New Drug for Dementia: Put System in Place to Move toward Practical Application

A new drug for dementia is likely to be put to practical use by the end of this year. A system for testing and treatment needs to be put in place so that people who really need the drug can use it safely.

A panel of experts at the Health, Labor and Welfare Ministry has approved at a meeting the manufacture and sale of a drug named lecanemab that was jointly developed by Eisai Co. and U.S. firm Biogen Inc. The drug is designed to remove a substance in the brain that is believed to cause Alzheimer’s disease.

In clinical trials, the drug was able to suppress the deterioration of symptoms, such as a decline in memory, by 27% after 1½ years of administration, according to Eisai. The company said that this is equivalent to delaying the progression of the disease by 7½ months.

This is the first drug that works directly on the substance that causes dementia. Previously, approval for another drug with a similar function was applied for, but it was not approved due to inadequate efficacy. The endorsement of this new drug is good news.

However, the new drug only delays the progression of symptoms and does not cure the disease itself. Some doctors point out that it will be difficult for patients and their families to actually feel the effects.

It is hoped that the practical application of the new drug will serve as a springboard for the further promotion of research and development, with the goal of establishing a fundamental treatment method.

The key to the proper practical application is how to overcome the challenges.

Before treatment, it is necessary to determine whether a patient has early-stage Alzheimer’s disease for which the drug is intended. A special imaging test is to be performed, but there is a limited number of medical institutions equipped with the necessary equipment and personnel for the test.

Moreover, in the first place, few people with dementia see a doctor while the disease is still mild. Local governments and medical institutions need to provide opportunities for people to receive medical examinations as early as possible.

Another concern is the price of the drug, which is expected to be several million yen per year. Although the high-cost medical expense benefit system will be applied and the individual burden will be limited to less than ¥200,000 per year, the issue of whether the effects are commensurate with the costs cannot be avoided in view of insurance finances.

Caution against side effects is needed because there is a risk of brain bleeding and swelling. Most cases are said to be mild, but three deaths have been reported overseas in which a causal relationship with the drug cannot be ruled out.

In the United States, a genetic test to determine if there is a high risk of such side effects has to be conducted when using this drug, but doing so is not required in Japan. This will be another issue for future consideration.

Doctors should fully explain the drug, including the issues involved. In the future, it is important to make efforts to create an environment that makes it easier to use the drug while continuing to confirm its effectiveness and safety.

The Basic Law on Dementia calls for the realization of an inclusive society in which people with dementia participate. The hope is that the new drug will help create a society in which people can live positively even if they suffer from dementia.

(From The Yomiuri Shimbun, Aug. 23, 2023)