The use of intravesical hyaluronic acid for the treatment of BK virus haemorrhagic cystitis

Abstract

INTRODUCTION & OBJECTIVES: The treatment of haemorrhagic cystitis secondary to BK virus remains an area in which there is a dearth of evidence. Recent systematic reviews have identified that off-label use of intravesical hyaluronic acid could be considered as has a favourable side effect profile. We aim to present a case series of the use of intravesical hyaluronic acid, in the form of iAluRil, for the treatment of BK virus associated haemorrhagic cystitis. METHODS: A retrospective analysis of all intravesical iAluRil administrations was carried out from the period of January 2020 until July 2022. Four cases of haemorrhagic cystitis with proven BK viruria were included and their electronic medical records were reviewed to assess their response to treatment as well as any adverse effects of treatment. RESULTS: A total of four patients were identified during the study period. All were given a 1 g in 50 mL preparation of iAluRil instilled into the bladder. It was then held at least for 30 min before allowing the patient to void. The protocol for treatment involved weekly instillations for 4 weeks (induction phase), following by fortnightly for a total of 6 treatments, although one patient received 8 treatments. All four patients initially received intravenous cidofovir, which remains the most studied therapy for BK virus haemorrhagic cystitis and were referred for iAluRil after failing to respond to cidofovir. The case series had a 50% success rate, with two patients having complete resolution of haematuria, and two patients having ongoing haematuria with clots. Regarding side effects, the two patients with ongoing haematuria reported increased urinary frequency and urgency, and occasional suprapubic discomfort. The two patients with improvement in their symptoms reported no ongoing urinary symptoms after resolution of symptoms and completion of iAluRil therapy. CONCLUSIONS: This series demonstrates that iAluRil is safe for use in BK virus associated haemorrhagic cystitis, and can be efficacious in the treatment of haematuria.