Antagonistic Human FcγRIIB (CD32B) Antibodies Have Anti-Tumor Activity and Overcome Resistance to Antibody Therapy In Vivo: Cancer Cell | Immunology and Biotherapies | Scoop.it
From www.cell.com - April 14, 2015 1:21 PM
Highlights

 

•Fully human hFcγRIIB (CD32B) antibodies overcome resistance to therapeutic antibodies•hFcγRIIB mAbs augment standard-of-care anti-CD20 therapy in vitro and in vivo•hFcγRIIB mAbs restore drug responsiveness in refractory CLL cells in vivo•hFcγRIIB mAbs help overcome cell- and niche-specific resistance mechanisms

 

Summary

Therapeutic antibodies have transformed cancer therapy, unlocking mechanisms of action by engaging the immune system. Unfortunately, cures rarely occur and patients display intrinsic or acquired resistance. Here, we demonstrate the therapeutic potential of targeting human (h) FcγRIIB (CD32B), a receptor implicated in immune cell desensitization and tumor cell resistance. FcγRIIB-blocking antibodies prevented internalization of the CD20-specific antibody rituximab, thereby maximizing cell surface accessibility and immune effector cell mediated antitumor activity. In hFcγRIIB-transgenic (Tg) mice, FcγRIIB-blocking antibodies effectively deleted target cells in combination with rituximab, and other therapeutic antibodies, from resistance-prone stromal compartments. Similar efficacy was seen in primary human tumor xenografts, including with cells from patients with relapsed/refractory disease. These data support the further development of hFcγRIIB antibodies for clinical assessment.


Via Krishan Maggon