Consider another example from the pharma industry. In 1989, Pfizer scientists developed a new drug called sildenafil citrate. Researchers hoped the drug would expand blood vessels to treat angina and high blood pressure associated with heart disease. By the early 1990s, the drug appeared to be ineffective for its intended purpose. But the participants in the trials reported an interesting side effect—erections. It wasn’t long before researchers abandoned their initial hypothesis to pursue the astonishing alternative. And Viagra was born.49
