Posted online on November 30, 2004 on www.jco.org .Read the original study A study appearing in the Journal of Clinical Oncology (JCO) has found that a promising, highly targeted cancer drug called imatinib (Gleevec)âpreviously proven effective in treating several types of cancerâmay also be effective in treating AIDS-related Kaposi's sarcoma (KS).Kaposi's sarcoma is a form of cancer characterized by soft purplish lesions on the skin, mucous membranes, and internal organs. KS largely affects people living with HIV/AIDS, and can be the first sign that an HIV-positive person has developed AIDS. Although the number of people with KS has declined dramatically since the availability of effective therapy for HIV/AIDS, it remains a significant cause of death for AIDS patients.Imatinib works by blocking certain proteinsâcalled PDGF-R and c-kitâthat are responsible for the development of several types of cancer, such as chronic myelogenous leukemia and gastrointestinal stromal tumors. Because these same proteins play a role in the development of KS, researchers thought that imatinib might be an effective way to treat the disease.Researchers from Beth Israel Deaconess Medical Center, Harvard Medical School in Boston, gave 300 mg of imatinib twice daily to 10 male patients with KS, which had gotten worse in spite of chemotherapy and treatment for HIV/AIDS. Half of the people in this study showed a partial decrease of their KS lesions, and for the remaining five patients, their disease was stable and they were no longer developing new lesions after four weeks.However, researchers found that imatinib caused more severe side effects in KS patients, such as diarrhea, than in patients with other cancers in previous trials who received the same dose. Although the reason for these side effects is unclear, researchers believe that imatinib may interact with treatment for HIV/AIDS, which can also cause diarrhea.What Does This Mean for Patients?Researchers noted that once patients develop KS, it often returns after treatment with current therapies and may require several rounds of treatment. Given this, further research is needed to determine whether the benefits of a lower dose of imatinib outweigh the potential side effects. In the meantime, patients with KS should talk to their doctors about treatment options, as well as the availability of clinical trials investigating new therapies like imatinib for KS.