First-in-human radiofrequency vapor ablation in Barrett’s oesophagus

In an initial patient series, radiofrequency vapor ablation (RFVA) appears to be safe and effective for ablating Barret’s oesophagus dysplasia. Dr Sanne Noortje van Munster (St. Antonius Hospital, the Netherlands) presented the results of the preclinical and first-in-human data [1].

Radiofrequency ablation (RFA) is highly effective in the ablation of dysplastic Barrett’s oesophagus. However, for optimal contact with the oesophageal wall, multiple deployment steps and/or multiple treatment endoscopies may be required. To try and solve that problem, AquaMedical’s RFVA system generates vapor/steam at 100°C using an RF electrode at the catheter tip to ablate tissue. The 7Fr RFVA catheter is passed through the biopsy channel of a standard endoscope with distal attachment cap and is used to create focal (∼1 cm2) ablations in the oesophagus. In this study, the investigators sought to produce preliminary data with regard to RFVA safety and efficacy in patients with flat dysplastic Barrett’s oesophagus.

The RFVA system was tested for feasibility in three models. Firstly, the researchers used an in vitro lean-beef model to test increasing doses of RFVA and increasing numbers of RFA applications (total 10 ablations/modality/dose), which both resulted in increasing depth of ablation. The range of ablation depth with 2–5s vapor (0.75 mm–1.5 mm) was comparable to 1–4× RFA applications (0.58 mm–1.5 mm). With this knowledge, they then tested RFVA in a subacute porcine study (n=6). No differences were found between any doses and treatments tested on the pigs (3/5s vapor and 1–2× RFA), and no complications occurred. However, the researchers noted that the 3s RFVA was comparable to 2× RFA, whereas 5s RFVA produced slightly deeper ablation. Based on the porcine data, the researchers selected a conservative 1s and 3s dose for human testing.

In the ongoing first-in-human (FIH) study, a total of 42 RFVAs were applied in 12 patients. Per-patient, 4 ablations (2/dose) were applied at 1 cm distance. No adverse events occurred and patient-reported pain scored only 0–1 out of 10 during 14 days post-treatment. Follow-up endoscopy was performed in 6 patients and showed a median squamous conversion rate for the 1s and 3s ablations of 73% and 98%, respectively. Biopsies of endoscopically eradicated areas showed histologically normal squamous epithelium.

In conclusion, in this first preliminary series of patients, the Aqua RFVA system was safe for oesophageal ablation and successfully converted dysplastic Barrett’s oesophagus into histologically normal squamous epithelium.

1. Van Munster S et al. UEG Week 2019, Abstract LB09.



Posted on 23 October 201925 March 2024