I seem to recall from an Economist podcast a few years ago (and a brief glance at wikipedia confirm) that humalog was a human biologic, instead of the more common insulin extracted from pig pancreas. The option to take animal or human insulin is likely welcome to folks with adverse reactions or maybe a religious prohibition.
As you can imagine, we don't just extract humalog from human pancreases. They instead modify plants to generate the exact molecule humans would. This is somewhat common these days, but it does take some effort and innovation to cultivate, versus the naturally occurring substances previously used.
I don't know if human insulin is any more effective (wikipedia citations suggest no but...), but the impression I got from the podcast was not really, and that the drug was considered a net loss for its developers.
What I did learn today is that in 2006, we restricted the supply of products competing with Humalog (https://en.wikipedia.org/wiki/Insulin_(medication)#Principle...):
> Since January 2006, all insulins distributed in the U.S. and some other countries are synthetic "human" insulins or their analogues.
If we truly cared about affordability, why ban additional supply? Even if not everyone can use it, forcing people who need the human insulin to compete with those who could choose seems likely to drive up prices.
tl;dr: Humalog was an alternative to an already existing treatment, and by 2009 it already was enjoying 3 years of import protections from the treatment it intended to replace.
