Purpose: This trial was designed to compare the efficacy of adjuvant STEALH liposome-encapsulated cisplatin (SPI-77) to "standard-of-care" carboplatin therapy in dogs with osteosarcoma (OSA) in the context of a randomized study design.
Methods: The study included 40 pet dogs with spontaneously arising OSA which were randomized to receive SPI-77 (350 mg/m(2) i.v. every 3 weeks for four treatments) or carboplatin (300 mg/m(2) i.v. every 3 weeks for four treatments) along with amputation of the affected limb. Median disease-free (DFS) and overall survival (OS) were compared using standard life-table analysis.
Results: The median follow-up was 693 days (range 321-730 days). Of 38 dogs eligible for follow-up, 25 were dead of their disease, 9 were alive and disease-free (8 receiving SPI-77, 1 receiving carboplatin; P=0.02), 2 were free of disease when they were lost to follow-up at 321 and 395 days, and 2 had died of an unrelated disease. The median DFS times for dogs treated with SPI-77 and carboplatin were 156 and 123 days, respectively ( P=0.19). The median OS times for dogs treated with SPI-77 and carboplatin were 333 and 207 days, respectively ( P=0.18).
Conclusions: While STEALTH liposome encapsulation of cisplatin allowed the safe administration of five times the maximally tolerated dose of free cisplatin to dogs without concurrent hydration protocols, this did not translate into significantly prolonged DFS or OS. However, a larger proportion of dogs receiving SPI-77 enjoyed long-term DFS when compared with dogs receiving carboplatin.