Two’s company, three’s a crowd: the continuing saga of three-drug regimens for extensive-stage small cell lung cancer

Small-cell lung cancer (SCLC) is an aggressive tumor that accounts for 13–15% of all lung cancer cases and is the seventh most common cause of cancer-related death in the U.S. with a 5-year overall survival rate of 6.3% (1). At initial diagnosis, about 2/3 of patients have extensive-stage disease (ES-SCLC), for which all treatment is given with palliative intent. Platinum-based, two-drug chemotherapy has been the standard first-line treatment for patients with ES-SCLC for over 20 years. In the U.S., the most common regimens utilized are carboplatin plus etoposide (CE) or cisplatin plus etoposide (PE), which yield a response rate of 50–70% and a median overall survival time of 8–11 months (2). Despite the remarkable activity of initial chemotherapy, nearly all patients relapse within months and the benefits of second-line therapy are limited. Thus, there is a desperate need for more effective first-line therapy.