Pfizer Inc. has reported top-line results from two randomized phase III studies of the irreversible pan-HER kinase inhibitor dacomitinib in patients with advanced non-small cell lung cancer (NSCLC).

Both trials evaluated dacomitinib in populations of previously treated patients with advanced NSCLC.  The ARCHER 1009 trial, which included patients previously treated with chemotherapy (second/third line), did not meet its objective of demonstrating statistically significant improvement in progression-free survival (PFS) when compared with the EGFR inhibitor erlotinib.

Separately, the NCIC CTG BR.26 trial, which included patients with advanced NSCLC after standard therapy with both chemotherapy and an EGFR tyrosine kinase inhibitor had failed, did not meet its objective of prolonging overall survival (OS) versus placebo.
 
An ongoing, third phase III trial, ARCHER 1050, is evaluating PFS of dacomitinib in a different patient population than was studied in ARCHER 1009 and BR26.  ARCHER 1050 compares dacomitinib versus gefitinib in treatment-naïve (without prior treatment) patients with EGFR-mutant advanced NSCLC.  The results are expected in 2015.

“While we are disappointed in the results, lung cancer is a complex disease, and the use of targeted agents to treat specific patient populations continues to evolve,” said Dr Mace Rothenberg, senior vice president of Clinical Development and Medical Affairs and chief medical officer for Pfizer Oncology. “We are analyzing the findings from both ARCHER 1009 and BR.26 to better understand the effects of dacomitinib in molecularly defined subgroups of patients with advanced NSCLC, including those with EGFR mutations.”

The ARCHER 1009 trial evaluated dacomitinib versus erlotinib in two co-primary populations of patients with advanced NSCLC previously treated with at least one chemotherapy regimen – all patients and patients with KRAS wild-type NSCLC. The study did not demonstrate that dacomitinib improved PFS in either of the co-primary populations compared to erlotinib.
 
The BR.26 trial was a double-blind, placebo-controlled, randomized study evaluating dacomitinib in patients with locally advanced or metastatic NSCLC after prior treatment, which included at least one chemotherapy regimen and one EGFR inhibitor treatment regimen.  This study was designed, conducted and led by NCIC Clinical Trials Group (NCIC CTG).
 
“We are pleased to have had the opportunity to assess dacomitinib in the BR.26 trial,” said Dr Peter Ellis, BR.26 Study Chair and associate professor in the Department of Oncology, McMaster University, and medical oncologist at the Juravinski Cancer Centre, Hamilton, Ontario, Canada.  “While we are disappointed that the trial did not meet its primary endpoint, we are supportive of Pfizer’s commitment to continue to evaluate dacomitinib in the ARCHER 1050 trial.”
 
In both studies, the adverse events observed for dacomitinib generally were consistent with its known adverse event profile.  Full efficacy and safety data from ARCHER 1009 and BR.26 will be submitted for presentation at an upcoming medical meeting.

Dacomitinib is an oral, once-daily, irreversible pan-HER (pan-human epidermal growth factor receptor) kinase inhibitor.  Dacomitinib irreversibly inhibits the kinase activity of HER1/EGFR, HER2, and HER4 by binding covalently to the receptor tyrosine kinase domains and preventing autophosphorylation, thereby inhibiting downstream signaling and leading to tumour-growth inhibition and apoptosis.
 
Dacomitinib is an investigational compound and has not received regulatory approval in any country.
 
Pfizer has entered into a collaborative development agreement with SFJ Pharmaceuticals Group to conduct ARCHER 1050 across multiple sites in Asia (including Japan) and Europe.

The NCIC Clinical Trials Group (NCIC CTG) is a cancer clinical trials cooperative group that conducts phase I-III trials testing anti-cancer and supportive therapies across Canada and internationally.  It is a national research program of the Canadian Cancer Society.  The NCIC CTG's Central Operations and Statistics Office is located at Queen's University in Kingston, Ontario, Canada.

Both Canadian and international investigators and patients participated in this trial.  In Australia, the Australasian Lung Cancer Trials Group (ALTG) coordinated participation, in collaboration with the NHMRC Clinical Trials Centre at the University of Sydney.  In Italy, the National Cancer Institute of Naples (Italy) lung cancer group coordinated participation.

Pfizer Oncology is committed to the discovery, investigation and development of innovative treatment options to improve the outlook for cancer patients worldwide.