Calcium Channel Blocker in Myotonic Dystrophy Type 1

Launched by UNIVERSITY OF ROCHESTER · Jul 10, 2025

Keywords

ClinConnect Summary

This clinical trial is exploring whether a medication called amlodipine, usually used to lower blood pressure, is safe and well-tolerated in adults with Myotonic Dystrophy Type 1 (DM1). Researchers want to see if amlodipine can help improve muscle strength, reduce muscle stiffness (called myotonia), and enhance daily functioning by affecting how calcium moves in muscle cells. The study will gradually increase the dose of amlodipine over several weeks, and the main focus is to monitor blood pressure and any side effects to make sure the drug is safe for people with DM1. The study will also look at how the medication might affect muscle strength, mobility, tiredness, and overall function through simple tests and questionnaires.

Adults between 18 and 65 years old who have a confirmed genetic diagnosis of DM1 and some muscle weakness and stiffness may be eligible to join. Participants need to be able to walk and willing to stop other medications for muscle stiffness before starting the trial. During the study, all participants will take amlodipine daily, starting with a low dose that may increase, and they will have regular check-ups to track their health and muscle function. People with certain health issues like serious heart conditions, low blood pressure, liver problems, or allergies to amlodipine will not be able to join. This early-stage trial will help researchers understand if amlodipine is safe and useful for people with DM1, paving the way for larger studies in the future.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • Male or Female between the ages 18 and 65, inclusive.
• • A genetically confirmed diagnosis of DM1, having a repeat expansion in the DMPK gene with at least 100 CTG repeats.
• • Grip strength less than 50% predicted based on age, height, and sex.
• • Video hand opening time is 4 sec or greater for at least one hand.
• • Ambulatory and able to walk 10 meters.
• • Willingness to discontinue anti-myotonia drugs at least 2 weeks prior to screening.
• • Highly effective method of contraception in women with childbearing potential.
• Exclusion Criteria:
• • Congenital DM1 as defined by symptom onset in the first 4 weeks of life.
• • Abnormal liver function tests (LFTs): alanine aminotransferase (ALT), or aspartate aminotransferase (AST) \>3 x upper limit of normal. Total bilirubin \> 1.5 mg/dL, or INR \> 1.3, or evidence of current active or chronic infection with hepatitis C, hepatitis B or other hepatobiliary conditions other than DM1 (or attributed to DM1) that cause abnormal liver laboratory parameters (e.g., hemochromatosis, Wilson's disease, autoimmune hepatitis)
• • Current or recent infection requiring antibiotic treatment within 2 weeks prior to screening.
• • Abnormal vital signs, including systolic blood pressure \< 90 mmHg and diastolic blood pressure \< 60 mmHg.
• • Treatment with concomitant medications with potential interactions with amlodipine, these may include but are not limited to sildenafil, cyclosporin, atorvastatin at high dosages (80 mg daily), simvastatin (at dosages higher than 20 mg daily) or strong inhibitors of CYP3A4.
• • A history of syncope.
• • A history of symptomatic hypotension.
• • Initiation or change in doses of concomitant medications, including herbal supplements, if in the opinion of the Investigator, may impact the results of the study.
• • Women of childbearing potential must have a negative pregnancy test, cannot be planning a pregnancy, and cannot be breastfeeding at any time during the study.
• • Known history of substance and/or alcohol abuse within one year prior to screening.
• • The presence of comorbidities that, in the opinion of the Investigator, may influence study results, including, but not limited to, uncontrolled diabetes, generalized or mononeuropathy of the upper extremities, or cervical radiculopathy resulting in weakness and atrophy.
• • Concurrent treatment with calcium channel blocker.
• • Known ischemic or non-ischemic moderate or severe heart failure as defined by symptoms suggestive of heart failure or reduced left ventricular ejection fraction (LVEF) on echocardiogram \< 55%.
• • Moderate or severe aortic stenosis or other obstruction of the left ventricle outflow tract.
• • Known sensitivity or allergy to amlodipine.