Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors and Lung Cancer: History, Epidemiology, and Market Outlook.

Lung cancer is a leading cause of death for both men and women. The treatment of lung cancer has been stifled with pessimism for many years. However, molecularly targeted therapies directed at pathologic epidermal growth factor receptor tyrosine kinases have come to market and, with them, a new tone to an old diagnosis. Treatment of lung cancer is a complex science that requires not only anatomical knowledge of the patient but also an understanding of the patient's overall physiologic condition. When patients are treated appropriately, this drug can transform the natural progression of their disease and improve survival. Interestingly, the clinical solidarity of these first-generation tyrosine kinase inhibitors (TKIs) has become the prelude to a second wave of advances in molecular targeting that we can expect to further improve how we classify and treat lung cancers. Cancers that become resistant to epidermal growth factor receptor (EGFR)-specific TKIs through a secondary mutation are likely to be dependent on the activated kinase for their growth and survival. Therefore, discovering a secondary means of inhibiting EGFR T790M may be therapeutically necessary. This has prompted the preclinical and clinical development of second and third-generation kinase inhibitors. Tumor subtypes are also now being identified, potentially allowing patients to be treated with drugs that most benefit their tumor subtype. We used the TriNetX research platform to analyze the rate of patients being prescribed first, second, and third-generation EGFR TKIs and propose a rationale for the trends seen over time.