Cancer biomarkers: not such a great model to follow

The development and use of biomarkers in the field of cancer is well ahead of any other indications. In particular, several cancer biomarkers have been co-developed as companion diagnostics associated with specific drugs:

• Her2 expression test (e.g. HercepTest) supporting Herceptin (trastuzumab) prescription for breast cancer
• BCR-Abl / Philedelphia chromosome supporting Gleevec (imatinib) prescription for CML
• BRAF V600E expression supporting PLX4032 (vemurafenib) administration for melanoma (not approved yet)

While these companion diagnostics represent a major progress in the area of personalized medicine, all three cases provide a relatively poor model for the development of advanced biomarkers / companion diagnostics in other diseases. Indeed, for these three biomarkers, there is a direct connection between the biomarker: presence of target and the biological process of interest: sensitivity to the drug. Unfortunately, in many other diseases, this direct relationship does not exist or at least has remained elusive until now. Thus, the experience from the cancer biomarker field teach us very little about the complex process of biomarker biological qualification (i.e. the process of establishing the significance of a biomarker relationship to the biological process of interest). In my mind, the process of biomarker qualification is, and will be for the foreseeable future, the most  important aspect of biomarker development for which the lessons learned from the cancer biomarker field are not a great model to follow.


Thierry Sornasse for Integrated Biomarker Strategy