Differing approaches to analyse on-treatment cardiovascular events comparing daprodustat with darbepoetin: results from the ASCEND-ND trial

Background

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) represent a potential new therapeutic option to treat anaemia of chronic kidney disease (CKD).

Purpose

In the recent ASCEND-ND trial (NCT02876835)1, conducted in patients with anaemia of CKD not requiring dialysis, the HIF-PHI daprodustat was non-inferior to darbepoetin for cardiovascular (CV) events in the primary intention-to-treat analysis (HR 1.03; 95% CI 0.89, 1.19); however, a prespecified on-treatment analysis raised concerns about a higher risk of CV events associated with daprodustat compared to darbepoetin (HR 1.40; 95% CI 1.17, 1.68). Our analysis explored potential reasons to explain the differences between on-treatment and intention-to-treat analyses in ASCEND-ND.

Methods

Overall, 3872 patients were randomised to receive either oral daprodustat (daily) or darbepoetin alfa given weekly, every 2 weeks, or every 4 weeks in an open-label fashion (last dosing frequency for darbepoetin was 7% weekly, 15% every 2 weeks, and 78% every 4 weeks). Patients were followed for development of the composite CV outcome (all-cause death, first non-fatal myocardial infarction, or first non-fatal stroke). The prespecified on-treatment approach included CV events up to 28 days following the last non-zero dose date of randomised therapy (Figure 1). Post-hoc analyses used Cox regression models to assess the impact of different follow-up periods (indexed to last non-zero dose date, treatment stop (discontinuation) date, and dosing intervals) on the treatment effect estimate.

Results

Different definitions of “on-treatment” using alternative censoring approaches resulted in hazard ratios for the CV composite outcome for daprodustat vs. darbepoetin that ranged from 1.06 (95% CI 0.89, 1.27) censored at treatment stop date; 1.09 (95% CI 0.89, 1.33) censored at last non-zero dose date + dosing interval; 1.54 (95% CI 1.20, 1.97) censored at the last non-zero dose date (Figure 2). As a result of the differential dosing interval, the gap between the last non-zero dose date and CV event date was 15 [1 to 134] days in the daprodustat arm, and 35 [13 to 134] days prior in the darbepoetin arm. This resulted in identical patients (i.e., identical treatment stop dates and event dates) being more likely to count as “on-treatment” in the daprodustat arm (Figure 1). This artefactual difference was not observed in analyses that were indexed to the treatment stop date, nor in analyses that accounted for the different dosing intervals for darbepoetin.

Conclusion

In the ASCEND-ND trial, different dosing frequencies introduced longer intervals between the last non-zero dose date and date of CV outcomes in the darbepoetin arm, compared with daprodustat. This artefact led to inappropriate undercounting of CV events in the darbepoetin arm. Accounting for the differential intervals resulted in neutral effect estimates, which were consistent with those observed with intention-to-treat approaches.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): ASCEND-ND was funded by GlaxoSmithKline

Sacubitril/valsartan compared to ramipril in high risk post myocardial infarction patients stratified according use of mineralocorticoid receptor antagonists: insight from PARADISE MI trial

Background

Mineralocorticoid receptor antagonists (MRAs) reduce the risk of cardiovascular death or heart failure admission in patients with myocardial infarction (MI) and left ventricular systolic dysfunction (LVSD) combined with either heart failure (HF) or diabetes. Whether use of MRA and initiation of sacubitril/valsartan are safe and whether MRAs modify the effect of sacubitril/valsartan initiation in high-risk MI patients is unknown.

Purpose

This analysis examined whether background treatment with a MRA modifies the treatment effect and safety of sacubitril/valsartan in patients with a MI and LVSD and/or pulmonary congestion.

Methods

In the PARADISE MI Trial (Prospective ARNI vs. ACE inhibitor trial to DetermIne Superiority in reducing heart failure Events after Myocardial Infarction) N=5661 patients were randomized to either sacubitril/valsartan (97/103 mg twice daily) or ramipril (5 mg twice daily) within 7 days of their MI. The primary outcome in this analysis was the composite of worsening HF (HF hospitalization or outpatient worsening) or cardiovascular death evaluated by the clinical endpoint committee (CEC-adjudicated) or the investigators. Safety was defined as symptomatic hypotension, hyperkalemia >5.5 mmol/L or permanent drug discontinuation.

Results

A total of 2338 patients (41%) were treated with an MRA and they were more often Caucasian (79% vs. 73%), had worse left ventricular ejection fraction (34±8 vs. 38±10%), a higher KILLIP Class (63% vs. 55% in class II or more) and a lower estimated Glomerular filtration rate (71 vs. 73 ml/min/1.73 m2), than patients not taking an MRA. Age (63 years), sex (24% females), and frequency of diabetes (42%) did not differ. The treatment effect of sacubitril/valsartan compared with ramipril was similar in patients taking or not taking an MRA: hazard ratio (MRA): (95% confidence interval [CI]): 0.96 (0.77, 1.19) versus (95% CI: 0.87 (0.71, 1.05), respectively, for the primary endpoint (p value for interaction = 0.51) (CEC adjudicated) (Figure 1); similar findings were observed if investigator reported endpoints were evaluated (P=0.61 for interaction). Safety of sacubitril/valsartan compared to ramipril initiation was not changed by +/−MRA use, but an increase in symptomatic hypotension was observed (HR(MRA): 1.37 and HR: 1.39, P<0.001) in both groups (P=0.968 for interaction), whereas an increased risk of hyperkalemia or permanent drug discontinuation was not observed in the sacubitril/valsartan group (P>0.05 for all comparisons).

Conclusions

As expected, patients taking MRAs had a higher risk. Use of a MRA did not modify the treatment effect and safety of initiation of sacubitril/valsartan compared to ramipril in the post MI setting in patients with LVSD and/or congestion. Our analyses support that sacubitril/valsartan and MRAs can be used simultaneously.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Novartis sponsored Randomized clinical trial