Archon measures a panel of four biomarkers including a group of three tumor antigens and one tumor autoantibody. Each tumor antigen in our test, both individually and as a panel, has been extensively studied by numerous investigators. Dozens of peer reviewed scientific publications support the validity of these antigens as biomarkers for early lung cancer. The novelty of our test includes proprietary scoring algorithms and methodology as well as the combination of testing at least one autoantibody with tumor antigens.
Analysis of a multiplex biomarker panel increases the test sensitivity and specificity, thereby reducing false positives and negatives. Tumors produce antigens, and the body mounts an immune response to those antigens at the earliest stages. Our algorithm combines the values for each of the biomarkers to give a score that indicates the probability that a patient has lung cancer, as depicted below:
It is important to note that we do not report a “positive” or “negative” for lung cancer but instead categorize patients based on their likelihood of having lung cancer at the time of the test. That way physicians who see many current or former smokers can make sure that at least the high scoring patient are followed up with radiographic screening.
Nevertheless, in order to permit our test to be compared to other diagnostic modalities, it useful to offer sensitivity and specificity information that assumes a particular cut off.
Accuracy is defined as the proportion of true results (true positives, TP, and true negatives, TN) in a population that has been tested. (TP + TN)/(TP+FP+TN+FN). With a sensitivity of 74% and a specificity of 80% the accuracy is 77%.
The sensitivity of Archon is 74% when the specificity is set at 80%. For examples if there is a group of 1,000 high-risk patients, about 2% (20) will have lung cancer. Of that group, 15 of the 20 cancers will test positive using Archon. A specificity of 80% means that 200 patients without lung cancer will also test positive.
Specificity is defined as the number of patients who test negative in the absence of disease divided by the total number of patients who do not have disease. The specificity of Archon is 80% when the sensitivity is 74%. For examples if there is a group of 1000 high-risk patients, about 98% or 980 will not have lung cancer. Of that group, about 780 will test negative for Archon and about 5 of the patients with lung cancer will also test negative.