Ipsen to acquire Memo Therapeutics for up to EUR 700m

Ipsen has agreed to acquire Memo Therapeutics AG in a deal worth up to 700 million EUR in total consideration, adding potravitug, a clinical-stage monoclonal antibody targeting BK polyomavirus (BKPyV) in kidney transplant recipients, to its rare disease pipeline.

Under the terms of the share purchase agreement, Memo Therapeutics shareholders will receive 200 million EUR at closing on a cash-free, debt-free basis, with the remainder payable through development, regulatory and commercial milestones. Ipsen said the transaction is expected to close in Q3 2026, subject to customary conditions. The deal's impact has been factored into Ipsen's existing full-year guidance.

The asset and the data

Potravitug is a monoclonal antibody directed against the VP1 capsid protein of BKPyV, working by blocking viral attachment to and entry into host cells, thereby limiting replication. It carries FDA fast-track designation, granted in May 2023, and EU orphan drug designation awarded in December 2025.

The acquisition is underpinned by topline results from the Phase II SAFE KIDNEY II trial, which enrolled 95 patients across 22 sites in the United States and is described as the largest placebo-controlled study conducted in this population. By week 38, 24.4% of potravitug-treated patients had achieved undetectable BKPyV DNA in the blood compared with 13.0% in the placebo group. Viral load reductions of greater than two log units were observed in 40.3% of patients on active treatment versus 24.7% on placebo. On the histological side, biopsy-confirmed BKPyV-associated nephropathy declined from 51.2% to 31.6% in the treatment arm by week 20, with no equivalent change recorded in the control group. Potravitug was reported to be well tolerated, with no treatment-related serious adverse events.

Ipsen intends to initiate the pivotal Phase II/III SAFE KIDNEY III trial later in 2026, supported by the full dataset presented at the American Transplant Congress earlier this year.

Christelle Huguet, EVP and Head of R&D at Ipsen, said the company saw in potravitug "the opportunity to add a promising first-in-class asset to our rare disease pipeline and address the significant clinical consequences of BK virus-associated nephropathy in kidney transplant recipients, where current standards of care can compromise transplant success and graft outcomes."

Market context and competitive landscape

BKPyVAN represents a genuine area of unmet need in transplant medicine. Roughly 30% of kidney transplant recipients develop high-level BKPyV viraemia within the first year after transplant, and the standard management approach of reducing immunosuppression to control the virus carries a direct trade-off: lower immunosuppression raises the risk of graft rejection. There are currently no approved targeted therapies for the condition. With more than 100,000 kidney transplants performed worldwide each year, including more than 28,000 in the United States alone, the addressable patient population is clinically significant.

Ipsen's broader rare disease franchise spans oncology-adjacent indications and neuroscience, and the Memo Therapeutics deal extends that footprint into infectious complications of transplantation, a category that has attracted limited large-pharma attention to date. Several academic and early-stage groups are working on antiviral approaches to polyomavirus, but no competitor has yet advanced a BKPyV-specific therapy to a pivotal trial stage, leaving potravitug in a relatively clear regulatory path if Phase III data hold.

One structural point worth noting: under the transaction, Memo Therapeutics' other assets, including its DROPZYLLA antibody discovery platform and a collaboration with CSL on a recombinant IgG project, will be carved out into a new entity, Memorises Bio, and retained by existing Memo shareholders. Ipsen is acquiring the potravitug programme only, which keeps the deal focused but means the novel discovery platform remains independent.