On one level the second positive read out of phase III data for Eli Lilly’s osteoporosis drug, arzoxifene, within the space of a month provides real encouragement over the drug’s regulatory and commercial prospects and could represent the first meaningful internally generated new molecular entity the US pharma giant has delivered to the market in over five years (see table below).

However, on a very different level a review of the developmental history of arzoxifene points to a product which has already missed a significant opportunity, presenting a perfect case study in how clinical setbacks, patent expiries, patent challenges and the development of superior competing products can all conspire to massively reduce a drug’s chances of commercial success.