It’s the Planck constant of the pharmaceutical industry: if you’re going to build a commercially successful drug, it needs to be either first- and/or best-in-class. Either one can create incumbent market share leaders – and incumbents in drugs, like incumbents in the legislature, are enormously difficult to dislodge. As a consequence, the first/best-in-class principles are used to justify enormous risk and enormous expenditures. They’ve even created a market for priority review vouchers.
And yet they're becoming less relevant -- or at least relevant for shorter periods of time.
