Eisai Advances Home-Administered Subcutaneous Version of Leqembi for Early Alzheimer’s Treatment

SmartCom APP learned that an experimental Alzheimer's drug developed by Japanese pharmaceutical giant Eisai Co., Ltd. for home use by patients has shown very promising preliminary treatment results. Early study results indicate that the effects of this new version of the drug, a subcutaneous injection formulation, surpass those of its already approved Alzheimer’s treatment drug — the infusion formulation Leqembi. This research may pave the way for enhancing the body's absorption efficiency of this medication.

The study, presented Wednesday at a conference in Boston, showed that after six months of treatment, the injectable drug was 14% more effective at clearing amyloid plaques, a toxic protein linked to Alzheimer’s disease, than the leading injectable drugs currently on the market. The subcutaneous injection version of Leqembi achieved an 11% higher drug concentration in the blood compared to other versions.

However, the new version of the drug did not reduce the incidence of brain swelling and bleeding, which are the most concerning side effects of Leqembi. Tokyo-based Eisai stated that the incidence of the main side effects—brain swelling and bleeding—was very similar between the two versions.

Data shows that Leqembi is the first drug that clearly demonstrates the ability to slow the progression of Alzheimer's disease. It must be administered intravenously every two weeks in a hospital or treatment center. This usage scenario could be an obstacle for Alzheimer’s patients using this drug, as they may require caregivers to take them to appointments. Bloomberg Intelligence analysts have stated that they expect the rollout of the drug to be gradual. The drug received full approval in the U.S. this July.

Eisai and its key partner Biogen (BIIB.US) are hoping for a swift approval of the subcutaneous version of the drug. This method would allow patients or caregivers to administer Leqembi at home, eliminating the need to visit a hospital or treatment center every two weeks.

Eisai and Biogen hope to capture market share before the approval of competitor Eli Lilly's (LLY.US) product. Currently, donanemab, an Alzheimer's treatment drug developed by Eli Lilly, is undergoing regulatory review and requires only one injection per month. Research results show that this drug can quickly remove amyloid proteins, and some patients may stop treatment after approximately one year.

The Leqembi injection developed by Eisai may allow for twice-weekly injections at home. The company's ongoing study compared 72 patients receiving the new formulation with 322 patients receiving Leqembi. The study did not compare the final cognitive outcomes of the two versions.

A spokesperson said that if the trial results remain unchanged over the entire 12-month period, Eisai hopes to apply for U.S. regulatory approval of the injectable formulation before the end of March 2024. At the Clinical Trials on Alzheimer's Disease conference held in Boston, some doctors expressed cautious optimism about the new version of Leqembi.

At the conference, researchers also presented data from a subset of patients from an early large dataset that Eisai's drug was approved in July. The analysis focused on a group of patients with milder conditions, who had lower levels of tau, another protein associated with Alzheimer’s, in their brains. In this group, about 60% of patients treated with Leqembi showed improvement after 18 months, compared to only 28% of low-tau patients receiving a placebo.

This discovery, while still in its preliminary stages, has excited the doctors present at the conference, as it suggests that if drugs like Leqembi are administered early in the disease process, it may be possible to halt the progression of the disease. Eisai Co., Ltd. is already conducting a large-scale trial aimed at proving whether Leqembi can prevent Alzheimer's disease.

Some doctors also seem excited about the prospects of Leqembi injections. Paul Newhouse, director of the Center for Cognitive Medicine at Vanderbilt University Medical Center, said in an interview before Eisai's presentation: "If it works, it will be a big deal." "If a patient is not at home, they can receive the injection at their local doctor’s office, eliminating the need for a long trip to an infusion center."

"This is a huge benefit for Alzheimer's patients," Newhouse said, who has been using Leqembi in his research for many years because it may reduce financial costs and logistical impacts. He mentioned that Vanderbilt University is still establishing a clinical infusion program for this drug.

Even with the convenient, injectable new version, the entire treatment process related to Leqembi remains complex. "Patients must undergo a specialized PET brain scan to detect amyloid proteins to determine if they are eligible for this medication. They also need to have MRI scans during the treatment process to monitor for side effects," Newhouse stated.