Roche Diagnostics hopes that a cardiac prognostic test it currently sells can help identify patients at risk for adverse reactions to cox-2 inhibitors, CEO Heino von Prondzynski said during a conference call with investors this week.
"We … expect to have an opportunity for cox-2 inhibitor patient stratification" with the diagnostic, which looks for the protein NT-proBNP, von Prondzynski said during a section of the call devoted to clinical immunodiagnostics.
The existing NT-proBNP diagnostic, currently sold worldwide, measures the plasma level of the peptide known as N-terminal pro-brain natriuretic protein, which is released by the cleavage of B-type natriuretic protein, itself produced by the heart's left ventricle when it is struggling to pump. BNP acts to decrease the heart's workload by dilating blood vessels, changing blood volume, and altering blood electrolyte levels.
The peptide is both a prognostic and a diagnostic marker: High plasma levels of NT-proBNP distinguish congestive heart failure from diseases with similar symptoms, and the concentration of the marker increases with the severity of heart failure, according to Roche.
Roche describes the existing diagnostic as a "risk-stratification tool for patients who may require more aggressive therapy." The company makes no mention of testing patients taking cox-2 inhibitors.
In a March 23 statement, Roche noted that NT-proBNP "has the potential to detect early stages of CHF in the absence of clinically obvious symptoms. In addition, it can be used for the assessment of prognosis for patients with CHF and for patients who have previously had a myocardial infarction." The statement also cites a Feb. 17 New England Journal of Medicine study that used NT-proBNP levels to predict long-term mortality in patients with stable coronary artery disease.
Because NT-proBNP may be useful in predicting the long-term mortality of patients with stable coronary artery disease, and in detecting early CHF, the test may be useful in the development of a diagnostic for monitoring patients undergoing treatment with cox-2 inhibitors. However, Roche has not indicated that this is the case.
Roche has granted non-exclusive licenses for the development, manufacture, and marketing of immunoassays that detect NT-proBNP to: Dade Behring; Ortho-Clinical Diagnostics, a Johnson & Johnson subsidiary; and Diagnostic Products Corporation. The company also granted Inverness Medical Innovations and Syn X Pharma, now a unit of Nanogen, nonexclusive rights to point-of-care testing related to the development, manufacturing, and marketing of NT-proBNP immunoassays.
Prondzynski's brief statement in the conference call comes at a time when the entire family of cox-2 inhibitors has come under fire from the US Food and Drug Administration and patient-advocacy groups. Most recently, the FDA has asked GD Searle, Pfizer, and Merck, the manufacturers of Celebrex, Bextra, and Vioxx, respectively, to include a boxed warning informing physicians about the products' possible increased risk for cardiovascular events and serious, "potentially life-threatening" gastrointestinal bleeding.
Merck voluntarily removed Vioxx from the market in September after the drug was linked to an increased risk of heart attack and stroke.
The FDA also asked Pfizer to withdraw its drug Bextra due to its link to an increased rate of "serious and potentially life-threatening skin reactions," according to FDA documents. The drug is the only one of the cox-2 inhibitors known to be associated with this side effect.
Roche representatives and Prondzynski did not immediately return telephone calls seeking comment.