Restoring mortality data in the FOURIER cardiovascular outcomes trial of evolocumab in patients with cardiovascular disease: a reanalysis based on regulatory data

Abstract

Objective: The FOURIER trial showed a benefit of the PCSK9 inhibitor evolocumab over placebo with respect to cardiovascular outcomes in patients with cardiovascular disease. However, we observed some inconsistencies between the information in the Clinical Study Report (CSR) and that in the 2017 primary trial results publication. We aimed to restore the mortality data in the FOURIER trial based on the information contained in the death narratives in the CSR.

Methods: Mortality data in the primary results publication were compared with that in the CSR. In cases of discrepancy between the sources, an independent committee blindly readjudicated and restored the cause of death according to the information in the CSR narratives.

Results: For 360/870 deaths (41.4%), the cause of death adjudicated by the FOURIER clinical events committee differed from that declared by the local clinical investigator. When comparing the CSR information with the 2017 primary results publication, we found 11 more deaths from myocardial infarction in the evolocumab group (36 vs 25) and 3 less deaths in the placebo group (27 vs 30, respectively). In the CSR, the number of deaths due to cardiac failure in the evolocumab group was almost double those in the placebo group (31 vs 16). While cardiac and vascular deaths were not assessed as separate outcomes in the original trial analysis, after readjudication, we noted that cardiac deaths were numerically, but non-significantly, higher in the evolocumab group (113) than in the placebo group (88; relative risk (RR) 1.28, 95% CI 0.97 to 1.69, p=0.078), whereas non-cardiac vascular deaths were similar between groups (37 in each; RR 1.00, 95% CI 0.63 to 1.58, p=0.999). The reported HR for cardiovascular mortality in the original trial analysis was 1.05 (95% CI 0.88 to 1.25); after readjudication, we found a greater (although still non-significant) relative increase in cardiovascular mortality in the evolocumab treatment group (RR 1.20, 95% CI 0.95 to 1.51, p=0.13).

Conclusion: After readjudication, deaths of cardiac origin were numerically higher in the evolocumab group than in the placebo group in the FOURIER trial, suggesting possible cardiac harm. At the time the trial was terminated early, a non-significantly higher risk of cardiovascular mortality was observed with evolocumab, which was numerically greater in our readjudication. A complete restoration of the FOURIER trial data is required. In the meantime, clinicians should be sceptical about prescribing evolocumab for patients with established atherosclerotic cardiovascular disease.

Trial registration numbers: NCT01764633.

Keywords: adult cardiology; cardiology; clinical pharmacology; clinical trials; epidemiology; medical ethics.

Figure 1

Example of myocardial infarction death misreported as sudden cardiac death. PPD, protection of personal data. AMG 145: evolocumab (experimental group). Death endpoint: report by local clinical investigator. Adjudication: FOURIER Clinical-events Committee classification (CV, non-CV, unknown). Adjudicated cause of death: FOURIER Clinical-events Committee specific classification of death.

Figure 2

Example of myocardial infarction death misreported as non-cardiovascular death. PPD, protection of personal data. AMG 145: evolocumab (experimental group). Death endpoint: report by local clinical investigator. Adjudication: FOURIER Clinical-events Committee classification (CV, non-CV, unknown). Adjudicated cause of death: FOURIER Clinical-events Committee specific classification of death.