Therapeutic effects of a new photosensitizer for photodynamic therapy of early head and neck cancer in relation to tissue concentration.
OBJECTIVE
Talaporfin sodium (Laserphyrin, Meiji Seika, Tokyo, Japan) is a second-generation photosensitizer developed in Japan. It is characterized by both mild and short-term skin photosensitivity. The objective of this study was to evaluate the efficacy and the pharmacokinetic characteristics in tumor tissues in patients with head and neck cancer.


METHODS
(1) Four hours after administration intravenous injection of talaporfin sodium (40 mg/m(2)), 100mg tissue specimens were taken from the central part of the tumor. The samples were analyzed by reverse phase liquid chromatography and concentrations were measured. (2) Four hours after intravenous injection of talaporfin sodium (40 mg/m(2)), we gave 60-150 J/cm(2) of 664 nm laser irradiation with a diode laser (PD laser, Panasonic, Japan). Biopsies were performed at 4 weeks and at 3 months after treatment and periodically thereafter to confirm the treatment efficacy of photodynamic therapy (PDT).


RESULTS
Of the 14 patients who grope informed consent, more than 1 microg/g of talaporfin sodium was found in the tumor tissues in 13. Moreover, in 9 patients, tumor-to-normal-tissue ratios ranged from 2.32:1 to 5.69:1, which indicates that more than double the amount of talaporfin sodium was maintained within the tumor than in normal tissues. We have enrolled 22 patients with head and neck cancer with no clinically recognizable metastases after obtaining written informed consent to participate in this study. PDT using talaporfin sodium exhibited the equivalent efficacy to that of conventional PDT using hematoporphyrin derivative (HpD).


CONCLUSIONS
The results using a combination of talaporfin sodium and PD laser achieved a primary treatment outcome equivalent to that of conventional PDT. This method has also proven to be advantageous because of the reduced incidence of side effects such as photosensitivity and local edema.
Yoshida
Tomoyuki
T
Otorhinolaryngology, Head and Neck Surgery, Tokyo Medical University Hachioji Medical Center, 1163 Tatemachi, Hachioji city, Tokyo 193-0998, Japan. jibitom@tokyo-med.ac.jp
Tokashiki
Ryoji
R
Ito
Hiroyuki
H
Shimizu
Akira
A
Nakamura
Kazuhiro
K
Hiramatsu
Hiroyuki
H
Tsukahara
Kiyoaki
K
Shimizu
Shigetaka
S
Takata
Daisuke
D
Okamoto
Isaku
I
Suzuki
Mamoru
M
D000328:Adult; D000368:Aged; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007275:Injections, Intravenous; D007822:Laryngeal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009367:Neoplasm Staging; D010610:Pharyngeal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011166:Porphyrins / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
D017319:Photosensitizing Agents; D011166:Porphyrins; C053434:Talaporfin