IsoPSA, a blood test developed by Cleveland Diagnostics that detects cancer-derived PSA, is more accurate in diagnosing prostate cancer than a conventional PSA test and reduces the need for biopsies by nearly half, according to the results of a U.S.-based study.
The findings were published in the journal European Urology under the title, “The Single-parameter, Structure-based IsoPSA Assay Demonstrates Improved Diagnostic Accuracy for Detection of Any Prostate Cancer and High-grade Prostate Cancer Compared to a Concentration-based Assay of Total Prostate-specific Antigen: A Preliminary Report.”
IsoPSA is still the focus of studies and has not been approved for use in the United States.
“The IsoPSA test provides two necessary parameters for a successful test: specificity of the organ’s tissue and specificity of the cancer. The trial proved that it is more accurate in diagnosing cancer and lowering the number of unnecessary biopsies among patients at low risk to the disease,” Eric Klein, MD, chairman of the Glickman Urological and Kidney Institute at Cleveland Clinic in Ohio, said in a press release.
Prostate-specific antigen (PSA) is a protein produced by the prostate gland and secreted into semen. It can be measured in the blood as an indicator of diseases affecting the prostate gland, like prostate cancer.
But PSA’s use in screening men for prostate cancer remains controversial. Results might lead to the diagnosis and treatment of cancers that would never be life-threatening, such as benign cancers or tumors that grow extremely slowly — a phenomenon called overdiagnosis and overtreatment.
PSA exists in different structural forms in the blood called isoforms. While conventional PSA tests measure the concentration of PSA in the blood, many scientists believe that measuring the entire spectrum of PSA isoforms could give a more accurate diagnosis.
Cleveland Diagnostics’ (CDx) IsoPSA test assesses specific structural changes in PSA to diagnose prostate cancer.
The study, conducted at Cleveland Clinic, showed that the IsoPSA test has a high level of accuracy in diagnosing prostate cancer and the ability to reduce more than 40 percent of unnecessary biopsies.
These findings further confirm the results obtained in previous trials conducted by the same Cleveland Clinic team. Klein presented the findings from this study at the 2018 annual meeting of the American Urological Association (AUA), held May 18-21 in San Francisco.
“We are happy about the publication of the research results, which support CDx’s commercialization process and indicate very major economic potential for the company,” said Eli Arad, CEO of Merchavia, an investment company that holds 8 percent of Cleveland Diagnostics.
In November 2017, Cleveland Diagnostics signed a licensing agreement with Genomic Health. The agreement gave Genomic Health exclusive licensing rights in the U.S. and most countries worldwide to develop and commercialize the IsoPSA test, in exchange for $10 million (with an immediate payment of $2 million) and future milestone payments.