Safety and effectiveness of a new enzyme-targeting radiosensitization treatment (KORTUC II) for intratumoral injection for low-LET radioresistant tumors.

Linear accelerator-based radiotherapy has little effect on tumors such as malignant melanoma, various types of sarcoma, and most locally-advanced neoplasms that have grown to several centimeters or more. These tumors contain many hypoxic cancer cells or large amounts of anti-oxidative enzymes, and are therefore resistant to low linear energy transfer radiation. Therefore, it was necessary to develop a new radiosensitizer to overcome these situations. We previously developed a new enzyme-targeting radiosensitization treatment named KORTUC I, which uses 3% w/v hydrogen peroxide solution-soaked gauze. We developed a new radiosensitizer for intratumoral injection (KORTUC II), comprising a combination of hydrogen peroxide and sodium hyaluronate. After providing a fully informed written consent, 52 patients with unresectable or recurrent neoplasms (53 lesions) were enrolled in the KORTUC II trial. The present study of 52 patients with unresectable or recurrent neoplasms showed that KORTUC II is safe when injected intratumorally, well tolerated, and can efficiently exert a radiation sensitizing effect. Because this radiosensitizer is safe and less expensive than other methods, and can be applied for almost every type of low-LET radio-resistant neoplasm, it has potential for worldwide and immediate use.