Very low doses of GM-CSF administered alone or with erythropoietin in aplastic anemia.
PURPOSE AND RATIONALE: There has been no previously published experience with granulocyte-macrophage colony-stimulating factor (GM-CSF) at doses less than 15 micrograms/m2/d in patients with aplastic anemia, and most observations have been made at doses of 100 to 500 micrograms/m2/d (2.5 to 12.5 micrograms/kg/d). The benefits of using considerably lower doses, if effective, should include a decrease in cost and in side effects. We have therefore used very low doses of GM-CSF to treat a group of patients with aplastic anemia. Additionally, since severe anemia is often a problem in these patients, we recently started administering erythropoietin along with the GM-CSF. Herein we report the results of very-low-dose GM-CSF therapy in patients with aplastic anemia and our preliminary findings in those individuals who received combination therapy.


METHODS
We administered recombinant human GM-CSF subcutaneously at doses of 5 to 20 micrograms/m2/d ("very-low-dose GM-CSF") to 12 patients with aplastic anemia. In addition, a 13th patient received erythropoietin together with the GM-CSF regimen, and three of the 12 individuals who initially received 1 or more months of GM-CSF alone were later also given erythropoietin (4,000 U/d subcutaneously).


RESULTS
In five of 12 patients (42%) treated with very-low-dose GM-CSF, an increase in neutrophil counts (2.0- to 6.7-fold) was noted, and one of these subjects attained a bilineage response (neutrophil counts, 0.3 to 1.75 x 10(9)/L; platelet counts, 8 to 169 x 10(9)/L). Moreover, a sixth patient showed a rise in platelet counts (19 to 80 x 10(9)/L) without a concomitant increase in neutrophils. Constitutional side effects were minimal. Combining erythropoietin and very-low-dose GM-CSF produced a bilineage response (neutrophils, 1.0 to 3.0 x 10(9)/L; hemoglobin, 7.4 to 9.4 g/dL) in the one patient who received erythropoietin together with the GM-CSF from the time that GM-CSF was initiated. In one of the other patients who were given combination therapy, the addition of erythropoietin appeared to enhance the response; this patient demonstrated a neutrophil response to GM-CSF alone and a trilineage response (neutrophils, 0.8 to 3.75 x 10(9)/L; hemoglobin, 7.0 to 13.1 g/dL; and platelets, 10 to 34 x 10(9)/L) to the combination. No toxicity was associated with the addition of erythropoietin.


CONCLUSIONS
Our observations suggest that (1) very low doses of GM-CSF (5 to 20 micrograms/m2/d subcutaneously) may be used initially in neutropenic patients with aplastic anemia, and the dose subsequently increased only in patients who do not respond; and (2) the administration of erythropoietin together with GM-CSF is well tolerated, can augment responsiveness in some patients, and deserves further study.
Kurzrock
R
R
Department of Clinical Immunology and Biological Therapy, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Talpaz
M
M
Gutterman
J U
JU
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000741:Anemia, Aplastic / Q000097:blood / Q000473:pathology / Q000628:therapy*; D001424:Bacterial Infections / Q000150:complications; D001853:Bone Marrow / Q000473:pathology; D004921:Erythropoietin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007279:Injections, Subcutaneous; D007958:Leukocyte Count; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000628:therapy; D009504:Neutrophils / Q000473:pathology; D010976:Platelet Count; D011994:Recombinant Proteins; D013921:Thrombocytopenia / Q000628:therapy; D013997:Time Factors
D006454:Hemoglobins; D011994:Recombinant Proteins; D004921:Erythropoietin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor