Ipsen, the Paris-based pharmaceutical group, said on July 1, 2026 that it had signed a definitive agreement to buy all shares of Memo Therapeutics AG, a privately held biotech company based in Schlieren near Zurich.
Memo's shareholders will receive €200 million (about $228 million) at closing on a cash-free, debt-free basis. Further payments tied to development, regulatory approval and sales milestones could bring the total to more than €700 million (about $800 million). Ipsen said the deal was already factored into its full-year guidance and was expected to close in the third quarter of 2026, subject to customary conditions; a later Ipsen release dated July 22, 2026 announced that the acquisition had been completed.
Ipsen is not taking all of Memo. Before closing, the assets and employees not tied to the lead drug, potravitug, are being moved into a newly formed company, Memorises Bio, which stays with Memo's existing shareholders.
What Memo built
Potravitug is a monoclonal antibody against the BK polyomavirus (BKPyV). It binds the virus's VP1 capsid protein and is designed to stop the virus attaching to and entering cells. Most people carry the virus from childhood without symptoms, but in kidney-transplant patients on immunosuppressive drugs it can reactivate and damage the new kidney, a condition known as BK polyomavirus-associated nephropathy that can lead to graft loss.
There is no approved targeted treatment. Doctors usually reduce immunosuppression instead, which raises the risk of the body rejecting the transplant. The US Food and Drug Administration granted potravitug fast-track designation in May 2023, and the European Union gave it orphan drug designation in December 2025.
In the Phase II SAFE KIDNEY II trial, which enrolled 95 patients at 22 US sites, 24.4% of treated patients had undetectable BK virus DNA in the blood at week 38, against 13.0% on placebo. A more than 100-fold drop in viral load was seen in 40.3% of treated patients versus 24.7% on placebo, and biopsy-confirmed nephropathy in the treated group fell from 51.2% to 31.6% by week 20. No treatment-related serious adverse events were reported. European Biotechnology noted that the result was not clear-cut: Memo said in July 2025 that the trial had not shown a statistically significant effect on undetectable viral DNA. A further trial, SAFE KIDNEY III, is planned to start later in 2026.
“We are thrilled to have attracted Ipsen to take this important medicine forward.”
Why Ipsen is buying
Ipsen focuses on oncology, rare disease and neuroscience, and has been buying outside drugs to fill its pipeline. The Memo agreement came days after it agreed to buy US-based Kartos Therapeutics in a deal worth up to $1.75 billion for the Phase III blood cancer drug navtemadlin, according to BioXconomy.
"With potravitug, we have the opportunity to add a promising first-in-class asset to our rare disease pipeline," said Christelle Huguet, Ipsen's executive vice-president and head of research and development.
Erik van den Berg, Memo's chief executive, said Ipsen's experience in developing and selling rare-disease medicines put it in a position to take the drug forward for kidney-transplant patients.
The investors and the funding
Memo's backers include Ysios Capital, Kurma Partners, Pureos Bioventures, Swisscanto, Vesalius Biocapital and Adjuvant Capital. In November 2023 the company closed a CHF 25 million (about $28 million) Series C round led by Pureos Bioventures, with existing investors including Swisscanto, Vesalius Biocapital, Adjuvant Capital, Verve Ventures, Schroders Capital, GF Group, Fresenius Medical Care Ventures and Redalpine. A CHF 20 million (about $22 million) extension in 2024, in which Kurma Partners invested, took the Series C to CHF 45 million.
Kurma Partners, part of the Eurazeo group, said the sale followed earlier exits from its portfolio, including the sale of ImCheck to Ipsen in 2025. Centerview Partners was Memo's exclusive financial adviser, with Goodwin and Baker McKenzie as legal counsel. Bredin Prat and Lenz & Staehelin advised Ipsen.
What stays behind
Memorises Bio will take Memo's DROPZYLLA antibody discovery platform and its collaboration with CSL on recombinant polyclonal immunoglobulin, known as the Rec-IgG project, along with the employees not working on potravitug. Memo has described DROPZYLLA as a way to turn human immune responses into antibody drugs for viral infections and cancer.
The structure lets Ipsen buy a single clinical asset while Memo's investors keep the platform and its partnership. Neither company disclosed how many employees move to Ipsen or to Memorises Bio.
