To a limited extent, we do. There are some studies in which research groups try to enhance the regenerative capabilities of mammals in a way that resembles the regeneration seen in amphibians. See the journal article linked below, as an example.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3152998/

It is important to keep such research in perspective. I see it as "proof-of-concept" research - studies with biologically intriguing findings that might amount someday to something effective, treatment-wise. For now though, regenerative therapies are underwhelming IMHO.