All-trans retinoic acid

All-trans retinoic acid (ATRA) is a drug used for the treatment of acute promyelocytic leukemia (AML subtype M3). It is marketed as Vesinoid®.

It is usually prescribed over 3 months at about 8 capsules per day. There are now other forms available.

ATRA is a form of vitamin A. It works in AML-M3 because most cases of this involve a chromosomal translation of chromosomes 15 and 17, which causes genetic fusion of the retinoic acid receptor (RAR) gene to the promyelocytic leukemia (PML) gene. This fusion PML-RAR protein is responsible for preventing immature myeloid cells from differentiating into more mature cells. This block in differentiation is thought to cause leukemia. ATRA acts on PML-RAR to lift this block, causing the immature promyelocytes to differentiate to normal mature blood cells.