FA Dyclonine Study Review

19th Sep 2014 Diseases, Friedreich's Ataxia

Freidreich’s ataxia (FA) is a recessive disease causing progressive damage to the nervous system. It is the most prevalent inherited cause of ataxia and affects about 1 in 50,000 people in the United States. Despite its prevalence, there is no cure or treatment beyond supportive care.

A recent article was published in the Human Molecular Genetics journal in regards to a potential new therapy for FA. The drug, dyclonine, was developed for use as a topical anesthetic and is found in the over the counter throat lozenge, Sucrets, as well as some Cepacol throat sprays. FA is caused by a genetic deficiency in the mitochondrial protein frataxin (FXN) and dyclonine was noticed to increase FXN protein in animal models. When the drug was given a mouse model of FA it prevented a performance decline during balance beam tests. A proof-of-concept clinical study was performed on eight patients, which showed an increase in buccal cell FXN.

Mice used in this study were tested with level balance beams of varying thickness that required them to walk from one end to the other in order to seek shelter. Mice were timed and video recorded in order to count the number of foot slips. The individual in charge of recording the data was blinded to which treatment group the mouse was in. Mice that were dosed with dyclonine had statistically significant improvements. Not only did their performance on the beams not worsen like the affected controls, but they even improved their time to cross.

The second part of the study involved using dyclonine as an oral rinse, since that is already FDA-approved, and then swabbing the cheeks for buccal cells. The cells were compared to pre-treatment cells from the same patients. Six of the eight showed an increase in FXN, two showed no increase, but two healthy controls showed increased levels. Interestingly, the patients with the most neurological impairment were the ones that showed the highest increase from the dyclonine mouth rinse. Neurological impairment was determined with a FARS (Friedreich’s Ataxia Rating Scale) score.

What’s next? Further clinical studies are required to see if the results achieved from the oral rinse can be duplicated systemically and show the same improvements as observed in the mouse model. Additionally, optimal dosing, toxicology, and pharmacokinetics all need to be studied and better understood before testing can proceed. Despite the questions that still need addressed, dyclonine could be a new treatment option for people affected by Friedreich’s ataxia.