The combination of statin therapy and PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibition markedly lowers low-density lipoprotein cholesterol (LDL-C) and reduces cardiovascular event rates. Whether residual inflammatory risk as measured by on-treatment high sensitivity C-reactive protein (hsCRP) remains an important clinical issue in such patients is uncertain.

We evaluated residual inflammatory risk among 9738 patients participating in the SPIRE-1 and SPIRE-2 cardiovascular outcomes trials (Studies of PCSK9 Inhibition and the Reduction in Vascular Events), who were receiving both statin therapy and bococizumab, according to on-treatment levels of hsCRP (hsCRP_OT) and LDL-C_OT measured 14 weeks after drug initiation. The primary end point was nonfatal myocardial infarction, nonfatal stroke, hospitalization for unstable angina requiring urgent revascularization, or cardiovascular death.

At 14 weeks, the mean percentage change in LDL-C among statin-treated patients who additionally received bococizumab was −60.5% (95% confidence interval [CI], −61.2 to −59.8; P<0.001; median change, −65.4%) as compared to 6.6% (95% CI, −1.0 to 14.1; P=0.09; median change, 0.0%) for hsCRP. Incidence rates for future cardiovascular events for patients treated with both statin therapy and bococizumab according to hsCRP_OT <1, 1 to 3, and >3 mg/L were 1.96, 2.50, and 3.59 events per 100 person-years, respectively, corresponding to multivariable adjusted hazard ratios of 1.0, 1.16 (95% CI, 0.81–1.66), and 1.62 (95% CI, 1.14–2.30) (P-trend=0.001) after adjustment for traditional cardiovascular risk factors and LDL-C_OT. Comparable adjusted hazard ratios for LDL-C_OT (<30, 30–50, >50 mg/dL) were 1.0, 0.87, and 1.21, respectively (P-trend=0.16). Relative risk reductions with bococizumab were similar across hsCRP_OT groups (P-interaction=0.87).

In this post hoc analysis of the SPIRE trials of bococizumab in a stable outpatient population, evidence of residual inflammatory risk persisted among patients treated with both statin therapy and proprotein convertase subtilisin-kexin type 9 inhibition.

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01975376, NCT01975389.