Friday, the US FDA approved a much-anticipated new drug that is meant to slow the mental decline of people with Alzheimer’s disease who are in the early stages of the disease.

Leqembi, also known as lecanemab, was approved by the FDA only days after the agency was sharply criticized in a congressional report for its approval of another Alzheimer’s drug, Aduhelm.

And despite trial data showed that using a monoclonal antibody to treat patients includes risks of brain bleeding and swelling, the approval was given.

The FDA has granted approval for two drugs through its accelerated approval process, which allows for faster approval of medications for serious conditions with unmet medical needs.

Eisai and Biogen’s joint development, Leqembi and Aduhelm, has been hailed as a major breakthrough in the battle against Alzheimer’s disease by the FDA. In a statement, the agency said that these drugs “represent an important advancement in the ongoing fight to effectively treat Alzheimer’s disease.” 

According to Billy Dunn of the FDA’s Center for Drug Evaluation and Research, Alzheimer’s disease has a severe and immeasurable impact on the lives of those who suffer from it, as well as on their loved ones.

According to Dunn, leqembi is “the latest therapy to target and affect the underlying disease process of Alzheimer’s, instead of only treating the symptoms of the disease.”

Leqembi showed a 27 percent reduction in the rate of cognitive loss in Alzheimer’s patients, according to preliminary results from a study that were published in September.

Over the course of 18 months, the phase three study included roughly 1,800 participants who were split between receiving the drug and a placebo.

The full study data, which was published in the New England Journal of Medicine, provided more detail on the results but also raised questions about how often “adverse effects,” such as brain bleeding and swelling, occur.

According to the findings, 17.3% of patients who received the drug developed brain bleeds, compared to 9% of individuals who received a placebo.

Additionally, 12.6% of individuals taking the medication exhibited brain swelling, as opposed to only 1.7% of those receiving a placebo.

In both arms of the drug study, deaths were recorded at almost the same rates.

Tau and amyloid beta are two of the most important proteins involved in Alzheimer’s disease, and their accumulation in tangles and plaques (together referred to as aggregates) is what ultimately leads to the death of brain cells and a resulting reduction in brain volume.

Amyloid is what Leqembi goes after.

Aduhelm was formerly marketed by Biogen and Eisai, however, there was much debate regarding its efficacy, and its approval in 2021 resulted in three high-level FDA resignations.

According to an 18-month investigation by the US Congress, the approval process for Aduhelm was marked by “irregularities” and was met with criticism from both the FDA and Biogen.

According to a congressional report, Biogen, based in Cambridge, Massachusetts, has set an “excessively high price” of $56,000 per year for Aduhelm.

Leqembi’s starting cost, according to Eisai, will be $26,500 annually.

Image Credit: Adam Glanzman/Bloomberg via Getty Images