Alvocidib (INN; also known as Flavopiridol or HMR-1275) is a flavonoid alkaloid CDK9 kinase inhibitor under clinical development for the treatment of acute myeloid leukemia, by Tolero Pharmaceuticals, Inc. It has been studied also for the treatment of arthritis and atherosclerotic plaque formation The target of Flavopiridol is the positive transcription elongation factor P-TEFb. Treatment of cells with Flavopiridol leads to inhibition of P-TEFb and the loss of mRNA production.