Objective: Treatment of peripheral artery disease (PAD), Fontaine Stage IIb with vasoactive substances is of limited efficacy and does not last beyond the active treatment. Glyceryl trinitrate (GTN) is a vasodilating agent that relaxes vascular smooth muscle cells. The aim was to prove the concept that GTN sublingual powder has sustained clinical efficacy and adequate safety in these patients.
Methods: This was a multicentre, randomised, double blind, placebo controlled, forced titration, proof of concept study (phase IIa). Patients had a treadmill test at baseline, after 12 weeks of GTN/placebo administration, and at 19 and 26 weeks (without treatment). Primary objectives were an increase in initial claudication distance (ICD) and absolute claudication distance (ACD) at 12 weeks.
Results: Ninety-five patients were screened and 73 randomised, of which 53 patients completed the 12 week treatment phase (GTN 26, placebo 27). At a baseline ICD of 59.2 ± 32.8 m (GTN) and 57.5 ± 39.7 m (placebo), GTN led to a placebo corrected ICD increase of 23.2% vs. baseline (p = .35). Baseline ACD was 105.3 ± 52.9 m (GTN) and 106.1 ± 95.0 m (placebo), and GTN led to a placebo corrected increase of 3.6% (p = .44), with substantial interindividual variation. The change in claudication distance was greater in patients with an ICD of ≥50 m at baseline (ΔICD 29.3%; p = .19), and an ACD ≥ 100 m (ΔACD 8.5%; p = .40). The effect lasted beyond the active treatment period as shown by a 49.3% increase in ICD (p = .31) and a 20.6% increase in ACD (p = .21) by week 26. GTN sublingual powder was well tolerated.
Conclusion: Intermittent treatment with nitroglycerin sublingual powder may represent a potential treatment option for patients with PAD stage Fontaine IIb, with an immediate and a sustained effect. The observed increases in ACD and ICD were however not statistically significant in this phase IIa proof of concept study. Further studies are required.
Keywords: Arteriogenesis; Claudication; Glyceryl trinitrate; Nitroglycerin; Peripheral artery disease; Sublingual powder.
Copyright © 2020 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.