Elamipretide (MTP-131)

Elamipretide (MTP-131) is a treatment that Stealth BioTherapeutics is developing for mitochondrial diseases, including Leber’s Hereditary Optic Neuropathy, or LHON.

Mitochondria are the cells’ powerhouses. Elamipretide is designed to restore dysfunctional mitochondria’s energy production, saving the cells and reducing organ damage. Doctors can apply it directly to the eyes to treat mitochondrial eye disease, or administer it as an injection to treat mitochondria disorders elsewhere.

How elamipretide works

Mitochondria are small structures in cells responsible for producing energy and carrying out other tasks. They have their own DNA, which carries some of the genes responsible for their function. Remaining genes reside in the cell’s nucleus. Mitochondrial diseases are caused by mutations of mitochondrial DNA or DNA in the nucleus. The abnormalities lead to mitochondria malfunctioning.

The energy production process in mitochondria mainly involves metabolism of lipids, or fats. One of the essential lipids involved in the process is cardiolipin. Without sufficient cardiolipin, mitochondria are misshapen and cannot produce enough energy for the cell. This means the cells become inactive and eventually die. Cells that require a lot of energy to function, like muscle and brain cells, are particularly vulnerable to mitochondrial dysfunction.

Elamipretide is designed to penetrate the cell and enter mitochondria, helping to protect cardiolipin. This promotes cell health by restoring energy production and reducing oxidative stress on the cell.

Elamipretide in clinical trials

The Phase 1/2 MMPOWER clinical trial (NCT02367014) evaluated elamipretide’s safety, tolerability and ability to treat mitochondrial myopathy, or muscle cell dysfunction due to malfunctioning mitochondria. It improved patients’ scores on a measure of exercise capacity known as the six-minute walk test, results showed.

Stealth is also conducting two other elamipretide trials. MMPOWER-2 (NCT02805790) is following up mitochondrial disease patients who participated in the MMPOWER trial. Those who complete MMPOWER-2 may be invited to participate in a third trial (NCT02976038) to evaluate the long-term safety and tolerability of daily elamipretide injections.

The second trial (NCT02693119) is investigating the safety, tolerability, and effectiveness of elamipretide applied to the eyes to treat LHON.

Stealth continues to recruit participants in the United States for a Phase 3 trial (NCT03323749) to evaluate daily elamipretide injections’ safety and ability to treat mitochondrial myopathy. An extension trial will follow the study. In part one of the Phase 3 trial, participants will be randomly assigned to receive either elamipretide or a placebo injection. In part two, all participants will have the option of receiving elamipretide for up to 144 weeks.

Other information

The U.S. Food and Drug Administration has granted elamipretide orphan drug status. This designation  helps facilitate the development of treatments for rare diseases. The FDA has also given the therapy a fast track designation aimed at accelerating its approval.


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