Anti-HER agents in gastric cancer: from bench to bedside

Despite some advances in the past few years, the search for effective treatment modalities for advanced gastric and gastro-esophageal junction cancer is far from over. Available data clearly demonstrate that the development of new drugs will have little, if any, chance of success if it is not guided by in-depth knowledge of disease biology. However, using biologic agents to target key molecular pathways, such as those regulated by human epidermal growth factor receptor (HER) family members, may be effective. Indeed, the positive results achieved by the anti-HER2 agent trastuzumab in a phase III trial in HER2-positive patients support this approach. Many new anti-HER molecules are now under evaluation for the treatment of gastric and gastro-esophageal junction cancer, but so far attempts to identify reliable predictive factors from phase I and II trials have produced inconclusive results. In addition, large phase III trials are still being conducted in molecularly unselected populations. Refining patient selection is essential to maximize the benefit of targeted agents, to avoid significant toxicities and for the development of alternative therapeutic approaches in patients who have nonresponsive disease.

Clinical, laboratory and molecular factors predicting chemotherapy efficacy and toxicity in colorectal cancer

Colorectal cancer (CRC) treatment has evolved significantly over the last ten years with the use of active chemotherapeutic agents including fluoropyrimidines, oxaliplatin and irinotecan plus targeted monoclonal antibodies bevacizumab, cetuximab and panitumumab. The addition of newer chemotherapeutic agents and targeted therapies has improved patient outcomes at the cost of increased toxicity with not all patients benefiting from these treatments. It is necessary for clinicians to more accurately predict clinical outcomes particularly in the predominantly elderly CRC patient population. This review aims to summarise existing data regarding the use of clinical and laboratory variables plus molecular markers in predicting response, survival and toxicity to chemotherapy agents and targeted monoclonal antibodies currently used in the treatment of CRC.

Implications of KRAS mutation status for the treatment of metastatic colorectal cancer

Targeted agents have become an integral part of the treatment of a number of malignant diseases and regimens containing agents that disrupt the epidermal growth factor receptor (EGFR) signaling pathway are now considered a standard therapeutic approach for a range of tumor types. Recently, the mutational status of the KRAS gene in tumors was shown to be predictive of outcome to treatment with EGFR-targeted therapies in metastatic colorectal cancer (mCRC). The immoglobulin (Ig) G1 EGFR-targeting monoclonal antibody (mAb), cetuximab, has been shown to provide significant clinical benefits when added to standard irinotecan- and oxaliplatin-containing chemotherapy regimens, first-line, in patients with KRAS wild-type mCRC. Its effects on tumor response and resectability of metastases make cetuximab a particularly useful treatment option for patients with bulky or initially unresectable disease. With an ever-increasing array of management options available, it is important that patients with mCRC receive the treatment that offers them the best chance of prolonged survival. In view of this, testing for tumor KRAS mutation status should be mandatory at diagnosis of mCRC, prior to treatment decision-making.