Natriuretic peptides as a surrogate endpoint in clinical trials - a riddle wrapped in an enigma

Effects of canagliflozin on NT-proBNP stratified by left ventricular diastolic function in patients with type 2 diabetes and chronic heart failure: a sub analysis of the CANDLE trial

Background

Identification of the effective subtypes of treatment for heart failure (HF) is an essential topic for optimizing treatment of the disorder. We hypothesized that the beneficial effect of SGLT2 inhibitors (SGLT2i) on the levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) might depend on baseline diastolic function. To elucidate the effects of SGLT2i in type 2 diabetes mellitus (T2DM) and chronic HF we investigated, as a post-hoc sub-study of the CANDLE trial, the effects of canagliflozin on NT-proBNP levels from baseline to 24 weeks, with the data stratified by left ventricular (LV) diastolic function at baseline.

Methods

Patients (n = 233) in the CANDLE trial were assigned randomly to either an add-on canagliflozin (n = 113) or glimepiride treatment groups (n = 120). The primary endpoint was a comparison between the two groups of the changes from baseline to 24 weeks in NT-pro BNP levels, stratified according to baseline ventricular diastolic function.

Results

The change in the geometric mean of NT-proBNP level from baseline to 24 weeks was 0.98 (95% CI 0.89–1.08) in the canagliflozin group and 1.07 (95% CI 0.97–1.18) in the glimepiride group. The ratio of change with canagliflozin/glimepiride was 0.93 (95% CI 0.82–1.05). Responder analyses were used to investigate the response of an improvement in NT-proBNP levels. Although the subgroup analyses for septal annular velocity (SEP-e′) showed no marked heterogeneity in treatment effect, the subgroup with an SEP-e′ < 4.7 cm/s indicated there was an association with lower NT-proBNP levels in the canagliflozin group compared with that in the glimepiride group (ratio of change with canagliflozin/glimepiride (0.83, 95% CI 0.66–1.04).

Conclusions

In the subgroup with a lower LV diastolic function, canagliflozin showed a trend of reduced NT-pro BNP levels compared to that observed with glimepiride. This study suggests that the beneficial effects of canagliflozin treatment may be different in subgroups classified by the severity of LV diastolic dysfunction.

Effect of canagliflozin on N-terminal pro-brain natriuretic peptide in patients with type 2 diabetes and chronic heart failure according to baseline use of glucose-lowering agents

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of a deterioration in heart failure (HF) and mortality in patients with a broad range of cardiovascular risks. Recent guidelines recommend considering the use of SGLT2 inhibitors in patients with type 2 diabetes (T2D) and HF, irrespective of their glycemic control status and background use of other glucose-lowering agents including metformin. However, only a small number of studies have investigated whether the effects of SGLT2 inhibitor in these patients differ by the concomitant use of other glucose-lowering agents.

METHODS

This was a post-hoc analysis of the CANDLE trial (UMIN000017669), an investigator-initiated, multicenter, open-label, randomized, controlled trial. The primary aim of the analysis was to assess the effect of 24 weeks of treatment with canagliflozin, relative to glimepiride, on N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration in patients with T2D and clinically stable chronic HF. In the present analysis, the effect of canagliflozin on NT-proBNP concentration was assessed in the patients according to their baseline use of other glucose-lowering agents.

RESULTS

Almost all patients in the CANDLE trial presented as clinically stable (New York Heart Association class I to II), with about 70% of participants having HF with a preserved ejection fraction phenotype (defined as a left ventricular ejection fraction ≥ 50%) at baseline. Of the 233 patients randomized to either canagliflozin (100 mg daily) or glimepiride (starting dose 0.5 mg daily), 85 (36.5%) had not been taking any glucose-lowering agents at baseline (naïve). Of the 148 patients who had been taking at least one glucose-lowering agent at baseline (non-naïve), 44 (29.7%) and 127 (85.8%) had received metformin or a dipeptidyl dipeptidase-4 (DPP-4) inhibitor, respectively. The group ratio (canagliflozin vs. glimepiride) of proportional changes in the geometric means of NT-proBNP concentration was 0.95 (95% confidence interval [CI] 0.76 to 1.18, p = 0.618) for the naïve subgroup, 0.92 (95% CI 0.79 to1.07, p = 0.288) for the non-naïve subgroup, 0.90 (95% CI 0.68 to 1.20, p = 0.473) for the metformin-user subgroup, and 0.91 (95% CI 0.77 to 1.08, p = 0.271) for the DPP-4 inhibitor-user subgroup. No heterogeneity in the effect of canagliflozin, relative to glimepiride, on NT-proBNP concentration was observed in the non-naïve subgroups compared to that in the naïve subgroup.

CONCLUSION

The impact of canagliflozin treatment on NT-proBNP concentration appears to be independent of the background use of diabetes therapy in the patient population examined. Trial registration University Medical Information Network Clinical Trial Registry, number 000017669. Registered on May 25, 2015.