Therapy of human ovarian cancer xenografts with intraperitoneal liposome encapsulated muramyl-tripeptide phosphoethanolamine (MTP-PE) and recombinant GM-CSF.

Three intraperitoneal human ovarian cancer xenografts (OS, HU, and LA) were used to assess the antitumour activity of intraperitoneal therapy with liposome encapsulated MTP-PE. MTP-PE led to significant prolongation of survival in all three xenograft models, but with varying efficacy. In one tumour model (OS), 80% of mice were cured of tumour by twice weekly therapy for 4 weeks, whereas in another xenograft model (LA), the median survival time was approximately doubled compared to PBS injected and placebo liposome injected controls (median survivals: 30 vs 62.5 days respectively). The antitumor efficacy of MTP-PE did not correlate with the extent of peritoneal neutrophil infiltration after intraperitoneal therapy. Combined therapy with liposome encapsulated MTP-PE and recombinant murine granulocyte-macrophage colony stimulating factor led to increased survival of mice bearing the LA and HU xenografts, compared to tumour bearing mice treated with either agent singly.