Abstract

<h2>Studies in target-based treatment</h2> Razelle Kurzrock Phase I Program, Division of Cancer Medicine, M. D. Anderson Cancer Center, Houston, Texas Requests for reprints: Razelle Kurzrock, Phase I Program, Division of Cancer Medicine, Unit 422, M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009. Phone: 713-794-1226; Fax: 713-792-0334 or 713-563-0566. E-mail: rkurzroc@mdanderson.org Molecular Cancer Therapeutics has inaugurated a new feature-Spotlight on Clinical Response-whose objective is the rapid publication of breaking discoveries regarding target- or mechanism-based clinical responses in cancer. Targeted molecules are poised to alter the landscape of clinical cancer treatment. For example, because they can distinguish cancer cells from their normal counterparts, agents such as imatinib mesylate, a Bcr-Abl and Kit kinase inhibitor, can result in remarkable responses with minimal host toxicity in patients suffering from diseases characterized by abnormalities in the targeted kinases. Indeed, studies of imatinib mesylate in early-stage chronic myelogenous leukemia, whose hallmark is the aberrant Bcr-Abl protein, show response rates of more than 90%. Furthermore, gastrointestinal stromal tumors (GIST), a notoriously chemotherapy-refractory sarcoma, characterized by activating Kit kinase mutations, can show dramatic metabolic responses within days after initiation of treatment. With the wealth of new knowledge in this field, and numerous novel