The emergence of precision medicine has ushered in a groundbreaking era for the treatment of myeloid malignancies, with the ability to integrate individual molecular data into patient care.
Over the past decade, insights from research focusing on the mutations driving the malignant transformation of myeloid cells have provided the basis for the development of novel targeted therapies.1 With the recent U.S. Food and Drug Administration approval of several novel therapies for different acute myeloid leukemia (AML) indications, the current treatment landscape for AML is evolving rapidly.2
In addition, there has been substantial progress in the development of novel therapeutic strategies for other myeloid neoplasms, with numerous molecularly based therapies in early clinical trials in myeloproliferative neoplasms (MPNs) and myelodysplastic syndromes (MDSs). These advancements have been translated into optimized algorithms for diagnosis, prognostication, and treatment.
AML: Historical perspective
AML comprises a heterogeneous group of blood cell malignancies that require different treatment approaches and confer different prognoses.2 These include acute promyelocytic leukemia (APL) and core binding factor (CBF) AML, both of which have high rates of remission and prolonged survival. The remaining non-APL, non-CBF types can be divided by their cytogenetic-molecular profiles, as well as fitness for intensive chemotherapy. AML can also arise secondary to other myeloid neoplasms, especially after exposure to hypomethylating agents (HMAs), chemotherapy, or irradiation as prior treatment for the primary malignancy.
Historically, anthracycline- and cytarabine-based chemotherapy with or without allogeneic hematopoietic stem-cell transplant (allo-HSCT) was the standard of care in AML treatment with curative intent.1 In the palliative setting, low-dose cytarabine or HMAs were also treatment options. Despite 5 decades of clinical use of these options, researchers have continued to evaluate different dosing schedules of cytosine arabinoside (cytarabine or ara-C) and daunorubicin – the first two agents approved for the treatment of AML – during induction and consolidation treatment phases.
However, recent discoveries have led to the clinical development of targeted agents directed at isocitrate dehydrogenase (IDH), FMS-like tyrosine kinase 3 (FLT3), and BCL2.2 These developments, and the highly anticipated combinations arising from them, continue to challenge traditional treatment approaches, raising the question of whether intensive chemotherapy should remain the optimal standard of care.
Novel therapeutics in AML
Since 2017, several new therapies have been approved for the treatment of AML, including gemtuzumab ozogamicin, two FLT3 inhibitors (gilteritinib and midostaurin), two IDH inhibitors (ivosidenib and enasidenib), a BCL2 inhibitor (venetoclax), an oral HMA agent (azacitidine), a hedgehog inhibitor (glasdegib), and a liposomal formulation of CPX351. In addition, oral decitabine/cedazuridine may be used as an alternative oral HMA in AML, but it is currently the only FDA-approved treatment for chronic myelomonocytic leukemia (CMML) and MDS.2 Because AML subsets are very heterogeneous, an open question remains about how to best integrate these new agents into frontline and salvage combination regimens.