PGN650 Tumor Imaging PDF Print E-mail

First-in-Class PS-Targeting Monoclonal Antibody Fragment for Tumor Imaging

PS-Targeted Antibodies in Molecular Imaging

Our preclinical research has found that phosphatidylserine (PS) is both a specific marker of tumor blood vessels and becomes exposed on dying tumor cells themselves. We have also observed that chemotherapies and radiation therapy increase the amount of exposed PS on tumor blood vessels.

We believe that our unique technology can achieve several important milestones, including:

  • Further validation of bavituximab's therapeutic target:
    Images in humans delineating the specificity of exposed PS in tumors could further validate and support PS as a promising new therapeutic target for antibody therapy across multiple tumor types, and also support PS-targeting antibodies and fragments as potential candidates for antibody-drug conjugates (ADC).

  • Evaluating the effectiveness of cancer therapies:
    Since cells expose PS on their surface when they are dying, cancer treatments that are killing tumor cells will cause an increase in PS exposure in the tumor. Therefore, PS-targeted imaging agents may have the ability to image the anti-tumor effectiveness of potentially any cancer therapy and thus facilitate optimization of therapies for individual patients.

  • Companion diagnostic to bavituximab therapy:
    The amount of exposed PS on tumor blood vessels may be indicative of bavituximab’s potential to initiate a robust immune response to cancer. PS-targeting imaging agents may therefore hold potential as companion diagnostics to select optimal patients for bavituximab treatment.

The global imaging agent market is expected to exceed $15 billion by 2015, with the majority of the market being in the United States 1

Clinical Trial Currently Enrolling Patients

Under an exploratory IND, we have initiated an open-label, single-center trial at Washington University in St. Louis, Missouri. Up to 12 healthy subjects with various solid tumor types will be administered a single dose (4 mCI) of the clinical PET imaging agent 124I-PGN650. The primary goal of the trial is to examine radiation dosimetry in critical and non-critical organs. The secondary objectives are tumor imaging and safety.

About I-124 PGN650

I-124 PGN650 is a first-in-class phosphatidylserine (PS)-targeting F(ab’)2 fully human monoclonal antibody fragment (PGN650) joined to the PET imaging radio-isotope iodine-124 that represents a new approach to imaging cancer. PS is a molecule usually located inside the membrane of healthy cells, but "flips" and becomes exposed on the outside of cells that line tumor blood vessels, creating a specific target for the imaging of multiple solid tumor types. In preclinical studies, I-124 PGN650 accumulates in tumor vasculature and provides exceedingly clear in vivo tumor images. Read more..

1. Global Industry Analysts, Inc: Imaging Agents: A Global Strategic Business Report