Advancements in Alzheimer’s Treatment

A new class of Alzheimer’s treatments has garnered significant attention in recent years. However, the results have fallen short of commercial success. Nevertheless, Japanese pharmaceutical company Eisai has recently reported compelling data that could potentially boost the adoption of its Alzheimer’s drug, developed in collaboration with Biogen.

During a scientific presentation at an Alzheimer’s disease conference, Eisai shared promising findings regarding a new variant of its Alzheimer’s therapy named Leqembi. Unlike the currently approved medication, which is administered through intravenous infusion, this new version is injected under the skin. According to Eisai, this subcutaneous injection demonstrated a 14% increase in its ability to clear amyloid brain plaques, which are believed to be linked to Alzheimer’s disease.

Financial analysts on Wall Street believe that these new data could prove influential in supporting the FDA’s approval of the subcutaneous version of Leqembi. This regulatory approval could potentially alleviate some of the challenges associated with taking the drug.

Currently, patients receiving Leqembi must visit infusion centers twice a month for lengthy hour-long infusions. This can be particularly daunting for Alzheimer’s patients who struggle with cognitive impairments or dementia. However, if a subcutaneous injection option becomes available, it could be administered by patients within their own homes.

Despite these significant advancements, concerns about the safety profile of the drug remain prevalent. Medications such as Leqembi carry the risk of a condition known as ARIA, which involves potentially dangerous brain swelling. Eisai acknowledged that patients who received the subcutaneous version of Leqembi experienced slightly higher rates of ARIA compared to those in an earlier trial who received the infused version. However, due to the small sample size in the injected version study, precise comparisons cannot be made at this time.

It is worth noting that the rates of ARIA among patients receiving the injected Leqembi remained lower than those observed in a similar infused Alzheimer’s drug trial conducted by Eli Lilly, known as donanemab. It is important to highlight that donanemab is currently awaiting FDA approval.

According to TD Cowen analyst Phil Nadeau, these findings suggest that the subcutaneous version of Leqembi could indeed be a viable option. Nadeau does, however, caution that regulators might request Eisai to conduct additional trials to test lower doses of the new injection in an effort to achieve lower ARIA rates. Despite this potential risk, Nadeau maintains an Outperform rating on Biogen stock, with a target price of $305.

Biogen Stock and Eisai’s Progress in Alzheimer’s Treatment

Biogen stock (BIIB) has experienced a slight decline of 0.5% in Thursday’s trading, whereas Eisai’s American depositary receipts have seen a modest increase of 0.2%.

Aduhelm’s Commercial Failure and the Promise of Leqembi

In mid-2021, Biogen and Eisai obtained FDA approval for their Alzheimer’s therapy called Aduhelm. However, the treatment faced severe criticism for its questionable efficacy, leading to its failure in the market. On the other hand, Leqembi, another Alzheimer’s therapy developed by the two companies, has shown promising results. In a Phase 3 trial, Leqembi demonstrated a 27% reduction in cognitive decline among early-stage Alzheimer’s patients over a period of 18 months. The FDA granted accelerated approval for Leqembi in January of this year, followed by full approval in July. Medicare has expanded its coverage of the drug since then.

Skepticism in Wall Street and Sales Projections

Despite the success of Leqembi, Wall Street remains doubtful. Sales projections are far from reaching the $20 billion per year estimate that analysts had initially projected for Aduhelm.

Challenges and Potential Solutions

Analysts have highlighted several challenges faced by Eisai and Biogen, including safety concerns, logistical complications related to drug administration, and extensive testing requirements for patients on the drug. Patients are required to undergo MRIs both before and during treatment.

However, there is hope that a subcutaneous formulation of Leqembi could alleviate some of these challenges. Mark Goodman, an analyst from Leerink Partners, suggested that a subcutaneous version of the drug would eliminate the need to establish infrastructure around infusion centers and significantly improve ease of administration. Goodman rates Biogen stock as Outperform with a target price of $365.

Revenue Projections and Expert Ratings

Myles Minter, an analyst from William Blair, predicts that Leqembi will reach its peak global revenue of $8 billion by 2030. Minter has an Outperform rating for Biogen stock.

Positive Developments from Eisai

In addition to the progress with the subcutaneous formulation, Eisai reported other positive data regarding its Alzheimer’s program. This includes new long-term data from its Phase 3 Lecanemab trial, which showed continued benefits for patients on intravenous Leqembi even six months after the 18-month trial period ended.


While Biogen stock faces skepticism and Aduhelm lags behind sales projections, the approval and success of Leqembi offer hope for the future. Overcoming the challenges posed by safety concerns, logistical complexities, and extensive testing requirements, Biogen and Eisai strive to make significant advancements in Alzheimer’s treatment.

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