Need for better Blood Tests
- Posted by Robin at 15:04
- 0 comments
I think an unrecognized problem that needs to be addressed is to find a better set of measures, than currently exist, that provide a more rapid and sensitive feedback on the benefits of a treatment.
At the moment there are 3 main ways to determine the state of a DMD patient.
1) CK tests
2) Physiological Assessment
3) Muscle Biopsy
I'll point out why these are not inadequate for the tasks that face us ahead.
1) CK Tests are insensitive. (a) In DMD their range is 20K +/- 10K, which is a 50% range variability range, when a clinical measure of 5% is what is needed. (b) They vary greatly depending on the child’s physical activity and age.
2) Physiological Assessments take too long (a) They may take many years to get a good measure of a treatment and (b) in the short term they measure strength, when fibrosis is the real pathological mechanism.
3) Muscle Biopsies have ethical issues (a) they are painful and invasive and (b) they are really a one-shot wonder because there is not enough evidence to support longitudinal contamination.
So is there a better solution?
I think that measures such as p63, TGF-Beta, TNF-A, ROS, cytokines, AT-2, TSP-1 etc, etc could provide a better feedback mechanism for clinicians. But it is necessary that these measures are presented as part of a pathological model. In DMD there is no accepted pathological model, the model is complex, with several arms relating to ca+2, inflammation and fibrosis. As a parent I would want to know how a drug affects the DMD pathology and for this I would like to see a pathological model which is loosely coupled to a set of pathological markers.
We have struggled to prove steroids work, and it has taken years, when the boys are on and off a cocktail of various versions of drugs I don’t think the current measures are sufficient to provide a good clinical assessment.