Sunday, October 19, 2008
In an editorial from the Lancet,
Medical groups have expressed doubts about the validity, effectiveness, and clinical usefulness of direct-to-consumer genetic testing. More harm than good is done, for example, by false reassurance from unproven genetic tests or by unreliable information that could lead patients to terminate a pregnancy or seek surgery.
These are the concerns from the field and they may be valid. They may also not be valid. Let's examine each:
1. Doubts about validity-
What exactly is valid? Is valid the genotype? Is it the validity of the phenotype which the genotype is said to "predict" Is it the validity of the studies which back up the test? In the case of genotype, I would say the test is valid. In the case of the 2 others...it clearly is not.
2. Doubts about effectiveness-
Effectiveness in what? Predicition? Prevention? Guidance of therapy. On all of these counts, the doubts of effectiveness are valid.
3. Doubts of clinical usefulness-
Well, what IS clinical usefulness? Is it, the ability to derive a new use/diagnosis from a test result? Is it the ability to put into action a clinical plan to prevent or treat disease? If it is either of these, the data is not there for most DTC tests....But I also have said that clinical usefulness could just be the ability to plan for future risk or future care. In this case predisposition testing for Alzheimer or Parkinson Disease may be useful......depending on the test and its clinical evidence....To answer this question a genetic test needs:
A. A clinical study showing predictive outcome. I.E. in a prospective manner, that would be very nice. Especially if I am to tell a patient how likely they are to get this condition and when....
B. Some clinical data showing outcomes in treating patients with genetic predisposition. I.E. in the case of the BRCA1 or BRCA2 genes.
C. Some clinical data showing that an intervention on persons with a certain SNP or mutation, prevents the prior expected outcome.
Even if we had none of these things......some may say "Why not let people buy this sort of information to do with it what they wish" That is not clinically useful. It may be socially useful, but some have real questions about that as well...
In my humble opinion, this buyer beware is a very libertarian/conservative view. Which may or may not be so bad. Unless we have harm being done to citizenry.
So, is harm being done?
But these data revolve around clinically valid tests. Most importantly, almost all medical societies are against DTC testing b/c of possible harm. But some argue that these motivated genetic test subjects wishing for DTC testing, self select to minimize the harm....which could be the case. But that assumes the tests are actually valid.
So what happens when the tests do not meet the criteria above? Well, no one knows the answer. But there are a ton of ethicists who are arguing against such testing. Why is this important?
Well, put simply. Medical Ethicisists most often fall along the lines of patient autonomy. In fact alot of people debate about this principle seeming to be absolute. So if most ethicists think the patient should have ultimate choice in their care, why are they against DTC testing???? Good question.
So here we are, in a position with not much data, and we won't likely have it for several years. We have ethicists who put patient autonomy first, against DTC testing. We have doctors, against DTC testing. We have government against DTC testing. Now, with the recent FDA warnings to labs promoting tests without evidence, the writing is on the wall.
“Because you do not have marketing clearance or approval from the FDA, marketing OvaSure is in violation of the law,”
That could just as easily be any other genetic test marketed to physicians or consumers. The FDA has weighed in and DTC is likely to be in its sights. Despite their detractors, the FDA is unstoppable here.
So, the answer is simple....we all have to await clinical data and trials for a clinical tool. Is that such a stretch? Is that such a bad thing? Well, it very well may be if your investors are on your case. Or if you need to pay your bills and your university salary is paltry. Or it may be if you have a mortgage whose rates are climbing? I hope you see what I am saying.....money clouds medicine, most importantly genomic medicine.
The Sherpa Says: In a time when Wall Street has a black eye from its fraud and scandal let's not let Genomic Medicine get punched too. It already has too many detractors....