Tanaka Hideki, Koga Yoshikatsu, Sugahara Mayumi, Fuchigami Hirobumi, Ishikawa Akihiro, Yamaguchi Toru, Banba Akiko, Shinozaki Takeshi, Matsuura Kazuto, Hayashi Ryuichi, Sakashita Shingo, Yasunaga Masahiro, Yano Tomonori
Department of Head and Neck Surgery, National Cancer Center Hospital East, Kashiwa 277-8577, Japan.
Department of Otorhinolaryngology, Head and Neck Surgery, Tokyo Medical University, Shinjuku 160-0022, Japan.
Pharmaceuticals (Basel). 2024 Sep 22;17(9):1246. doi: 10.3390/ph17091246.
: Near-infrared photoimmunotherapy (NIR-PIT) was recently approved for the treatment of unresectable locally advanced or recurrent head and neck cancers in Japan; however, only one clinical dose has been validated in clinical trials, potentially resulting in excessive or insufficient dosing. Moreover, IRDye700X (IR700) fluorescence intensity plateaus during treatment, indicating a particular threshold for the antitumor effects. Therefore, we investigated the NIR laser dose across varying tumor sizes and irradiation methods until the antitumor effects of the fluorescence decay rate plateaued. : Mice were subcutaneously transplanted with A431 xenografts and categorized into control, clinical dose (cylindrical irradiation at 100 J/cm², frontal irradiation at 50 J/cm²), and evaluation groups. The rate of tumor IR700 fluorescence intensity decay to reach predefined rates (-0.05%/s or -0.2%/s) until the cessation of light irradiation was calculated using a real-time fluorescence imaging system. : The evaluation group exhibited antitumor effects comparable to those of the clinical dose group at a low irradiation dose. Similar results were observed across tumor sizes and irradiation methods. : In conclusion, the optimal antitumor effect of NIR-PIT is achieved when the fluorescence decay rate reaches a plateau, indicating the potential to determine the appropriate dose for PIT using a real-time fluorescence monitoring system.
近红外光免疫疗法（NIR-PIT）最近在日本被批准用于治疗不可切除的局部晚期或复发性头颈癌；然而，在临床试验中仅验证了一种临床剂量，这可能导致给药过量或不足。此外，IRDye700X（IR700）荧光强度在治疗期间达到平稳状态，表明存在抗肿瘤作用的特定阈值。因此，我们研究了不同肿瘤大小和照射方法下的近红外激光剂量，直至荧光衰减率的抗肿瘤作用达到平稳状态。
将小鼠皮下移植A431异种移植物，并分为对照组、临床剂量组（100 J/cm²柱状照射，50 J/cm²正面照射）和评估组。使用实时荧光成像系统计算在停止光照射前肿瘤IR700荧光强度衰减至预定义速率（-0.05%/秒或-0.2%/秒）的速率。
评估组在低照射剂量下表现出与临床剂量组相当的抗肿瘤作用。在不同肿瘤大小和照射方法中均观察到类似结果。
总之，当荧光衰减率达到平稳状态时可实现NIR-PIT的最佳抗肿瘤作用，这表明使用实时荧光监测系统确定PIT合适剂量具有可能性。
