Subcutaneous Injection Version of Alzheimer's Drug "Lecanemab" Officially Approved

Recently NHK News on-line reported the following:

アルツハイマー病治療薬「レカネマブ」皮下注射型が正式承認

2026年9月17日 3:28

医療・健康

厚生労働省は、アルツハイマー病の治療薬「レカネマブ」の自宅投与が可能となる皮下注射タイプについて16日、正式に承認しました。

現在の治療薬は点滴投与のため医療機関に通う必要があり、今後、患者の負担軽減が期待されます。

承認されたのは、日本の製薬大手「エーザイ」がアメリカの「バイオジェン」と共同で開発した、アルツハイマー病の治療薬、「レカネマブ」の皮下注射タイプです。

この薬は、アルツハイマー病の患者の脳にたまる「アミロイドβ」という異常なたんぱく質を取り除くことができ、症状の進行を抑えることが期待され、3年前にアルツハイマー病の原因物質に直接働きかける薬としては国内初の治療薬として点滴投与タイプが承認されています。

この皮下注射タイプについて「エーザイ」が厚生労働省に承認申請を行い、先月開かれた専門家部会で使用が了承されたことを受けて、厚生労働省が16日、正式に承認しました。

現在の点滴投与タイプでは医療機関に2週に1回通う必要があり、投与に1時間ほどかかりますが、皮下注射タイプでは、医師の指導のもと自宅での投与が可能になり、患者や付き添いの家族などの負担軽減が期待されます。

薬が使われる対象は、アルツハイマー病による認知症を発症する前の軽度認知障害の人や、軽度認知症の人となっています。

今後、中医協＝中央社会保険医療協議会で、公的医療保険の適用と価格について結論が出され、早ければ年内にも患者に使われるものとみられます。

Translation

Subcutaneous Injection Version of Alzheimer's Drug "Lecanemab" Officially Approved

September 17, 2026, 3:28 AM

Medical & Health

On the 16th, the Ministry of Health, Labour and Welfare officially approved a subcutaneous injection version of the Alzheimer's drug "Lecanemab," which allows for administration at home.

Current versions of the drug require intravenous infusion, necessitating visits to medical facilities; the new version is expected to reduce the burden on patients.

The approved product is the subcutaneous injection version of "Lecanemab," an Alzheimer's drug jointly developed by the major Japanese pharmaceutical company Eisai and the U.S. company Biogen.

This drug works by removing "amyloid-beta"—an abnormal protein that accumulates in the brains of Alzheimer's patients—and is expected to slow the progression of symptoms. An intravenous infusion version was approved three years ago, marking the first time in Japan that approval was given to a drug targeting the underlying cause of Alzheimer's disease.

Eisai applied to the Ministry of Health, Labour and Welfare for approval of this subcutaneous injection version. Following endorsement by an expert panel last month, the Ministry officially granted approval on the 16th.

While the current intravenous version requires visits to a medical facility every two weeks and takes about an hour to administer, the subcutaneous injection version allows for administration at home under a doctor's guidance. This is expected to alleviate the burden on patients, accompanying family, etc.

The drug is intended for use by individuals with mild cognitive impairment (MCI)—a stage preceding the onset of dementia caused by Alzheimer's—and those with mild dementia.

Hereafter, the Central Social Insurance Medical Council (Chuikyo) will reach a conclusion regarding the application of public health insurance and pricing; and the drug is expected to be available for patient use as early as within this year.

So, Japan has officially approved a subcutaneous injection version of the Alzheimer's drug "Lecanemab" which can be administrated at home. In the coming months, the Central Social Insurance Medical Council will reach a decision on the insurance and pricing matters. Apparently, the subcutaneous injection version will reduce the inconvenience on patients and families in visiting clinics regularly.