Conatumumab, a fully human agonist antibody to death receptor 5, induces apoptosis via caspase activation in multiple tumor types.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) binds to death receptors 4 and 5 (DR4, DR5) to transduce apoptotic signals. Conatumumab (AMG 655) is an investigational, fully human monoclonal agonist antibody (IgG(1)) to human DR5, which induces apoptosis via caspase activation. In this study, we demonstrate that conatumumab binds to DR5, activating intracellular caspases in vitro in the presence of a cross-linker. We also show that conatumumab has activity in vivo and inhibits tumor growth in colon (Colo205 and HCT-15), lung (H2122) and pancreatic (MiaPaCa2/T2) xenograft models. Conatumumab also enhances the antitumor activity of chemotherapeutics in vivo. Caspase activation in Colo205 tumors is dose-dependent and correlated with serum concentrations of conatumumab. We demonstrate for the first time that increases in serum caspase-3/7 activity and levels of M30 (neoepitope of caspase-cleaved cytokeratin-18) are linked to activation of the extrinsic apoptotic pathway using conatumumab in a preclinical model. These data suggest that conatumumab has potential as a therapeutic agent for treating patients with multiple tumor types, and that serum caspase-3/7 and M30 levels may serve as biomarkers of conatumumab activity.
Kaplan-Lefko
Paula J
PJ
Amgen Inc., Thousand Oaks, CA, USA. pkaplan@amgen.com
Graves
Jonathan D
JD
Zoog
Stephen J
SJ
Pan
Yang
Y
Wall
Jason
J
Branstetter
Daniel G
DG
Moriguchi
Jodi
J
Coxon
Angela
A
Huard
Justin N
JN
Xu
Ren
R
Peach
Matthew L
ML
Juan
Gloria
G
Kaufman
Stephen
S
Chen
Qing
Q
Bianchi
Allison
A
Kordich
Jennifer J
JJ
Ma
Mark
M
Foltz
Ian N
IN
Gliniak
Brian C
BC
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000819:agonists*; D023041:Xenograft Model Antitumor Assays
D000911:Antibodies, Monoclonal; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C554537:conatumumab; D053148:Caspase 3; D053179:Caspase 7