Additional Study Information: The main purpose of this study is to learn how the study drug (NMD670) works and how safe the study drug is compared with placebo. A placebo is an inactive material that looks like the study drug but does not have any active study drug. Researchers use a placebo to see if the study drug works better or is safer than taking nothing. You will be in this study for up to 8 weeks. During the study, you will visit the study center at least 6 times. If you are eligible to participate in this study, you will be seen by a doctor with expertise in CMT care who will be leading the research study at a site near you. You will be randomly assigned (by chance) to receive NMD670 or placebo. You will have a 50% (1 in 2) chance of receiving NMD670 and a 50% (1 in 2) chance of receiving placebo. You, the study doctor, and any other study staff will not be told if you are receiving NMD670 or placebo. However, this information will be given to the study doctor if it becomes necessary for your safety. During this study, you will take the NMD670 or placebo oral tablets twice a day for 21 days. The study doctor or study staff will give you instructions on how to take the tablets. Laboratory tests, physical examinations, heart tests, CMT questionnaires, assessments, and strength/mobility tests will be conducted as part of this study. You do not have to pay for the study drug or placebo tablets, study supplies, or tests that are part of the study. You may also receive reimbursement for study-related travel expenses.