Trial in Progress: A Multicentre, Parallel Arm, Open-Label Trial of Frontline R-CHOP/Polatuzumab Vedotin-RCHP and Glofitamab in Younger Patients with Higher Risk Diffuse Large B Cell Lymphoma (COALITION)

Abstract Background: R-CHOP remains a standard frontline treatment for patients with DLBCL and high-grade B-cell lymphoma (HGBL). A significant proportion of patients will have refractory disease or subsequently relapse, particularly those with high-risk features such as an elevated IPI score or rearrangements of MYC and BCL2 and/or BCL6 (double/triple hit (DH/TH)). This population remains in need of improved induction treatments that can reduce the requirement for subsequent therapies which are associated with significant toxicities and diminishing response rates. Rationale: Glofitamab is a novel full-length bispecific antibody with a unique 2:1 configuration (two CD20 binding domains and one CD3 binding domain). In combination with a single pre-dose of obinutuzumab, glofitamab has demonstrated >70% complete remission in aggressive B-cell lymphoma at the recommended target dose in a phase 1 trial (Carlo-Stella, EHA 2021). Pre-clinical studies suggest that glofitamab's activity is retained in the presence of concomitant cytotoxic and CD20 antibody therapies, making it an attractive agent for combination with R-CHOP-like induction. Polatuzumab vedotin (pola) is an antibody-drug conjugate approved for R/R DLBCL in combination with BR, and is currently in evaluation for the front-line treatment of DLBCL in combination with RCHP in a randomised trial. The safety and preliminary efficacy of glofitamab in combination with R-CHOP, or pola-RCHP as a front-line treatment for high risk DLBCL is being evaluated. Study Design and Methods: This is a parallel-arm phase Ib/II trial. Treatment consists of an initial cycle of R-CHOP, followed by 5 cycles of combination induction treatment and 2 cycles of consolidation glofitamab monotherapy. Key inclusion criteria are: age 18-65 years, a diagnosis of DLBCL or HBGL, high-risk features (IPI ≥3 or NCCN-IPI ≥4 or presence of DH/TH), treatment naïve or after 1 cycle of R-CHOP, ECOG 0-3. The primary endpoint is the safety of the combination and secondary endpoints include complete response rates at interim and end of treatment FDG-PET assessments by Lugano criteria, progression free survival and overall survival. Correlative studies assessing baseline immunologic profiles, tumour phenotype and potential resistance mechanisms are planned. Approximately 40 patients will be treated in each arm across 12-14 Australian sites. The trial commenced recruitment in July 2021 (NCT04914741). The ability to recruit prior to either cycle 1 or cycle 2 allows seamless cross-referral from non-trial sites. Figure 1 Figure 1. Disclosures Minson: Hoffman La Roche: Research Funding; Novartis: Research Funding. Hamad: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Seymour: AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sunesis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Morphosys: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mei Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Dickinson: Celgene: Research Funding; Amgen: Honoraria; Takeda: Research Funding; MSD: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead Sciences: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodation, expenses, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau.