticosteroid or anticonvulsant therapy for at least 2 weeks prior to study treatment. Inhaled non-absorbable and topical corticosteroid use are permitted as indicated. 7. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 with no deterioration over the previous 2 weeks. 8. Women of child-bearing potential and male subjects shall agree to take medically acceptable contraception measures while on study treatment and for 3 months following completion of study treatment. All women of child-bearing potential must have a negative blood pregnancy test at screening. Women must remain abstinent or use contraceptive methods with a failure rate of ≤1% per year during the study treatment period and for 2 months after the final dose of glofitamab, 3 months after the final dose of tocilizumab (if applicable), 12 months after rituximab or chemotherapy, or 18 months after the final dose of obinutuzumab. Women must refrain from donating eggs during this same period. A woman is considered of childbearing potential if she is postmenarchal, has not reached a postmenopausal state (≥12 continuous months of amenorrhea with no identified cause other than menopause), and is not permanently infertile due to surgery (i.e., removal of ovaries, fallopian tubes, and/or uterus) or another cause as determined by the investigator (i.e., Müllerian agenesis). The definition of childbearing potential may be adapted for alignment with local guidelines or regulations. Examples of contraceptive methods with a failure rate of ≤1% per year include bilateral tubal ligation, male sterilization, hormone-releasing intrauterine devices, and copper intrauterine devices. Hormonal contraceptive methods must be supplemented by a barrier method. The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the individual. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or post ovulation methods) and withdrawal are not adequate methods of contraception. If required per local guidelines or regulations, locally recognized adequate methods of contraception and information about the reliability of abstinence will be described in the local Informed Consent Form. For men who are not surgically sterile (or with azoospermia for other reasons): Investigators will discuss sperm conservation prior to initiation of study treatment for male participants. Participants who agree to remain abstinent (refrain from heterosexual intercourse) or use contraception, and agree to refrain from donating sperm, as defined below: With a female partner of childbearing potential who is not pregnant, men must remain abstinent or use a condom plus an additional contraceptive method that together result in a failure rate of ≤1% per year during the study treatment period and for 2 months after the final dose of glofitamab, 3 months after the final dose of tocilizumab (if applicable), 6 months after rituximab, ICE (ifosfamide, carboplatin, and etoposide) or obinutuzumab. Men must refrain from donating sperm during this same period. The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the individual. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or post ovulation methods) and withdrawal are not adequate methods of contraception. If required per local guidelines or regulations, locally recognized adequate methods of contraception and information about the reliability of abstinence will be described in the local Informed Consent Form. 9. Patients with 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. 10. Adequate hematologic function (unless attributable to the underlying disease, as established by extensive bone marrow involvement or associated with hypersplenism secondary to the involvement of the spleen by DLBCL per the investigator), defined as follows: \- ANC ≥1.0 x109/L ( ≥1000/μL) Participants with a history of benign ethnic neutropenia may be included with ANC ≥0.75x109/L (≥750/μL). \- Platelet count ≥50x109/L (≥50,000/μL) without a transfusion in the week prior to starting study treatment. 11. Adequate renal function, defined as an estimated CrCl ≥ 45 mL/min. 12. Participants who have a negative HIV test at screening, with the following exception: Individuals with a positive HIV test at screening are eligible provided they are stable on anti-retroviral therapy for at least 4 weeks, have a CD4 count ≥200/μL, have an undetectable viral load, and have not had a history of opportunistic infection attributable to AIDS within the last 12 months. Exclusion Criteria: * An individual, who meets ANY of the following criteria, will be excluded from participation in this trial: 1. Patients receiving any investigational drug, biological, immunological therapy within the previous 21 days before enrollment. 2. Presence of any severe or uncontrolled systemic disease or condition, including serious ca