A review of novel STING bulking agents

The objective of this study was to review the literature to compare the efficacy and complications of polyacrylate-polyalcohol copolymer (PPC) and polyacrylamide hydrogel (PAHG) with the current standard of care, dextranomer/hyaluronic acid (Dx/HA), when used to treat VUR in the paediatric population.

PubMed, Embase and Cochrane databases were searched. Keywords included Vesicoureteral reflux (VUR), endoscopic; endoscopic injection, endoscopic treatment, dulking material, dextranomer/hyaluronic acid copolymer, polyacrylate-polyalcohol copolymer, Deflux, Dexell, Vantris, Bulkamid, outcome, treatment and children. Prospective or retrospective studies comparing PAHG/PPC directly with Dx/HA were included for review.

Four studies were identified comparing PPC with Dx/HA. All studies showed superior efficacy (on micturating cystourethrogram (MCUG) at 3 months) of PPC over Dx/HA. However, 1 study identified a significantly higher rate of vesicoureteric junction obstruction (VUJO) in the PPC group. One study was identified comparing PAHG with Dx/HA which showed similar efficacy on 3-month MCUG.

Current data suggest PPC confers a higher resolution rate of VUR and PAHG confers comparable resolution rates for VUR compared with Dx/HA in the paediatric population. However, the incidence of late-onset VUJO in one study is concerning, and high-quality randomised controlled trials with long-term follow-up are needed before making further recommendations.