[Reporter's View] Expectations for new Alzheimer's drugs

Last month, a new drug for Alzheimer's disease, Leqembi, was approved in Korea.

 

Leqembi, which was developed by Eisai and Biogen, targets the amyloid beta (Aβ) protein in the brain, which is considered one of the most likely causes of Alzheimer's disease.

 

The industry welcomed Leqembi’s arrival because there had been no promising new drugs to treat Alzheimer's disease until now.

 

Until now, donepezil, galantamine, rivastigmine, and memantine were used for Alzheimer's, but all were only able to relieve symptoms such as cognitive impairment and do not fundamentally treat dementia.

 

Since then, a number of brain function improvement drugs have been introduced to prevent Alzheimer's disease but failed to prove their effectiveness.

 

In 2022, acetyl-L-carnitine, which was used as a brain function enhancer, failed to prove its efficacy during clinical reevaluations, which led to its indication being removed.

 

Oxiracetam also failed to prove its efficacy during clinical reevaluations last year and was removed from the market.

 

Choline alfoscerate formulations also remain mired in controversy.

 

The reason for the market exit of these drugs that had been used to improve brain function is lack of efficacy.

 

The main problem with these drugs is that they have a jagged effect, which means that they may or may not improve the patient’s condition, depending on how the patient is feeling that day.

 

Side effects have also slowed the development of Alzheimer's disease treatments.

 

Alzheimer's is one of the leading causes of dementia, and it is believed that abnormal proteins such as amyloid beta protein and tau protein build up in the brain, causing nerve cells to die slowly.

 

However, in the case of amyloid-targeted therapies, amyloid-related imaging abnormalities(ARIA), which are abnormal signals such as brain edema or microhemorrhage observed on MRI scans, may occur with their use.

 

Aduhelm, which came close to commercialization before Leqembi also failed due to high rates of side effects in addition to its lack of efficacy.

 

The good news is that other treatments have emerged that have shown promise in early Alzheimer's disease, including Leqembi and Lilly's donanemab.

 

Both treatments target the amyloid beta protein, which is responsible for the development of dementia, and have shown efficacy in clinical trials with manageable side effects.

 

In clinical trials, Leqembi improved a composite measure of cognitive function.

 

This allowed patients with mild cognitive impairment to return to daily life to conduct day-to-day activities.

 

Just as it is meaningful to extend the number of survival days of cancer patients by administering chemotherapy drugs, administering Leqembi is expected to have a similar effect.

 

As we severely lack treatment options for Alzheimer's disease, new drugs are needed to expand treatment opportunities for patients.

 

After the history of failures recorded in the development of Alzheimer's disease treatments, it would be interesting to see if the new Alzheimer's drugs can reverse the fate.

 

It is the reporter’s hope the new drugs will be able to address the dire unmet needs of Alzheimer's patients in Korea.