Prompt diagnosis and treatment of acute promyelocytic leukemia (APL), the M3 subtype of acute myeloid leukemia (AML), is very important because patients with APL can quickly develop life-threatening blood-clotting or bleeding problems if not treated. In fact, treatment might need to be started even if the diagnosis of APL is suspected but hasn't been confirmed yet by lab tests.
The treatment of APL typically differs from the treatment of most other types of AML. The most important drugs for treating APL are non-chemo drugs called differentiating agents, like all-trans-retinoic acid (ATRA). Other treatments might include chemotherapy (chemo) and transfusions of platelets or other blood products.
Treatment is typically divided into 3 phases:
The goal of induction, the first part of treatment, is to get the number of leukemia cells to very low levels, putting the APL into remission. The most important drug in the initial treatment of APL is all-trans-retinoic acid (ATRA). This is usually combined with one of these:
ATRA plus ATO is often the preferred treatment in people at lower risk of the leukemia coming back, as it tends to have fewer side effects. Chemo or Mylotarg is more likely to be included in treatment if this risk is higher.
A bone marrow biopsy is usually done about a month after starting treatment, to see if the leukemia is in remission. Induction is typically continued until the APL is in remission, which might take up to 2 months.
Once APL is in remission, consolidation is needed to keep it in remission and try to get rid of the remaining leukemia cells. Which drugs are used depends on what was given for induction, as well as other factors. Patients typically get some of the same drugs they got during remission, although the doses and timing of treatment might be different. Some of the options include:
Consolidation typically lasts for at least several months, depending on the drugs being used.
For some patients, especially those at higher risk of the APL coming back, consolidation may be followed by maintenance therapy, which uses lower doses of drugs over a longer period of time. People who have a lower risk of the leukemia coming back and who have a good response to ATRA plus ATO might not need maintenance therapy, although this is still being studied.
The most common options for maintenance therapy are ATRA alone, or ATRA along with chemo (6-mercaptopurine (6-MP) and/or methotrexate). Maintenance therapy is typically given for about a year.
Treatment for APL that doesn't go away or that comes back after initial treatment is discussed in If Acute Myeloid Leukemia (AML) Doesn't Respond or Comes Back After Treatment.
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Last Revised: August 21, 2018