286. Biodistribution and Cearance Following Intraperitoneal Injection of Murine Interleukin-12 Plasmid Formulated with a Novel Polymeric Delivery System

Abstract

Intraperitoneal delivery of an interleukin-12 (IL-12) plasmid formulated with a novel polymeric delivery system (PPC) into nanocomplexes has shown efficacy in treating a variety of disseminated peritoneal malignancies in mice. Pre-clinical GLP studies were conducted to evaluate the biodistribution of plasmid following intraperitoneal administration of increasing doses of PPC formulated murine IL-12 plasmid into CD-1 mice. In the study a total of 54 male mice and 54 female mice were evaluated. Animals were divided equally into control group, low dose (10 mg; ∼1.5 mg/m2) and high dose (250 mg, ∼38 mg/m2) groups. The doses selected for this study were based upon preliminary toxicology studies and represent significant multiples of the starting dose currently being used in Phase I clinical testing. Specifically the low and high doses are approximately 2.5 and 60 times the starting dose in humans based on a 25 g mouse and a 70 kg human. Animal tissues were harvested at 3, 30 and 88 days after treatment and analyzed using a qPCR assay that was determined to be sensitive to ∼10 copies of plasmid/mg DNA and quantifiable at >100 copies/mg DNA. A total of 11 samples were collected from each animal and included; injection site, blood, gonads, liver, heart, kidneys, lung, mesenteric lymph nodes, spleen, left femur and brain. The results indicated that following IP dosing, plasmid was detectable in all examined tissues with the highest levels located in the organs of the peritoneal cavity and at the site of injection. Considerably lower plasmid levels were found in the blood, heart, femur (marrow) and brain. Distribution did not appear to be affected by dose with proportional levels found in all tissues at the different doses. An approximate 95% clearance occurred within 1 month with 99% clearance by three months in almost all tissues, however slightly higher levels still remained at the sight of injection at the end of the study. In summary these data indicate that plasmid formulated with PPC and injected IP will lead to both local and systemic uptake of plasmid. However, the plasmid is readily cleared from all tissues over time.Full-time employee of Expression Genetics, Inc. Intraperitoneal delivery of an interleukin-12 (IL-12) plasmid formulated with a novel polymeric delivery system (PPC) into nanocomplexes has shown efficacy in treating a variety of disseminated peritoneal malignancies in mice. Pre-clinical GLP studies were conducted to evaluate the biodistribution of plasmid following intraperitoneal administration of increasing doses of PPC formulated murine IL-12 plasmid into CD-1 mice. In the study a total of 54 male mice and 54 female mice were evaluated. Animals were divided equally into control group, low dose (10 mg; ∼1.5 mg/m2) and high dose (250 mg, ∼38 mg/m2) groups. The doses selected for this study were based upon preliminary toxicology studies and represent significant multiples of the starting dose currently being used in Phase I clinical testing. Specifically the low and high doses are approximately 2.5 and 60 times the starting dose in humans based on a 25 g mouse and a 70 kg human. Animal tissues were harvested at 3, 30 and 88 days after treatment and analyzed using a qPCR assay that was determined to be sensitive to ∼10 copies of plasmid/mg DNA and quantifiable at >100 copies/mg DNA. A total of 11 samples were collected from each animal and included; injection site, blood, gonads, liver, heart, kidneys, lung, mesenteric lymph nodes, spleen, left femur and brain. The results indicated that following IP dosing, plasmid was detectable in all examined tissues with the highest levels located in the organs of the peritoneal cavity and at the site of injection. Considerably lower plasmid levels were found in the blood, heart, femur (marrow) and brain. Distribution did not appear to be affected by dose with proportional levels found in all tissues at the different doses. An approximate 95% clearance occurred within 1 month with 99% clearance by three months in almost all tissues, however slightly higher levels still remained at the sight of injection at the end of the study. In summary these data indicate that plasmid formulated with PPC and injected IP will lead to both local and systemic uptake of plasmid. However, the plasmid is readily cleared from all tissues over time. Full-time employee of Expression Genetics, Inc.