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ProteoMedix Prepping Prostate Cancer IVD for Market Launch

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NEW YORK (360Dx) – Swiss diagnostics firm ProteoMedix is pursuing the CE-IVD mark for its proteomic prostate cancer test.

The company earlier this year raised CHF 5.2 million ($5.3 million) in equity funding to finance its development and commercialization efforts and is currently planning a prospective clinical trial for the test, said CEO Ralph Schiess.

It has finished converting the test, which was developed on a mass spec platform, to an ELISA format and manufactured the first lot of IVD kits. And in September, the company and collaborating researchers published a study in BJU International evaluating the performance of the ELISA version of the test.

Named PMX-Dx, the test measures the levels of the proteins thrombospondin 1 (THBS1) and cathepsin D (CTSD) in serum and combines that with patient age and total and free PSA levels to distinguish between patients with high-grade prostate cancer (Gleason score of 7 or above) and low-grade prostate cancer or a benign prostate condition.

Designed to help men likely to have either low-grade prostate cancer or a benign condition avoid unnecessary biopsies, the PMX-Dx test is intended for use in patients with a total prostate-specific antigen level of between 2 and 10 ng/ml and a negative digital rectal exam consistent with an elevated prostate volume.

According to Schiess, this group of men "is highly overdiagnosed when using the PSA test alone, as benign enlargement of the prostate often leads to elevated PSA in serum."

Additionally, he noted, this population tends to be weighted towards older patients, where avoiding unnecessary procedures are particularly burdensome.

ProteoMedix was launched in 2010 as a spinout from the lab of Swiss Federal Institute of Technology researcher Ruedi Aebersold. The company's protein biomarker discovery approach was based on a glycoprotein enrichment technique developed in Aebersold's lab.

The company initially hoped to launch the test in 2015 but delayed those plans to run additional clinical studies.

In the BJU International study, the researchers evaluated the test in 474 men enrolled at a single center between 2011 and 2016 who had serum collected prior to undergoing prostate biopsy. They split the cohort into a 237-subject training set (130 men with a positive biopsy) and a 237-subject validation set (108 men with a positive biopsy).

In the validation set, the PMX-Dx test distinguished between biopsy-negative and biopsy-positive patients with an area under the curve of .86 and with 90 percent sensitivity and 62 percent specificity. In the same patients, free PSA alone performed with an AUC of .64 and specificity of 23 percent at 90 percent sensitivity.

The PMX-Dx distinguished between high-grade and low-grade or benign disease with an AUC of .83 and 90 percent sensitivity and 48 percent specificity.

ProteoMedix is now recruiting for a prospective trial in which it plans to evaluate the test in 438 patients enrolled at seven site across Austria, Denmark, and Germany. That study will likewise look at the test's ability to distinguish between patients with negative and positive prostate biopsies and high-grade and low-grade or benign disease. The estimated completion date is August of 2019.

The prostate cancer testing field is a relatively crowded one with a number of diagnostic and prognostic tests either in development or available from firms including Genomic Health, Myriad Genetics, GenomeDx, Opko Health, and Metamark.

In terms of protein tests, Opko Health's 4kscore is among the most widely used, with the company selling around 70,000 to 80,000 per year. The test uses four prostate-specific biomarkers to measure the risk of aggressive prostate cancer in patients with elevated PSA levels. In a prospective 26-site study of 1,012 men scheduled for prostate biopsy published in 2015, Opko and its collaborators found that the test identified aggressive prostate cancer with an AUC of .82.

But, Opko has struggled to secure Medicare coverage for the test. Medicare contractor Novitas originally issued a positive LCD for the test in May of 2016, but withdrew that determination after another Medicare contractor, Palmetto issued a conflicting LCD not to cover the test. In May, Novitas issued a draft local coverage determination of non-coverage of the test. However, on the company's Q3 2018 earnings call, Steven Rubin, Opko's executive vice president, said Novitas had continued to provide coverage of the test and the company was still working to obtain a positive coverage determination.

Another potential competitor on the protein front is Cleveland Diagnostics' IsoPSA test, which analyzes PSA isoforms to assess a patient's risk prior to biopsy of having aggressive prostate cancer. Last year, Genomic Health licensed the test and is working with Cleveland Diagnostics to develop and commercialize the technology.

Schiess said that while it was difficult to directly compare these different tests given the different cohorts they used, ProteoMedix believes its specific emphasis on men with negative DREs and enlarged prostates differentiated it from other products on the market. He added that the company expects the fact that the test will be available as an IVD kit as opposed to a laboratory-developed test will also prove an advantage.

"What we really observed is that our markers [can be measured] in the same sample as a PSA test, so it really makes sense to have this test in the same labs where the PSA tests are done," he said.

Schiess said ProteoMedix is also working on a second test that will predict the risk of aggressive disease in patients diagnosed with prostate cancer. He said the company plans to develop a blood-based test that it will position as an alternative to existing tissue-based tests like Genomic Health's Oncotype DX and Myriad's Polaris.

He said the company was currently testing sets of protein markers in a retrospective study.