Viagra
A Serendipity Story
Serendipity Stories bring the practice of serendipity to life in real-world examples.
In the mid-1980s, Pfizer’s cardiovascular research team was seeking a breakthrough that could save the lives of millions of heart patients. The pharmaceutical giant had identified a promising compound that could potentially revolutionize treatment for angina—the crushing chest pain that strikes when the heart doesn’t get enough oxygen. Dr. Ian Osterloh, leading the project, felt cautiously optimistic as they moved into human trials with their drug, code-named UK-92,480.
But when Phase II efficacy trials began in 1992, the results were devastating. The compound barely outperformed a placebo. After years of research and millions invested, Pfizer was facing an expensive failure. Most companies would have pulled the plug immediately—in pharmaceuticals, failed drugs typically get shelved, their research files sealed and forgotten.
However, Pfizer’s culture of meticulous documentation meant nothing went unnoticed—including an awkward observation that would change everything. Dr. David Brown, a soft-spoken investigator running safety trials in Merthyr Tydfil, Wales, had been encountering something odd for weeks. Male volunteers kept reporting an unexpected side effect, but Brown felt too awkward to mention it in his formal reports.
Finally, during a routine conference call with Pfizer headquarters, Brown felt it was time to share what he’d heard. He mentioned that many patients were experiencing enhanced erections and were asking if they could keep taking the pills after the trial ended. It wasn’t what anyone had anticipated, but when they looked into the data, the evidence was undeniable.
Osterloh and his team had been studying cardiovascular medicine for decades—erectile dysfunction wasn’t exactly their area of expertise. But in that moment of awkwardness, they began connecting the dots. The drug worked by blocking an enzyme called PDE5, which affected blood flow. If it was meant to improve circulation in one part of the body, perhaps it could work in another.
Instead of viewing the side effect as irrelevant noise, the team connected it to a massive unmet medical need. Millions of men suffered from erectile dysfunction in silence, with few effective treatments available.
What happened next was gutsy. Instead of cutting their losses, Pfizer executives made a decision: they would invest another $340 million to start their trials over, this time targeting erectile dysfunction—a condition barely discussed in polite company, let alone boardrooms.
It wasn’t easy. Conservative executives questioned whether Pfizer, known for serious cardiovascular and infectious disease treatments, should risk its reputation on what some dismissively called a “lifestyle drug.” Marketing teams worried about advertising something so sensitive. Regulatory experts warned that the FDA might be skeptical of a company pivoting from heart disease to sexual dysfunction.
But Osterloh’s team pressed forward, committing to their serendipitous discovery. They redesigned their trials completely, recruiting men with erectile dysfunction instead of heart patients. The results were unmistakable—participants reported dramatic improvements, and many asked to continue treatment after the trials had ended.
When the FDA approved Viagra in March 1998, Pfizer had transformed a cardiovascular failure into the fastest-selling drug in pharmaceutical history. Within three months, it generated $400 million in U.S. revenue alone.1 Patients who had suffered in silence for years suddenly had hope restored, relationships rekindled, and confidence rebuilt.
The financial success of Viagra was staggering; at its peak, it was generating over $2 billion annually.2 But the real lesson demonstrates the value of the practice of serendipity. Pfizer actively sought solutions, remained open to the unexpected, connected seemingly unrelated information, and had the courage to pursue their discovery.
References:
1 Feuerstein, A. (2019, February 13). Pfizer still holds the lead in the erectile dysfunction market even as Viagra sales falter. CNBC. https://www.cnbc.com/2019/02/13/pfizer-holds-lead-in-erectile-dysfunction-market-as-viagra-sales-fall.html
2 Richter, F. (2023, March 28). Chart: Viagra sales went soft as exclusivity expired. Statista. https://www.statista.com/chart/29581/worldwide-sales-of-viagra/
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