An analysis of multiple clinical trials compared erlotinib (Tarceva) alone to combining Tarceva with other targeted therapies as second-line treatment for advanced non-small cell lung cancer (NSCLC). In the various trials, Tarceva was combined with bevacizumab (Avastin), bortezomib (Velcade), everolimus (Afinitor), sorafenib (Nexavar), sunitinib (Sutent), entinostat, tivantinib, and R1507. While combined therapy produced more side effects, it was more effective than Tarceva alone. Notably, the trials included many patients who had not been tested for mutations in the EGFR and KRAS genes. In patients who had EGFR mutations and/or lacked KRAS mutations, Tarceva alone tended to control cancer progression better than combined therapy, highlighting the importance of biomarker testing to identify which patients are most likely to benefit from different therapies.