DxDiscovery has a portfolio of projects that are in various stages of development. The status of each project is summarized below. Importantly, development of a diagnostic assay is not a single discovery or event, but a process with many steps and stakeholders:
Diagnostics development pipeline at DxDiscovery
Concept – The most important step in diagnostics development is choosing the right disease. Selection of diseases for diagnostics development begins with an evaluation of current diagnostics. DxDiscovery is focused on the immunoassay platform – detection of biomarkers that are shed from microbes that indicate an active infection. We limit ourselves to diseases where standard culture or nucleic acid detection techniques are not useful. Examples in the DxDiscovery portfolio include invasive candidiasis and Lyme disease. Alternatively, diseases that require a rapid result, low cost or a need for little or no infrastructure are good matches with the immunoassay format. Examples in the DxDiscovery portfolio of this latter situation include pertussis and sickle cell disease.
Target discovery – The next step in assay development is identification of the biomarker to be detected by an immunoassay. In some cases, the target is known or obvious. Examples would be the capsular polysaccharide of Cryptococcus neoformans or surface antigens on the pertussis bacterium. In other cases, the target is not known and must be discovered. We utilize the novel InMAD strategy for target discovery. An examples of an infection where the target is not known is invasive candidiasis.
Target validation – Once a putative target is discovered through InMAD, the target must be validated before proceeding to antibody production. Target validation may include a bioinformatics component in which target uniqueness is evaluated. Finally, we determine the assay sensitivity that will be required for a successful diagnostic test. This sensitivity target drives selection of an assay platform.
Monoclonal antibody production – The most important component of an immunoassay is a high quality monoclonal antibody for target capture or identification. Considerable effort is expended in developing immunization and screening strategies that will yield antibodies having properties needed for immunoassay performance. Candidate mAbs are carefully evaluated for binding activities before being advanced to assay development.
Assay prototype – Once the needed mAbs are in hand, the product development process moves to a prototype assay. Typically, an immunoassay uses the ELISA or lateral flow immunochomatographic format. The choice of assay platform depends on intended use. For example, a test to be done largely in a reference laboratory should be well suited for testing large numbers of samples, e.g., the ELISA format. If a test is to be used at the point of care, the lateral flow dipstick might be the best choice.
Preclinical testing – Preclinical testing involves many of the steps for approval by regulatory agencies. These include sample matrix effects, limits of detection, precision and trueness, total analytical error, reproducibility, bias and imprecision studies, etc.
Clinical testing – The final step in immunoassay development is establishing the clinical value of the test. Will the test provide the true answer to the clinical question? Such testing requires a determination of sensitivity and specificity and may require a comparison to existing assays.
Regulatory approval – Ultimately, most diagnostic tests must receive clearance by regulatory agencies such as the FDA.