Pfizer stops clinical trial development program for PCSK9 inhibitor

After finding issues in clinical trials and assessing the current market, Pfizer Inc. announced Nov. 1 that it was discontinuing development of bococizumab, its investigational proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitor.

The company said the decision would decrease its GAAP and adjusted earnings by approximately $0.04 per share. Pfizer will record the charge in the fourth quarter of 2016.

Analysts projected that sales of bococizumab would reach $958 million by 2022, according to a Bloomberg article. Pfizer's common stock shares fell approximately 2.4 percent in pre-market trading following the announcement.

“The totality of clinical information now available for bococizumab, taken together with the evolving treatment and market landscape for lipid-lowering agents, indicates that bococizumab is not likely to provide value to patients, physicians, or shareholders,” the company said in a news release.

Pfizer studied bococizumab to lower low-density lipoprotein (LDL) cholesterol and improve cardiovascular outcomes. The company launched the SPIRE phase 3 program, which included six bococizumab trials.

In late June, Pfizer announced that two of the SPIRE trials had met their primary endpoint. The top-line results showed that patients who received the medication had a significant reduction in LDL cholesterol at 12 weeks compared with a placebo group.

Now that all six SPIRE studies are complete, Pfizer said it had found an “unanticipated attenuation of [LDL-cholesterol] lowering over time. as well as a higher level of immunogenicity and higher rate of injection-site reactions with bococizumab than shown with the other agents in this class.”

Pfizer said it would also discontinue two ongoing cardiovascular outcomes studies that are evaluating bococizumab.

“As a company, we understand that developing new and important medicines for patients is a critical, but difficult undertaking,” James Rusnak, MD, PhD, chief development officer of cardiovascular and metabolic diseases for Pfizer global product development, said in a news release. “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. 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.”

The FDA approved the first two PCSK9 inhibitors in the summer of 2015: alirocumab (Praluent, Regeneron Pharmaceuticals and Sanofi Aventis) and evolocumab (Repatha, Amgen). Although the companies expected the medications to be blockbusters, the drugs have fallen far short of sales goals since their approval. The drugs have been shown to lower LDL cholesterol in some patients, but the companies are awaiting results of cardiovascular outcomes trials that could expand or decrease their use.