Liposomal doxorubicin in the treatment of AIDS-associated Kaposi's sarcoma: clinical, histological and cell biological evaluation.

AIDS-associated Kaposi's sarcoma (KS) in eight patients was treated with the systemic application of liposomal doxorubicin (20 mg/m2 per cycle). After six cycles of treatment a significant regression of KS was observed in all patients. Tumour volume was reduced from 556 +/- 635 mm3 before therapy to 42 +/- 134 mm3 after therapy as determined by ultrasonography of selected tumours. Histological examination revealed a reduction of tumour-like structures and the absence of KS spindle cells in involved areas after therapy. In vitro experiments with KS-derived cell cultures, which most likely represent the KS spindle cells, suggested that liposomal doxorubicin may cause regression of KS via two different mechanisms: (i) by highly specific inhibition of KS spindle cell proliferation and (ii) by induction of monocyte chemoattractant protein-1 expression in KS spindle cells, which may result in increased recruitment of phagocytic cells (monocytes/macrophages) into the lesions. A cooperative action of both mechanisms may explain the high efficacy of liposomal doxorubicin in the treatment of AIDS-KS.