Why aren't pancreas transplants possible?

Possible, but...: Pancreas transplants are done for t1dm, but they don't always work. Usually done when also transplanting a kidney, or other organ. Rejection is an issue, and anti-rejection meds are needed, so the risks of the transplant/meds have to be balanced with just treating the t1dm with insulin. Also, there is autoimmunity, which is still there, and which may kill the new b-cells.