The mechanism of cytotoxicity of alemtuzumab and rituximab in chronic lymphocytic leukemia (CLL) is not well understood. We obtained fresh CLL cells from early-intermediate stage high-risk patients just prior to treatment with alemtuzumab and rituximab to study mechanisms of action and resistance. Alemtuzumab had minimal direct cytotoxicity but caused significant complement dependent cytotoxicity (CDC) although a subpopulation of CLL cells had intrinsic resistance. Rituximab had no direct cytotoxicity and caused minimal CDC in cells from most patients. These data suggest that CDC has a therapeutic role in patients treated with alemtuzumab and that measures to decrease resistance to CDC could increase efficacy.
- Chronic lymphocytic leukemia (CLL)
ASJC Scopus subject areas
- Cancer Research