indication

Indicated in the treatment of esophageal cancer.

pharmacology

Porfimer is a photosensitizing agent used in the photodynamic therapy (PDT) of tumors. Porfimer is indicated for the palliation of patients with completely obstructing esophageal cancer, or of patients with partially obstructing esophageal cancer who cannot be satisfactorily treated with Nd:YAG laser therapy, reduction of obstruction and palliation of symptoms in patients with completely or partially obstructing endobronchial nonsmall cell lung cancer (NSCLC), and the treatment of microinvasive endobronchial NSCLC in patients for whom surgery and radiotherapy are not indicated. The cytotoxic and antitumor actions of porfimer are light and oxygen dependent. Tumor selectivity in treatment occurs through a combination of selective retention of porfimer and selective delivery of light.

mechanism of action

Cellular damage caused by porfimer is a consequence of the propagation of radical reactions. Radical initiation may occur after porfimer absorbs light to form a porphyrin excited state. Spin transfer from porfimer to molecular oxygen may then generate singlet oxygen. Subsequent radical reactions can form superoxide and hydroxyl radicals. Tumor death also occurs through ischemic necrosis secondary to vascular occlusion that appears to be partly mediated by thromboxane A2 release.

half life

10-452 hours