If COH decides to go down the path of analoging the scaffold...

If COH decides to go down the path of analoging the scaffold they will then need to assess the potential of each analogue as a new API (new compounds, without any (pre)clinical data). Which means any potential lead goes through in vitro trials, in vivo trials, preclinical trials and then onto phase I. This is assuming that they can build a scaffold which is more effective than bisantrene without negative side effects. So they may in fact spend years of grants and time to only confirm that bisantrene is a superior inhibitor. There is some literature on bisantrene analogues, but none in the context of FTO if you wanted to look into it further.
As well as that, there is patent overlap between what COH is claiming and what Race is. Race's patents include analogues of bisantrene, however as I am not a patent attorney I couldn't tell you what it would mean if COH did develop a more effective FTO inhibitor out of the anthracene scaffold. I imagine many years in court, and by that time we hope another company will have aquired the IP for bisantrene.