Abstract 1456: Efficacy of photo-immunotherapy in combination with surgical resection on a pancreatic cancer patient derived orthotopic xenograft (PDOX)

Abstract

Abstract Complete tumor resection improves overall survival of pancreatic cancer patients. We have previously showed that UVC irradiation in combination with fluorescence-guided surgery (FGS) completely cured metastatic pancreatic cancer by eradicating minimal residual cancer after FGS. Recently, photoimmunotherapy (PIT), that uses a target-specific photosensitizer based on a near-infrared (NIR) phthalocyanine dye, IR700, demonstrated in vivo tumor shrinkage after irradiation with NIR light without any side effects. In this study, we used a clinically applicable model of pancreatic cancer to examine the use of PIT to eradicate minimal residual cancer of a patient derived orthotopic xenograft (PDOX). We found that anti-CEA-IR700 could label and illuminate PDOX strongly enough for PIT in both subcutaneous and orthotopic models. Furthermore, we succeeded in detecting fluorescence from the minimal residual cancer of the PDOX. The local recurrence rate of BLS only and BLS + PIT group was 85.7% and 28.6%, respectively. BLS + PIT tended to reduce the recurrence rate compared to BLS only, and there was marginally significant difference (p = 0.051). The average recurrent tumor weight of BLS only and BLS + PIT group was 1149.0 ± 794.6 mg and 210.8 ± 336.9 mg, respectively. The average recurrent tumor weight of BLS + PIT group was significantly less than BLS only (p = 0.015). In conclusion, anti-CEA-IR700 is able to label and illuminate the PDOX strongly enough for PIT. PIT reduces recurrence by eradicating microscopic disease undetectable with BLS, and might be applicable to pancreatic cancer patients. Citation Format: Yukihiko Hiroshima, Ali Maawy, Takashi Murakami, Nzola De Magalhães, Daisuke Kawaguchi, Kenichi Matsuo, Kuniya Tanaka, Michael Bouvet, Robert M. Hoffman, Itaru Endo. Efficacy of photo-immunotherapy in combination with surgical resection on a pancreatic cancer patient derived orthotopic xenograft (PDOX). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1456. doi:10.1158/1538-7445.AM2015-1456