TUSTIN, Calif.—In February, Peregrine Pharmaceuticals Inc. announced the publication of results from a study conducted at University of Texas (UT) Southwestern Medical Center regarding phosphatidylserine-positive exosomes in cancer detection, specifically ovarian cancer. Researchers were able to distinguish between healthy subjects and patients with ovarian tumors based on the levels of exosomes containing phosphatidylserine (PS) found in their plasma.
Originally used in cancer therapy, and eventually found already existing in ovarian tumors, previous research has suggested that PS is an immunosuppressant used by tumors to restrict the body’s ability to fight the cancer. The study also provided positive data showing that further analysis of the PS-positive exosome levels may allow researchers to distinguish between malignant and benign tumors.
The study’s positive proof-of-concept data were recently published online by the peer-reviewed journal Oncotarget in a paper titled “Detection of phosphatidylserine-positive exosomes as a diagnostic marker for ovarian malignancies: a proof-of-concept study.” Researchers analyzed plasma samples from 34 patients with ovarian tumors and 10 healthy subjects for the presence of PS-expressing exosomes in a blinded test.
Findings showed that patients with malignant ovarian cancer displayed significantly higher blood PS exosome levels than those with benign tumors (median 0.237 vs. -0.027) and the malignant and benign groups displayed significantly higher blood PS exosome levels than the healthy subjects (median 0.237 vs -0.158 and -0.027 vs -0.158, respectively).
“These initial proof-of-concept results are encouraging, as they appear to support the underlying concept that the measurement of PS-positive exosome levels in blood could be a simple way to detect and monitor cancer. While the work is still early, we think these data serve as an important first step in highlighting the diagnostic potential of this platform,” said Steven W. King, president and CEO of Peregrine. “This type of diagnostic technology is particularly important in an area such as ovarian cancer, in which screening options are limited and the ability to detect the disease at an early stage is inadequate. We look forward to continuing to explore the potential of the technology platform in ovarian as well as other types of cancer.”
Licensed from UT Southwestern Medical Center in July 2016, Peregrine is currently advancing the proprietary exosome-based cancer diagnostic technology in hopes of developing an optimized test for further clinical testing. To advance this goal, the company is seeking a strategic partner for collaboration on developing and commercializing the technology.
In an interview with DDNews, King expressed a vested interest in finding a partner with the infrastructure to give this platform global reach and a hope that this technology can be optimized for more general use. He also added that he feels Peregrine’s platform will fit nicely with the latest trend in developments in liquid biopsies, where a test is done on a sample of blood to look for cancer cells from a tumor circulating in the blood or for pieces of DNA from tumor cells that may be in the blood.
Currently there are no effective screening modalities for ovarian cancer, and the only way to establish malignancy is by histiologic confirmation, making the ability to detect ovarian cancer in its early stages extremely low. These findings could aid in early detection in high-risk patients, as well as better treatment and monitoring both pre- and post-treatment and give medical professionals better evidence in the event of the cancer returning.
“There is a significant and growing interest in the healthcare industry around the ability to detect cancer and monitor its progression with more readily accessible blood tests. With this area being one of the fastest-growing segments of the oncology diagnostics market, we believe that our exosome-based technology represents a significant product development and licensing opportunity,” stated Stephen Worsley, vice president of business development at Peregrine. “Based on the fact that PS is a marker associated with a broad range of cancer types, we believe our platform has potential applications in several solid tumors beyond ovarian cancer. With that in mind, we look forward to aligning with a partner to help explore the potential of this promising technology.”