EUS-Guided Injection of Paclitaxel (OncoGel) Provides Therapeutic Drug Concentrations in the Porcine Pancreas

Background: OncoGel (ReGel/Paclitaxel) is an intratumoral injectable formulation of the chemotherapeutic drug Paclitaxel, developed for the local treatment of solid tumors. Methods: Eight pigs were sedated by general anesthesia and OncoGel (Macromed Inc.) was injected under EUS-guidance with a 22-gauge needle into the tail of the pancreas. The endpoints of this study were imaging by CT, gross and microscopic evidence of inflammation of the pancreas, clinical tolerance and local tissue distribution of paclitaxel. Results: Eight Yorkshire breed pigs with an average age of 101.3 days and an average weight of 108.4 pounds underwent injection of 1 ml (n = 2), 2 ml (n = 2), 3 ml (n = 2) or 4 ml (n = 2) of OncoGel (1 ml = 6 mg Paclitaxel). An intra-pancreatic, hyperechoic focus with an average diameter of 2.1 cm was visible by EUS. The animals were monitored for 7 (n = 4) and 14 (n = 4) days. No fever, vomiting or anorexia was observed during this period. Blood levels of amylase and lipase were normal. At sacrifice, a depot of OncoGel with an average diameter of 1.5 cm could be located in the tail of the pancreas grossly (figure 1) and histologically. Cross sectional histological and CT studies demonstrated a capsule-forming depot without evidence of pancreatic necrosis. Mean Paclitaxel tissue concentrations are shown in table 1. Clinically, the animals appeared to tolerate the procedure without sequelae. Conclusions: The EUS-guided injection of OncoGel into the porcine pancreas was technically successful and well tolerated. Clinically significant tissue concentrations of paclitaxel were detected in and adjacent to the depot. This technique could provide localized treatment of pancreatic malignancy. Table 1Mean Paclitaxel tissue concentrations in μg/g Distance from depot OncoGel 3 ml OncoGel 4 ml Center 98.4 134.9 2 cm 56.2 26.8 4 cm 9.5 14.9 Open table in a new tab