Fixed-Duration Glofitamab Monotherapy Continues to Demonstrate Durable Responses in Patients with Relapsed or Refractory Large B-Cell Lymphoma: 3-Year Follow-up from a Pivotal Phase II Study

Background: Glofitamab is a CD20xCD3 bispecific antibody that engages and redirects T cells to eliminate B cells. In this Phase II study (NCT03075696) of patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL), fixed-duration glofitamab monotherapy induced high complete response (CR) rates and durable responses with manageable toxicity (Dickinson, et al. N Engl J Med 2022). As a result, glofitamab monotherapy was approved by the FDA and EMA for use in patients with R/R LBCL after ≥2 prior lines of therapy. Here, we present updated data with an extended follow-up of over 3 years, a landmark analysis assessing outcomes of patients in CR, and exploratory biomarker analyses after end of treatment (EOT) evaluating the risk and benefit of fixed-duration treatment.

Methods: Patients with LBCL and ≥2 prior therapies received obinutuzumab pretreatment (1000mg) on Day (D)1 of Cycle (C)1. Intravenous glofitamab was then given as step-up doses during C1 (2.5mg on D8; 10mg on D15), followed by the target dose (30mg) on D1 of C2-12 (21-day cycles). The primary endpoint was independent review committee (IRC)-assessed CR rate using Lugano criteria (Cheson, et al. J Clin Oncol 2014). Progression-free survival (PFS) and overall survival (OS) post-hoc analyses were performed in responders (landmark for CR at EOT). A modified AVENIO circulating tumor (ct)DNA analysis workflow (Roche; Research Use Only) was used for next-generation sequencing based on personalized cancer profiling; ctDNA was quantified as mutant molecules per milliliter of plasma (MMPM). CD19-positive B-cell count was measured centrally with the T, B, and natural killer cell (TBNK) assay.

Results: As of May 17, 2024, 155 patients were enrolled; 154 patients had received ≥1 dose of study treatment. Baseline characteristics have been previously published (Dickinson, et al. N Engl J Med 2022). Median number of prior therapies was 3 (range: 2-7); 33% had received prior chimeric antigen receptor T-cells and 84% were refractory to their most recent regimen. Median time on study was 41.0 months (range: 0-52), with all patients with ongoing remission being treatment-free for ≥2 years following EOT.

The IRC-assessed CR rate was 40% and overall response rate was 52%. After a median follow-up of 37.7 months (range: 0-51) in patients with a CR, median duration of CR was 29.8 months (95% CI: 22.0-not estimable [NE]). In patients with a CR at EOT, the PFS and OS rates 2 years after EOT were 57% and 77%, respectively.

The incidence of adverse events (AEs) and serious AEs was stable compared with earlier analyses; two new Grade ≥3 AEs (neutropenia [Grade 3] and adenocarcinoma pancreas [Grade 4]) were reported. No new cytokine release syndrome events, infections, other cytopenia, or fatal AEs were reported since the previous analysis.

Baseline ctDNA levels were previously shown to be prognostic in patients treated with glofitamab monotherapy. Patients with a CR at EOT and evaluable for ctDNA at baseline (27/45; 60%) showed a rapid and sustained decrease of ctDNA levels on treatment, maintained 12 months after EOT in patients with ongoing remission (baseline [n=27]: median MMPM 37.48 [range 3.13-23544.37]; C3 [n=27]: median MMPM 0.55 [range 0.00-471.18]; EOT [n=27]: median MMPM 0.29 [range 0.00-49.59]; 12 months follow-up [n=18]: median MMPM 0.04 [range 0.00-95.08]. B-cell depletion occurred in all patients during treatment; recovery of B cells and immunoglobulins was observed starting around 18 months after glofitamab treatment in patients with a sustained response after EOT.

Conclusions: With this extended follow-up of over 3 years, durable responses continued to be observed with fixed-duration glofitamab in patients with R/R LBCL. The safety profile remains manageable and consistent with previous analyses. ctDNA kinetics showed that molecular response to glofitamab was rapid and sustained after EOT. Evidence of B cell and immunoglobulin recovery after EOT was observed in patients in remission. These data support the potential for long-lasting remissions and a beneficial effect on immune system recovery in patients with R/R LBCL treated with fixed-duration glofitamab.

Dickinson:Genmab: Consultancy, Honoraria, Speakers Bureau; Kite: Consultancy, Honoraria, Speakers Bureau; Adicet Bio: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau. Carlo-Stella:Scenic Biotech: Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Merck Sharp & Dohme: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Janssen Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi, ADC Therapeutics, Celgene/Bristol-Myers Squibb, Karyopharm Therapeutics, Roche, Novartis, Scenic Biotech, Janssen Oncology, Merck Sharp & Dohme, SOBI, AbbVie, Genmab, AstraZeneca: Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Consultancy, Honoraria, Research Funding; AstraZeneca, Celgene/Bristol-Myers Squibb, Incyte, Janssen Oncology, Takeda, Novartis, ADC Therapeutics, Roche, Gilead, SOBI, Merck Sharp & Dohme: Honoraria; ADC Therapeutics, Roche, Sanofi: Research Funding; Sanofi, ADC Therapeutics: Consultancy; Humanitas University, Milano (Italy): Current Employment; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; SOBI: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria; Karyopharm Therapeutics: Membership on an entity's Board of Directors or advisory committees. Morschhauser:Epizyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Consultancy, Honoraria, Other: Payment for Expert Testimony, Honoraria for Scientific Lectures; Chugai: Honoraria; Eisai: Honoraria; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genmab: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead Sciences: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Consultancy. Bachy:Novartis: Honoraria, Other: Personal Fees; BeiGene: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie, Roche, Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria; Bristol Myers Squibb: Honoraria, Other: Personal Fees, Research Funding; Amgen: Research Funding; ADC Therapeutics: Honoraria; Pfizer: Honoraria, Other: Personal Fees; Kite, a Gilead Company: Consultancy, Honoraria, Other: Personal Fees. Cartron:MedXcell: Consultancy; Takeda: Honoraria; Beigene: Consultancy, Honoraria; Janssen: Honoraria; Roche, BMS, Gilead, Novartis, Takeda, Beigen, Janssen, AbbVie: Honoraria; Roche, BMS, AbbVie, Ownards therapeutics, MAbQi, MedXcell, BeiGene: Consultancy; MAbQi: Consultancy; Novartis: Honoraria; Ownards therapeutics: Consultancy; Gilead: Honoraria; Abbvie: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Corradini:GlaxoSmithKline: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Gilead/Kite: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; Daiichi Sankyo: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Roche: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; Sanofi: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Novartis: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; SOBI: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Takeda: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; Pfizer: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Kyowa Kirin: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Incyte: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); Janssen: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; Bristol Myers Squibb: Other: Support for travel and accommodations; Celgene: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; Amgen: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations; AbbVie: Other: Honoraria (for consultancy, participation in advisory boards, or lectures); support for travel and accommodations. Bartlett:Washington University School of Medicine: Current Employment; ADC Therapeutics: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Roche/Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Millennium: Research Funding; Janssen: Research Funding; Kite Pharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Forty Seven: Research Funding; Celegne: Research Funding; BMS: Research Funding; Autolus: Research Funding; Foresight Diagnostics: Membership on an entity's Board of Directors or advisory committees. Iacoboni:Autolus, Bristol-Myers Squibb, Kite/Gilead, Miltenyi, Novartis: Consultancy; AbbVie, AstraZeneca, Autolus, Bristol-Myers Squibb, Kite/Gilead, Miltenyi, Novartis, Lilly and Sandoz: Honoraria; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support; BMS: Consultancy, Honoraria; AstraZeneca: Honoraria, Other: Travel support; AbbVie: Honoraria, Other: Travel Support; Autolus: Consultancy; Miltenyi: Consultancy, Honoraria; Novartis: Honoraria; AbbVie, AstraZeneca, Kite/Gilead, Miltenyi: Other: Travel support. Khan:Epizyme, AstraZeneca, Genentech, Beigene, Morphosys, Acerta, TG Therapeutics: Research Funding; Lilly USA, Genentech, AstraZeneca, ADC Therapeutics, SeaGen, BeiGene, Kite Pharma, BMS, Abbvie, Incyte, Acrotech, Celgene, Amgen, Karyopharm, Genmab, Genzyme: Speakers Bureau. Hertzberg:Roche, Takeda, AbbVie: Membership on an entity's Board of Directors or advisory committees; Roche, Takeda, Janssen, Pfizer, Gilead: Honoraria; Roche/Genentech, Janssen: Research Funding. Falchi:Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Research Funding; Genentech, Roche, Genmab, Abbvie, Sanofi, EvolveImmune: Honoraria; AbbVie, Genentech, ADC Therapeutics, Seagen, Ipsen: Membership on an entity's Board of Directors or advisory committees; Taylor Francis: Other: Journal Editor; Genmab: Consultancy, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; EvolveImmune: Consultancy; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Memorial Sloan Kettering Cancer Center: Current Employment; Genentech, Roche, Genmab, AbbVie, Innate, BeiGene: Research Funding; Kaplan: Other: CME Presentation: Projects in Knowledge. Trněný:Caribou Biosciences: Consultancy; Takeda: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Incyte: Consultancy; Abbvie: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Bristol-Myers Squibb: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Gilead Sciences: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Roche: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Amgen: Consultancy, Honoraria; Genmab: Consultancy; Novartis: Consultancy, Honoraria; MorphoSys: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Autolus: Consultancy; SOBI: Consultancy, Honoraria, Other: Travel, Accomodations, Expenses; Swixx BioPharma: Honoraria. Mulvihill:F. Hoffmann-La Roche Ltd: Current Employment, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months. Berthier:F. Hoffmann-La Roche Ltd: Current Employment, Current equity holder in publicly-traded company. Bottos:F. Hoffmann-La Roche Ltd: Current Employment, Current equity holder in private company, Current holder of stock options in a privately-held company, Ended employment in the past 24 months. Relf:F. Hoffmann-La Roche Ltd: Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months; F-star Therapeutics: Divested equity in a private or publicly-traded company in the past 24 months; Roche Products Ltd: Current Employment. Bene Tchaleu:Genentech, Inc.: Current Employment, Current holder of stock options in a privately-held company. Lundberg:F. Hoffmann-La Roche Ltd: Current Employment, Current equity holder in publicly-traded company, Current holder of stock options in a privately-held company, Patents & Royalties. Hutchings:AbbVie, AstraZeneca, Genmab, Johnson & Johnson, Merck, F. Hoffmann-La Roche Ltd, Takeda: Honoraria; AbbVie, AstraZeneca, Bristol Myers-Squibb, Celgene, Genentech, Inc., Genmab, Incyte, Johnson & Johnson, Merck, Novartis, F. Hoffmann-La Roche Ltd, Takeda: Research Funding; AbbVie, AstraZeneca, Genmab, Johnson & Johnson, Merck, F. Hoffmann-La Roche Ltd, Takeda: Consultancy.