Pfizer announced today that its lung cancer drug, dacomitinib, failed in two late-stage studies involving patients who had previously undergone chemotherapy for advanced non-small cell lung cancer (NSCLC). Dacomitinib is an oral drug, meant to be taken only once each day, and described as a pan-HER (pan-human epidermal growth factor receptor) kinase inhibitor; this experimental drug, which has not yet received regulatory approval in any country, is intended to inhibit the growth of tumors. 

“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. 

About 85 percent to 90 percent of all lung cancers — the leading cause of cancer death in both men and women worldwide — are NSCLC. Lung cancer mainly occurs in older people, with an average age at the time of diagnosis of 70. This cancer is thought to start as areas of pre-cancerous changes in the lung and can start in the cells lining the bronchi and parts of the lung. Unseen on an x-ray, they also do not cause symptoms. Approximately 75 percent of NSCLC patients are diagnosed with metastatic, or advanced, disease, which, because it is so difficult to treat, results in a five-year survival rate of only five percent. Each year, the American Cancer Society reports, more people die of lung cancer than of colon, breast, and prostate cancers combined.

“We are analyzing the findings from both [studies] to better understand the effects of dacomitinib in molecularly defined subgroups of patients with advanced NSCLC, including those with EGFR mutations,” Rothenberg stated in a press release. One of the two randomized Phase 3 studies found the experimental drug did not demonstrate statistically significant improvement in progression-free survival (PFS) when compared with Roche’s erlotinib, marketed as Tarceva. The second study, which compared the drug to a placebo, also provided evidence of failure in meeting its goal of prolonging overall survival (OS). The company will continue its third Phase 3 trial, known as ARCHER 1050, with results expected in 2015. In this ongoing study, researchers will be evaluating PFS of dacomitinib in patients who have not previously undergone treatment and will compare the results to those of gefitinib, marketed as Iressa, marketed by AstraZeneca and Teva.

“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,” said Dr. Peter Ellis, study chair, and associate professor in the Department of Oncology at McMaster University. Full data from the two trials will be submitted for presentation at an upcoming medical meeting, Pfizer noted.