Ipsen has entered into a definitive share purchase agreement to acquire Memo Therapeutics AG for 200 million EUR on a cash-free and debt-free basis, with deferred payments potentially bringing total consideration to over 700 million EUR. The acquisition centers on potravitug, a first-in-class monoclonal antibody targeting BK polyomavirus (BKPyV) reactivation in kidney transplant recipients, a serious complication with no approved targeted treatments. The transaction is expected to close during Q3 2026, subject to customary closing conditions, and its impact is factored into Ipsen’s current full-year guidance.

Clinical data supports pivotal trial

The Phase II SAFE KIDNEY II trial, the largest placebo-controlled study for BKPyV-associated nephropathy (BKPyVAN) with 95 patients across 22 U.S. sites, demonstrated the efficacy of potravitug. Topline results showed higher rates of viral load reduction or undetectable levels compared to placebo at week 20, alongside histological improvement. By week 38, 24.4% of treated patients achieved undetectable BKPyV-DNAemia versus 13.0% in the placebo group. Additionally, >2-log10 viral load reductions occurred in 40.3% of the potravitug group versus 24.7% of the placebo group. Biopsy-proven BKPyVAN declined from 51.2% to 31.6% by week 20 in the treatment arm, with no change in the placebo group. The drug was well tolerated, with no treatment-related serious adverse events reported.

Transaction structure and strategic fit

Under the agreement terms, Memo Therapeutics AG's shareholders will receive the upfront payment at closing, with additional contingent payments based on development, regulatory approval, and sales milestones. As a condition precedent, assets and employees not related to potravitug will be transferred to a newly incorporated company, Memorises Bio, which will be retained by Memo Therapeutics AG's shareholders. This carve-out includes the collaboration with CSL on the Rec-IgG Project and the DROPZYLLA antibody discovery platform. Christelle Huguet, PhD, EVP, Head of R&D at Ipsen, stated the acquisition reinforces the company's commitment to transformative solutions for patients with significant unmet needs.

Potravitug mechanism and regulatory status

Potravitug is a monoclonal antibody directed against the BK virus VP1 capsid protein, blocking viral attachment and cellular entry to prevent infection and replication. The U.S. Food and Drug Administration (FDA) granted fast-track designation to potravitug in May 2023, and it received orphan drug designation in the European Union in December 2025. The totality of evidence from the Phase II trial supports the initiation of a pivotal Phase II/III SAFE KIDNEY III trial later this year. Erik van den Berg, CEO of Memo Therapeutics AG, highlighted that Ipsen's expertise in rare diseases will ensure the breakthrough asset reaches its full potential.