MD1003 is an experimental treatment for adrenoleukodystrophy (ALD) developed by MedDay Pharmaceuticals. The treatment is also being tested in clinical trials for multiple sclerosis and amyotrophic lateral sclerosis.

How MD1003 works

ALD is a rare genetic disorder that affects the nervous system, causing neurodegeneration. It also causes adrenal insufficiency, where the adrenal glands do not produce enough steroid hormones. ALD is caused by mutations in a gene called ABCD1, which encodes for a protein that is involved in the breakdown of very long-chain fatty acids (VLCFAs). The mutations lead to VLCFA buildup in the nervous system and the blood, causing the loss of the protein coat that surrounds the nerve fibers and protects them. Without this protein coat, called the myelin sheath, the nerve fibers are fragile and have difficulty carrying information to and from the brain.

There are three types of ALD. MD1003 is being developed to treat adrenomyeloneuropathy (AMN), the adult-onset form of the disease. It is a high dose of vitamin B called biotin. While the normal suggested daily suggested intake level of biotin is in the range of 30 micrograms, MD1003 contains 300 milligrams.

The exact mechanism of MD1003 is not known. However, biotin is a co-factor for many enzymes involved in the breakdown of fatty acids. It is also involved in the synthesis of myelin. It is possible that MD1003 is stimulating the process of myelin synthesis so that the damaged myelin sheath on the nerve fibers can be replaced.

MD1003 in clinical trials

A Phase 2/3 clinical trial (NCT02961803) tested the effect of biotin at 300 milligrams per day compared to placebo in patients with AMN. A total of 67 patients with AMN were recruited for the study. Patients received either 100 milligrams of MD1003 three times per day (40 patients) for 12 months, or placebo (20 patients). After 12 months, the placebo group also received 100 milligrams of MD1003 three times per day for 12 months.

The primary outcome measured was the distance that patients could walk in two minutes before the trial began and after 12 months. The results have not been published; however, it has been noted that taking high doses of biotin can cause abnormal results when patients are tested for adrenal insufficiency. Many patients with AMN also have Addison’s disease, in which the adrenal glands do not produce enough steroid hormones. Frequent testing is important to ensure that patients are taking the right dosage of corticosteroid replacement therapy, so MedDay is addressing this issue as MD1003 is being developed.


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