It's more akin to if Australia owned a patent not an individual Australian. According to US law, a tribe has the same standing as a whole other country, hence the sovereign part of sovereign immunity.
It was sort a Hail Mary though by the pharmaceutical company, since state colleges fall under the same doctrine as they are legally part of the state government, and it's already been ruled that that isn't any sort of shield for reviewing the status of their patents. This just confirms that the same things applies to other countries and tribes as well as individual states.
Also, patents, copyrights, and trademarks are not recognized internationally anyway, you have to file in each jurisdiction. There are some exceptions like the EU countries, but buy and large they're jurisdiction by jurisdiction.