MTP-PE IN LIPOSOMES AS A BIOLOGICAL RESPONSE MODIFIER IN THE TREATMENT OF CANCER - CURRENT STATUS

MTP-PE in liposomes is a BRM which can be given relatively safely to patients with cancer. The maximum tolerated dose appears to be higher than the optimal dose inducing immunomodulatory effects such as cytokine induction and monocyte/macrophage activation. The most consistently induced cytokines measured in the plasma of patients a few hours after MTP-PE are TNF and IL-6. Indirect evidence supports the assumption that increased levels of TNF and IL-6 are signs of macrophage activation occurring in situ in tissues taking up liposomal MTP-PE shortly after injection. These tissues are mainly lungs, liver and spleen, as shown in 4 patients injected with radiolabelled liposomes containing MTP-PE. Assuming that activated monocytes and macrophages cannot eliminate gross tumor load, the main targets for MTP-PE are micrometastases after removal of the primary tumor. Thus, adjuvant treatment using liposomal MTP-PE in combination with chemotherapy is a major goal for the future.