Pfizer Discontinues Development of PCSK9 Inhibitor

Pfizer has recently announced it will no longer pursue the development of its investigational PCSK9 inhibitor, bococizumab.

Clinical information about the drug, along with the increased market landscape for cholesterol-lowering drugs, indicate that bococizumab would not be of value to patients, physicians, or other stakeholders, Pfizer reported in a press release.

The manufacturer discontinued the bococizumab SPIRE developmental program, which includes 2 ongoing cardiovascular studies, and 6 completed lipid-lowering studies. The ongoing studies will be discontinued as well.

Through the analysis of the completed studies, Pfizer discovered that the drug loses efficacy in lowering low-density lipoprotein cholesterol over time. They also found that the drug causes a higher level of immunogenicity, and more injection site reactions compared with other similar medications.

In order for a high cholesterol treatment to be effective in preventing heart attacks and strokes, medications need to be effective and durable in a long-term setting.

“As a company, we understand that developing new and important medicines for patients is a critical, but difficult undertaking. Accordingly, we continually evaluate our development programs as data emerge to support prudent decisions that provide value both to the patients we serve and our shareholders,” said James Rusnak, MD, PhD, chief development officer, Cardiovascular and Metabolic Diseases, Pfizer Global Product Development. “We are disappointed by this outcome, but remain committed to investing in innovation, concentrating our pipeline on areas where we can bring transformational therapies to address unmet needs, including in patients with cardiovascular and metabolic diseases. We thank the investigators, their patients, and support staff who have participated in this important research program.”

Pfizer is currently informing all regulatory authorities about this decision, and they are also ensuring that investigators from the ongoing clinical trials are told about the next steps. If patients have questions or concerns, they should consult with the physician in the clinical trial, Pfizer advised.

The discontinuation of the development program is estimated to have a negative stock impact of $0.04 per share, and their third quarter results have been revised to reflect this change. Pfizer previously announced that 4 of the lipid-lowering studies reached their primary endpoints.

They also revealed top-line results from the other 2 lipid-lowering studies that demonstrated a reduction in LDL cholesterol levels from baseline compared with placebo in patients with primary hyperlipidemia, or mixed dyslipidemia at-risk of cardiovascular events who were taking statins, according to Pfizer.

The drug was said to be safe and well-tolerated in the lipid-lowering studies.

“To honor the altruism of trial participants, and to maximize the clinical and scientific knowledge derived from the halted trials, Pfizer has committed to ensuring that the data will be made available to study leaders for independent analysis and prompt public presentation,” said Paul M. Ridker, MD, co-chair Executive Committee, SPIRE clinical trials program. “We believe the available data will allow us to test the core scientific questions posed by the overall program which is in the best interest of patients who volunteered in these clinical trials, and for patients worldwide who suffer from heart disease.”