AspenBio Pharma Inc reported results from the company’s recently completed AppyScore™ ELISA-based pivotal clinical trial.

The study was designed to evaluate the utility of the AppyScore blood-based test in aiding in the evaluation of patients suspected of having acute appendicitis.

The Statistical Analysis Report showed higher sensitivity (96%) and negative predictive value (92%) but lower specificity (16%) than seen in the 2008 ELISA-based study. Also, the report showed a wider range in prevalence of acute appendicitis between sites than had been anticipated. Significant additional data analysis and experiments were undertaken to investigate the variability in prevalence and specificity between the two studies.

The overall prevalence of appendicitis was similar to that seen in the previous trial, however inter-site variability was notably larger, with a wider range of patients enrolled with acute appendicitis observed between sites. While this observation required further investigation, the company determined that this finding did not have a clinically meaningful impact on the performance of the assay. An audit of protocol compliance confirmed that the sites complied with the study protocol and patient enrollment criteria, which was also verified by the independent monitors who inspected sites on a regular basis. The company believes that the large inter-site variability in the prevalence reported is an indication of the clinical challenge of diagnosing appendicitis and the judgment of independent emergency department physicians in evaluating acute abdominal pain.

The company performed significant secondary analyses to explore the observed change in specificity from the 2008 trial. These analyses suggest that the apparent differences between the two studies were due to the conditions of transport for samples from the sites to the central laboratory, where the testing was conducted. An increase in AppyScore test values that occurred in the "pre-measurement" phase between blood draw at the hospital and the testing at the central laboratory, which involved time and transportation, resulted in an apparent increased level of false positives and, accordingly, decreased specificity. The company believes that this phenomenon should be mitigated by the cassette version of the assay which will be run on site in the hospital’s laboratory shortly after blood draw.

Full results are available online.

Source: AspenBio Pharma