To evaluate the safety and effectiveness of soft-tissue augmentation of the urethral sphincter with calcium hydroxylapatite (CaHA; Coaptite) compared with glutaraldehyde cross-linked bovine collagen (Contigen) in female patients with stress urinary incontinence due to intrinsic sphincter deficiency and without associated urethral hypermobility.

This 12-month prospective, randomized, comparative, multicenter, single-blind, parallel, clinical trial of CaHA and collagen for soft-tissue augmentation of the urethral sphincter in the treatment of stress urinary incontinence enrolled 296 women. Up to five injections were performed in the first 6 months of the trial. Twelve-month postinjection efficacy data were available for 231 patients.

The results indicated that CaHA and collagen were both well tolerated in this study. No systemic adverse events were observed with either product. We used the Stamey Urinary Incontinence Scale to grade the improvement, which was the primary endpoint of the study. At 12 months, 83 (63.4%) of 131 CaHA patients compared with 57 (57.0%) of 100 collagen patients showed improvement of one Stamey grade or more (P = 0.34). More CaHA patients required only one injection (n = 60; 38.0%) during the study compared with the Contigen patients (n = 36; 26.1%; P = 0.034). Also, the average total volume of material injected during the course of the study was less for CaHA than for collagen (4.0 mL versus 6.6 mL, respectively; P <0.0001).

The results of the study have demonstrated that Coaptite is an appropriate and well-tolerated treatment for patients with incontinence due to intrinsic sphincter deficiency. This new soft-tissue augmentation material has a good safety profile and appears to provide durable improvement.