U.S. regulators on Friday approved an Alzheimer's drug developed by Japanese drug maker Eisai Co. and U.S. firm Biogen Inc. for treatment in the early stage of the fatal, brain-robbing disease.

The new drug, lecanemab, removes a type of protein called amyloid beta, which is considered the cause of the disease. The U.S. Food and Drug Administration granted fast-track approval to the drug as it awaits further data to confirm the treatment's clinical benefits, a step paving the way for full-fledged approval.

Photo shows Eisai Co.'s envisaged vials and packages for its new Alzheimer's drug, lecanemab. (Photo courtesy of Eisai Co.)(Kyodo)

The drug will cost $26,500 annually, according to Eisai, adding that the price tag has been set to promote broader patient access and reduce the overall financial burden.

The FDA welcomed the "important advancement in the ongoing fight to effectively treat Alzheimer's disease," saying that the treatment option is the latest therapy to target and affect the underlying disease process of Alzheimer's instead of only treating the symptoms of the disease.

The treatment with lecanemab is intended to be initiated in patients with mild cognitive impairment or the mild dementia stage.

While the FDA's accelerated approval was based on the observed reduction of amyloid beta, further study has shown that lecanemab curbed the progression of symptoms, such as worsening memory and impairment in judgment, by 27 percent compared with a placebo, according to Eisai.

The additional data has been submitted to the FDA for review for regular approval, the Japanese company said.

Eisai revealed it is also planning to apply for approval to use the drug in Japan, with CEO Haruo Naito telling a press conference Saturday in Tokyo that the firm would begin the application procedures "without delay" and no later than March.

Regarding the drug's cost, Naito said Eisai would "thoroughly discuss" pricing under Japan's medical fee system with regulatory authorities and the government.

In 2021, a panel at Japan's health ministry refused to approve aducanumab, another Alzheimer's disease drug jointly developed by Eisai and Biogen. The drug, however, was approved by the FDA the same year.

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