To assess clinical safety (primary) and efficacy (secondary) of histotripsy for treatment of symptomatic benign prostatic enlargement in a first-in human study.

Twenty-five male subjects with moderate to severe lower urinary tract symptoms, prostate size between 30 and 80 g, and no evidence of prostate cancer were enrolled at 2 sites in a prospective, single-arm study. Treatment consisted of acoustic energy delivery through the perineum with integrated real-time transrectal ultrasound monitoring using the Vortx R_x system. Follow-up evaluations were performed on postoperative day 1 and 1, 3, and 6 months.

Twenty-five men underwent histotripsy treatment with no serious intraoperative adverse events. Postoperatively, 3 cases of transient urinary retention (<3 days), 1 case of urinary retention (8 days in duration, defined as serious), a minor anal abrasion, and microscopic hematuria were considered device-related adverse events. Debulking of targeted prostate tissue was not observed with transrectal ultrasound imaging or with endoscopic visualization, and clinically meaningful improvement in uroflow or postvoid residual urine (PVR) did not occur. However, International Prostate Symptom Score improvement at 1 month was 12.5 (52.4%) ± 6.6 points (n = 25), at 3 months was 11.9 (50.8%) ± 7.6 points (n = 24), and at 6 months was 10.4 (44.0%) ± 7.6 points (n = 24) (P <.001).

Prostate histotripsy was safe and well tolerated in this pilot human trial with improvement in lower urinary tract symptoms.