Pfizer dumps a fading pipeline star, giving up on its PCSK9 drug bococizumab

Paul M. Ridker, MD

Paul M. Ridker, MD, SPIRE clinical trials program

You can scratch any hopes you might have had that Pfizer could mount a come-from-behind win and seize the lead from Amgen and Sanofi/Regeneron in the race of PCSK9 cholesterol drugs. The pharma giant has decided to drop its candidate, bococizumab, citing waning efficacy results, a poor market reception for the pioneers, signs of an immune response to the drug and side effects that would have likely marred its debut.

Pfizer will now slam the brakes on two late-stage studies — Spire-1 and Spire-2 — designed to test their drug in 32,000 patients, a massively expensive endeavor that went looking for the kinds of outcomes data that could win over payers. And it’s taking a $0.04 R&D charge on the move.

Pfizer’s shares dropped 2.2% on the decision in pre-market trading Tuesday.

The move marks the termination of one of the pharma giant’s biggest late-stage clinical efforts, leaving it still in the hunt for new drugs that can whip up some enthusiasm from analysts.

Amgen and Sanofi/Regeneron sparked big hopes for their franchise plays in this field, battling each other for first-mover position and vowing to jump out in front in the struggle to seize a market worth billions. So far, though, the companies have been brutally disappointed by the anemic initial demand for these therapies, as payers kick back on the cost. That soft launch combined with evidence that Pfizer’s drug may not have measured up well, evidently played a key role in the decision to kill it after spending hundreds of millions of dollars on development.

Barclays discussed it with Pfizer execs, and came away with this conclusion:

Of note, the decision to discontinue bococizumab was not influenced by any ongoing outcomes data or feedback from the data monitoring committee; the trials are still blinded. In our view, the culprit was the presence of anti-drug antibodies (ADAs). Of note, from the published phase 2 data from bococizumab, the ADA rate was ~7%.  It seemed to us that the presence of ADAs in some patients on bococizumab became problematic, with a minority of patients having a ‘substantial level’ of ADAs and a larger number having a higher background level. In our view, this likely wouldn’t have affected the overall probability of success in the SPIRE-1 or SPIRE-2, but it would present challenges commercially, where Amgen’s Repatha or Regeneron’s Praluent haven’t seen an ADA rate in that range. And it does explain an attenuation of LDL-C effect with bococizumab.

Pfizer had already read out data from the first 4 of 6 studies in the late-stage program, regularly touting its efficacy and promoting its marketing hopes in the field. Now The Medicines Company, partnered with Alnylam, will move up to the third spot in this race with a PCSK9 drug that a may only need twice-yearly dosing.

Pfizer has one of the weakest late-stage pipelines in Big Pharma, and this setback was noted by several analysts, including Leerink’s Seamus Fernandez, who said: “This removes an important Ph3 pipeline product for PFE while eliminating a major pot’l competitor for AMGN (MP) and SNY/REGN.”

Aside from the newly acquired PARP talazoparib, the checkpoint inhibitor avelumab partnered with Merck KGaA and the SGLT2 diabetes drug ertugliflozin partnered with Merck, Pfizer doesn’t have much that’s new in late-stage studies. Much of its Phase III effort is now given to biosimilars.

Pfizer promised to hustle out the data on its defunct PCSK9 drug for further discussion.

“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. 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,” stated Paul M. Ridker, MD, Co-chair Executive Committee, SPIRE clinical trials program and director for Cardiovascular Disease Prevention, Brigham and Women’s Hospital.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
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Atlas Venture Cambridge, MA

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