Vascular-targeted photodynamic therapy (VTP) of a canine-transmissible venereal tumour in a murine model with Pd-bacteriopheophorbide (WST09).

Abstract Treatment of canine-transmissible venereal tumour (CTVT) with local vascular-targeted photodynamic therapy (VTP) using Pd-bacteriopheophorbide (WST09) as a drug is suggested as an alternative to conventional chemotherapy. Male CD1 nude mice were subcutaneously grafted with the xenograft-transmissible canine venereal tumour (XTVT). The VTP protocol delivered once consisted of intravenous administration of WST09 (10 mg kg(-1)) followed by immediate local illumination with a diode laser (763 nm). Controls included animals treated with light or WST09 alone. Macroscopic and microscopic evaluations of tumour response were conducted 10, 24 and 48 h after treatment. Upon VTP, tumours underwent necrosis that lasted 8-10 days and exhibited complete healing by 25-35 days, reaching an overall long-term cure rate (83%) by 90 days after treatment. This study suggests that VTP with WST09 can efficiently treat CTVT in a single session, as compared with 4-6 sessions of chemotherapy and thus may be feasible for common veterinary practice, particularly under ambulatory conditions.