Forbes just published a list of “Best Selling Drugs of All Time” (see here). I created the following chart from the data cited (click on it for a larger view):

“Tellingly,” notes the Forbes author, Simon King, “each of the products in the list above best positioned to record an increase in peak annual sales over the next five years is a biologic; Humira, Enbrel, Rituxan, Herceptin and Lantus being the chief candidates. This is driven by a number of factors – the later launch of certain brands, for example – but also illustrates the robustness of leading biologic franchises that do not face direct substitutable generic competition.”

But I have another take on the ascendancy of biologics in terms of dollar sales. Many of these drugs are so damn expensive that relatively few sales are required to reach the annual sales numbers heretofore reached by small molecules such as Lipitor and Plavix.

However, even some “small molecules” may command high prices in the future. Pfizer’s Xalkori (crizotinib), for example, is a small molecule drug that was recently approved to treat a rare form of lung cancer. Pfizer plans to charge $115,200 a year per patient for treatment with Xalkori. At that rate, Pfizer needs only about 9,000 patients worldwide to generate $1 billion in annual sales of Xalkori. In comparison, 1,671,000 Lipitor patients are required to generate the same sales figure (see chart here).