With FDA filing, Mitsubishi Tanabe aims to bring ALS med edavarone to U.S. next year

Japanese drugmaker Mitsubishi Tanabe is hoping to end a drought in the U.S. for new medicines that can treat the devastating neurodegenerative disease amyotrophic lateral sclerosis.

The FDA has kicked off its review of Mitsubishi's edaravone, setting up a possible approval in June 2017. If would be the first ALS treatment to reach the U.S. market since Sanofi's Rilutek (riluzole) in 1995.

After 20 years without a new therapy--and a string of late-stage clinical trial failures--the 30,000 U.S. patients with ALS must be wary of false hopes. But there are some grounds for optimism. 

Edaravone (also known as MCI-186) is already on the market in Japan and South Korea, where it is sold under the Radicut brand for ALS as well as acute ischemic stroke. The drug has been used as a stroke treatment there for years, so it has a full bank of patient exposure data.

Radicut picked up the ALS approval last year. Since then, it has been used in hundreds of ALS patients, according to Mitsubishi, which intends to sell it as Radicava in the U.S.

The drug is billed as a free radical scavenger that removes the oxygen-containing molecules that build up in people with ALS and damage nerves. Rilutek works by blocking nerve-cell death but has modest effects, extending the lives of ALS patients by only a couple of months. 

ALS is the most common type of motor neurone disease (MND), accounting for around 80% of all cases worldwide, but has yet to benefit from the boom in orphan drug R&D that has been seen in other rare diseases. 

If approved by the FDA, edaravone would launch into a tiny market valued by GlobalData at just $38 million in the U.S. in 2013--and set to shrink to just $16 million by 2020 thanks to generic competition to Rilutek and "the lack of alternative treatments in the ALS pipeline."

The arrival of edaravone on the market is expected to expand the market, but that will not translate to a big increase in value, according to GlobalData, which sees the drug as an add-on to Rilutek. And that view is backed up by Mitsubishi's own figures: Sales of Radicut came in at 1.6 billion yen ($15 million) in the quarter ended June 30, pretty much in line with the same period last year despite the new ALS indication.

Nevertheless, Mitsubishi set up a U.S. marketing arm called MT Pharma America earlier this year, in anticipation of edaravone's approval, so it is clearly hoping for a solid return from the drug. The company has said it sees edaravone as the first step in building a specialty pharma business in the U.S.

The start of the FDA review has been welcomed by the ALS Therapy Development Institute (ALSTDI), which said it is "looking forward to hearing the final decision by the FDA less than a year from now."

Looking beyond edaravone, the ALSTDI notes that two other compounds could move toward potential regulatory filings at the FDA over the next year, namely Cytokinetics' tirasemtiv and AB Science's masitinib.

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