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989 A Randomized Phase II Study of Mosunetuzumab SC Plus Polatuzumab Vedotin Demonstrates Improved Outcomes Versus Rituximab Plus Polatuzumab Vedotin in Patients (Pts) with Relapsed or Refractory (R/R) Large B-Cell Lymphoma (LBCL)

Program: Oral and Poster Abstracts
Type: Oral
Session: 627. Aggressive Lymphomas: Pharmacologic Therapies: Chemotherapy-free Combinations for Relapsed Aggressive Lymphomas
Hematology Disease Topics & Pathways:
Lymphomas, Bispecific Antibody Therapy, B Cell lymphoma, Diseases, Treatment Considerations, Biological therapies, Immunotherapy, Lymphoid Malignancies
Monday, December 9, 2024: 5:30 PM

Julio C. Chavez, MD1, Adam J. Olszewski2*, Mariana Bastos-Oreiro3*, Sarit E. Assouline, MD4, Izidore S. Lossos, MD5, Catherine Diefenbach6, Nilanjan Ghosh7*, Dipenkumar Modi, MD8, Waleed Sabry, MD, MSc. PhD, FRCPE9*, Seema Naik, MD10*, Nirav N. Shah, MD11, Ronan Foley, MD, FRCPC12*, Daniel J Hodson, MD-PhD13, Sneha Makadia14*, Song Pham15*, Elicia Penuel14*, Hao Wu14*, Wahib S. Ead14*, Iris To14*, Connie Lee Batlevi14, Michael C. Wei14* and L. Elizabeth Budde16

1Department of Malignant Hematology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL
2Legorreta Cancer Center at Brown University, Lifespan Cancer Institute, Providence, RI
3Hospital General Universitario Gregorio Marañón, Madrid, Spain
4Jewish General Hospital, McGill University, Montreal, QC, Canada
5University of Miami/Sylvester Comprehensive Cancer Center, Miami, FL
6Perlmutter Cancer Center at NYU Langone Health, New York, NY
7Levine Cancer Institute/Atrium Health, Charlotte, NC
8Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI
9Saskatoon Cancer Centre, Saskatoon, SK, Canada
10Penn State Cancer Institute, Hershey, PA
11Medical College of Wisconsin, Milwaukee, WI
12Juravinski Hospital and Cancer Centre, Hamilton, ON, Canada
13Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
14Genentech, Inc., South San Francisco, CA
15Hoffmann-La Roche Ltd, Mississauga, ON, Canada
16City of Hope National Medical Center, Duarte, CA

Background: The ongoing Phase Ib/II study (NCT03671018) evaluates mosunetuzumab (Mosun) plus polatuzumab vedotin (Pola; M-Pola) in pts with R/R LBCL. The Phase II single-arm expansion cohort showed a manageable safety profile and highly durable responses with M (IV administration)-Pola at primary analysis (Budde et al. Nat Med 2024). To delineate the contribution of Mosun to the M-Pola combination, we conducted an analysis of a Phase II randomized cohort evaluating M (SC administration)-Pola vs rituximab (R)-Pola in R/R LBCL.

Methods: Eligible pts had confirmed R/R LBCL (diffuse LBCL [DLBCL] not otherwise specified, follicular lymphoma [FL] Grade [Gr] 3b, high-grade B-cell lymphoma [HGBCL], or transformed [tr]FL) and had received ≥1 prior therapy (including an anti-CD20 antibody). Pts were randomized 1:1 to M (SC)-Pola or R-Pola (stratified by number of prior therapies [1 vs ≥2]). Treatment cycles were 21 days. Mosun SC was given with Cycle (C)1 step-up dosing (5mg on C1 Day [D]1; 45mg on C1D8, C1D15, and D1 of C2-8) to mitigate cytokine release syndrome (CRS). Hospitalization was not mandatory. Pola IV (1.8mg/kg) was given on D1 of C1-6. Rituximab IV (375mg/m2) was given on D1 of C1-8. Pts on R-Pola with disease progression during or at end of treatment (EOT) or stable disease at EOT could cross over to receive M-Pola (up to 8 cycles of cumulative Pola). Primary endpoint was best ORR using Lugano 2014 criteria. CRS events were defined per ASTCT criteria.

Results: As of January 30, 2024, 80 pts were enrolled to receive M (SC)-Pola (n=40) or R-Pola (n=40). 20 pts on R-Pola received crossover treatment with M-Pola, and 1 pt in the R-Pola arm did not receive treatment (study withdrawal). For M-Pola vs R-Pola, median age was 71.5 vs 67.0 years, 48% vs 54% had IPI 3-5, and 78% vs 85% had Ann Arbor Stage III/IV disease, 68% vs 82% of pts had DLBCL, 8% vs 3% of pts had Gr 3b FL, and 25% vs 15% of pts had HGBCL; among pts with DLBCL and HGBCL, 13% vs 23% had trFL. Median number of prior therapies in the M-Pola vs R-Pola arms was 2 (range 1-5) vs 3 (range 1-9), 35% vs 39% of pts received prior CAR-T, and 15% vs 23% had prior ASCT. A total of 50% vs 62% of pts on M-Pola vs R-Pola were primary refractory (relapse <6 months after first-line [1L] therapy), 71% (n=10/14) vs 80% (n=12/15) were refractory to CAR-T, and 13% vs 8% had early relapse (6-12 months after 1L therapy).

For M-Pola vs R-Pola, ORR was 78% (95% CI: 61.6-89.2) vs 50% (95% CI: 33.8-66.2), CR rate was 58% (95% CI: 40.9-73.0) vs 35% (95% CI: 20.6-51.7), median duration of response was NR vs 10.1 months (95% CI: 3.6-NR; HR 0.40 [95% CI: 0.1-1.2]), median duration of CR was NR in both arms (HR 0.38 [95% CI: 0.1-1.3]), and median PFS was NR vs 6.4 months (95% CI: 4.7-NR; HR 0.48 [95% CI: 0.2-1.0]). OS was NR in the M-Pola and R-Pola arms (median follow-up 18 months).

Adverse events (AEs) occurring in ≥30% of pts with M-Pola were injection-site reaction (55%), diarrhea (48%), fatigue (35%), and constipation (30%). AEs in ≥30% of pts with R-Pola were nausea (36%), diarrhea (33%), and fatigue (33%). Serious AE rates were similar between arms (M-Pola, 33%; R-Pola, 26%). The most common Gr 3/4 AE in both arms was neutropenia (M-Pola, 30%; R-Pola, 21%). One Gr 3 febrile neutropenia event occurred with M-Pola. Gr 5 AEs occurred in 2 (5%) pts on M-Pola (both COVID-19 related) vs 1 (3%) pt on R-Pola (hepatic failure). CRS events occurred in 4 (10%) pts on M-Pola (all Gr 1/2, all during C1, all resolved). Median CRS duration was 3 days (range 2-5), and 1 pt was treated with tocilizumab. In pts experiencing CRS, mean IL-6 and IFN-γ levels were elevated ~2-fold 24 hours after Mosun SC treatment. Peripheral neuropathy (PN) occurred in 4 (10%) pts on M-Pola (Gr 1, n=3; Gr 2, n=1) and 2 (5%) pts on R-Pola (all Gr 1). One neurologic event potentially consistent with ICANS was observed with M-Pola (Gr 2 seizure). Serious infections occurred in 9 (23%) pts on M-Pola and 7 (18%) pts on R-Pola (mainly COVID-19/COVID-19 pneumonia). Treatment was discontinued due to AEs in 3 pts on M-Pola (PN, n=2 [1 Pola related]; COVID-19 pneumonia, n=1]); and 2 pts on R-Pola (PN, n=1; pain in extremity, n=1 [neither treatment related]).

Conclusions: Fixed-duration outpatient M (SC)-Pola improved efficacy, with higher ORR and CR rate, promising durability, low rates of CRS events, and no excess toxicities vs R-Pola in pts with R/R LBCL. These results strongly support the continued evaluation of the M (SC)-Pola regimen being investigated in the Phase III SUNMO study (NCT05171647).

Disclosures: Chavez: GenMab: Consultancy, Research Funding; Cellectis: Consultancy; Lilly: Honoraria, Speakers Bureau; Merck: Research Funding; Janssen: Honoraria; ADC Therapeutics: Consultancy; Novartis: Consultancy; Kite, a Gilead Company: Consultancy; AstraZeneca: Consultancy; Allogene: Consultancy; Abbvie: Consultancy; BeiGene: Consultancy, Honoraria, Speakers Bureau. Olszewski: Genmab, Schrodinger, ADC Therapeutics, Beigene, Bristol-Myers Squibb: Consultancy; Genmab, Schrodinger, Genentech, Precision Biosciences, Artiva, Pfizer, Kymera Therapeutics: Research Funding. Bastos-Oreiro: AbbVie, BMS, Incyte, Janssen, Kite, Lilly, Novartis, Roche: Honoraria, Speakers Bureau; Hospital Gregorio Maranon: Current Employment; Kite, Roche: Research Funding; Spanish Society of haematology, Madrid association of haematology, GELTAMO: Membership on an entity's Board of Directors or advisory committees. Assouline: BeiGene: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Genentech/Roche: Consultancy, Honoraria; Novartis Canada Inc.: Research Funding; AstraZeneca: Consultancy, Honoraria; F. Hoffman-La Roche Ltd.: Consultancy, Honoraria; Ipsen: Consultancy; Gilead: Honoraria; Abbvie: Consultancy, Honoraria; Pfizer: Consultancy. Lossos: Not specified: Patents & Royalties; University of Miami: Current Employment; ADCT: Research Funding. Diefenbach: NYU Grossman School of Medicine/Perlmutter Cancer Center at NYU Langone Health: Current Employment; Gilead Sciences: Current equity holder in publicly-traded company; OverT Therapeutics: Current equity holder in private company; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Celgene: Consultancy; FATE Therapeutics: Research Funding; Genentech/Roche: Consultancy, Research Funding; Genmab: Consultancy; I MAB: Consultancy; Incyte: Consultancy, Research Funding; MEI Pharma: Research Funding; Merck: Consultancy, Research Funding; Millenium: Research Funding; MorphoSys: Consultancy; Seattle Genetics: Consultancy, Research Funding. Ghosh: TG Therapeutics, Genentech/Roche, Bristol Myers Squibb, Gilead, Morphosys, AbbVie: Research Funding; Seagen, TG Therapeutics, AstraZeneca, Pharmacyclics, Janssen, Bristol Myers Squibb, Gilead Sciences, Beigene, Incyte, Karyopharm, Roche/Genentech, Novartis, Loxo Oncology, Genmab, Adaptive Biotech, ADC Therapeutics and Syncopation: Consultancy; Roche/Genentech, AbbVie, BMS: Research Funding; AstraZeneca, Pharmacyclics, Janssen, BMS, Kite Pharma, BeiGene, Incyte, Lava Therapeutics, Roche/Genentech, Novartis, Loxo Oncology, AbbVie, Genmab, Prepromene, and ADC Therapeutics, Ascentage and Ipsen.: Honoraria; AstraZeneca, Pharmacyclics, Janssen, BMS, Gilead Sciences, Kite Pharma, BeiGene, Incyte, Lava Therapeutics, Roche/Genentech, Novartis, Loxo Oncology, AbbVie, Genmab, Adaptive Biotech, Prepromene, Ascentage and Ipsen: Consultancy. Modi: Karyopharm: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees; Beigene: Speakers Bureau; AstraZeneca: Research Funding; AstraZeneca: Consultancy; Karyopharm: Membership on an entity's Board of Directors or advisory committees; ADC therapeutics: Membership on an entity's Board of Directors or advisory committees. Naik: Janssen,Onclive: Honoraria. Shah: Miltenyi Biomedicine, Lilly Oncology: Research Funding; Gilead-Kite, BMS-Juno, Miltenyi, Lilly Onclogy, Novartis, Seattle Genetics, Janssen, Abbvie, Cargo, Beigene, Galapagos, AstraZeneca: Consultancy, Honoraria; Tundra Therapeutics: Current holder of stock options in a privately-held company. Foley: Novartis and Gilead: Other: Advisory boards ; Novartis, Gilead and Janssen: Honoraria; Gilead, Novartis, Celgene: Speakers Bureau. Hodson: Astra Zeneca, GSK: Research Funding. Makadia: Genentech: Current Employment, Current equity holder in publicly-traded company, Other: have stock in Genentech. Pham: Roche Canada: Current Employment. Penuel: Genentech, Inc.: Current Employment; F. Hoffmann-La Roche Ltd: Current equity holder in publicly-traded company. Wu: Roche/Genentech: Current Employment. Ead: Genentech: Current Employment, Current equity holder in private company, Current holder of stock options in a privately-held company. To: Genentech, Inc.: Current Employment, Current equity holder in publicly-traded company; Genentech, Inc.: Patents & Royalties. Batlevi: Memorial Sloan Kettering Cancer Center: Ended employment in the past 24 months; BMS, Seattle Genetics, Kite, Karyopharm, TG Therapeutics, ADC Therapeutics, AbbVie, Genentech, Inc., Treeline Bioscience: Consultancy; Regeneron, Moderna: Divested equity in a private or publicly-traded company in the past 24 months; Epizyme, Autolus, Roche, Vincerx: Research Funding; Dava Oncology, TouchIME, Medscape: Honoraria; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Current Employment, Current equity holder in publicly-traded company. Wei: F. Hoffmann-La Roche Ltd: Current equity holder in publicly-traded company; Genentech, Inc.: Current Employment, Patents & Royalties. Budde: ADC Therapeutics, AstraZeneca, AbbVie, F. Hoffmann-La Roche Ltd, Genentech, Inc., Genmab, Jenssen, Regeneron: Consultancy; AstraZeneca, Mustang Therapeutics, Merck: Research Funding; ADC Therapeutics, AstraZeneca, AbbiVe, Roche, Genentech, Genmab, Jenssen, Regeneron: Consultancy; AstraZeneca, Mustang Therapeutics, Merck: Research Funding; City of Hope National Medical Center: Current Employment.

OffLabel Disclosure: All study therapy constituted investigational or off-label use. Mosunetuzumab (Lunsumio) is a bispecific CD20-directed CD3 T-cell engager indicated for the treatment of adult patients with relapsed or refractory FL after two or more lines of systemic therapy. Polatuzumab vedotin (Polivy) is a CD79b-directed antibody-drug conjugate indicated: in combination with a rituximab product, cyclophosphamide, doxorubicin, and prednisone (R-CHP) for the treatment of adult patients who have previously untreated DLBCL, NOS or HGBL and who have an IPI score of 2 or greater; and in combination with bendamustine and a rituximab product for the treatment of adult pts with relapsed or refractory DLBCL, NOS after at least two prior therapies. Rituximab (Rituxan) is a CD20-directed cytolytic antibody indicated for the treatment: in adult patients with Non-Hodgkin's Lymphoma (NHL), including relapsed or refractory, low grade or follicular, CD20-positive B cell NHL as a single agent, and previously untreated follicular, CD20-positive, B-cell NHL in combination with first line chemotherapy and, in patients achieving a complete or partial response to a rituximab product in combination with chemotherapy, as single-agent maintenance therapy; non-progressing (including stable disease), low-grade, CD20-positive, B-cell NHL as a single agent after first-line cyclophosphamide, vincristine, and prednisone (CVP) chemotherapy; previously untreated diffuse large B-cell, CD20-positive NHL in combination with (cyclophosphamide, doxorubicin, vincristine, and prednisone) (CHOP) or other anthracycline-based chemotherapy regimens.

*signifies non-member of ASH