Highly efficient destruction of squamous carcinoma cells of the head and neck by photochemical internalization of Ranpirnase.

INTRODUCTION: Photochemical Internalization is a novel drug delivery technology for cancer treatment based on the principle of Photodynamic Treatment. Using a photosensitizer that locates in endocytic vesicles membranes of tumor cells, Photochemical internalization enables cytosolic release of endocytosed antitumor agents in a site-specific manner. The purpose of the present in-vitro study was to explore whether Photochemical Internalization is able to enhance the efficacy of Ranpirnase, a cytotoxic amphibian ribonuclease, for eradication of squamous cell carcinoma of the head and neck. METHODS: Cell viability was measured in 8 primary human cell lines of squamous cell carcinoma of the head and neck after treatment with Ranpirnase and Photochemical Internalization. For Photochemical Internalization the photosensitizer disulfonated tetraphenyl porphine was incubated with tumor cells followed by exposure to blue light (435 nm). RESULTS: Our study demonstrates significant enhancement of antitumor activity of Ranpirnase by Photochemical Internalization. Treatment responses were heterogeneous between the primary cancer cell lines. Combining Photochemical Internalization with Ranpirnase resulted in 4.6 to 1,940-fold increased cytotoxicity when compared with the ribonuclease alone (P < 0.05). CONCLUSION: Cytotoxicity of Ranpirnase can be markedly enhanced by Photochemical Internalization in squamous cell carcinoma of the head and neck.

Photodynamic therapy of bladder cancer - a phase I study using hexaminolevulinate (HAL).

OBJECTIVES: To assess the safety and feasibility of hexaminolevulinate (HAL) based photodynamic therapy (PDT) as adjuvant treatment after transurethral resection of the bladder (TURB) in patients with intermediate or high-risk urothelial cell carcinoma (UCC) of the bladder. MATERIALS AND METHODS: Seventeen patients received 50 ml of either a 16 mM (4 patients) or 8 mM HAL (13 patients) solution instilled intravesically. Bladder wall irradiation was performed using an incoherent white light source coupled via a quartz fiber assembled into a flexible transurethral irrigation catheter. Each patient received 3 treatments with HAL-PDT 6 weeks apart. After PDT, patients were followed by regular cystoscopy for up to 21 months to assess time to recurrence. Reported adverse events (AEs) were coded according the World Health Organization Adverse Reaction Terminology (WHO-ART). Efficacy was assessed by cystoscopy, cytology, and histology, and was defined as the number of patients who were tumor-free at 6 or 21 months after initial PDT treatment. Transient bladder irritability was reported by 15 of the 17 patients and resolved completely in all patients. No evidence of a cumulative effect of treatment on the incidence of AEs could be detected. PDT treatment was performed without any technical complications. Furthermore preliminary assessment of efficacy showed that of the 17 patients included, 9 (52.9%; 95% CI: 27.8-77.0) were tumor-free at 6 months, 4 (23.5%; 95% CI: 6.8-49.9) were tumor-free at 9 months, and 2 (11.8%, 95% CI: 1.5-36.4) were tumor-free after 21 months. CONCLUSIONS: PDT using hexaminolevulinate and an incoherent white light system with the special flexible irradiation catheter system is technically feasible and safe and may offer an alternative in the treatment of non-muscle-invasive intermediate and high-risk bladder cancer.