Personalized medicine in its most practical sense is the use of very specific laboratory tests to determine if a patient should receive a drug.
We now know that subtle differences in genetic makeup can have significant influences on the effectiveness of prescription drugs, and genetic profiling is becoming ever more easy and cost-effective.
It is inevitable that genetic profiling will become intrinsically tied to drug therapy at some point in the future, but how quickly it will happen, and what can be done to accelerate it, are useful questions to ask.
Rate of Advancement
We can begin to answer the question of rate by looking at the number of CDx tests that have been released in recent years.
Our company recently updated BiomarkerBase™ (our database of biomarkers in clinical use) to include every biomarker-based IVD test that has received pre-market approval (PMA) since 1994. PMA tests are the most stringently reviewed by FDA and admittedly represent the minority of IVD tests to reach market each year, but they are at least a place to start.
Of the tests approved since 1994 there has been essentially an even split between biomarkers that are used for companion diagnostics versus those that are used for diagnostics/prognostics (interestingly, none of the approved biomarkers are used for both, although several diagnostic biomarkers are being used in active clinical drug trials so that could change).
Of the approved CDx biomarker IVDs, 60% of them are for one target alone (Her2), and only five unique biomarkers are represented in the remaining 40% of approved tests.
Two new PMAs approved in 2011 incorporated two novel biomarkers, and through July of this year, 2012 has already seen two more novel biomarkers (and as many approved tests as in all of 2011).
At least on the PMA level, progress is being made, but it does seem to be quite slow. It will be interesting to see how the trends in 510(k)-cleared tests and LDTs influence this assumption (stay tuned as we complete the addition of these data in BiomarkerBase™).
Variables for Advancement
1. Commercial Incentive and/or Regulatory Compulsion – Advancement of personalized medicine will increase in proportion to the influence that these factors have on drug developers.
2. Discovery of Companion Diagnostic (CDx) Biomarkers – Biomarkers are the most essential technical variable for advancement, as they form the basis of all companion diagnostic tests. Without the biomarker there is no test, and without the test there is no personalized medicine.
3. Biomarker-Based Testing of Clinical Trial Candidate Patients – Once the potential CDx biomarkers for a drug are identified, clinical trials need to be structured to maximize the utility of those biomarkers (and any discovered during the trial) after the drug is approved.
4. Commercialization of CDx Biomarkers into In Vitro Diagnostic (IVD) Tests – Those of us who have worked to develop IVD tests understand that the technical challenges are often only a small part of the barriers to commercialization.
5. Acceptance and Adoption by Physicians – Once a test is on the market, how quickly is it picked up and used for those patients to whom it is targeted?
There are many different aspects to each of these variables, and we are currently preparing a report exploring them in detail. Hopefully we will identify opportunities to accelerate personalized medicine. Stay tuned.