Pfizer had bet heavily that Torcetrapib, a novel cholesterol remedy it was developing, would be the blockbuster to replace Lipitor and help save the company.

As Henri Termeer, chief executive of Genzyme, a big biotechnology firm, argues, “the blockbuster model becomes less important over time as specialised therapies take off.”

Because BMS will keep the North American marketing rights for Erbitux, ImClone's blockbuster cancer drug, much of the firm's current revenue will not go to the buyer.