temoporfin

Temoporfin, marketed under the brand Foscan among others, is a photosensitizing agent used in photodynamic therapy (PDT) for cancer. It is a chlorin-based porphyrin derivative that is administered systemically and tends to accumulate in malignant tissue, enabling selective targeting when activated by light.

Mechanism of action involves administration followed by light exposure. After intravenous administration, temoporfin localizes in tumor tissue. When illuminated with red light in the approximate 652-nanometer range, it reaches an excited triplet state and transfers energy to molecular oxygen, generating singlet oxygen and other reactive species. These reactive entities cause direct tumor cell damage, vascular disruption, and an inflammatory response that contributes to tumor control.

Administration and light delivery are integral to PDT with temoporfin. It is given by intravenous infusion, and light activation is performed at a defined time after administration using a calibrated light source to deliver a prescribed fluence to the tumor area. The timing of illumination is chosen to optimize tumor selectivity and is determined by treatment guidelines and tumor site.

Clinical use and scope include indications for palliative treatment of recurrent oropharyngeal and other head and neck cancers in patients where curative options are not feasible. Temoporfin has also been investigated in studies for other solid tumors and for endobronchial or esophageal lesions, with varying levels of evidence.

Safety considerations center on photosensitivity, which can persist for weeks after treatment, necessitating avoidance of bright light and sun exposure. Other adverse effects may include local pain, edema, nausea, fever, and transient liver enzyme elevations. Regulatory status varies by region, with approvals in some jurisdictions for head and neck cancer palliation.