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Eyeing 2013 Launch of Mass Spec Preterm Birth Test, Sera Closes $19.3M Round, Names Critchfield CEO

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This story originally ran on Nov. 15.

By Adam Bonislawski

Sera Prognostics said this week that it has closed a $19.3 million Series A financing round and appointed former Myriad Genetics president Gregory Critchfield as its new CEO.

The money, which follows on a $1.4 million Series A-1 round Sera closed in October 2010, will be used to complete a multi-center, 3,000-patient clinical trial of its protein biomarker-based preterm birth diagnostic and to commercialize the test. The company aims to complete patient recruitment and data analysis by the end of 2012 and to have a laboratory-developed version of the test on the market sometime in the first half of 2013, Critchfield told ProteoMonitor.

Based on intellectual property licensed from the University of Utah and Brigham Young University, Sera's preterm birth panel consists of three proprietary peptides plus six additional proteins. According to Critchfield, the company plans to launch the diagnostic as a mass spec-based test, which would make it one of the most ambitious clinical efforts to date for mass spec-based proteomics.

While several proteomics-based tests, including Vermillion’s OVA1, Healthlinx’s OvPlex, and Crescendo Bioscience’s Vectra DA, have gone to market in recent years, these products all use an immunoassay platform, not mass spec. Biodesix’s VeriStrat lung cancer diagnostic runs on a MALDI-MS platform, but this test relies on comparisons of broad proteomic profiles rather than mass spec measurements of discrete proteins, as the Sera test plans to do.

Initial discovery work identifying the three proprietary peptides used in the preterm birth test was done on an Applied Biosystems Q-Star Pulsar I QTOF machine. That study, which was detailed in a paper published in the May edition of the American Journal of Obstetrics & Gynecology, used immunoassays to measure the additional six proteins in the panel. However, Critchfield said, Sera has since then decided to move measurement of all the test's analytes to a mass spec platform.

"Mass spec has the distinct advantage in that if you can fragment the protein and measure it, you know exactly what it is you're measuring," he said. He acknowledged that mass spec sample prep procedures like trypsin digestion "can be a little complex," but said that automation had made this less of an impediment.

"Our belief is that mass spectrometry is a very viable method for doing this initially," he said. Critchfield added that the company has yet to choose a specific mass spec platform for running the test, saying that "there are several candidate machines." He also noted that Sera hasn't settled on a particular type of mass spec assay for measuring the various peptides and proteins. The company, he said, has done development work showing that selected-reaction monitoring mass spec would be one feasible approach, but it has yet to make any final decisions.

Sera is also working on an immunoassay version of the test that could eventually be "put into a kit and sold to laboratories all over the world" as an in vitro diagnostic, Critchfield said.

The biomarker panel is intended as a general screening test for preterm birth, he said. There are approximately 525,000 preterm births – defined as birth before 37 weeks of gestation – in the US each year, and according to the March of Dimes, the annual public healthcare cost of caring for preterm infants is more than $26 billion.

Currently there are no tests on the market for predicting whether an asymptomatic woman will go on to have a premature delivery, and, Critchfield said, even in the case of women defined as being high risk for preterm birth, existing indicators – such as a previous preterm birth or a shortened cervix – perform poorly.

"45 percent of pregnancies are in first-time mothers, so you can't ask her if she's had a preterm birth beforehand because she hasn't been pregnant before," he said. He added that mothers who have had a previous preterm birth have only about a 30 percent chance of giving birth preterm in subsequent pregnancies. The risk is roughly the same for women exhibiting a shortened cervix.

"In more than 80 percent of women who deliver today, there's no way to know what their risk is," Critchfield said. "What we're hoping to do is flip those statistics around so the great majority of women who are at risk are identified."

If women at risk of preterm birth are identified early, physicians can intervene with measures including progesterone treatment, weight management, and bed rest, he said.

In a study published in the November 2010 issue of the American Journal of Obstetrics and Gynecology, the test demonstrated sensitivity of 86.5 percent and specificity of 80.6 percent for preterm birth at 28 weeks of pregnancy. In February, the company presented data at the Society for Maternal-Fetal Medicine's annual meeting in which the test predicted preterm birth at 24 and 28 weeks gestation with 94 percent sensitivity and 85 percent specificity.

Provided these numbers hold up in the ongoing trial, they would be good enough for the test to be clinically useful, Critchfield said. "Most experts believe that anywhere in the mid-80s for sensitivity and specificity is good enough."

Critchfield joined Sera's board of directors last year after being president of Myriad from 1998 to 2010. He became executive chairman of Sera's board in April.

This week's funding round was led by venture capital firms InterWest Partners, Domain Associates, and Catalyst Health Ventures and also included new investor Osage University Partners and Sera founder UpStart Life Sciences Capital.

InterWest Partners' Doug Fisher, Domain Associates' Kim Kamdar, and Catalyst Health Ventures' Joshua Phillips will be joining Sera's board of directors.


Have topics you'd like to see covered in ProteoMonitor? Contact the editor at abonislawski [at] genomeweb [.] com.

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