Radiotherapy in Combination With Glofitamab in Relapsed/Refractory Diffuse Large B Cell Lymphoma (Radio-GLO)

Radiotherapy in Combination With Glofitamab in Relapsed/Refractory Diffuse Large B Cell Lymphoma: The Phase II Radio-GLO Study

The goal of this clinical trial is to see if a new combination of standard of care radiotherapy treatment prior to administering the study drugs obinutuzumab and glofitamab in relapsed/refractory Diffuse Large B Cell Lymphoma patients is effective. The main question it aims to answer is:

If you are able to tolerate the study treatments, and whether your cancer responds to the study treatment, compared with other reported studies of standard care treatments.

Participants will have three parts they need to complete over a 5 year period.

• Screening period over a 28 day period
• Treatment period - Radiotherapy followed by 12 treatment cycles every three weeks (total time approx. 37 weeks)
• Follow up, up to 4 years. Additional PET imaging studies will be performed in a cohort of patients (up to 6) who are willing to undergo infusions of 89Zr-Df-Crefmirlimab and 18F-Granzyme B for evaluation of the impact of radiotherapy plus glofitamab with relapsed diffuse large B-cell lymphoma.

Study Overview

• Status: Not yet recruiting
• Conditions: Relapsed /Refractory DLBCL
• Intervention / Treatment: Drug: Glofitamab; Radiation: Radiotherapy; Drug: Obinutuzumab; Other: 89Zr-Df-crefmirlimab; Other: 18F-granzyme B

Detailed Description

Clinical trial looking at Radiotherapy in combination with glofitimab in relapsed/refractory Diffuse Large B Cell lymphoma. Where Relapsed/refractory diffuse large B-cell lymphoma after ≥ 2 therapies OR after 1 line AND transplant or CAR-T ineligible. The primary end points is to see what proportion of patients who achieve a complete metabolic response in the absence of prohibitive toxicity following radiotherapy (25Gy in 5 fractions) plus 12 cycles of glofitamab therapy with each cycle delivered every 3 weeks. The secondary endpoints are to assess overall toxicity, to evaluate overall response rates, duration of Response (DOR), time to treatment failure, progression free survival, overall survival, patient report outcome measure - Using EORTC QLD-C30, EORTC IL46 and PRO-CTCAE.

Additional PET imaging studies will be performed in a cohort of patients (up to 6) who are willing to undergo infusions of 89Zr-Df-Crefmirlimab and for evaluation of the impact of radiotherapy plus glofitamab on CD8+ T cell biodistribution in the body and in relapsed diffuse large B-cell lymphoma.

Additional PET imaging studies will be performed in a cohort of patients (up to 6) who are willing to undergo infusions of 18F-Granzyme B to image active immune responses to treatment with radiotherapy plus glofitamab in patients with relapsed diffuse large B-cell lymphoma.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 2

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • Douglas, Queensland, Australia
      • Townsville University Hospital
      • Contact: Dr. Joel Wight; Email: Joel.Wight@health.qld.gov.au
    • Woolloongabba, Queensland, Australia, 4102
      • Princess Alexandra Hospital
      • Contact: A/Prof. Colm Keane; Email: colm.keane@health.qld.gov.au
  • South Australia
    • Bedford Park, South Australia, Australia, 5042
      • Flinders Medical Centre
      • Contact: Dr. Kate Manos; Email: Kate.Manos@sa.gov.au
  • Victoria
    • Heidelberg, Victoria, Australia, 3084
      • Austin Hospital
      • Contact: Prof. Eliza Hawkes; Email: eliza.hawkes@onjcri.org.au
  • Western Australia
    • Murdoch, Western Australia, Australia
      • Fiona Stanley Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age 18 years.
2. Histologically proven relapsed/refractory CD20+ve DLBCL or a recognised subtype, including follicular large B-cell lymphoma and high grade B-cell lymphoma.
3. Prior systemic treatment: ≥2 lines OR after 1 line AND autologous stem cell transplant/CAR-T ineligible
4. Eastern Collaborative Oncology Group (ECOG) performance status 0 to 2.
5. Measurable FDG avid disease on baseline PET/CT scan
6. At least one site of active, PET positive disease that can be safely irradiated. Patients with disease only in previously irradiated sites that cannot be safely irradiated again due to tissue tolerance will be excluded.

7. Adequate bone marrow function including:

   • Haemoglobin >8.0 g/dL
   • White cell count (WCC) ≥2000/μL
   • Neutrophils >1.0 x 109/L
   • Platelets >75 x 109/L at the time of study entry, unless attributed to lymphoma. Red cell transfusion is permitted.
8. Adequate renal function with serum creatinine ≤1.5 x ULN or creatinine clearance (CrCl) ≥ 45mL/min (using Cockcroft-Gault formula, Modification of Diet in Renal Disease Study Equation, 24hr urine collection, eGFR or a formal nuclear medicine technique) unless attributed to lymphoma (e.g. ureteric obstruction).
9. Adequate hepatic function with AST/ALT ≤3x ULN and total bilirubin ≤1.5 x ULN (except subjects with Gilbert syndrome, who can have a total bilirubin ≤3 mg/dL or ≤51.3 μmol/L) unless attributed to lymphoma (e.g. liver infiltration or biliary obstruction).
10. Adequate left ventricular ejection fraction of >40% as demonstrated on a Gated Cardiac Blood Pool Scan or echocardiogram.
11. Life expectancy > 3 months.

12. Patients of childbearing potential willing to adhere to the following contraceptive precautions:

    For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating eggs, as defined below:

    Women must remain abstinent or use contraceptive methods with a failure rate of <1% per year during the treatment period and for at least 6 months after the final dose of obinutuzumab and 2 months after the final dose of glofitamab. Women must refrain from donating eggs during this same period.

    A woman is considered to be of childbearing potential if she is postmenarcheal, 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 (e.g., Müllerian agenesis). The definition of childbearing potential may be adapted for alignment with local guidelines or requirements.

    Examples of contraceptive methods with a failure rate of <1% per year include bilateral tubal ligation, male sterilization, hormonal contraceptives that inhibit ovulation, hormone-releasing intrauterine devices, and copper intrauterine devices.

    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 patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not acceptable methods of contraception. If required per local guidelines or regulations, locally recognized acceptable methods of contraception and information about the reliability of abstinence will be described in the local Informed Consent Form.

    For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm, as defined below:

    With a female partner of childbearing potential or pregnant female partners, 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 treatment period and for at least 6 months after obinutuzumab, and 2 months after the final dose of glofitamab or tocilizumab to avoid exposing the embryo. 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 patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not acceptable methods of contraception.

13. Written, informed consent.

Exclusion Criteria:

1. Patient has failed only one prior line of therapy and is a candidate for stem cell
2. Transplantation or CAR-T cell therapy
3. Excessively bulky or rapidly progressive disease that, in the opinion of the investigator, requires rapid debulking or is unsafe to be irradiated
4. Richter's transformation from CLL. Transformation from other low-grade histology (e.g. Follicular lymphoma, Marginal zone lymphoma etc) is permitted
5. Refractory to prior therapy with glofitamab or other anti-CD3/CD20 bispecific antibodies, defined as progression during or within 3 months of cessation.
6. Treatment with radiotherapy, chemotherapy, immunotherapy, immunosuppressive therapy, or any investigational agent for the purposes of treating cancer within 4 weeks or 5 half-lives (whichever is shorter) prior to first study treatment.
7. Current central nervous system, meningeal involvement or spinal cord compression by lymphoma. Previous involvement is permitted if there is currently no active CNS disease.
8. Patients with active, known or suspected autoimmune disease. Patients with well controlled type I diabetes mellitus, coeliac disease, residual hypothyroidism due to autoimmune condition only requiring hormone replacement, vitiligo or psoriasis not requiring systemic treatment, or other conditions not expected to recur in the absence of an external trigger are permitted to enrol.
9. Subjects with a condition requiring systemic treatment with either corticosteroids (>10mg daily prednisone equivalents) or other immunosuppressive medications within 14 days of study drug administration without prior discussion with the medical monitor. Inhaled or topical steroids, and adrenal replacement therapy are permitted in the absence of active autoimmune disease.
10. Prior solid organ transplantation or allogeneic bone marrow transplantation within 6 months.
11. Prior malignancy active within the previous 2 years except for those treated with curative intent and with a <20% chance of relapse. Low-grade prostate cancer under observation or well controlled on hormone therapy is permitted. Resected or locally treated non-melanoma skin cancer is permitted.
12. Uncontrolled or severe cardiovascular disease (NYHA class III or IV heart failure; myocardial infarction within the last 6 months of study entry); unstable angina; unstable cardiac arrhythmias; clinically significant pericardial disease.
13. Any other serious active disease or infection that in the opinion of the investigator takes precedence over the DLBCL, or will impact on the ability to deliver study treatment.
14. Any positive test result for hepatitis B or hepatitis C virus during screening indicating acute or chronic infection. Latent hepatitis B with undetectable viral load by PCR is allowable provided appropriate anti-viral prophylaxis is given as per institutional guidelines.
15. Any positive test for human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome (AIDS) unless the viral load is fully suppressed for >2 years with a CD4 count of >350x106/L and compliant with antiretroviral therapy.
16. Any history of severe hypersensitivity reactions to other monoclonal antibodies.
17. A history of allergy or intolerance (unacceptable AEs) to study drug components.
18. Patients incarcerated or without Medicare
19. Medical or psychiatric conditions that compromise the patient's ability to give informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Intervention; Radiotherapy will be delivered at 25Gy in 5 fractions to all PET/CT-avid nodal, and selected extranodal disease sites >1.5cm diameter. Following RT, patients will commence systemic therapy and receive one dose of 1000mg obinutuzumab (IV) followed by an initial step-up dose ramp of glofitamab on day 15 and day 22 (D15 2.5mg IV, D22 10mg IV), then 30mg intravenously every 3 weeks for cycles 2-12. Participants will have FDG PET/CT scans at the start of the study, after cycles 2, 4/5 and 8/9, at the end of treatment after cycle 12, and again if the disease returns (where possible). For up to 6 patients at approved sites, an additional PET sub-study will involve two extra scans using each tracer, one before treatment starts and one after cycle 2. After finishing treatment, participants will attend follow-up clinic visits every 3 months during the first year, and then every 6 months from years 2 to 5.

Drug: Glofitamab; Glofitamab is the treatment of adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) after two or more prior systemic therapies.; Other Names: Columvi; Radiation: Radiotherapy; 25 Gy in 5 fractions.; Drug: Obinutuzumab; Obinutuzumab as a pre-treatment to reduce the risk of CRS induced by glofitamab is approved in Australia.; Other Names: Gazyva; Other: 89Zr-Df-crefmirlimab; 89Zr-Df-crefmirlimab infusion and imaging (24hrs+/- 4 hours) - must be at least 5 days prior to the first fraction of radiotherapy of study treatment, A second infusion of 89Zr-Df-crefmirlimab and imaging will be after Cycle 2 (15 days +/- 3 days); Other Names: 89Zr-DF-IAB22M2C; Other: 18F-granzyme B; Eligible participants will receive an initial injection of 18F-CSB-321 followed by PET imaging up to 14 days prior to commencing therapy. 370 MBq (±10%) of 18F-CSB-321 is injected, without the need of pre-medications. Participants will be monitored for adverse events up to 2 hours post-injection.; Other Names: CSB-321; [AI18F]-NODA-CSB-321

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Complete Response Rate After Radiotherapy and Glofitamab Treatment	The study will assess how many participants achieve a complete metabolic response after radiotherapy and 12 cycles of glofitamab treatment, without severe side effects that require stopping treatment early	37 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety assessment through adverse events	The study will assess the safety and effectiveness of treatment, including side effects such as cytokine release syndrome (CRS) and infections. All adverse events will be graded according to CTCAE v 5.0.	5 years total
Assessment of impact of side effects on patient's quality of life - EORTC-QLQ-C30	The EORTC QLQ-C30 is a patient-reported outcome measure that evaluates health-related quality of life across multiple domains. It includes five functional domains, physical, role, cognitive, emotional, and social functioning. As well as nine symptom domains covering fatigue, pain, nausea and vomiting, dyspnoea, appetite loss, insomnia, constipation, diarrhoea, and financial impact. In addition, it contains a global health status/quality-of-life scale. Responses are recorded using both 4-point and 7-point rating scales. Changes in global health status from baseline will be analysed. For the functional domains, higher scores indicate better levels of functioning, while higher scores on symptom domains represent greater symptom severity or burden.	5 years
Overall Toxicity (all grades)	Overall Toxicity (all grades) and adverse events of special interest of treatment will be collected and graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 5.0.	5 years
Overall Response Rate to study treatment	Overall Response Rate as defined by the number of subjects with a best overall response of complete remission (CR), partial remission (PR) as assessed by CT plus PET, defined by the Lugano Response assessment for Non Hodgkin Lymphoma, at the completion of treatment or during the study.	5 years
Time to Treatment failure	Time to Treatment failure will be calculated from the date of study enrolment until a progression event occurs. Progression events are defined as clinical or radiological documented disease progression.	5 years
Progression-free Survival	Progression-free Survival will be calculated from the date of study enrolment until a progression event occurs, or death from any cause. Patients alive without progression will be censored at date last known to be alive.	5 years
Overall survival	Overall survival will be measured from study entry to date of death from any cause; surviving patients will be censored at date last known to be alive.	5 years
Assessment of impact of side effects on patient's quality of life - PRO-CTCAE	PRO-CTCAE assessments will be analysed to evaluate data integrity, describe baseline symptom burden, monitor symptom trajectories over time, assess the emergence and evolution of patient-reported adverse events, and explore concordance between patient-reported outcomes and investigator-rated adverse events. Results will be summarized descriptively by reporting the frequency and percentage of participants selecting each response level for each PRO-CTCAE item. Comparisons between treatment arms will be undertaken at the individual question level.	5 years
Assessment of impact of side effects on patient's quality of life - EORTC-IL4	The EORTC-IL4 is a disease-specific quality-of-life instrument developed to supplement the EORTC QLQ-C30 by capturing additional symptoms and concerns relevant to the study population. Questionnaire responses will be summarised descriptively at each assessment time point. Scores will be calculated and transformed according to EORTC scoring guidelines, where applicable. Changes from baseline will be evaluated over time to assess the impact of treatment on patient-reported symptoms and health-related quality of life. Higher scores on symptom-related items indicate a greater symptom burden or level of concern, whereas higher scores on functioning-related items indicate better functioning and quality of life.	5 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood markers linked to treatment response and side effects	Blood samples will be used for biomarker analysis, which will include but is not limited to: DNA (deoxyribonucleic acid) genotyping, RNA (ribonucleic acid) and/or miRNA (micro-RNA) expression, ctDNA analysis and soluble serum/plasma factors related to immune and tumour response in order to correlate potential biomarkers with treatment responses and toxicity.	5 years
Gut bacteria changes linked to treatment response and side effects	Studying whether changes in gut bacteria are associated with how patients respond to treatment and their risk of side effects.	5 years
Advanced PET scan measures	Change from baseline in PET radiomic features associated with intra-tumoral activated T-cell infiltration after cycle 2 of glofitamab. CT imaging in this instance will be used to 'locate' the tumor and will not be used for diagnostic purposes.	12 months
Tissue markers linked to treatment response and side effects	Tissue samples will be collected to evaluate the role of prognostic and predictive biomarkers. Tissue samples will be collected (core biopsies-minimum of 3, ideally 5-6 cores- or surgical biopsies as part of the standard study assessments and should be preserved as formalin-fixed paraffin-embedded (FFPE) specimens.	5 years

Collaborators and Investigators

• Sponsor: Olivia Newton-John Cancer Research Institute
• Collaborators: Hoffmann-La Roche; Austin Health; Princess Alexandra Hospital, Brisbane, Australia; Flinders Medical Centre; Townsville Hospital; Fiona Stanley Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): December 1, 2026
• Primary Completion (Estimated): December 1, 2031
• Study Completion (Estimated): December 1, 2032

Study Registration Dates

• First Submitted: May 20, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: DLBCL; glofitamab; relapsed/refractory Diffuse Large B Cell lymphoma; Raditherapy; Radio-GLO; Obinutuzumab - Gazyva, Gazyvaro; Columvi
• Additional Relevant MeSH Terms: Neoplasms; Immune System Diseases; Neoplasms by Histologic Type; Lymphatic Diseases; Lymphoproliferative Disorders; Immunoproliferative Disorders; Lymphoma, Non-Hodgkin; Lymphoma, B-Cell; Lymphoma; Hemic and Lymphatic Diseases; Lymphoma, Large B-Cell, Diffuse; Therapeutics; Radiotherapy; obinutuzumab; glofitamab
• Other Study ID Numbers: ONJ2026-003

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Data sharing to occur at publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No