The concept of targeted tumor therapeutics and the “magic bullet” was formulated by Paul Ehrlich already at the end of the 19th century. The directed delivery of drugs to diseased cells without harming healthy cells is the final goal of targeted therapies. Especially tumor therapy is in need of magic bullets, which would demonstrate successful drug targeting. The integration of antibodies to mediate specific targeting to tumor cells was a major step forward in the field of targeted tumor therapeutics. However, after initial enthusiasm several problems appeared and led to disenchantment of magic bullets. Since then a number of novel ideas contributed to the optimization of targeted drugs and the development of Ontak, the first approved chimeric targeted cancer drug. A number of other antibody-based therapies for the treatment of cancer have now been approved lending strong support for these types of molecules, and the development of new drugs is ongoing. Conjugated targeted toxins utilize antibodies, cytokines or growth factors for specific binding to overexpressed tumor-specific structures on the cell surface and then induce cell death by different mechanisms dependent on the toxin. Besides antibodies, organelle-like liposomes and other carriers are used to deliver toxic substances to tumor cells. The main objective of all these targeted therapies is the selective killing of neoplastic cells. As conventional therapies against cancer do not achieve complete remission of tumors, the continued development of new and improved therapies, such as targeted tumor therapies, is of great interest. Many excellent groups are currently working on the optimization of existing therapies and to gain new insights into the mechanisms underlying the successful elimination of tumor cells by chimeric toxins and other targeted therapies. This special issue of Current Drug Targets aims to present reviews on different topics concerning the field of targeted tumor therapies. The selected authors of this issue describe relevant work in the corresponding area as well as the latest results of some groups working on targeted tumor therapeutics. This review issue will be published as a contribution to the Fabisch- Symposium on Targeted Tumor Therapies held from 1-3 April 2009 in Berlin, Germany. We organized this second symposium on Targeted Tumor Therapies after the great success of the first symposium in 2006. The first symposium summarized ongoing efforts on the development of anti-tumorigenic targeted drugs and presented the success of recent clinical studies with targeted anti-tumor drugs. Thus, the second symposium aims to tie up to the success of the first symposium. This effort will be greatly supported by this special review issue of Current Drug Targets.
Current Drug Targets aims to cover the latest and most outstanding developments on the medicinal chemistry and pharmacology of molecular drug targets e.g. disease specific proteins, receptors, enzymes, genes. Each issue of the journal will be devoted to a single timely topic, with series of in-depth reviews, written by leaders in the field, covering a range of current topics on drug targets. These issues will be organized and led by a guest editor who is a recognized expert in the overall topic. As the discovery, identification, characterisation and validation of novel human drug targets for drug discovery continues to grow; this journal will be essential reading for all pharmaceutical scientists involved in drug discovery and development.