Interventions for polyoma virus-associated hemorrhagic cystitis.

PURPOSE OF REVIEW: Polyoma virus-associated haemorrhagic cystitis (PVA-HC) is a painful and high-morbidity complication after allogeneic hematopoietic stem cell transplantation (allo-HCT). It is characterized by haematuria caused by bladder inflammation and high BK-virus replication. Its incidence is changing due to expanding donor sources, including haploidentical grafts. It is difficult for clinicians to know how to treat PVA-HC, and there is limited evidence. Given evolving transplant protocols and the absence of standardized treatments, this review will examine the literature regarding interventions to treat PVA-HC.

RECENT FINDINGS: Supportive care remains the foundation of treatment. Interventions include urological procedures and immunomodulation. Recent literature highlights targeted approaches such as intravesical cidofovir, which delivers antiviral effects directly to the bladder mucosa, and adoptive virus-specific T-cell therapies. Hyperbaric oxygen therapy has also been explored. However, studies are generally small, retrospective, heterogeneous in design, and lack control groups.

SUMMARY: PVA-HC continues to present significant clinical challenges after allo-HCT. While novel antiviral and immunotherapy methods show promise, their effectiveness and safety need thorough evaluation. Future multicentre trials and standardized protocols are essential to guide targeted treatments, risk stratification, and potential preventive measures. A multidisciplinary management approach is highly recommended.