Treatment for patients with acute promyelocytic leukemia (APL), the M3 subtype of acute myeloid leukemia (AML), differs from treatment for patients with other AML subtypes. APL is one of the most frequently cured AML subtypes.
APL affects marrow cells called promyelocytes, which is the step in blood cell formation that comes after the development of myeloblasts. The promyelocytes have abnormal chromosome changes, usually a rearrangement (translocation) of pieces of chromosomes 15 and 17. Click below to read more about APL treatments:
All-trans retinoic acid (ATRA), a substance that comes from vitamin A, often brings APL into remission. ATRA is also known as tretinoin. ATRA helps the promyelocytes affected by APL develop into fully functioning cells (neutrophils). This process reduces the number of leukemic blast cells in the marrow. And since ATRA also helps improve blood cell counts, it often lessens chemotherapy's side effects.
About 70 percent to 80 percent of APL patients go into remission after being treated with ATRA and an anthracycline, such as idarubicin (Idamycin®). Nevertheless, some setbacks can occur, such as:
- Hemorrhage (heavy bleeding) during the treatment's initial phases
- Resistance to treatment
- The return of APL (relapse)
Patients in remission must get long-term follow-up care to determine whether they are cured or need further therapy.
For APL patients who have a white cell count of 10,000 per microliter or greater when they're diagnosed, the chemotherapy drug cytarabine is sometimes added during induction or postremission therapy.
The ideal duration of maintenance therapy is also being investigated. Currently, it consists of 2 years of 6-mercaptopurine (6-MP), methotrexate, and ATRA.
The drug arsenic trioxide (Trisenox®) is sometimes given
- For induction of remission and consolidation in patients with acute promyelocytic leukemia (APL) who are refractory to, or have relapsed from, retinoid and anthracycline chemotherapy, and whose APL is characterized by the presence of the t(15;17) translocation or PML/RARA gene expression.
- In combination with tretinoin for the treatment of adults with newly-diagnosed low-risk acute promyelocytic leukemia (APL) whose APL is characterized by the presence of the t(15;17) translocation or the PML/RARA gene expression.
Clinical trials are under way to study the use of ATRA with other classes of drugs.
- Download or order The Leukemia & Lymphoma Society's free fact sheet, Acute Promyelocytic Leukemia Facts.
- For information about the drugs mentioned on this page, visit Drug Listings.