• Hisashi Tsukada, Plamena Entcheva-Dimitrov, Armin Ernst, Samaan Rafeq, John H Keating, Kirk P Seward, and Lonny Yarmus.
• Department of Thoracic Surgery, Brigham and Women's Hospital, Boston, MA, USA.
• Respirology. 2018 Apr 1; 23 (4): 399-405.

Background And ObjectiveIntratumoral administration of chemotherapeutic agents is a treatment modality that has proven efficacious in reducing the recurrence of tumours and increases specificity of treatment while minimizing systemic side effects. Direct intratumoral injection of malignant airway obstruction has potential therapeutic benefits but tissue drug concentrations and side-effect profiles are poorly understood.MethodsBronchial wall injection of generic paclitaxel (PTX) (102 injections of 0.05, 0.5, 1.5 or 2.5 mg/mL in 10 healthy pigs), saline (14 injections in 2 healthy pigs) or Abraxane (ABX) (24 injections of 0.5 mg/mL in 4 healthy pigs) was performed with a microneedle infusion catheter. Local histopathology, plasma and tissue PTX concentrations were evaluated at 7, 20 or 28 days post-injection.ResultsInjection of generic PTX directly into the bronchial wall at doses up to 1.5 mg/mL only caused minimal tissue injury. Dose-limiting tissue reaction was observed at 2.5 mg/mL. Plasma PTX was detectable for up to 5 days but not at 28 days, with area under the curve (AUC)(0-5d) 20- to 50-fold lower than the AUC(0-∞) of 6300 ng h/mL for the approved intravenous dose. At 7 and 28 days post-injection, bronchial PTX tissue concentrations were above a 10-nmol/L cancer therapeutic level. PTX was not found in peripheral tissues. Similar results were observed between ABX and generic PTX.ConclusionResults of these studies confirm the administration of PTX directly into the bronchial wall is safe and feasible. PTX was detectable in plasma for <7 days but tissue concentrations remained therapeutic throughout the follow-up period.© 2017 Asian Pacific Society of Respirology.

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