At this point all the major solutions are using an algorithm that would probably fall under the umbrella of "Model Predictive Control" rather than a vanilla PID controller. An absurd spate of patent trolling occurred back in the early 2000s related to Controller definitions like these though. Researchers patented the use of a "PID controller in artificial pancreas systems" [1][2] which slowed down the development of APSs by many years.

The way the Supreme Court recently changed patent law [3] for software has definitely had a positive effect for APS development. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769814/ [2] https://patents.google.com/patent/US20150306314 [3] https://en.wikipedia.org/wiki/Alice_Corp._v._CLS_Bank_Intern...