CHAPTER 21: Present Status of Photodynamic Therapy for Lung Cancer in Japan

The best photodynamic therapy (PDT) candidates in lung cancer are patients with central-type, early-stage lung carcinoma (ESLC), because of their endoscopic accessibility and the limited effectiveness of PDT. In order to achieve greater therapeutic efficacy, improvements of photosensitizers and the laser delivery system in PDT are still needed. In Japan, talaporfin sodium (mono-l-aspartyl chlorin e6; NPe6, Laserphyrin®) was considered to be a promising photosensitizer, and a diode laser system (Panalas 6405, PD Laser®) was developed for PDT applications with talaporfin sodium. After confirmation of safety in a phase I clinical study from April 1995 to December 1996, a phase II clinical study was performed from October 1997 through to March 2000 in order to investigate the anti-tumor effects and the safety of talaporfin sodium. On a per-lesion basis, the complete response rate was 84.6% and the overall response rate was 94.9%. The skin photosensitivity test showed no photosensitivity in 84.8% of patients by 14 days after drug administration. The phase II clinical study demonstrated the excellent anti-tumor effects and safety of talaporfin sodium. Therefore, the Japanese government approved this second-generation PDT for central-type ESLC in October 2003, and reimbursement through National Health Insurance began in June 2004. Currently, this second-generation PDT has been a standard modality of PDT for central-type ESLC in Japan.