Memo Therapeutics presents Phase II data on potravitug for BKPyV
Memo Therapeutics AG has presented further analyses from its SAFE KIDNEY II Phase II trial of potravitug at the 63rd European Renal Association Congress in an oral session delivered by Dr Abdolreza Haririan, Professor of Medicine at the University of Maryland and a trial investigator.
The new analyses used propensity-score matching to construct an external control arm from a multicentre real-world cohort of kidney transplant recipients, addressing a baseline imbalance in BKPyV infection severity that complicated the original randomised comparison. All potravitug-treated patients were matched to controls with absolute standardised mean differences below 0.10 — a threshold considered indicative of high-quality covariate balance — making the post-matching groups substantially comparable.
Trial data
The matched analysis showed potravitug-treated patients fared meaningfully better on both viral kinetics and clearance. By week 20, the cumulative probability of achieving at least a 1-log₁₀ reduction in viral load was 64.1% in the potravitug arm versus 44.8% in matched controls, corresponding to a hazard ratio of 1.60 (95% CI 1.00–2.58; p=0.05). On the harder endpoint of viral clearance, 44.9% of potravitug recipients cleared the virus by week 20 versus 27.3% of controls, with an HR of 1.89 (95% CI 1.07–3.33; p=0.028). Kaplan–Meier curve separation was observed early and sustained throughout follow-up.
Haririan said the analyses "strengthen the conclusions from the SAFE KIDNEY II trial, demonstrating a consistently favorable antiviral effect of potravitug versus matched controls, with statistically significant improvement observed for cumulative probability of viral clearance."
Erik van den Berg, chief executive of MTx, described potravitug as potentially "the first targeted therapy for kidney transplant recipients with BK polyomavirus infection" and said the company intends to initiate the pivotal SAFE KIDNEY 3 programme later this year.
Regulatory position and market context
Potravitug received FDA Fast Track designation in May 2023 and EU Orphan Drug designation in December 2025. The Zurich-based company plans to begin a Phase III trial in 2026, with the programme positioned squarely in an unmet-need setting: there are currently no approved therapies for BKPyV infection in transplant recipients.
The scale of the problem is substantial. More than 100,000 kidney transplants are performed globally each year, BKPyV reactivates in up to half of recipients, and the majority of those with viraemia go on to develop BKPyV nephropathy — a condition that materially increases the risk of graft loss and death. MTx has cited a peak annual market opportunity of up to $2 billion, though that projection is company-issued and should be treated with caution at this stage of development.
The competitive landscape for post-transplant infectious complications is thin in targeted antibody approaches; immunosuppression reduction remains the current clinical default despite its own risks to graft survival. Academic groups and a handful of smaller biotechs have investigated antiviral strategies, but no late-stage programme with regulatory traction comparable to potravitug has been publicly disclosed. The FDA's Fast Track pathway, combined with EU orphan status, gives MTx a regulatory toolkit that could accelerate review if Phase III data are positive. Investors will focus on the trial design, patient-selection criteria, and primary endpoint choice for SAFE KIDNEY 3 as the programme moves toward initiation.