The first generation photosensitizers are haematoporphyrin
derivatives such as Photofrin® and are the most
commonly used photosensitizers. Haematoporphyrin derivatives
were originally synthesized by combining haematoporphyrin
with 5% sulphuric acid in acetic acid at room
Subsequently, the mixture was treated with
an aqueous base and then neutralized. This led to the formation
of a complex mixture of dimers and oligomers
primarily involving ester and ether linkages. Partial
purification of the most active of these oligomers by highperformance
liquid chromatography (HPLC) or sizeexclusion
gel chromatography lead to Photofrin, 90–95%
of which is the active component.
Photofrin is marketed by QLT PhotoTherapeutics
(Vancouver, Canada) and has been accepted in the clinic
in several countries for the treatment of early- and latestage
lung cancer, superficial and advanced oesophageal
cancer, bladder cancer, superficial and early-stage gastric
cancers, early stage cervical cancer and cervical dysplasia
(a precancerous condition).
In addition, Photofrin is being investigated as a
possible therapy against Karposi’s sarcoma, cancers of the
head and neck, brain, intestine, lung, breast and skin
(both primary and metastatic breast cancers), as well as
urinary bladder, abdominal and thoracic cancers. Other
conditions include Barrett’s oesophagus, psoriasis and
arterial restenosis, and all of these conditions are being
investigated in clinical trials with mostly promising results.
Derivations of Photofrin are also being used.
Photoheme is produced in Russia and has been
accepted by the Pharmacological Committee of Russia for
a wide range of clinical uses including skin, breast,
oropharingeal, lung, larynx and gastrointestinal cancers, as
well as psoriasis and prophylaxis for corneal transplant
opacity and recurrent blindness.