Toxicity profile of small-molecule IAP antagonist GDC-0152 is linked to TNF-α pharmacology.

Abstract

Inhibitor-of-apoptosis (IAP) proteins suppress apoptosis and are overexpressed in a variety of cancers. Small-molecule IAP antagonists are currently being tested in clinical trials as novel cancer therapeutics. GDC-0152 is a small-molecule drug that triggers tumor cell apoptosis by selectively antagonizing IAPs. GDC-0152 induces NF-κB transcriptional activity leading to expression of several chemokines and cytokines, of which tumor necrosis factor alpha (TNF-α) is the most important for single-agent tumor activity. TNF-α is a pleiotropic cytokine that drives a variety of cellular responses, comprising inflammation, proliferation, and cell survival or death depending on the cellular context. As malignant and normal cells produce TNF-α upon IAP antagonism, increased TNF-α could drive both efficacy and toxicity. The toxicity profile of GDC-0152 in dogs and rats was characterized after iv dose administration once every 2 weeks for four doses. Findings in both species consisted of a dose-related, acute, systemic inflammatory response, and hepatic injury. Laboratory findings included elevated plasma cytokines, an inflammatory leukogram, and increased liver transaminases with histopathological findings of inflammatory infiltrates and apoptosis/necrosis in multiple tissues; a toxicology profile consistent with TNF-α-mediated toxicity. Dogs exhibited more severe findings than rats, and humans did not exhibit these findings, at comparable exposures across species. Furthermore, elevations in blood neutrophil count, serum monocyte chemoattractant protein-1, and other markers of inflammation corresponded to GDC-0152 exposure and toxicity and thus may have utility as safety biomarkers.

• Authors: Rebecca I Erickson, Jacqueline Tarrant, Gary Cain, Sock-Cheng Lewin-Koh, Noel Dybdal, Harvey Wong, Elizabeth Blackwood, Kristina West, Ronald Steigerwalt, Michael Mamounas, John A Flygare, Kenjie Amemiya, Donna Dambach, Wayne J Fairbrother, Dolores Diaz
• Journal: Toxicological sciences : an official journal of the Society of Toxicology (Toxicol Sci) Vol. 131 Issue 1 Pg. 247-58 (Jan 2013) ISSN: 1096-0929 [Electronic] United States
• PMID: 22956632 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Chemokines
• Cyclohexanes
• Inhibitor of Apoptosis Proteins
• Pyrroles
• Tumor Necrosis Factor-alpha
• GDC-0152

Topics

• Animals
• Antineoplastic Agents (blood, toxicity)
• Chemokines (blood)
• Cyclohexanes (blood, toxicity)
• Dogs
• Female
• Inhibitor of Apoptosis Proteins (antagonists & inhibitors)
• Liver (drug effects, immunology, metabolism, pathology)
• Lung (drug effects, immunology, metabolism, pathology)
• Male
• Pyrroles (blood, toxicity)
• Rats
• Rats, Sprague-Dawley
• Species Specificity
• Systemic Inflammatory Response Syndrome (chemically induced, immunology, pathology)
• Toxicity Tests
• Tumor Necrosis Factor-alpha (blood, pharmacology)