Augmented antitumor activity against B-cell lymphoma by a combination of monoclonal antibodies targeting TRAIL-R1 and CD20.

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Maddipatla S, Hernandez-Ilizaliturri FJ, Knight J, Czuczman MS

Augmented antitumor activity against B-cell lymphoma by a combination of monoclonal antibodies targeting TRAIL-R1 and CD20.

Clin Cancer Res. 2007 Aug 1;13(15 Pt 1):4556-64.

PubMed ID

17671142 [ View in PubMed

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Abstract

PURPOSE: Mapatumumab and lexatumumab are fully humanized, high-affinity immunoglobulin G(1 lambda) monoclonal antibodies (mAb) that target/activate the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 1 (TRAIL-R1) and receptor 2 (TRAIL-R2), respectively, triggering the extrinsic apoptotic pathway. Theoretically, synergistic antitumor activity should be observed by combining TRAIL-R mAbs with agents (e.g., rituximab) that activate the intrinsic apoptotic pathway. EXPERIMENTAL DESIGN: To this end, targeted antigen expression in a NHL-cell panel was evaluated by flow cytometry. NHL cells were exposed to mapatumumab or lexatumumab followed by rituximab, isotype, or RPMI. DNA synthesis was quantified by [(3)H]-thymidine incorporation assays. Induction of apoptosis was detected by flow-cytometric analysis. For antibody-dependent cellular cytotoxicity (ADCC) and complement-mediated cytotoxicity (CMC) studies, standardized (51)Cr-release assays were done. We inoculated severe combined immunodeficiency (SCID) mouse with Raji cells i.v. The animals then were treated with various combinations of rituximab, mapatumumab, lexatumumab, and isotype alone or in combination. RESULTS: In vitro exposure to mapatumumab resulted in significant apoptosis (30-50%) and decreased DNA synthesis in sensitive lymphoma cells. Mapatumumab/rituximab combination resulted in a significant inhibition of cell proliferation (90% reduction) when compared with mapatumumab (60% reduction) or rituximab (5% reduction). In vivo, the median survival time of animals treated with mapatumumab and rituximab was longer (not reached) than those treated with rituximab monotherapy [33 days (95% confidence interval, 29-37), log-rank test, P = 0.05]. CONCLUSIONS: Mapatumumab induces apoptosis, cell growth arrest, ADCC, and CMC. The combination of mapatumumab plus rituximab is more effective in controlling lymphoma growth in vivo than either antibody. Rituximab and mapatumumab warrant further evaluation against B-cell lymphoma.

DrugBank Data that Cites this Article

Drugs

Lexatumumab

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Lexatumumab	Tumor necrosis factor receptor superfamily member 10B	Protein	Humans	Unknown	Not Available	Details