As I think more about the role of biomarkers in the total healthcare delivery process, it appears to me that they can be organized into four categories. A recent press release described a company that is focusing its research on biomarkers to assess the efficacy of cancer treatments (see: Singulex to Develop Assays to Assess Efficacy of Cancer Therapeutics). Below is an excerpt from the article (boldface emphasis mine):
Singulex today announced that it secured the second phase of its Fast Track Small Business Innovation Research ...contract from the National Cancer Institute (NCI). The company will use the funds to develop biomarker assays that will be useful in determining whether a potential cancer therapeutic is effective. Because the levels of specific proteins vary depending on disease state, biomarkers, or proteins associated with a disease, can be measured to determine whether a disease is progressing. In addition, by measuring changes to disease-associated biomarkers following treatment with a specific drug, pharmaceutical developers can assess whether a drug candidate demonstrates efficacy...."Singulex's powerful assay to detect VEGF, a protein implicated in many cancers, overcomes the limitations of traditional biomarker detection technologies and allows drug developers to see normal levels of VEGF in blood and assess the efficacy of anti-VEGF drugs such as Avastin," said [the CEO] of Singulex.
In a recent note, I commented on the potential value of biomarkers for assessing therapeutic efficacy, the same direction that Singulex is moving (see: Moving Resources from the Therapeutic to the Diagnostic Silo). The measurement of therapeutic efficacy has a "downstream role" in the concept of personalized medicine as I described it in a recent note (see: Continuing Discussion of the Role of Lab Medicine in Personalized Medicine). Based on all of the above, here is what might be described as a first cut at the major biomarker functionality categories:
- Diagnose disease, particularly in its early stages (see references to the early health model)
- Function in concert with biotech drugs as companion diagnostics to select candidates for treatment
- Exclude patients from treatment who may suffer a serious side effect (see: Genetic Testing to Cull Out the "Un-Right Patient" as a Candidate for a Particular Drug Therapy; Personalized Medicine and Help/Harm Companion Lab Testing).
- Assess the efficacy on a continuing basis of treatment with a particular drug
Obviously, there is nothing novel about assessing efficacy of treatment or stage of disease with an analyte. Measurement of blood urea nitrogen (BUN) has been used for many decades to assess the severity of renal disease. Presumably these emerging efficacy biomarkers will show far greater sensitivity and specificity in this regard. Also unique these days is that certain companion diagnostics are being developed in tandem with some biotech drugs (see: Some Interesting Insights into Companion Diagnostics).