Understood now - a history of anthracycline use in the past - presumably for some form of malignancy ?
No personal experience in the aviation field, I'm afraid. Though I have heard of an ATCO who had an osteosarcoma as a teenager and was treated, successfully, with anthracyclines. After he qualified as an ATCO some doubt was cast on the long term cardiac effects of these drugs by a "fatal accident enquiry" in Scotland after a plane crash ( = Coroner in England). As a result of the bad publicity the CAA chased and hounded all who were known to have used anthracyclines, and this went on for many years.
I should think it is possible that a past history of anthracycline treatment would still be regarded as a significant obstacle to getting an initial JAR class 1.
Good luck, though, and do report any future progress !