Work

Efficacy and Safety of Adoptive BK Polyomavirus-Reactive T-Cell Therapy for Active Infection or Disease in Transplant Recipients: A Systematic Review

Year: 2026

Type: review

Abstract: BACKGROUND AND OBJECTIVES: BK polyomavirus (BKPyV) causes haemorrhagic cystitis (HC) after allogeneic haematopoietic cell transplantation (HCT) and nephropathy (BKPyVAN) after kidney transplantation, with no antiviral of established efficacy. We evaluated the clinical activity and treatment-emergent safety of adoptively administered BKPyV-reactive T cells. METHODS: PubMed, Europe PMC and ClinicalTrials.gov were searched to 1 September 2026 with citation checking; full-length reports of therapeutic infusion were eligible and prophylaxis-only reports excluded, following PRISMA 2020 and SWiM. RESULTS: = 70%). Response did not follow the expected phenotype gradient (69.1% HC, 70.0% DNAemia, 75.0% BKPyVAN, overlapping intervals), and organ-level outcomes diverged: haematuria or cystitis resolved in 19 of 25 (76.0%), whereas no cohort documented consistent renal recovery once nephropathy was established. In the only placebo-controlled trial, more kidney recipients achieved a week-24 viral load decline with biweekly posoleucel than placebo, but three placebo-controlled posoleucel trials after HCT, including a phase III HC trial of 97 participants, were discontinued in December 2023 for futility without safety concerns. Acute graft-versus-host disease ranged from 0% to 25% (4.0% BKPyV-restricted, 12.2% whole-cohort denominators), rejection occurred in 4 of 69 (5.8%) exposed kidney recipients versus 0 of 19 on placebo, and one fatal cytokine-release syndrome was reported. CONCLUSIONS: BKPyV-reactive T cells show reproducible virological activity and acceptable short-term tolerability, but overlapping, mostly uncontrolled evidence does not establish comparative clinical efficacy or graft benefit. Development should target persistent DNAemia after failed reduction in immunosuppression and before irreversible fibrosis.

Source: Viruses

DOI: 10.3390/v18101166

Authors: Felix Bratosin, Shiva Charana Kodimala, Alexei Croitor, Vlad Dema, Ovidiu Rosca

Institutions: The University of Texas Health Science Center at Houston, St. Mary’s Health Care System, Victor Babeș University of Medicine and Pharmacy Timișoara

Language: English

Topic: Polyomavirus and related diseases

Subfield: Oncology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,137