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Mobidiag's Array-Based Test for Sepsis Gets Boost from UK, Finnish Patient Study


By Justin Petrone

Finnish molecular diagnostics company Mobidiag is hoping a recent study carried out by partners at hospitals at the UK and in Finland will lead to wider adoption of an internally developed array-based assay for sepsis diagnosis.

According to a paper on the study, published in The Lancet this month, the samples were investigated for bacterial species by both conventional culture methods and the company's Prove-it Sepsis assay at two centers.

Researchers from University College London Hospitals and Helsinki University Hospital Laboratory assessed Mobidiag's Prove-it Sepsis test in a cohort of 2,107 positive blood-culture samples out of 3,318 blood samples from patients with clinically suspected sepsis. According to the researchers, 86 percent of the samples surveyed included a pathogen covered by the Prove-it assay. The assay had a clinical sensitivity of 95 percent, a specificity of 99 percent, and had 100 percent sensitivity and specificity for methicillin-resistant Staphylococcus aureus bacteraemia.

The researchers also determined the Prove-it assay was an average of 18 hours faster than the conventional culture-based method, which takes between one and two additional working days to complete.

"The local antibiotic susceptibility patterns of each common bacterial species is well known in most teaching hospitals and guides the empirical treatment of patients with sepsis," the authors wrote in the paper. "Knowledge of an organism’s identity allows for more efficiently targeted diagnostic investigations," they wrote. "Specific disease complexes arise from specific bacterial types and individually tailored management and investigation strategies are needed to treat and identify their underlying cause."

In an accompanying comment, Shin Lin of Stanford University's School of Medicine and Samuel Yang of Johns Hopkins School of Medicine noted that Prove-it has some setbacks, such as not providing antibiotic susceptibility information other than MRSA, but that the use of both molecular and culture techniques is the "best of both worlds," and the development of the assay is a "major advance."

"Taking these features into account, the Prove-it sepsis assay cannot replace standard methods but could have a role alongside them," Lin and Yang concluded.

Helsinki-based Mobidiag has sold its Prove-it Sepsis test, which enables researchers to simultaneously identify 64 bacterial species, to clinicians in Europe since it was CE-IVD marked last year (see BAN 11/4/2008). CEO Jaakko Pellosniemi told BioArray News this week that the recent study might be able to give Mobidiag traction in a market where it is competing against an established technology.

"The main conclusions are very strong. They believe that this is a major advancement in sepsis diagnostics," Pellosniemi said. "There is a now a strong indication that molecular methods can deliver excellent results," he said. "Because the patients are in severe condition and the mortality is high it is vital that the results are delivered earlier so that antimicrobial treatment can be delivered."

The next step for Mobidiag and partners will be to expand the scope of the ongoing study to determine what kind of impact the use of Prove-it Sepsis has on treatment decisions and, ultimately, patient health. "We are going to continue with the pharmacoeconomic studies," said Pellosniemi. "Since the antimicrobial treatment will be changed because of the results of our test, we will show that it has an effect on the treatment and the outcome," he said.

While Mobidiag currently only sells to European customers and has not yet discussed a route to the US or other foreign markets, Pellosniemi said that it was "encouraging" that the firm's sepsis test had received attention from researchers at Stanford and Johns Hopkins.

Mobidiag currently sells two other assays for which it has obtained CE marks. Prove-it Herpes, which received its CE Mark in June, tests for the presence of seven herpesviruses in a sample and was developed in cooperation with the Hospital Districts of Helsinki and Uusimaa and the University of Helsinki. Prove-it Sepsis for Bone and Joint Infections, which was released for research use last month, tests for the presence of 64 bacterial species involved in infections such as osteomyelitis and septic arthritis. Osteomyelitis is the infection of bone or bone marrow, while septic arthritis is the infection of the fluid and tissue of a joint. The Prove-it Sepsis application for Bone and Joint infections was developed in cooperation with Hospices Civils de Lyon in France.

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Pellosniemi said that Mobidiag will add more assays to its Prove-it menu next year. Like the current tests, these new panels will be designed for infectious disease research. He declined to provide additional details about the new arrays, but said they are designed to meet the needs of customers, some of whom expect to run a number of tests on the firm's platform.

"Some customers are looking just for one particular solution," said Pellosniemi. "Then there are customers who appreciate the broad menu we can offer," he said. "That menu will be widened next year. There will be new applications," he added. "Usually, if you look at it from the doctors' perspective, they are taking care of, for example, sepsis patients, and in that case viruses are not that important," he continued. "But from the labs' perspective, they are looking at a broader menu we can offer."

To meet the needs of its customer base of clinical laboratories, Mobidiag earlier this year rolled out its Prove-it StripArray platform, which enables the readout of up to 96 samples at a time, a tripling of the throughput of Mobidiag's initial TubeArray platform that the company released in 2008 (see BAN 5/19/2009).

Mobidiag has sold the systems and accompanying assays directly since each became available, but in September the company inked a deal with Inverness Medical to distribute its products in Germany. The agreement was later expanded to cover distribution in France and Italy, Pellosniemi said, and Mobidiag is looking to sign up distributors for other European markets in the next few months. Pellosniemi said that roughly 20 labs are already using the company's assays.

"The sales are growing, the size of our organization is something we are comfortable with, and we are building our distribution network," Pellosniemi said of Mobidiag's sales effort

In addition to culture, all the assays that the company has debuted so far compete against a variety of molecular diagnostic tests being developed for non-array platforms. For example, Jena, Germany-based SIRS-Lab has launched a multiplexed PCR test for sepsis called VYOO, which received CE-IVD marking last year. In 2006, Cepheid had its Smart VZV assay for herpes identification CE-IVD marked. Like SIRS-Lab's test, Smart VZV is also a multiplex PCR-based assay.

While a number of companies developing array-based molecular diagnostics, such as Agendia or Almac Diagnostics, have decided to focus on oncology, Pellosniemi said that Mobidiag is committed to the infectious disease-testing space.

"The starting point for the company has been infectious diseases and the founders of the company already in the 1990s were interested in infectious diseases," he said. "We saw that molecular methods have not been used in hospitals for routine testing and we saw that there is a market for these multiplexing tests that we can offer with technology we have," he said.

"The question is what infection a patient has, and one test covers all the answers," he added. "That’s very strong arena for microarrays and a molecular approach."

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