Optimized conventional chemotherapy
i.e. Small molecule therapy (drugs ending with –mib, -nib)
Targeted cancer drugs are designed to interfere with specific molecules that the tumor needs for growth and progression. Traditional cytotoxic chemotherapy usually kills rapidly dividing cells in the body by interfering with cell division. A main goal of targeted therapies is to eliminate cancer cells with more accuracy and therefore fewer side effects.
Over the last decade, the discovery and development of small molecule cancer drugs has been revolutionised. Most importantly, we have moved from a general approach that mainly involved cytotoxic chemotherapy to a personalised medicine strategy that focuses on the development of molecular drugs in order to target specific genetic characteristics of cancer cells. While monoclonal antibodies target specific antigens found on the cell surface, such as transmembrane receptors or extracellular growth factors, small molecules can penetrate the cell membrane to interact with targets inside a cell.
Many small molecule drugs that inhibit critical cancer targets have been developed, e.g. the epidermal growth factor receptor (EGFR) kinase inhibitors gefitinib and erlotinib that inhibit EGFR in patients with non small cell lung cancer (NSCLC); the EGFR/ERBB2 inhibitor lapatinib for ERBB2-positive breast cancer; or for example the vascular epidermal growth factor receptor (VEGFR) kinase inhibitor sorafenib that is used in renal cancer. Also, inhibitors of the protein kinase ALK by crizotinib and of another kinase BRAF by vemurafenib have recently been approved for the treatment of NSCLC patients with certain characteristics.