Befiradol (also known as NLX-112) was initially developed by Pierre Fabre as a selective serotonin-1A receptor agonist for the treatment of cancer pain and neuropathic pain. However, these trials were discontinued. In 2013, the development and commercialization rights were licensed to Neurolixis. Neurolixis studied befiradol in Parkinson’s disease (PD) patients that exhibit dyskinesia. Dyskinesia is a side effect that appears after several years of action Levodopa, a drug that remains the gold standard treatment for PD. In 2019, FDA gave a positive response to Neurolixis’s befiradol to be tested in Phase 2 clinical in Parkinson's disease patients suffering from debilitating levodopa-induced dyskinesia.

Elamipretide or SS-31 (D-Arg-2', 6'-dimethyltyrosine-Lys-Phe-NH2) is a mitochondria-targeted antioxidant. Elamipretide, is a peptide compound that readily penetrates cell membranes, and targets the inner mitochondrial membrane where it binds reversibly to cardiolipin. In preclinical or clinical studies, elamipretide increases mitochondrial respiration, improves the electron transport chain function and ATP production and reduces formation of pathogenic ROS levels. This elamipretide-cardiolipin association has been shown to normalize the structure of the inner mitochondrial membrane, thereby improving mitochondrial function. Functional benefit is achieved through improvement of ATP production and interruption and potential reversal of damaging oxidative stress. Stealth BioTherapeutics is investigating elamipretide in late stage clinical studies in three primary mitochondrial diseases—primary mitochondrial myopathy, Barth syndrome and Leber’s hereditary optic neuropathy – as well as an earlier stage clinical study in dry age-related macular degeneration.