By Grace Pavlath, PhD
Because CMT is often a slowly progressive disease, measuring the impact of a potential treatment during a typical clinical trial of 12-24 months can be elusive. Current clinical outcome measures are inadequate in detecting such progression and potential improvements. Biomarkers play important roles in improving the drug development process for CMT because they allow clinicians to more quickly and sensitively determine if a drug is changing the underlying pathology that eventually leads to loss of sensation, weakness and loss of muscle mass in CMT.
Biomarkers are chemicals produced by the body which can be found in tissues, or fluids like blood. Efforts are ongoing in the CMT field to identify biomarkers of degenerating axons or Schwann cells that could measure disease severity and/or progression. Neurofilament light chain (photo) shows the greatest promise as a marker of axonal damage as it is elevated in blood samples from CMT1A and CMT1X patients, and correlates with disease severity. A recent report describes the first Schwann cell-specific protein, TMPRSS5, that is elevated in blood samples of CMT1A patients.
Ultimately, it will be important to have several methods to measure the impact of a drug to slow, stop or even reverse the progression of CMT. Biomarkers like Neurofilament light chain and TMPRSS5 could be useful and effective measurement tools in clinical trials.