title: Treatment of large solid tumors in mice with daunomycin-loaded sterically stabilized liposomes.
abstract: Previous work on the effects of sterically stabilized liposomes on the growth of experimental solid tumors used protocols that began drug treatment when tumor volume was small (<0.01 mL). The goal of the present work was to compare the antitumor efficacy of daunomycin-loaded sterically stabilized liposomes versus free daunomycin in animals with large (>0.5 mL) experimental tumors. BALB/c nude mice were transplanted with 2.3 x 10(6) 3T3 cells transfected with an activated HER2 gene. After 8 days, when mean tumor volume was 0.52 mL, mice were treated with intraperitoneal daunomycin-loaded polyethylene glycol-stabilized liposomes (daunomycin 6 mg/kg, including tracer [(3)H]daunomycin), free daunomycin (6 mg/kg), or vehicle. Both control and free daunomycin-treated mice survived an average of 15 days after tumor cell inoculation (and 7 days after treatment), while mice receiving daunomycin-loaded sterically stabilized liposomes survived for 32 days. Tumors were well vascularized and contained no necrotic centers. These studies demonstrate that sterically stabilized daunomycin-loaded liposomes are more effective in prolonging life span than an equivalent dose of free daunomycin even when therapy is initiated after the tumor volume reaches 2% of body weight.
authors: Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90095, USA.
authors: P L
authors: PL
authors: Golden
authors: J
authors: J
authors: Huwyler
authors: W M
authors: WM
authors: Pardridge