THE CHALLENGE OF DESIGNING CLINICAL-TRIALS FOR AIDS-RELATED KAPOSIS-SARCOMA

Kaposi's sarcoma (KS) is a frequent cause of morbidity and mortality i n patients with human immunodeficiency virus (HIV) infection. Several characteristics of KS pose challenges for the conduct of clinical tria ls. Kaposi's sarcoma patients often have multiple, irregularly shaped lesions, making accurate assessment of tumor size difficult. The lesio ns may have varying degrees of nodularity. Involvement of the lung or other visceral organs often consists of multiple irregular lesions. Co nventional oncology staging systems cannot be applied effectively to K S because there is no clear primary lesion. Kaposi's sarcoma is affect ed by the status of the underlying HIV infection, and there are report s of KS lesions regressing in response to effective antiretroviral the rapy. A system for staging and response assessment irt KS, developed b y the AIDS Clinical Trials Group (ACTG), has proven to be a useful too l for the conduct of trials in KS. A newer system that also attempts t o assess patient benefit in response to therapy is now being developed by the National Cancer Institute, FDA, and AIDS Malignancy Consortium . These tools, as well as careful methodology in the conduct of clinic al trials, should help optimize the clinical development and evaluatio n of new therapies for KS.