NEW YORK (GenomeWeb) – A prostate cancer biomarker study published last month in PLOS One provides a glimpse at a new addition to German diagnostic firm Protagen's commercial strategy, CEO Stefan Müllner told GenomeWeb this week.
While the company has by and large abandoned its early efforts in oncology to focus on autoimmune disease, the study demonstrates the potential usefulness of its protein array platform for identifying novel drug targets, Müllner said, noting that the company is now exploring opportunities in this area.
He said that the company has established through the prostate cancer work and other studies that the autoantibody markers it identifies as characteristic of a given disease are often directed against potentially interesting drug targets.
This, he noted, means that in addition to serving as signatures for purposes like disease diagnosis and patient stratification, the markers may also serve as a source of drug targets.
In the case of the PLOS One study, which Protagen undertook in collaboration with researchers at Targos Molecular Pathology, Weill Cornell Medical College, and the Medical University of Innsbruck, the researchers identified five autoantibodies upregulated in patients with high levels of prostate inflammation, among them an autoantibody targeting the protein SPOP, which, Müllner noted, is a protein of significant interest among prostate cancer researchers.
He said Protagen has begun speaking to potential pharma partners about using its technology for target discovery.
Protagen's SeroTag platform allows researchers to simultaneously measure autoantibody levels for thousands of antigens to detect expression patterns linked to disease. Its diagnostic development strategy has been to identify such signatures and use them to detect disease and track a patient's response to particular therapies.
To this end, the company has what it asserts is the largest human antigen expression library in the world, a collection of more than 7,000 human proteins that includes more than 95 percent of published, disease-associated autoantigens. According to Protagen, all of these proteins have been sequence-verified by mass spectrometry.
Müllner told GenomeWeb this week that the prostate cancer work was part of oncology research that the company had moved away from after finding it difficult to get traction with clinicians in that field.
"We had to face the reality that autoantibody-based biomarkers are not convincing for the pathologists in oncology," he said, noting that in Protagen's experience these pathologists were skeptical of markers outside the bounds of traditional immunohistochemistry or PCR-based techniques. "We tried very hard to convince diagnostic companies and pharma companies that we have something here, but we got no buy in."
This echoes sentiments expressed this week to GenomeWeb by Arizona State University researcher Phillip Stafford, who with his colleagues is using peptide arrays to develop autoantibody diagnostics. Stafford noted that, in his case, he and his colleagues had struggled to get funding for their work from the National Cancer Institute due to skepticism about their approach. Instead, Stafford said, they turned the bulk of their focus toward infectious disease research with the hope of coming back to cancer once they have amassed more proof of their method's effectiveness.
Protagen, likewise, shifted focus, moving into autoimmune work, which, Müllner noted, "is an area where you do not have to explain why autoantibody signatures are important."
Drug target ambitious aside, development of markers for autoimmune disease remains Protagen's primary business, and Müllner said the company had recently closed deals with several pharma firms (which he declined to name) for work on markers for patient stratification in this area. In the past, the company has inked deals with drugmakers including Pfizer, Biogen Idec, SuppreMol, and Bayer.
Protagen is also completing the development of marker panels in systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis that it plans to license to a large diagnostics company for sale initially as research-use-only assays and, down the line, CE marked assays. It also hopes to partner with a US-based CLIA lab in order to offer the panels in that country.
In late 2014, Protagen closed the first part of a financing round targeting €10 million ($12.5 million), but was not able to complete a second close planned for late 2015, Müllner said, blaming a sluggish environment for biotech funding in Germany. The company is now working to raise additional funds from old investors, he said.