I hope my posts weren't too abrupt, I was rushing to get out the door. I also didn't mean to imply it won't ever work, just that the companies selling stem cell therapy today have not undergone robust clinical studies showing it to be effective. All the class action lawsuits against the company selling it in the US would suggest otherwise.If you look at where the real science is today, it is very hard to imagine that anyone has a full blown successful stem cell therapy for lung disease.
I also need to correct something, there are clinical studies underway. There are 39 clinical studies, 14 are active. There are 12 studies that have completed, only two have published results. When results are published, it is usually because they don't have any. One of the two is the Lung Institute, the company that the FDA is trying shut down. The other one was a study done in Brazil and was legit but it was an open, non-randomized study with only 4 patients. It doesn't much look like much came from that.
However there is a lot of valid research going on so it remains hopeful. Here are some useful links I tried to keep it current, nothing older than 2017.
Feb 2018 Researchers have identified a lung stem cell that repairs the organ's gas exchange compartment, according to a new study from the Perelman School of Medicine at the University of Pennsylvania.