Edaravone, sold as under the brand names Radicava and Radicut, is an intravenous medication used to help with recovery following a stroke and to treat amyotrophic lateral sclerosis. The label carries a warning about the potential for hypersensitivity reactions to edaravone, and adverse effects include bruising, gait disturbances, headache, skin inflammation, eczema, problems breathing, excess sugar in urine, and fungal skin infections. The mechanism by which edaravone might be effective is unknown. The drug is known to be an antioxidant, and oxidative stress has been hypothesized to be part of the process that kills neurons in people with ALS.
Medical uses
Edaravone is used to help people recover from stroke in Japan, and is used to treat ALS in the US and Japan. It was approved for ALS in the US in 2017 based on a small randomized controlled clinical trial with people who had early-stage ALS in Japan, who were administered the drug for 6 months; it had failed two earlier trials in people with all stages of ALS. It is given by intravenous infusion. There is no data on whether it is safe for pregnant women to take, and it is unknown if edaravone is secreted in breast milk.
Adverse effects
The label carries a warning about the potential for hypersensitivity reactions to edaravone. The following adverse effects in at least 2% more people given the drug than were given placebo: bruising, gait disturbances, headache, skin inflammation, eczema, problems breathing, excess sugar in urine, and fungal skin infections.
Pharmacology
The mechanism by which edaravone might be effective in ALS is unknown. The drug is known to be an antioxidant, and oxidative stress has been hypothesized to be part of the process that kills neurons in people with ALS. The half-life of edaravone is 4.5 to 6 hours and the half-lives of its metabolites are 2 to 3 hours. It is metabolized to a sulfate conjugate and a glucuronide conjugate, neither of which are active. It is primarily excreted in urine as the glucuronide conjugate form.
History
Researchers first developed the free radical scavenger edaravone in late 1980s as a treatment for stroke. The approach, introduced by Koji Abe, now at Okayama University Hospital in Japan, aimed to prevent the swelling of the brain which may occur after a stroke. It has been marketed in Japan by Mitsubishi Pharma for stroke since 2001 and is now generic. Mitsubishi Tanabe started a phase III clinical trial in ALS in 2011 in Japan and by June 2015, it had been approved for that use in Japan. The company had received Orphan Drug Designation for edaravone from the FDA and EU by 2016. In May 2017, I.V. edaravone was approved by the FDA to treat people with amyotrophic lateral sclerosis in the United States. The FDA approval was conditioned on Mitsubishi Tanabe completing several additional studies to clarify the risks of cancer and liver disease, among other effects of the drug. Formulation of edaravone by mouth called TW001 has been under development by Treeway for ALS; as of 2015 it had successfully completed Phase I trial and had received orphan status in the US and in Europe.
Society and culture
The price for the drug when it launched in Japan for stroke in 2001 was set by the Japanese government at 9,931 yen/ampule. When the drug launched in Japan for ALS in 2001, the price was $35,000; the price in Japan in 2017 was $5,000, the US price at launch was around $145,000. In the US the drug was approved for all people with ALS but it was unclear at approval whether insurers would agree to pay for the drug for all people with ALS, or only people in the early stages of the disease. There are three filed trials for edaravone, demonstrating it may work in less than 5% of all ALS population. Brand names include Radicut, ラジカット, Radicava, Xavron.
