Pfizer Inc. announced that the phase 3 SPIRE-AI (AutoInjector) trial of the investigational Proprotein Convertase Subtilisin Kexin type 9 inhibitor (PCSK9i) bococizumab administered with a pre-filled pen met its co-primary endpoints: percent change from baseline in low-density lipoprotein cholesterol (LDL-C) reduction at 12 weeks compared to placebo and proportion of patients successfully operating the pre-filled pen. The SPIRE-AI trial is the second study completed of the six SPIRE phase 3 lipid-lowering studies, and we expect it will be part of the potential regulatory filing for bococizumab.

“We are encouraged by this second positive result from our ongoing SPIRE clinical trial programme evaluating bococizumab,” said James M. Rusnak, MD, PhD, Therapeutic Area Clinical Head for Cardiovascular and Metabolism. “We believe the SPIRE programme and bococizumab have the potential to play an important role in understanding and helping to address the unmet needs of patients at high risk for cardiovascular disease. We continue to maintain focus on delivering our phase 3 programme, including the two outcomes studies.”

The phase 3 SPIRE-AI study – a 12-week, double-blind, placebo-controlled, randomized, parallel-group, multicenter, clinical trial in 299 patients with hyperlipidemia or mixed dyslipidemia receiving statin therapy and whose LDL-C =70 mg/dL – assessed the efficacy, safety, tolerability and subcutaneous administration of bococizumab 150mg and 75mg with a pre-filled pen. Co-primary endpoints included the percent change from baseline in fasting LDL-C at week 12 and the delivery system success rate, defined as the percent of patients whose attempts to operate the pre-filled pen met protocol-defined success.

Bococizumab was generally safe and well tolerated in this trial. Overall, the proportion of subjects experiencing treatment-related adverse events was similar among treatment groups. However, the trial was not designed to discern safety event differences among treatment groups. Complete study results of the SPIRE-AI trial will be presented at a future scientific forum.

Pfizer has created SPIRE (Studies of PCSK9 Inhibition and the Reduction of vascular Events), an extensive research program to study bococizumab, its investigational PCSK9i. The SPIRE phase 3 global clinical development programme involves approximately 32,000 patients and consists of six lipid-lowering studies (SPIRE-SI, SPIRE-AI, SPIRE-HR, SPIRE-FH, SPIRE-LL and SPIRE-LDL) as well as two cardiovascular outcomes studies (SPIRE-1 and SPIRE-2). The lipid-lowering studies are evaluating LDL-C lowering efficacy, safety, and tolerability of bococizumab in adult patients at risk of cardiovascular events, while the two cardiovascular outcomes studies are investigating the ability of bococizumab to reduce cardiovascular disease in a broad range of high-risk primary and secondary prevention patients. Pfizer’s outcomes programme for bococizumab is the only PCSK9i research programme explicitly assessing cardiovascular outcomes in high-risk patients with an LDL-C =100mg/dL, despite the use of highly effective statins.

SPIRE-SI (Statin Intolerance), the first of the six SPIRE phase 3 lipid-lowering studies to be completed met its primary endpoint of lowering LDL-C in adult patients with hyperlipidemia who are intolerant to statins. No new or unexpected safety findings for bococizumab were observed in the study.

Bococizumab is an investigational PCSK9i being studied for its potential to lower LDL-C and improve cardiovascular outcomes in a broad range of high-risk primary and high-risk secondary prevention patients. It works by blocking the function of the PCSK9 protein, which interferes with the clearance of LDL-C, a leading known risk factor for heart disease.

Bococizumab is an investigational compound and has not received regulatory approval in any country.