Vericel Corp. (VCEL)

[commoncentsinvestor]

I don't believe this is specific to MACI but it does speak of timelines.

http://www.baltimoresun.com/health/blog/bs-hs-ask-the-expert-knees-20150715-story.html

Found it interesting how quickly the process begins:

"Within six hours, the new cells cling to the damaged area and begin to grow. The new cells continue to grow, eventually filling in the damaged area in about three months."