Development of a MUC16-Targeted Near-Infrared Fluorescent Antibody Conjugate for Intraoperative Imaging of Pancreatic Cancer

Abstract

Surgical resection is currently the only potentially curative option for patients with pancreatic cancer. However, the 5-year survival rate after resection is only 25%, due in part to high rates of R1 resections, in which cells are left behind at the surgical margin, resulting in disease recurrence. Fluorescence-guided surgery (FGS) has emerged as a method to reduce incomplete resections and improve intraoperative assessment of cancer. Mucin-16 (MUC16), a protein biomarker highly overexpressed in pancreatic cancer, is a potential target for FGS. In this study, we developed a fluorescent MUC16-targeted antibody probe, AR9.6-IRDye800, for imageguided resection of pancreatic cancer. We demonstrated the efficacy of this probe to bind human pancreatic cancer cell lines in vitro and in vivo. In an orthotopic xenograft model, AR9.6-IRDye800 exhibited superior fluorescence enhancement of tumors and lower signal in critical background organs in comparison to a nonspecific IgG control. The results of this study suggest that AR9.6-IRDye800 has potential for success as a probe for FGS in pancreatic cancer patients, and MUC16 is a feasible target for intraoperative imaging.

Crystal structure of a human MUC16 SEA domain reveals insight into the nature of the CA125 tumor marker

“…Each of these three MUC16 antibodies has previously been shown to bind MUC16 11,12 . AR9.6 is under investigation as both an immunotherapy and tumor imaging agent 10,14,15 . Antibody 3A5 has undergone a phase I clinical trial as an antibody‐drug conjugate for the treatment of ovarian cancer, 27 while H1H8794P2 is derived from a study developing a T‐cell engaging bispecific antibody for the treatment of ovarian cancer 11,28 .…”

“…While MUC16 was initially discovered as a tumor marker overexpressed in ovarian cancer, 9 the protein has emerged as an important contributing factor in the development and progression of several other diseases including pancreatic and breast cancer 1 . Due to MUC16's central role in the metastasis and progression of pancreatic and ovarian cancer, several groups and companies have developed monoclonal antibodies, which target the TR domain for immunotherapy, antibody‐drug conjugates, and for image‐guided surgery 10–12 . However, despite the importance of human MUC16 SEA domains in the immunogenic properties of MUC16, the only structure reported to date is an NMR structure of a murine SEA domain homologue 5 .…”

“…1 Due to MUC16's central role in the metastasis and progression of pancreatic and ovarian cancer, several groups and companies have developed monoclonal antibodies, which target the TR domain for immunotherapy, antibody-drug conjugates, and for image-guided surgery. [10][11][12] However, despite the importance of human MUC16 SEA domains in the immunogenic properties of MUC16, the only structure reported to date is an NMR structure of a murine SEA domain homologue. 5 Here we report the purification and X-ray structure of a human SEA domain.…”

Preclinical Evaluation of a Humanized, Near-Infrared Fluorescent Antibody for Fluorescence-Guided Surgery of MUC16-Expressing Pancreatic Cancer

“…Organs were quantified in Image Studio as previously described. 21 Dynamic Contrast Enhancement. Male NU/J mice (6− 8 week old) were injected subcutaneously with T3M4 (1 × 10 6 ), Colo357 (1.5 × 10 6 ), or Panc1 (1.5 × 10 6 ) cells in 50% Matrigel in the left flank.…”

“…In our preliminary studies, we showed that MUCIN16, or MUC16, a glycoprotein that is expressed in 60−80% of pancreatic cancers, has potential as a novel target for FGS of pancreatic cancer with a murine MUC16-targeted antibody conjugated to a NIR dye, termed AR9.6−IRDye800. 21 Our initial studies showed significantly improved contrast enhancement of tumors with AR9.6−IRDye800 as compared to a nonspecific IgG control in subcutaneous and orthotopic xenograft models and, based on current recommendations for developing new FGS agents, warranted further investigation to refine and evaluate the agent for clinical translation. 22 Herein, our objective was to improve translational potential, to assess the preclinical efficacy of AR9.6−IRDye800 to support potential clinical translation, and to investigate the role of antigen expression and tumor microenvironment on accumulation and contrast.…”