How Do Hematopoietic Growth Factors Work?

Hematopoietic growth factor medications are produced by recombinant DNA technology and used clinically to increase the production of three major blood cell groups, namely, erythrocytes (red blood cells [RBCs]), megakaryocytes (give rise to platelets), and leukocytes (white blood cells) and to enhance the mature cell function. They work by binding to the receptors found on the membrane of the cells and produce cells belonging to the hemopoietic lineages. These drugs are used to treat secondary anemia (low RBCs) caused by renal failure, neutropenia (low neutrophil count), thrombocytopenia (low platelet count), and anemia caused by any disease or chemotherapy. They also have a greater effect on preventing infections following high-dose chemotherapy-associated neutropenia and anemia.

Hematopoiesis is the formation and development of functional mature blood cells from immature precursor cells present in the bone marrow by hematopoietic growth factors produced by the body. T lymphocytes, monocytes/macrophages, fibroblasts, and endothelial cells are the important cellular sources of most hematopoietic growth factors. Erythropoietin (EPO) is produced primarily by the adult kidney, and thrombopoietin (TPO) is produced in the liver and kidney.

Recombinant hematopoietic growth factors and their function include: 

• Ancestim, a recombinant stem cell factor that stimulates the proliferation of primitive hematopoietic and nonhematopoietic cells. It may also increase the activity of other hematopoietic growth factors, such as granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage-CSF (GM-CSF), and EPO.
• EPO recombinant factors, epoetin alfa and darbepoetin alfa increase RBCs by proliferation and differentiation of erythroid progenitor cells into normoblasts which are nucleated precursor cells in the erythropoietic lineage.
• G-CSF recombinant products, namely, filgrastim, lenograstim, and pegfilgrastim maintain neutrophil production during a steady state and increase neutrophil production during infections. They also decrease neutrophil maturation time and release mature neutrophils from bone marrow into the blood. They increase the circulating half-life of neutrophils and enhance their function.
• Oprelvekin, a TPO recombinant product--stimulates the production of megakaryocyte precursors, megakaryocytes, and platelets.
• GM-CSF recombinant products molgramostim and sargramostim are locally active and remain at the site of infection to localize and activate neutrophils. GM-CSF stimulates the proliferation, differentiation, and activation of mature neutrophils and monocytes/macrophages and enhances their function.

Hematopoietic growth factors are used for the following:

• Anemia of renal disease
• Anemia due to cancer chemotherapy
• Aplastic anemia
• Bone marrow transplantation 
• Congenital or acquired bone marrow failure
• Peripheral blood progenitor mobilization
• Anti-tumor vaccination therapy
• Chemotherapy and drug-induced neutropenia
• Immune-mediated thrombocytopenia
• Supportive care for leukemia patients

Side effects associated with hematopoietic growth factors include:

• Headache 
• Nausea 
• Injection site reactions
• Fever and Chills 
• Edema
• Shortness of breath
• Bone pain
• Hyperuricemia
• Skin rash
• Diarrhea
• Hypertension 

Serious side effects associated with hematopoietic growth factors may include:

• Cardiac arrhythmias
• Thrombocytosis 
• Venous fistula occlusion

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of hematopoietic growth factors include:

• Ancestim (Stemgen)
• Darbepoetin alfa (Aranesp)
• Eflapegrastim (Pending FDA Approval)
• Eltrombopag (Promacta)
• Epoetin alfa (Epogen, Eprex, Procrit, Retacrit)
• Epoetin alfa-epbx
• Erythropoietin
• Filgrastim (G-CSF, Granix, Neupogen, Nivestym, tbo-filgrastim, Zarxio)
• Filgrastim-aafi
• Filgrastim-sndz
• Methoxy polyethylene glycol / epoetin beta (Mircera)
• Oprelvekin (Neumega, Interleukin 11, il 11)
• Pegfilgrastim (Fulphila, Neulasta, Nyvepria, Ziextenzo, Udenyca)
• Pegfilgrastim-apgf
• Pegfilgrastim-bmez
• Pegfilgrastim-cbqv
• Pegfilgrastim-jmdb
• Peginesatide (Omontys)
• Romiplostim (Nplate)
• Sargramostim (gmcsf, Leukine)