Yesterday, the Japanese pharmaceutical giant Eisai announced that Leqembi has been approved in Japan. The intravenous infusion treatment has been given the green light as a treatment to slow the progression of mild cognitive impairment and mild dementia caused by Alzheimer’s disease. The approval entails a milestone payment to the Swedish biotech company BioArctic of EUR 17 million.
The development of lecanemab, marketed under the brand name Leqembi, is based on the antibody BAN2401 discovered by Professor Lars Lannfelt in the 1990s. This led Lannfelt and Pär Gellerfors to found the Swedish biotech company BioArctic in 2003. A couple of years later, the company entered into a collaboration with pharmaceutical giant Eisai for further development of the candidate.
Eisai is responsible for the development and regulatory applications for lecanemab globally. Since 2014, it has collaborated with Biogen on marketing and commercialisation of the product, where Eisai is the final decision-maker.
BioArctic has the right to commercialise the drug in the Nordic countries and is preparing for joint commercialisation in these countries with Eisai.
The Arctic mutation
During the early research phase in the 1990s, Professor Lannfelt’s research group made a clinical observation – the Arctic mutation. This mutation causes elevated levels of protofibrils, leading to the hypothesis that soluble protofibrils of amyloid-beta (Aβ) are a potential target protein for the treatment of Alzheimer’s disease.
Leqembi is a humanised monoclonal antibody of the type IgG1 (immunoglobulin gamma 1), directed against both soluble protofibrils and insoluble forms of Aβ.
Slowing down the course of the disease
In a press release, Eisai highlights that Leqembi is the very first and only fully approved treatment that has been proven to slow the progression of the disease and reduce the deterioration of cognitive and functional abilities. This is achieved by selective binding to – and elimination of the most toxic Aβ aggregates, the protofibrils, which are responsible for neurotoxicity in Alzheimer’s disease.
Eisai submitted a marketing authorisation application in Japan in January 2023 and the candidate was designated for priority review. Japan is the second country to grant approval of Leqembi, following the full approval in the United States in July 2023.
The approval is based on phase III data from Eisai’s large global clinical study Clarity AD, where the primary endpoint and all secondary endpoints were met with statistically significant results. Thus, the study confirmed the clinical benefits of Leqembi.
Milestone payment to BioArctic
BioArctic has no development costs for lecanemab in Alzheimer’s disease and is entitled to payments in connection with regulatory approvals and sales milestones as well as royalties on global sales.
In connection with the approval in Japan announced yesterday, a milestone payment of EUR 17 million, corresponding to just over SEK 200 million, was triggered. The market was probably expecting a positive response in Japan. The company’s share was initially traded up by 3 percent and when the stock market closed, the share stood at -0.75 percent.
In a press release, BioArctic’s CEO Gunilla Osswald expressed her satisfaction with the approval:
“The approval of LEQEMBI in Japan is another important step in the fight against Alzheimer’s disease. I am impressed by the diligent efforts of our partner Eisai to ensure that this important innovation can reach patients around the globe, and I am looking forward to more approvals in the year to come to give patients and doctors worldwide the opportunity of this new treatment.”