The new approval will allow patients who have completed the first 18 months of infusions at a medical office the option of continuing their treatment with a weekly injection they can do at home by themselves or with a caregiver.
In a statement, the companies said that the Food and Drug Administration had approved the new autoinjector formulation, called Leqembi Iqlik, and it will be available to patients in October.
The list price will be $375 per weekly injection, or $19,500 a year, Eisai said in a statement. The infused version of the drug costs about $26,500 a year when used every two weeks, or half that when used once a month.
Approved in 2023, Leqembi is a crucial growth drug for both Biogen and Eisai. But its rollout has been hampered due to the complexity of the regimen, including visits for infusions, and side effect concerns which require multiple MRI scans. The drug can cause brain swelling and brain bleeding, which is often asymptomatic but can lead to hospitalization or death.
In a safety communication Aug. 28, the FDA said it had identified six deaths from brain swelling in patients early in their treatment with the original Leqembi formula. The FDA's finding is consistent with a Bloomberg analysis earlier this year that found at least seven deaths occurred in patients after taking the drug.
As a result, the FDA has required Eisai to update prescribing information for the infused form of Leqembi to include a recommendation for an earlier MRI between the second and third dose, in addition to the three MRI scans that were already recommended later.
"While no data currently shows that earlier MRI screening reduces the risk of serious ARIA outcomes, early identification of ARIA-E is considered the best opportunity to potentially prevent serious or fatal events," Eisai said in a statement, referring to Amyloid-Related Imaging Abnormalities due to Edema/Effusion.
Eisai added that that additional MRI "does not reflect new safety concerns." The drug already has a black box warning about the potential for brain swelling and brain bleeding.
There are signs that Leqembi's growth is picking up. In the second quarter, the drug had global sales of approximately $160 million, including $63 million in US sales, Biogen reported in July.
Eisai and Biogen are also working on a self-injected form of the drug that can be used from the start of treatment. Eisai plans to file for approval of this form quickly after approval for the self-injected maintenance treatment, Lynn Kramer, the company's chief clinical officer, said in an interview prior to the approval.
The idea behind prolonged treatment with Leqembi is to maintain benefits achieved in the first 18 months, and prevent the disease process from revving back up again. The maintenance autoinjector was studied on 600 people at a range of doses, including 49 who got the final approved dose, the companies said. It had a safety profile similar to intravenous maintenance treatment but with fewer systemic reactions.
Leqembi's primary competitor is Eli Lilly & Co.'s Kisunla, which is given every four weeks as an infusion. It can be stopped in many patients after six months or a year if amyloid plaque levels decline to undetectable levels. Kisunla's global sales jumped to $48.6 million in the last quarter.