Relapsed or refractory disease
Arsenic trioxide (As2O3) is currently being evaluated for treatment of relapsed/refractory disease. Remission with arsenic trioxide has been reported. Studies have shown arsenic reorganizes nuclear bodies and degrades the mutant PML-RAR fusion protein. Arsenic also increases caspase activity which then induces apoptosis. It does reduce the relapse rate for high risk patients. In Japan a synthetic retinoid, tamibarotene, is licensed for use as a treatment for ATRA-resistant APL. Investigational agents
Some evidence supports the potential therapeutic utility of histone deacetylase inhibitors such as valproic acid or vorinostat in treating APL. According to one study, a cinnamon extract has effect on the apoptotic process in acute myeloid leukemia HL-60 cells. Prognosis
Prognosis is generally good relative to other leukemias. Because of the acuteness of onset compared to other leukemias, early death is comparatively more common. If untreated, it has median survival of less than a month. It has been transformed from a highly fatal disease to a highly curable one. The cause of early death is most commonly severe bleeding, often intracranial hemorrhage. Early death from hemorrhage occurs in 5–10% of patients in countries with adequate access to healthcare and 20–30% of patients in less developed countries. Risk factors for early death due to hemorrhage include delayed diagnosis, late treatment initiation, and high white blood cell count on admission. Despite advances in treatment, early death rates have remained relatively constant, as described by several groups including Scott McClellan, Bruno Medeiros, and Ash Alizadeh at Stanford University.Relapse rates are extremely low.
Acute promyelocytic leukemia (APML, APL) is a subtype of acute myeloid leukemia (AML), a cancer of the white blood cells. In APL, there is an abnormal accumulation of immature granulocytes called promyelocytes. The disease is characterized by a chromosomal translocation involving the retinoic acid receptor alpha (RARA) gene and is distinguished from other forms of AML by its responsiveness to all-trans retinoic acid (ATRA; also known as tretinoin) therapy. Acute promyelocytic leukemia was first characterized in 1957 by French and Norwegian physicians as a hyperacute fatal illness, with a median survival time of less than a week. Today, prognoses have drastically improved; 10-year survival rates are estimated to be approximately 80-90% according to one study. Signs and symptoms
The symptoms tend to be similar to AML in general with the following being possible symptoms:

Easy bleeding from low platelets may include:

Bruising (ecchymosis)
Gingival bleeding
Nose bleeds (epistaxis)
Increased menstrual bleeding (menorrhagia)
Brain bleed (intracerebral hemorrhage)

Pathogenesis
Acute promyelocytic leukemia is characterized by a chromosomal translocation involving the retinoic acid receptor alpha (RARA) gene on chromosome 17. In 95% of cases of APL, the RARA gene on chromosome 17 is involved in a reciprocal translocation with the promyelocytic leukemia gene (PML) on chromosome 15, a translocation denoted as t(15;17)(q24;q21).