Temoporphin, a second generation
photosensitizer, was launched in UK for the photodynamic therapy
(PDT) of advanced head and neck
cancers. This porphyrin derivative can
be synthesized from pyrrole and 3-hydroxybenzaldehyde. The pharmacological activity is
initiated, 4 days after intravenous injection, by laser-light photoactivation of temoporphin,
that has selectively accumulated in cancer tissues. The resulting generation of highly
reactive oxygen species leads to malignant cells death thereby inducing tumor necrosis up
to a depth of 15 mm. An advantage of temoporphin over other photosensitizing agents is
its extreme sensitivity to wavelengths of light that penetrate tissues, resulting in lower
light/dose and irradiation time. PDT with intravenous temoporphin has produced relatively
high complete and partial response rates in head and neck cancers, with higher response
rates generally observed with higher light dose. Temoporphin is well-tolerated and does
not preclude surgery/radiotherapy as a later option. Adverse effects were photosensitivity
and pain at the injection site.
용도
Temoporfin is a synthetic chlorin with light-activated actions. When administered systemically, temoporfin accumulates in tumor cells. When stimulated with light (650-652 nm) in the presence of oxygen, reactive oxygen species are generated, leading to necrosis within the tumor. Different approaches to using photodynamic therapy with temoporfin in palliative care are currently of interest.
