Gefitinib: current and future status in cancer therapy

The epidermal growth factor receptor (EGFR) is recognized as a key modulator of tumor cell function and is considered to be a viable drug target in a range of solid malignancies. Current knowledge of its role in tumor growth and progression has led to a newly active area of anticancer research, investigating agents that target the activity of this receptor. Of these agents, gefitinib is furthest in clinical development, having received regulatory approval in Japan in 2002, and in the United States and Australia in 2003. Gefitinib is an orally active, EGFR-tyrosine kinase inhibitor that blocks signal transduction pathways implicated in the proliferation and survival of cancer cells and other host-dependent processes promoting cancer cell growth. A plethora of preclinical studies have suggested promising outcomes for this agent and have led to ongoing clinical trials in a wide range of tumors, including non-small-cell lung, head and neck, colorectal, prostate, and breast, either as monotherapy or in combination with standard chemotherapy, hormonal therapy, or radiotherapy. Furthermore, as biologic agents are specifically designed to attack different pathways of tumor growth and progression, the potential for the combination of gefitinib with other agents, given either concurrently or sequentially, to prevent or delay disease recurrence is also being investigated. This article provides a detailed overview of gefitinib, the rationale for its use in a wide range of tumor types, and the current clinical development status of this novel agent.