PARIS, France & SCHLIEREN/ZURICH, Switzerland, July 1, 2026
Ipsen has announced a definitive agreement to acquire Memo Therapeutics AG, significantly strengthening its rare disease portfolio with the addition of potravitug, a first-in-class monoclonal antibody targeting BK polyomavirus (BKPyV) infection in kidney transplant recipients. The acquisition reinforces Ipsen’s strategic commitment to delivering innovative therapies for diseases with significant unmet medical needs while expanding its presence in transplant medicine. Potravitug, currently in Phase II clinical development, is being advanced for the treatment of BK polyomavirus-associated nephropathy (BKPyVAN), a serious complication that can lead to graft failure following kidney transplantation. The therapy has already received U.S. FDA Fast Track Designation and European Union Orphan Drug Designation, positioning it as one of the most promising investigational treatments in this underserved therapeutic area. Under the agreement, Ipsen will pay €200 million upfront, with additional development, regulatory, and commercial milestone payments bringing the total potential transaction value to more than €700 million, subject to customary closing conditions expected during the third quarter of 2026.
Phase II Data Strengthens Potravitug’s Clinical Potential
The acquisition is supported by encouraging clinical evidence from the Phase II SAFE KIDNEY II trial, the largest placebo-controlled study conducted in patients with BK polyomavirus-associated nephropathy following kidney transplantation. The study enrolled 95 patients across 22 clinical sites in the United States and demonstrated that potravitug delivered meaningful antiviral activity while improving important clinical outcomes. Results showed that 24.4% of patients treated with potravitug achieved undetectable BKPyV-DNAemia by Week 38, compared with 13.0% in the placebo group. More than 40% of treated patients achieved greater than two-log viral load reductions, significantly exceeding placebo outcomes.
The therapy also demonstrated notable histological improvements, with biopsy-confirmed BKPyVAN declining from 51.2% to 31.6% among treated patients while remaining unchanged in the placebo arm. Importantly, potravitug was well tolerated, with no treatment-related serious adverse events reported throughout the study, providing strong support for the planned SAFE KIDNEY III Phase II/III pivotal trial later this year.
Addressing a Critical Need in Kidney Transplant Medicine
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BK polyomavirus remains one of the most significant infectious complications affecting kidney transplant recipients. Although the virus is commonly acquired during childhood and usually remains dormant, immunosuppression following transplantation can trigger viral reactivation, resulting in BKPyV-associated nephropathy, progressive kidney damage, and eventual graft failure. Currently, no targeted therapies have received regulatory approval for this condition, leaving physicians to manage patients primarily by reducing immunosuppressive medications, an approach that increases the risk of transplant rejection.
With more than 100,000 kidney transplants performed worldwide each year and approximately 30% of kidney transplant recipients experiencing BKPyV reactivation, the medical need for effective antiviral therapies remains substantial. By adding potravitug to its development pipeline, Ipsen aims to address this unmet need while expanding its leadership in rare diseases and transplant medicine.
Strategic Acquisition Expands Ipsen’s Rare Disease Portfolio
The transaction also includes the transfer of Memo Therapeutics’ non-potravitug assets, including its proprietary DROPZYLLA® antibody discovery platform and ongoing collaborations, into a newly established company, Memorises Bio, which will remain under the ownership of existing Memo Therapeutics shareholders. This structure enables Ipsen to focus exclusively on advancing potravitug while allowing the remaining research platform to continue independent innovation. As regulatory activity and clinical development accelerate, Ipsen believes the acquisition strengthens its long-term strategy of building a diversified portfolio of transformative medicines across rare diseases, oncology, and neuroscience. With potravitug expected to enter pivotal development later in 2026, the acquisition positions Ipsen to potentially deliver the first targeted therapy for BK polyomavirus-associated nephropathy and improve long-term outcomes for kidney transplant recipients worldwide.
Source: Ipsen, Memo Therapeutics press release
