Currently, the CDK9
inhibitor flavopiridol is being evaluated in several phase I and II clinical trials for its anti-
cancer effects either as a single agent or in combination with other drugs in treatment of esophageal
cancer, B - cell chronic lymphocytic leukemia,
endometrial carcinoma, recurrent / metastatic squamous cell carcinoma and most relevantly, previously treated locally advanced or metastatic breast
cancer (http://www.cancernetwork.com/review-article/current-clinical-trials-flavopiridol/page/0/2).