[folli]

They usually last around 10 years with some options to extend for another 5-10 years.

By the way, that's one of the reasons drugs are so expensive: pharma co. needs to recoup the costs before the patents expire.

[BizarroLand]

The flip side of patent expiration is that a rival company would need the infrastructure and capability of manufacturing the drug.

For something like Aspirin, that's not a high bar to clear, an avid experimenter could probably do that in their basement, but for gene therapy drugs I feel confident in saying that it's orders of magnitude higher.

Then again, they could kickstarter it and say that if they get X orders or raise Y money they'll do it, make and sell the 20-30k doses for everyone and then close up shop with a healthy profit.