Amulirafusp alfa (IMM-0306) is a fusion protein of CD20 monoclonal antibody (mAb) with the CD47 binding domain of SIRPα, with human CD20 K d 2.45 nM and human CD47 K d 4.91 nM. Amulirafusp alfa binds to CD20 and CD47 on B cells, engages FcɣR, blocks CD47-SIRPα interaction, activates macrophages, NK cells, and complement cascade, mediates phagocytosis and cytotoxicity, inhibits apoptosis of Jurkat-CSR cells, reverses IL-16 tumor-promoting effects, and binds human/cynomolgus CD47 but not mouse/rat CD47. Amulirafusp alfa can be used for the research of hematological malignancies, relapsed or refractory CD20-positive B-cell non-Hodgkin’s lymphoma, relapsed or refractory B-cell non-Hodgkin lymphoma, and activated B-cell-like diffuse large B-cell lymphoma [1] [2] [3] [4].
In Vivo, Amulirafusp alfa (IMM-0306) (1.5 mg/kg; i.v.; weekly; 3 weeks) induces 100% complete remission in CB17-SCID mice bearing subcutaneous Daudi xenografts[1]. Amulirafusp alfa (IMM-0306) (5 mg/kg; i.v.; weekly; 4 weeks) achieves 89.98-92.7% tumor growth inhibition in CB17-SCID mice bearing orthotopic Raji xenografts[1]. Amulirafusp alfa (IMM-0306) (1 mg/kg; i.v.; weekly; 4 weeks) reduces tumor bioluminescence intensity in CB17-SCID mice bearing orthotopic Raji-luc xenografts[1]. Amulirafusp alfa (IMM-0306) (2.5 mg/kg; i.v.; Days 2, 4, 6, 9, 11, and 13) exerts dose-dependent antitumor efficacy in ABC-DLBCL xenograft models, with significantly enhanced activity in tumors with high IL-16 expression, reducing mean tumor volume to ~350 mm3 in pre-IL-16-overexpressing U-2932 xenografts by Day 14[4].
In Vitro, Amulirafusp alfa (0.0001-10000 nM) binds with high affinity to CD47 on Jurkat cells (EC50 = 16.83 nM), CD20 on Raji-CD47KO cells (EC50 = 18.92 nM), and both antigens simultaneously (EC50 = 11.48 nM; EC50 = 0.02462 μg/mL for dual cell binding)[1]. Amulirafusp alfa has higher binding affinity for purified CD20 (2.45 nM) than for purified CD47 (4.91 nM)[1]. Amulirafusp alfa binds to multiple B-cell lymphoma cell lines, human PBMC, and cynomolgus monkey PBMC, shows minimal binding to human RBC (no hemagglutination), and cross-reacts with human and cynomolgus CD47 but not mouse or rat CD47[1]. Amulirafusp alfa significantly inhibits apoptosis of Jurkat-CSR cells via SIRPα/CD47 pathway blockade, with an IC50 of 4.046 nM[1]. Amulirafusp alfa induces potent ADCC, ADCP, and CDC against Raji, Daudi, Jeko-1, Ramos, SU-DHL-4, and SU-DHL-10 B-cell lymphoma cells, with stronger ADCC than rituximab, greater phagocytic activity against lymphoma cells than rituximab, and reduced activity against normal cells[1]. Amulirafusp alfa (10 μg/mL; 30 min) potently induces antibody-dependent cellular phagocytosis of TMD-8 and U-2932 ABC-DLBCL cells in vitro, with efficacy increasing as the effector-to-tumor cell ratio rises[4].
References:
[1]. Yu J, et al. IMM0306, a fusion protein of CD20 mAb with the CD47 binding domain of SIRPα, exerts excellent cancer killing efficacy by activating both macrophages and NK cells via blockade of CD47-SIRPα interaction and FcɣR engagement by simultaneously binding to CD47 and CD20 of B cells. Leukemia. 2023 Mar;37(3):695-698.
[2]. Lijuan Deng, et al. Phase Ib/IIa Study of Amulirafusp Alfa (IMM0306) in Combination with Lenalidomide in Patients with Relapsed or Refractory CD20-Positive B-Cell Non-Hodgkin's Lymphoma. Blood Volume 144, Supplement 1, 5 November 2024, Page 3033.
[3]. Yang J, et al. Safety and efficacy of amulirafusp alfa (IMM0306), a fusion protein of CD20 monoclonal antibody with the CD47 binding domain of SIRPα, in patients with relapsed or refractory B-cell non-Hodgkin lymphoma: a phase 1/2 study. Journal of hematology & oncology. 2024 Dec 18;17(1):123.
[4]. Guan X, et al. Lymphoma cell-driven IL-16 is expressed in activated B-cell-like diffuse large B-cell lymphomas and regulates the pro-tumor microenvironment. Haematologica. 2025 Feb 1;110(2):425-438.
In Vivo, Amulirafusp alfa (IMM-0306) (1.5 mg/kg; i.v.; weekly; 3 weeks) induces 100% complete remission in CB17-SCID mice bearing subcutaneous Daudi xenografts[1]. Amulirafusp alfa (IMM-0306) (5 mg/kg; i.v.; weekly; 4 weeks) achieves 89.98-92.7% tumor growth inhibition in CB17-SCID mice bearing orthotopic Raji xenografts[1]. Amulirafusp alfa (IMM-0306) (1 mg/kg; i.v.; weekly; 4 weeks) reduces tumor bioluminescence intensity in CB17-SCID mice bearing orthotopic Raji-luc xenografts[1]. Amulirafusp alfa (IMM-0306) (2.5 mg/kg; i.v.; Days 2, 4, 6, 9, 11, and 13) exerts dose-dependent antitumor efficacy in ABC-DLBCL xenograft models, with significantly enhanced activity in tumors with high IL-16 expression, reducing mean tumor volume to ~350 mm3 in pre-IL-16-overexpressing U-2932 xenografts by Day 14[4].
In Vitro, Amulirafusp alfa (0.0001-10000 nM) binds with high affinity to CD47 on Jurkat cells (EC50 = 16.83 nM), CD20 on Raji-CD47KO cells (EC50 = 18.92 nM), and both antigens simultaneously (EC50 = 11.48 nM; EC50 = 0.02462 μg/mL for dual cell binding)[1]. Amulirafusp alfa has higher binding affinity for purified CD20 (2.45 nM) than for purified CD47 (4.91 nM)[1]. Amulirafusp alfa binds to multiple B-cell lymphoma cell lines, human PBMC, and cynomolgus monkey PBMC, shows minimal binding to human RBC (no hemagglutination), and cross-reacts with human and cynomolgus CD47 but not mouse or rat CD47[1]. Amulirafusp alfa significantly inhibits apoptosis of Jurkat-CSR cells via SIRPα/CD47 pathway blockade, with an IC50 of 4.046 nM[1]. Amulirafusp alfa induces potent ADCC, ADCP, and CDC against Raji, Daudi, Jeko-1, Ramos, SU-DHL-4, and SU-DHL-10 B-cell lymphoma cells, with stronger ADCC than rituximab, greater phagocytic activity against lymphoma cells than rituximab, and reduced activity against normal cells[1]. Amulirafusp alfa (10 μg/mL; 30 min) potently induces antibody-dependent cellular phagocytosis of TMD-8 and U-2932 ABC-DLBCL cells in vitro, with efficacy increasing as the effector-to-tumor cell ratio rises[4].
References:
[1]. Yu J, et al. IMM0306, a fusion protein of CD20 mAb with the CD47 binding domain of SIRPα, exerts excellent cancer killing efficacy by activating both macrophages and NK cells via blockade of CD47-SIRPα interaction and FcɣR engagement by simultaneously binding to CD47 and CD20 of B cells. Leukemia. 2023 Mar;37(3):695-698.
[2]. Lijuan Deng, et al. Phase Ib/IIa Study of Amulirafusp Alfa (IMM0306) in Combination with Lenalidomide in Patients with Relapsed or Refractory CD20-Positive B-Cell Non-Hodgkin's Lymphoma. Blood Volume 144, Supplement 1, 5 November 2024, Page 3033.
[3]. Yang J, et al. Safety and efficacy of amulirafusp alfa (IMM0306), a fusion protein of CD20 monoclonal antibody with the CD47 binding domain of SIRPα, in patients with relapsed or refractory B-cell non-Hodgkin lymphoma: a phase 1/2 study. Journal of hematology & oncology. 2024 Dec 18;17(1):123.
[4]. Guan X, et al. Lymphoma cell-driven IL-16 is expressed in activated B-cell-like diffuse large B-cell lymphomas and regulates the pro-tumor microenvironment. Haematologica. 2025 Feb 1;110(2):425-438.