AZD8931, an equipotent, reversible inhibitor of signaling by epidermal growth factor receptor, ERBB2 (HER2), and ERBB3: a unique agent for simultaneous ERBB receptor blockade in cancer.
OBJECTIVE
To test the hypothesis that simultaneous, equipotent inhibition of epidermal growth factor receptor (EGFR; erbB1), erbB2 (human epidermal growth factor receptor 2), and erbB3 receptor signaling, using the novel small-molecule inhibitor AZD8931, will deliver broad antitumor activity in vitro and in vivo.


METHODS
A range of assays was used to model erbB family receptor signaling in homodimers and heterodimers, including in vitro evaluation of erbB kinase activity, erbB receptor phosphorylation, proliferation in cells, and in vivo testing in a human tumor xenograft panel, with ex vivo evaluation of erbB phosphorylation and downstream biomarkers. Gefitinib and lapatinib were used to compare the pharmacological profile of AZD8931 with other erbB family inhibitors.


RESULTS
In vitro, AZD8931 showed equipotent, reversible inhibition of EGFR (IC(50), 4 nmol/L), erbB2 (IC(50), 3 nmol/L), and erbB3 (IC(50), 4 nmol/L) phosphorylation in cells. In proliferation assays, AZD8931 was significantly more potent than gefitinib or lapatinib in specific squamous cell carcinoma of the head and neck and non-small cell lung carcinoma cell lines. In vivo, AZD8931 inhibited xenograft growth in a range of models while significantly affecting EGFR, erbB2, and erbB3 phosphorylation and downstream signaling pathways, apoptosis, and proliferation.


CONCLUSIONS
AZD8931 has a unique pharmacologic profile providing equipotent inhibition of EGFR, erbB2, and erbB3 signaling and showing greater antitumor activity than agents with a narrower spectrum of erbB receptor inhibition in specific preclinical models. AZD8931 provides the opportunity to investigate whether simultaneous inhibition of erbB receptor signaling could be of utility in the clinic, particularly in the majority of solid tumors that do not overexpress erbB2.
Hickinson
D Mark
DM
AstraZeneca, Macclesfield, United Kingdom; AstraZeneca, Reims, France.
Klinowska
Teresa
T
Speake
Georgina
G
Vincent
John
J
Trigwell
Cath
C
Anderton
Judith
J
Beck
Sarah
S
Marshall
Gayle
G
Davenport
Sara
S
Callis
Rowena
R
Mills
Elizabeth
E
Grosios
Konstantina
K
Smith
Paul
P
Barlaam
Bernard
B
Wilkinson
Robert W
RW
Ogilvie
Donald
D
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D000077156:Gefitinib; D006258:Head and Neck Neoplasms / Q000188:drug therapy; D006801:Humans; D000077341:Lapatinib; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D011799:Quinazolines / Q000819:agonists / Q000494:pharmacology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors*; D020893:Receptor, ErbB-3 / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D066246:ErbB Receptors; D000077156:Gefitinib; D000077341:Lapatinib; D011799:Quinazolines; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; C548875:AZD 8931; C508053:ERBB2 protein, human