BKV
Our most advanced program, potravitug, a monoclonal antibody, targets BK polyomavirus (“BKPyV”) infection in kidney transplant recipients. BK polyomavirus infection is caused by the BK polyomavirus, which can become reactivated in immunosuppressed kidney transplant patients leading to an increased chance of decreased kidney functionality, kidney loss and reduced survival.
High unmet medical need
The reactivation of BKPyV in kidney transplant recipients poses a serious threat to the health and wellbeing of transplant patients.
Approximately 20% of kidney transplant patients develop BKPyV infection within 1 year post transplantation and up to 50% over the lifetime of the transplanted kidney. BKPyV infection doubles the risk of kidney loss and triples the risk of patient death. If left untreated, BKPyV infection can progress to BK polyomavirus-associated nephropathy (“BKPyV-nephropathy”) in up to 70% of cases.
There are no specific antiviral therapies for BKPyV infection available, with reduction of immunosuppression being the current standard of care. However, reducing immunosuppression increases the risk of kidney graft rejection and only gradually lowers BKPyV viral load, as immune system reconstitution is a slow process. Patients with prolonged exposure to a kidney-damaging viral load, have a 2-3x increased chance of kidney failure/loss and death within 5-10 years.
BKPyV infection in kidney transplant recipients presents a high unmet medical need. In the US, 500,000 patients have end-stage renal disease (“ESRD”) and are on permanent dialysis. Of the 500,000 patients with ESRD, 90,000 are on the waiting list for transplantation, with an average waiting time of 4 years before transplantation.
28,000 kidney and kidney & pancreas (co-) transplantations took place in the US in 2023 with the number of transplants in the US expected to continue to grow.
Worldwide, there are more than 100,000 kidney transplantations per year.
Mechanism of action
BKPyV is a member of the Polyomaviridae family and also known as Human polyomavirus 1.
The capsid of BKPyV is composed of pentamers of a single protein, VP1, which is the only part of the virus exposed on its surface. Potravitug binds to VP1 and blocks the attachment of the virus to its target cells in the body, supporting high functionality and a high barrier to viral resistance.
Potravitug
Potravitug is the most potent antibody in clinical trials for BKPyV infection.
Clinical trial
We have completed recruiting patients in the largest placebo-controlled clinical trial for the treatment of BKPyV infection in kidney transplant recipients ever conducted.
SAFE KIDNEY II (NCT05769582) is a Phase II double-blind, randomized, placebo-controlled trial with 90 patients in the USA. The trial aims to determine the safety, tolerability and efficacy of potravitug.
Results from the Phase II study were presented at the World Transplant Congress (“WTC”) in August 2025.