Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Medication classes used include interferons, antimetabolites, tyrosine kinase inhibitors (TKIs), and a fibroblast growth factor receptor (FGFR) inhibitor.
Interferons
Class Summary
Interferons are naturally produced proteins with antiviral, antitumor, and immunomodulatory actions. Alpha-, beta-, and gamma-interferons may be given topically, systemically, and intralesionally.
Interferon alfa-2a and interferon alfa-2b (Roferon-A, Intron A)
Naturally produced proteins with antiviral, antitumor, and immunomodulatory actions. Alpha-, beta-, and gamma-interferons may be administered topically, systemically, and intralesionally. Interferon alfa is recommended for the initial management of low-risk CML. In low-risk CML, significant numbers of patients achieve hematological and molecular remissions. These patients have prolonged survival.
Antimetabolites
Class Summary
Antimetabolites inhibit cell growth and proliferation.
Hydroxyurea (Hydrea)
Antineoplastic agent provides effective palliative treatment that primarily controls symptoms associated with leukocytosis, thrombocytosis, or hepatosplenomegaly due to MPD. Inhibitor of deoxynucleotide synthesis and DOC for inducing hematologic remission in CML. Less leukemogenic than alkylating agents such as busulfan, melphalan, or chlorambucil. Myelosuppressive effects last a few days to a week and are easier to control than alkylating agents. Busulfan has prolonged marrow suppression and can cause pulmonary fibrosis as well. Can be administered at higher doses in patients with extremely high WBC counts (>300,000) and adjusted accordingly as counts fall and platelet counts drop. Dose can be administered as a single daily dose or divided into 2 or 3 doses at higher dose ranges.
Anagrelide (Agrylin)
Reduces elevated platelet count in patients with essential thrombocythemia and polycythemia vera.
Ruxolitinib (Jakafi)
JAK1/JAK2 kinase inhibitor indicated for treatment of patients with intermediate or high-risk myelofibrosis, including primary myelofibrosis, post-polycythemia vera myelofibrosis and post-essential thrombocythemia myelofibrosis. Janus-associated kinases (JAKs) JAK1 and JAK2 mediate the signaling of a number of cytokines and growth factors that are important for hematopoiesis and immune function.
Tyrosine kinase inhibitors
Class Summary
These agents inhibit the activity of bcr-abl tyrosine kinase, resulting in decreased proliferation and increased apoptosis in Ph-positive cell lines.
Imatinib mesylate (Gleevec)
Specifically designed to inhibit tyrosine kinase activity of the bcr-abl kinase in Ph+ leukemic CML cell lines. Used to treat newly diagnosed adult patients with CML or those in blast crisis, accelerated phase, or in chronic phase after failure to interferon alfa therapy. Also indicated to treat pediatric patients with Ph+ chronic phase CML whose disease has recurred after stem cell transplant or who have demonstrated interferon alfa resistance. Well absorbed after oral administration, with maximum concentrations achieved within 2-4 hours. Elimination is primarily in feces in form of metabolites.
Dasatinib (Sprycel)
Multiple tyrosine kinase inhibitor. Inhibits growth of cell lines overexpressing BCR/ABL. Orphan drug indicated for chronic myeloid leukemia (CML) in individuals resistant to or intolerant of prior therapy (eg, imatinib [Gleevec]). Has been able to overcome imatinib resistance resulting from BCR/ABL kinase domain mutations.
Nilotinib (Tasigna)
Inhibits BCR/ABL kinase. In vitro, inhibits BCR/ABL –mediated proliferation of murine leukemic cell lines and human cell lines derived from Philadelphia chromosome–positive chronic myeloid leukemia. Under the conditions of the assays, was able to overcome imatinib resistance resulting from BCR/ABL kinase mutations in 32 of 33 mutations tested. In vivo, shown to reduce tumor size in a murine BCR/ABL xenograft model. Indicated for Philadelphia chromosome–positive chronic myeloid leukemia in adults whose disease has progressed or who cannot tolerate other therapies that include imatinib.
FGFR Inhibitors
Class Summary
Consider for relapsed or refractory myeloid/lymphoid neoplasms (MLNs) with fibroblast growth factor receptor 1 (FGFR1) rearrangement.
Pemigatinib (Pemazyre)
Orally bioavailable inhibitor of the FGFR types 1, 2, and 3 (FGFR1/2/3). Pemigatinib inhibits FGFR 1/2/3 phosphorylation and signaling, and decreases cell viability in cancer cell lines with activating FGFR amplifications and fusions. It is indicated for relapsed or refractory MLNs in adults with FGFR1 rearrangement.
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Peripheral smear of a patient with chronic myelogenous leukemia (CML) shows leukocytosis with extreme left shift and basophilia.
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Peripheral smear of a patient with chronic myelogenous leukemia (CML) in blastic phase shows several blasts.
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Peripheral smear of a patient with essential thrombocythemia (ET) shows markedly increased number of platelets. Some of the platelets are giant (arrow).
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Peripheral smear of a patient with agnogenic myeloid metaplasia (myelofibrosis) shows leukoerythroblastosis. This photomicrograph also shows giant platelets.
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Photomicrograph of a peripheral smear of a patient with agnogenic myeloid metaplasia (myelofibrosis) shows findings of leukoerythroblastosis, giant platelets, and few teardrop cells.
Tables
FAB |
WHO |
Chronic myelogenous leukemia |
Chronic myelogenous leukemia, BCR/ABL1 positive |
Polycythemia vera |
Polycythemia vera |
Essential thrombocythemia |
Essential thrombocythemia |
Agnogenic myeloid metaplasia/myelofibrosis |
Primary myelofibrosis* |
... |
Chronic neutrophilic leukemia, not otherwise specified |
... |
MPN, unclassified |
| *The 2016 WHO classification system distinguishes prefibrotic (prePMF) from overtly fibrotic PMF [4] | |
