BioArctic is cashing in on Eisai and Biogen growing sales in Alzheimer’s disease

The news is part of Biogen’s fourth-quarter 2025 financial results and marks an increase of about 31 percent compared to the royalty received by BioArctic for the fourth quarter of 2024. According to Biogen, Leqembi’s fourth quarter global in-market sales were approximately $134 million (about €113.5 million).

The Leqembi collaboration

BioArctic has collaborated with Japan’s Eisai since 2005 in a long-standing partnership focused on the research, development, and commercialization of treatments for Alzheimer’s disease. In 2015, they signed a Development and Commercialization agreement for Leqembi for Alzheimer’s disease. On the other hand, in 2014, Eisai expanded the Leqembi program by entering into a joint development and commercialization partnership with Biogen. Under today’s structure, Eisai leads all clinical development activities, regulatory filings, and global commercialization efforts. BioArctic retains the rights to market Leqembi in the Nordic region and is working together with Eisai to prepare for its launch in these markets. BioArctic said that it does not bear any development costs related to Leqembi for Alzheimer’s disease and is eligible to receive milestone payments tied to sales, in addition to royalties on worldwide sales.

Rival antibodies and emerging players

There is only one other monoclonal antibody for Alzheimer’s disease in the market, and it’s Eli Lilly’s Kisunla (donanemab). Both Leqembi and Kisunla target beta-amyloid aggregates that are believed to contribute to Alzheimer’s disease development.

Elli Lilly announced fourth quarter 2025 financial results only two days earlier than Biogen, saying that Kinsula sales reached $109 million (about €92.3 million), making it the US market leader in the amyloid-targeting therapy space. In the conference call, the company stated that Kisunla reached the 50% share of total Alzheimer’s disease prescriptions in the US, adding that the increase in sales might be due to overall market growth, increased awareness and diagnosis of Alzheimer’s disease, as well as increased prescriber adoption based on Kisunla’s clinical profile.

The competition between the two monoclonal antibodies is tight, and other companies are coming to compete. TrueBinding, a California biotech, is investigating TB006, a humanized monoclonal antibody targeting Galectin-3, a neuroinflammatory protein that, according to the company, has never been targeted before for neurological diseases. In a phase 1 trial, a one-month TB006 treatment showed improvements in Clinical Dementia Rating-Sum of Boxes (CDR-SB) in patients, indicating the potential of slowing or reducing clinical decline caused by Alzheimer’s. In May 2023, the FDA initially approved the use of TB006 for patients with dementia and Alzheimer’s disease through the Compassionate Use pathway, also known as the Expanded Access Program. In April 2025, the company obtained an FDA Renewal Approval. TrueBinding is now running a phase 2 trial, and results are expected in this quarter.

Eisai also developed Leqembi Iqlik, which contains the same active component as Leqembi but in a subcutaneous formulation. Unlike Leqembi, Kisunla, and TB006, which require intravenous administration in an in-hospital setting, Leqembi Iqlik comes as an autoinjector that can be self-administered at home. The FDA approved Leqembi Iqlik last year for the treatment of early Alzheimer’s disease as a maintenance dose following 18 months of intravenous treatment and it’s under review in Europe. With the PDUFA date of May 24, 2026, the FDA could approve Leqenbi Iqlik for use as a starting dose rather than just for maintenance.

European Biotechnology Magazine couldn’t find public confirmation that BioArctic will receive royalties specifically from Leqembi Iqlik sales beyond the existing royalty structure tied to global Leqembi revenue under its collaboration with Eisai. However, given BioArctic’s announcement regarding Eisai’s submission to the EMAfor intravenous maintenance dosing every four weeks with Leqembi, it is reasonable to expect that any commercial expansion of the therapy, including new formulations, could potentially contribute to BioArctic’s royalties.