On the 22nd, the Ministry of Health, Labor and Welfare will examine whether or not the drug for the treatment of Alzheimer's disease, which was jointly developed by a pharmaceutical company in the United States and Japan, should be approved.
The company says it is the first drug in the world to control the progression of the disease itself, but the evaluation of its effectiveness is divided internationally, and the focus is on how the Ministry of Health, Labor and Welfare's subcommittee evaluates it.
The screening will be conducted by the American pharmaceutical company "Biogen" and "Aducanumab" developed by Japanese "Eisai".
An application for approval was submitted last December as a drug to slow the progression of Alzheimer's disease, and an expert committee of the Ministry of Health, Labor and Welfare will decide whether to approve it on the afternoon of the 22nd.
It is said to have the effect of removing an abnormal protein called "amyloid β" that has accumulated in the brain and preventing nerve cells from being destroyed. It means that the deterioration of function was suppressed by 22%.
According to the company, there have been drugs that slow the progression of symptoms for several years, but it is the first drug in the world to slow the progression of the disease itself.
"Aducanumab" was conditionally approved by the US FDA = Food and Drug Administration in June, while EMA = European Medicines Agency said on the 17th last week, "Although amyloid β is reduced, the relationship with improvement of symptoms is proved. The focus is on how the Ministry of Health, Labor and Welfare's subcommittee evaluates its effectiveness, recommending that it not be approved.
It is estimated that there are 6 million people with dementia in Japan, of which 60% to 70% have Alzheimer's disease.
What is "Aducanumab"?
"Aducanumab" was developed by "Eisai" in Japan and "Biogen" in the United States as a treatment for Alzheimer's disease.
Alzheimer's disease is thought to be caused by the accumulation of an abnormal protein called "amyloid β" in the brain more than 10 years before the onset, which causes nerve cells to break down.
"Aducanumab" is an artificially produced antibody that is expected to have the effect of preventing the destruction of nerve cells and suppressing the progression of Alzheimer's disease itself by removing this "amyloid β".
However, since it is not possible to recover nerve cells that have once been destroyed, it is important to start treatment early, such as "MCI = mild cognitive impairment" before the onset of dementia and the initial state of Alzheimer's disease. It is said to be.
The result of the clinical trial is
Two clinical trials of "aducanumab" were conducted as the final stage "clinical trial" to confirm the efficacy and safety of the drug.
The two clinical trials were conducted internationally, including in the United States and Japan, and approximately 1,600 people each participated in people with "MCI = mild cognitive impairment" and mild Alzheimer's disease, which are considered to be the pre-stage of dementia.
In the clinical trial, "Aducanumab" was divided into a group to be administered in a small dose, a group to be administered in a large dose, and a group to be administered with a fake drug, and it was administered once a month for one and a half years for cognitive function. I investigated changes and so on.
However, at the stage of the interim analysis, it was difficult to confirm the efficacy, and the clinical trial was discontinued in the middle of the trial (2019).
However, according to the company, a detailed analysis of the dose of "aducanumab" and changes in symptoms, including the obtained data, showed that cognitive decline was suppressed by 22% in one of the two clinical trials. It means that the result was that.
In the other clinical trial, the effect of suppressing the decline in cognitive function could not be confirmed as a whole, but the company found that it was effective when analyzing the data of people who received a certain amount or more in detail. It is said that the same tendency as in the clinical trial was observed.
In addition, two clinical trials confirmed that "amyloid β" in the brain was reduced by 59% to 71%.
Regarding side effects, MRI examinations reported swelling of the brain and minor bleeding in 41% of people who received high doses of the drug.
Most of them were asymptomatic, but some had symptoms such as headaches.
Alzheimer's disease and treatment
Dementia is known to be caused by a variety of illnesses.
Alzheimer's disease is the most common cause, and is estimated to account for 60% to 70% of the total.
Alzheimer's disease is the first disease reported by German doctor Alois Alzheimer over 100 years ago.
In Alzheimer's disease, it is known that an abnormal protein, "amyloid β", gradually accumulates in the brain more than 10 years before symptoms appear, and it is thought that this causes nerve cells to break down and cognitive function to decline. , The detailed mechanism is not yet clear.
Conventional treatments for Alzheimer's disease delay the progression of symptoms by increasing the function of the remaining nerve cells for several years, but they cannot stop the nerve cells in the brain from breaking down. did.
Therefore, the development of a fundamental therapeutic drug that can suppress the progression of Alzheimer's disease itself is awaited.
Differences in correspondence overseas
Regarding "Aducanumab", there is a difference in the response between the United States and the EU = European Union.
Of these, the US FDA = Food and Drug Administration approved "Aducanumab" in June with a mechanism called "rapid approval" to provide early treatment to patients with serious illness.
An external expert committee has drawn negative conclusions about the approval, but the FDA said, "Clinical trials have confirmed a decrease in amyloid β, and the effect on the patient's symptoms is reasonably predicted." It was made.
However, because it is "accelerated approval", it is necessary to conduct additional clinical trials to verify the effect, and as a result, approval may be revoked if no effect is observed.
The company plans to conduct additional clinical trials over a period of about four years starting March next year.
Meanwhile, the EU's pharmaceutical regulatory agency, EMA = European Medicines Agency, recommended on the 17th of this month that "aducanumab" should not be approved by EU enforcement agencies.
Regarding the reason, EMA said, "Although this drug reduces amyloid β in the brain, it has not been proven to be related to improvement of symptoms. Overall, it has not been shown to be effective in treating Alzheimer's disease." increase.
In Japan, "Aducanumab" will be examined by the expert committee of the Ministry of Health, Labor and Welfare on the 22nd of this month.
Dementia and future estimates
According to the Ministry of Health, Labor and Welfare, it is estimated that there are more than 6 million people with dementia aged 65 and over in Japan, and it is estimated that about 7 million people will have dementia in 2025, and about 1 in 5 elderly people will have dementia. It has been.
Also, according to the WHO = World Health Organization, it is estimated that there are more than 55 million people with dementia worldwide, and it is expected to increase to 139 million by 2050.
Dementia is a common issue not only in Japan but around the world.