NEW YORK (360Dx) – Roche Diagnostics said last week that in launching a bleeding risk test it has made important strides that will benefit patients at risk of stroke who need to decide whether to take oral anticoagulants for atrial fibrillation.
The diagnostics behemoth has introduced a new test that runs on its Elecsys immunochemistry system for the lab and measures the level of a biomarker, GDF-15, in predicting a patient's risk of bleeding. GDF-15 — a biomarker of cellular ageing, cellular growth, oxidative stress — has been shown to be associated with bleeding risk in atrial fibrillation.
"About 33 million patients in the world have AF that we know are at risk of getting a stroke," Roland Diggelmann, the CEO of Roche Diagnostics, said on a conference call with analysts last week while reporting the firm's results for the first nine months of 2017. He noted that "about 50 percent of these patients receive no stroke prevention."
Clinicians currently use clinical risk scores to assess the risk for stroke and risk of major bleeding when they are trying to decide whether a patient with atrial fibrillation should receive an oral anticoagulant. They include ORBIT — a five-factor bleeding score that considers age, bleeding history, and kidney function among other factors — and HAS-BLED, a score that also includes several factors such as bleeding history or predisposition to bleeding, age, presence of hypertension, and others.
"Bleeding risk scores show only limited performance and have overlapping parameters with stroke risk scores, which makes a decision to prescribe oral anticoagulant challenging," Mathias Egermark, international business leader in the Roche Diagnostics centralized and point-of-care solutions business, said in an interview.
He added that the overlap between bleeding and stroke risk scores has made it "difficult to make a strong decision on the bleeding risk side," and no biomarker test has been available to help clinicians in their assessment of bleeding risk.
"GDF-15 differentiates a bleeding risk assessment from a stroke risk assessment, and that's why it will be very helpful for doctors," he said.
Roche launched the test in August after it receive CE marking, and it is available in European countries and others that accept the mark. However, it is not yet available in the US, and Roche said it is not able to comment on a US Food and Drug Administration clearance or potential product launch in the US.
The test is particularly important because it meets a critical unmet need by helping clinicians make the most appropriate decisions for stroke-prevention in patients with atrial fibrillation, said Egermark.
Atrial fibrillation, the most common cardiac arrhythmia, increases the risk of stroke fivefold and presents a lifetime risk of 25 percent, he noted, adding that a stroke can be debilitating or lead to death, and its treatment imposes a "high cost for society."
In 2016, in a paper published in the journal JAMA Cardiology, Jonathan Piccini, a researcher at Duke University Medical Center, and Gregg Fonarow, a researcher at the University of California, Los Angeles, said that more than 40 percent of all strokes in patients older than 80 years of age are attributable to AF.
They noted that patients with AF are more likely to develop "significant disability after a stroke," and that AF-related strokes are 2.5 times more likely to be fatal.
Taking oral anticoagulatants has been shown to reduce the risk of stroke by 64 percent, they said.
They noted that although the medical community has several highly effective therapies to prevent stroke, studies in a variety of clinical settings have shown that a "substantial proportion of patients with AF who are eligible for oral anticoagulation" do not receive it.
In 2014, a group of international investigators noted in a study published in the journal Circulation that of an estimated 33.5 million people with AF globally in 2010, about 20.9 million were men and 12.6 million were women.
They said that AF-associated mortality increased twofold and 1.9-fold in males and females, respectively, from 1990 to 2010.
Most patients with AF could be treated with the oral anticoagulant blood thinners that prolong clotting time and reduce the patient's risk of the onset of ischemic stroke, Egermark said. The problem with oral anticoagulants is that because of their mechanism of action, there is also a risk that they will cause severe bleeding. Bleeding risk is a major concern, and the major reason that about half of the patients with AF don't get treatment, Egermark noted.
GDF-15 had not been previous available as a marker predictive of bleeding, he said, because the data had not existed to support it.
That changed when in 2016, a Lancet journal study demonstrated that GDF-15 should be used as a predictor of bleeding in an ABC (age, biomarkers, and clinical history) bleeding risk score. The research team — which included a mix of investigators in the US, Sweden, and Canada — noted that the ABC score provides physicians with an improved understanding of each patient’s bleeding risk profile and can inform treatment decisions. Roche Diagnostics was among the companies funding the trial.
The researchers wrote that they found several biomarkers associated with major bleeding risk in patients with atrial fibrillation that were taking oral anticoagulation. "In particular, GDF-15, cardiac troponin, and markers of renal dysfunction showed robust associations with the outcome," they wrote.
They found that the five most predictive variables were high-sensitive cardiac troponin T, GDF-15, haemoglobin, previous bleeding, and age; GDF-15 is the strongest predictor of all, the researchers said.
"Increased concentrations of the biomarker GDF-15 showed a prominent association with subsequent major bleeding events. By contrast with several other clinical and biochemical risk factors, the GDF-15 concentration was not independently related to the risk of stroke in patients with atrial fibrillation," the researchers said.
As a result, the availability of GDF-15 in a diagnostic test might improve the differentiation between the risk of bleeding and risk of stroke, they noted.
With the new GDF-15 test, clinicians have an opportunity to make better decisions about the administration of anti-coagulants and can achieve better patient outcomes, Diggelmann noted. He said that the development and launch of the GDF-15 assay is one example of how the company continues to pursue tests that have high medical value, looks to influence treatment guidelines and algorithms, and supports this strategy with clinical studies.