Was Pfizer’s decision not to pursue Enbrel as an Alzheimer’s drug purely based on science, or was it based on the almighty dollar?

Pfizer is highly regarded for many blockbuster drugs. In particular, the company’s rheumatoid arthritis drug Enbrel stands out as a very successful anti-inflammatory medication to combat autoimmune disease. But in 2015, Pfizer researchers were startled to find that Enbrel also seemed to reduce a person’s risk of developing Alzheimer’s disease — by as much as 64%. So why did Pfizer decide not to pursue clinical testing of Enbrel’s effects on Alzheimer’s and why did Pfizer keep the promising data private?

As the company began to review hundreds of thousands of insurance claims, the data regarding Alzheimer’s was surprising and startling. However, insurance data was not enough. Enbrel would have to be put through the rigors of clinical trials for specific use for Alzheimer’s; for a company to win regulatory approval to use an existing drug for a completely different disease is not a walk in the park by any means.

Pfizer immunology researchers supported conducting clinical trials, at an estimated cost of $80 million. Pfizer executives mulled the idea over for years, then finally chose not to make their insurance findings public.

Why Did Pfizer Make This Decision?

Pfizer told The Washington Post that it conducted a three-year internal review of the insurance data and other evidence, and that in the end, it concluded that Enbrel had low promise as an Alzheimer’s treatment or preventative drug because the drug would never directly reach brain tissue. The company’s cost-benefit analysis was that clinical trial chances for success would be too low, and the company’s published findings simply explained that Enbrel did not meet the “rigorous scientific standards’’ for use as an Alzheimer’s drug.

The company clearly stated that science was indeed the single determining factor regarding why it did not move forward. Pfizer doubted the efficacy so much it didn’t even publish the data for fear of leading external scientists down the wrong path.

Not surprisingly, some scientists disagree with Pfizer’s approach. They say that a study of Enbrel’s potential for Alzheimer’s treatment and prevention would be crucial in that it could provide important information about how to slow cognitive decline in the very early stages. Other scientists agree with Pfizer that the research would have been a dead end.

Why It Is Important

Billions have been spent on Alzheimer’s research, but there is still no cure and no effective treatment or prevention for the extremely prevalent disease. Therefore, when one of the world’s largest drug companies decides not to pursue a potential medication, and also keeps the data under wraps, many in the scientific community were understandably upset. Many outside researchers agree that Pfizer should have at least made its findings available to scientists. Positive data as well as negative data furthers understanding and contributes to better, more informed decisions by researchers.

Pfizer is not unique in this instance; pharmaceutical companies regularly conduct internal discussions regarding new uses for established drugs. But was Pfizer’s decision solely driven by science, or was it driven by corporate finance as well? In 2018 Pfizer shut down its neurology division, laid off 300 employees and ended its Alzheimer’s research program.

Enbrel has also reached the end of its life cycle, the 20-year exclusive patent period in which Pfizer has experienced monopoly profits from the drug. In 2018 alone, Enbrel earned Pfizer $2.1 billion. With Enbrel’s sunset near, it is inevitable for generic competition to emerge and for Pfizer’s profits to dwindle. In short, the company will experience the law of diminishing returns, so there is little incentive for the company to further pursue Enbrel for any reason. With Enbrel soon to face generic competition, the business case for Pfizer is just not there.