The Alzheimer’s drug Leqembi, the first medicine proven to slow the course of the disease, may be able to be given as a set of two weekly shots at home, a study from drugmaker Eisai suggests, potentially providing a more convenient way for patients to get treatment.
The drug, which received full approval from the US Food and Drug Administration in July, currently has to be administered once every two weeks by intravenous infusion, which requires patients to spend about an hour each time at an infusion center.
A study presented Wednesday at the Clinical Trials on Alzheimer’s Disease conference in Boston showed a set of two shots once weekly produced similar results after six months to twice-monthly IV infusions in terms of safety, concentration of the drug in the blood and ability to clear plaque buildups in the brain known as amyloid, Eisai said.
“Some patients actually like going to an infusion center and having that level of care,” Scott said.
Eisai said it plans to file an application for FDA approval of the weekly shot form of Leqembi by the end of March next year. By that time, it anticipates having an additional six months’ worth of data on the subcutaneous form of administration.
The shots could be administered by the patient or by a caregiver, and it would be important for prescribers to ensure they know how to use it and are capable of taking it consistently each week, as well as to provide appropriate safety monitoring, said Dr. Michael Irizarry, Eisai’s senior vice president of clinical research in neurology.
Leqembi doesn’t reverse the memory loss and ability to think clearly that comes with Alzheimer’s, or even stop it completely; the drug was shown in a clinical trial to slow the disease’s progress — measured by scales of cognition and ability to perform daily tasks — by about a third compared with placebo, after a year and a half of treatment.
Additional data presented Wednesday showed that benefit was sustained when treatment was continued to two years, and also that patients experienced greater benefit when starting the drug earlier in the course of the disease, Eisai said.
Both Leqembi and another drug expected to be approved this year, Eli Lilly’s donanemab, work by clearing the amyloid plaque buildups in the brain associated with Alzheimer’s disease. Donanemab is also given by IV infusion, but just once a month.
In the results presented Wednesday, the weekly shot form of Leqembi was shown to reduce those plaques by about 14% more than the IV form after six months of treatment, Eisai and its partner Biogen said in a press release. About 15% of patients had injection site reactions, which the companies described as “mild and moderate in severity,” with redness, irritation or swelling.
The main safety concern with drugs in this class is a side effect known as amyloid-related imaging abnormalities, or ARIA — so named because it’s detected by brain imaging. Removal of amyloid plaques can be associated with both edema and hemorrhage, brain swelling and bleeding referred to as ARIA-E and ARIA-H, which can be severe or even potentially deadly in rare cases.
Rates of ARIA were similar for patients taking Leqembi as weekly shots compared with the IV infusion, or even slightly higher, presentation slides from Eisai showed. Almost 17% of patients getting weekly shots had ARIA-E, or brain swelling, compared with 13% who got the drug via IV. And 22% of those taking the shots had ARIA-H, or brain bleeding, versus 17% in the IV group.
Dr. Georges Naasan, an associate professor of neurology and medical director for the division of Behavioral Neurology and Neuropsychiatry at Mount Sinai, said he was “concerned about the potentially increased rate of ARIA, both ARIA-E and ARIA-H.”
The results on the weekly shots are from about 70 patients, compared with more than 700 who got the drug via IV.
Though Leqembi marks a breakthrough in the treatment of Alzheimer’s for being the first drug proven to slow the course of the disease, it hasn’t been widely used since it received conditional approval from the FDA in January or fuller approval in July.
Prescription data cited by financial research firm RBC Capital Markets suggests only about 500 patients may have been treated with the drug in September, although the firm notes it’s not clear that represents all patients with prescriptions. There are more than 6 million people in the US estimated to have Alzheimer’s disease and perhaps a million in the early stages who could qualify for the drug.
Eisai’s Scott declined to say how many patients are taking Leqembi, saying the company is in a quiet period ahead of reporting financial results next month. He noted Eisai had made a forecast for 10,000 patients to be taking Leqembi by the end of March 2024, and said “we are very comfortable with that number.”
Leqembi costs about $26,500 per year before insurance, and coverage was limited until the FDA granted full approval over the summer and the Centers for Medicare and Medicaid Services started to pay for the drug.
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Patients still face some out-of-pocket costs, and while CMS recently lifted some restrictions on payment for testing that comes along with use of Leqembi, those changes are still moving through the system, RBC analyst Brian Abrahams wrote in a research note.
The price of the subcutaneous version may be different, Scott said, but declined to provide further details. He noted because the medicine would be administered at home rather than in infusion centers, it would fall under Medicare Part D instead of Medicare Part B, which could mean lower out-of-pocket costs for seniors, but said those details aren’t yet clear and could vary among patients.
“We see a lot of excitement out there,” Scott said. “I think what everyone’s trying to understand is how do they best treat patients, and will they then get appropriately reimbursed for treating such patients.”