Ipsen’s buying streak continues with €700m Memo deal
Paris-based Ipsen has agreed to acquire Swiss biotech Memo Therapeutics AG in a deal worth more than €700m, adding the clinical-stage BK polyomavirus antibody potravitug to its rare-disease pipeline.
Why it matters: It is Ipsen’s second acquisition in a week, following its up-to-$1.75bn deal for Kartos Therapeutics. In two moves, the French pharma has added one late-stage oncology asset and one mid-stage rare-disease programme, reinforcing its strategy of buying niche medicines with clear development paths.
By the numbers: Ipsen will pay €200m upfront on a cash-free, debt-free basis. Memo shareholders are eligible for additional development, regulatory and sales-based milestone payments that could take total consideration above €700m.
Zoom in: Potravitug is a monoclonal antibody targeting BK polyomavirus-associated nephropathy, a serious complication in kidney transplant patients that can lead to graft loss and transplant failure.
- The antibody targets the BK virus VP1 capsid protein and is designed to block viral attachment and cellular entry, preventing infection of host cells and subsequent viral replication.
- The drug has FDA fast-track designation and EU orphan drug designation. Ipsen said the Phase II SAFE KIDNEY II dataset supports starting a pivotal Phase II/III trial later this year.
The data: In SAFE KIDNEY II, Ipsen and Memo reported higher rates of viral load reduction or undetectable BK polyomavirus (BKPyV) levels with potravitug than placebo, alongside histological improvement.
- At week 38, 24.4% of treated patients had undetectable BK polyomavirus DNA in the blood (BKPyV-DNAemia), compared with 13.0% in the placebo group. More than a 100-fold (2-log10) reduction in viral load occurred in 40.3% of treated patients versus 24.7% on placebo.
Yes, but: The Phase II readout was not unequivocal. Memo reported in July 2025 that SAFE KIDNEY II did not meet its primary endpoint of undetectable BKPyV DNAemia in blood with statistical significance, although treated patients showed higher viral response and biopsy-based resolution of BK polyomavirus nephropathy by week 20. The Swiss biotech still saw promise in other aspects of the trial and decided to pursue phase 3 discussions with the FDA.
Backstory: Memo had already been on the radar this year after signing a collaboration and option agreement with CSL worth up to CHF265m around recombinant polyclonal IgG candidates developed with its DROPZYLLA antibody platform.
Between the lines: That part of Memo is not going to Ipsen. Assets and employees not related to potravitug, including the CSL collaboration and DROPZYLLA platform, will be transferred into a newly incorporated company, Memorises Bio, retained by Memo’s shareholders.
What we’re watching: Whether Ipsen can turn potravitug’s mixed-but-promising Phase II profile into a registrational win. There are currently no approved targeted therapies for BK polyomavirus, leaving clinicians to manage infection by reducing immunosuppression, a trade-off that can increase the risk of rejection.
The bottom line: Ipsen is moving quickly to replenish and reshape its pipeline through external innovation. The Kartos deal brought in navtemadlin, an oral MDM2 inhibitor in Phase III development for myelofibrosis. Memo adds a rarer, transplant-focused infectious disease angle within Ipsen’s rare-disease franchise.
