Under the supervision of Nippon Petrochemical (Osaka, Japan), N-aspartyl chlorin e6 (NPe6) is being studied as a possible photosensitizer for PDT [93]. Phase I clinical trials are under way for the treatment of cutaneous malignancies[69] and it is also being investigated in Japan as a possible therapy for endobronchial lung cancer. Npe6 has been shown to be an effective photosensitizer against skin cancers with little or no long-term cutaneous photosensitivity.
The photodynamic activity of Npe6 also involves a combination of vascular (indirect effect) and direct anti-tumour photodamage, which is another potential advantage of this photosensitizer[94].