In order to investigate, whether
heme would induce a response in
myelodysplastic syndromes (MDS), 14 symptomatic patients (4 RA, 3 RARS and 7
RAEB) were treated with infusions of
heme arginate 3 mg/kg
body weight on 4 consecutive days, mostly for six cycles at 2-week intervals. Three of 14 patients (21%) showed an improvement in
anemia (97-152, 79-120 and 92-114 g/l) within a few weeks, and 1 showed a milder increase in
hemoglobin level (102-118 g/l). Of the 2 responders with marked
thrombocytopenia, 1 showed an improvement in the platelet count (7-37 x 10(9)/l) and her regular need for red cell and
platelet transfusions ceased. Some regression in bone marrow (BM) cytology was seen in all 3 responders. One of the responders is still in remission 41 months after cessation of the treatment, while in the other 2 the response lasted for 26 and 5 months. Four patients progressed during the treatment: 1 RA to
RAEB, 1
RAEB to RAEBt and 2
RAEB, both with very complex
chromosomal abnormalities at the beginning of the
therapy, to
acute erythroleukemia (AML-M6). Pretreatment
delta-aminolevulinic acid synthase and
heme synthase activities were generally low. Five patients had mild
thrombophlebitis, but not after the infusion procedure was changed. No other side-effects common to
growth factors occurred. In conclusion, it is likely that
heme arginate has a
therapeutic effect on some MDS patients, obviously by stimulating erythropoiesis. The response may be long-lasting.