Paclitaxel-eluting polymer film reduces locoregional recurrence and improves survival in a recurrent sarcoma model: a novel investigational therapy.

BACKGROUND: Locoregional recurrences occur in up to 50% of patients after macroscopically complete (R0/R1) resections of abdominal, pelvic, and retroperitoneal sarcomas. Efficacy of a drug-eluting polymer film in reducing locoregional recurrence rates was assessed in a murine recurrent sarcoma model.
METHODS: Poly(glycerol monostearate-co-caprolactone) polymer films were synthesized with and without 300 μg paclitaxel (Pax-film and unloaded film). Cytotoxicity was assessed against CS-1 (human chondrosarcoma) cells in vitro and in vivo in nude mice. Following R0/R1 resection of primary subcutaneous tumors, mice were blindly randomized to: (1) Pax-film implant, (2) unloaded film implant, (3) paclitaxel 300 μg IV (Pax IV), or (4) no other therapy ("untreated"). Locoregional recurrence, overall survival (OS), and tumor mitotic index were evaluated.
RESULTS: Pax-films, but not unloaded films, reduced CS-1 viability in vitro for >50 days (P < 0.001). In vivo, locoregional recurrence was observed in 2 of 12 Pax-film mice (17%), 9 of 13 unloaded film mice (69%), 8 of 9 Pax IV mice (89%), and 7 of 8 untreated mice (88%) (P < 0.01). Median OS was 81, 64, 48, and 56 days, respectively. Paclitaxel levels in local tissues were 50- to 300-fold greater in Pax-film mice compared with Pax IV mice. Tumor mitotic index adjacent to Pax-films was significantly lower than adjacent to unloaded films.
CONCLUSIONS: Tumor bed implantation of Pax-films after R0/R1 resection is superior to Pax IV as evidenced by reduced locoregional recurrence and improved OS in a murine recurrent sarcoma model. Continuous local drug exposure via polymer films represents a potentially novel approach for treatment of locally aggressive sarcomas.