Effect on blood pressure of combined inhibition of endothelin-converting enzyme and neutral endopeptidase with daglutril in patients with type 2 diabetes who have albuminuria: a randomised, crossover, double-blind, placebo-controlled trial

Background: Effective reduction of albuminuria and blood pressure in patients with type 2 diabetes who have nephropathy is seldom achieved with available treatments. We tested the effects of treatment of such patients with daglutril, a combined endothelin-converting enzyme and neutral endopeptidase inhibitor. Methods: We did this randomised, crossover trial in two hospitals in Italy. Eligibility criteria were: age 18 years or older, urinary albumin excretion 20-999 μg/min, systolic blood pressure (BP) less than 140 mm Hg, and diastolic BP less than 90 mm Hg. Patients were randomly assigned (1:1) with a computer-generated randomised sequence to receive either daglutril (300 mg/day) then placebo for 8 weeks each or vice versa, with a 4-week washout period. Patients also took losartan throughout. Participants and investigators were masked to treatment allocation. The primary endpoint was 24-h urinary albumin excretion in the intention-to-treat population. Secondary endpoints were median office and ambulatory (24 h, daytime, and night-time) BP, renal haemodynamics and sieving function, and metabolic and laboratory test results. This study is registered with ClinicalTrials.gov, number NCT00160225. Findings: We screened 58 patients, of whom 45 were enrolled (22 assigned to daglutril then placebo, 23 to placebo then daglutril; enrolment from May, 2005, to December, 2006) and 42 (20 vs 22) were included in the primary analysis. Daglutril did not significantly affect 24-h urinary albumin excretion compared with placebo (difference in change -7·6 μg/min, IQR -78·7 to 19·0; p=0·559). 34 patients had complete 24-h BP readings; compared with placebo, daglutril significantly reduced 24-h systolic (difference -5·2 mm Hg, SD 9·4; p=0·0013), diastolic (-2·5, 6·2; p=0·015), pulse (-3·0, 6·3; p=0·019), and mean (-3·1, 6·2; p=0·003) BP, as well as all night-time BP readings and daytime systolic, pulse, and mean BP, but not diastolic BP. Compared with placebo, daglutril also significantly reduced office systolic BP (-5·4, 15·4; p=0·028), but not diastolic (-1·8, 9·9; p=0·245), pulse (-3·1, 10·6; p=0·210), or mean (-2·1, 10·4; p=0·205) BP, and increased big endothelin serum concentration. Other secondary outcomes did not differ significantly between treatment periods. Three patients taking placebo and six patients taking daglutril had mild treatment-related adverse events-the most common was facial or peripheral oedema (in four patients taking daglutril). Interpretation: Daglutril improved control of BP in hypertensive patients with type 2 diabetes and nephropathy and had an acceptable safety profile. Combined endothelin-converting enzyme and neutral endopeptidase inhibition could provide a new approach to hypertension in this high-risk population.