AppyScore: Pivotal trial data

AspenBio said it will not submit a new 510(k) application to FDA for its AppyScore ELISA-based screen/triage blood test for acute appendicitis after data from a U.S. pivotal trial in 859 patients suspected of having the disease showed that the test led to an increased number of false positives when diagnosing appendicitis. Specifically, the test had a specificity of 16%, which was lower than that observed in a post hoc analysis of a previous pivotal trial of AppyScore showing that the specificity of the test at a threshold score of 14 was 33% (see BioCentury, Jan. 26, 2009). The test also had a negative predictive value (NPV) of 92% and a sensitivity of 96%.

AspenBio said an increase in AppyScore test values that led to a reduction in specificity were due to variables related to transportation shipping conditions and the length of sample delivery time from hospital sites where blood samples were drawn to the central laboratory that analyzed them. A post hoc analysis of the trial conducted to account for the increase in test values due to the time and transportation variables showed that AppyScore had an 89% NPV, 91% sensitivity and 28% specificity. However, the company said the post hoc analysis of the trial is not deemed as acceptable practice by FDA. Furthermore, AppyScore in combination with WBC or neutrophil count did not provide enhanced clinical utility of the test. ...