THE USE OF HEMATOPOIETIC GROWTH FACTORS IN CHILDREN WITH CANCER: RECOMBINANT HUMAN ERYTHROPOIETIN
Three points must be emphasized if the use of rhEPO is being considered: 1) disproportional anemia compared with neutropenia and thrombocytopenia suggests other causes of low hemoglobin/ hematocrit (iron deficiency, bleeding, or hemolysis) that will not be resolved with rhEPO; 2) not all patients will respond to rhEPO due to "end-organ" problems (myelodysplastic syndrome and, some anemias of chronic disease); and 3) some patients receiving cisplatin-containing regimens (due to renal damage) might respond better to rhEPO.
I. INDICATIONS AND CONTRAINDICATIONS
A. Proven indications
There are no proven indications in pediatric oncology.
B. Controversial indications
Anemia of chronic disease or secondary to chemotherapy to decrease the need of blood transfusions
Anemia associated with radiation therapy
Anemia secondary to myelodysplastic syndrome, when baseline serum EPO is low
Anemia after allogeneic bone marrow transplantation
C. Inappropriate indications
Anemia associated with cancer or myelodysplastic syndrome when the serum EPO is > 500 U/L
Anemia secondary to nutritional deficiencies (iron, folic acid, or vitamin B12), bleeding, or hemolytic anemia
Hypersensitivity to mammalian cell-derived products
Hypersensitivity to human albumin
II. ADMINISTRATION (rhEPO, epoetin alfa, Epogen, Procrit)
A. Baseline laboratory tests
Before starting rhEPO therapy, all patients should have a baseline serum EPO and ferritin measurement.
If ferritin is less than 100 p/L, prescribe iron supplementation (ferrous sulfate).
Starting dose: 150 U/kg/day SC 3 times a week
If there is no response within 2 to 4 weeks, the dose can be increased to 300 U/kg/day SC 3 times a week.
If the hematocrit (Hct) reaches 40%, stop the rhEPO dose until the Hct is 36%; restart at a 25% dose. Titration might be necessary.
If the Hct increases very rapidly (> 4 percentage points in 2 weeks), reduce the rhEPO dose by 25%.
Continue rhEPO until the patient is considered not to need red blood cell support.
rhEPO can be given concurrently with chemotherapy treatment.
Measure baseline serum EPO level before starting rhEPO (Table 6.1).
Perform a baseline CBC with platelet count and reticulocyte count. Thereafter, monitor the hematocrit and hemoglobin weekly until the Hct becomes stable.
Monitor blood urea nitrogen, creatinine, and potassium every 2 weeks for the 1st month and once a month thereafter.
Monitor ferritin once a month.
E. Formulation and preparation
Single-dose, preservative-free 1 mL vial containing rhEPO: 2000,3000,4000, or 10,000 U/mL of injectable solution. Each 1 mL of preservative-free solution contains the above amounts of rhEPO with 2.5 mg of albumin (human), 5.8 mg of sodium citrate, 5.8 mg of sodium chloride, and 0.06 mg of citric acid in water.
Multiple-dose, preserved 2 mL vial containing rhEPO: 10,000 U/mL.
Each 1 mL of preserved solution contains 10,000 U of rhEPO, 2.5 mg of albumin (human), 1.3 mg of sodium citrate, 8.2 mg of sodium chloride, 0.11 mg of citric acid, and 1% benzyl alcohol as preservative in water.
Do not dilute rhEPO or give with other drugs. However, before subcutaneous injection, it can be mixed in bacteriostatic 0.9% sodium chloride with benzyl alcohol 0.9% at 1:1. The benzyl alcohol acts as a local anesthetic.
Store at 2-8° C. Do not freeze or shake.
III. ADVERSE EFFECTS
Hypertension, local pain at site of injection, headache, fever, and diarrhea
Nausea, flu-like symptoms, thrombosis of vascular access devices, and seizures