Plasma kinetics of a cholesterol-rich microemulsion (LDE) in patients with Hodgkin's and non-Hodgkin's lymphoma and a preliminary study on the toxicity of etoposide associated with LDE

Background: Neoplastic diseases are often associated with low plasma low-density lipoprotein (LDL) cholesterol and diminished LDL clearance due to upregulation in cancer cells of the receptors that internalize the lipoprotein. Thus, it is possible to use LDL or cholesterol-rich microemulsions (LDE) that bind to LDL receptors as carriers of antineoplastic agents to concentrate those drugs into cancer tissues. Our aim was to determine whether LDL cholesterol concentration plus LDE increased clearance occur in lymphomas. Patients and methods: The LDE labeled with [H-3]-cholesteryl oleate was injected into four Hodgkin's and 12 non-Hodgkin's lymphoma patients and into 16 healthy control subjects and the LDE plasma residence time (RT) was determined from sequential plasma samples. Two volunteers with relapsed/refractory lymphoma were treated with 300 mg/m(2) body surface etoposide associated with LDE in six cycles at 3-week intervals. Results: The LDL cholesterol was lower in lymphoma patients than in controls (94 +/- 52 and 115 +/- 16 mg/dL, p = 0.0362, respectively). The LDE RT was 49% smaller in lymphoma patients than in controls (RT = 21.9 and 45.7 h; p = 0.0134), with positive correlation between RT and LDL cholesterol. LDE-etoposide showed no considerable toxicity in all cycles in the two treated patients and the disease remained stable during the treatment. Conclusions: Our results suggest that lymphomas over-express LDL receptors that make room for using LDE as drug-targeting vehicle and that the LDE-etoposide preparation is suitable for patient use.