Koo, 

Apabetalone is selective to the second bromodomain (relative to the first bromodomain) of BRD2, BRD3 and BRD4 as I recall. However, apabetalone is the only bromodomain selective inhibitor in clinical trials. And furthermore, apabetalone is the only bromodomain inhibitor that has made it to Phase 3 trials. All other bromodomain inhibitors are presumably pan BET inhibitors not selective for one bromodomain over another. These pan inhibitors are only being used for oncology indications I believe. So while a pan inhibitor may be useful for a fibrosis indication, it would face a lot of challenges getting approved due to the safety concerns that pan BET inhibitors have revealed to date. However, the safety profile of apabetalone is excellent and would therefore be an ideal candidate for a safe and effective bromodomain inhibitor for fibrosis..... assuming that bromodomain 2 selective BET inhibition is sufficient for the anti-fibrotic effects. The review that BKC posted didn't mention apabetalone (unless I missed it) but perhaps some of the papers it cited mentioned apabetalone. 

BearDownAZ