BD: Imatinib for chronic myeloid leukemia: the impact of its effectiveness and long-term side effects

The development of effective, selective therapies has long chal-lenged researchers trying to improve treatment options for cancer patients. The allure of such therapies has always been that so-called “targeted therapies ” would by their very nature limit toxic effects commonly associated with traditional cytotoxic agents. Moreover, if the targeted agents are effective, such therapies might improve clinical responses, alter disease biology, and ultimately improve survival for a multitude of cancer patients. The threats to such promising approaches include serious or unexpected toxic effects (ie, narrow therapeutic indices) or partially effective therapies that could allow the emergence of drug resistance. To date, the success of imatinib mesylate (IM) in the treatment of chronic phase chronic myeloid leukemia (CML) remains the best example of successful targeted therapy. This is true despite challenges as a result of its toxicity profile and the finding that drug resistance does occur. IM has transformed this leukemia with a previously optimistic life expectancy of 4–6 years with interferon-based treatments (1) into a true chronic illness with overall survival rates that appear to be increasing each year. However, there are still concerns about long-term tolerability and long-term efficacy with IM. In this issue of the Journal, the article by Gambacorti-Passerini et al. (2) adds “real-life, long-term ” tolerability data t