Disappearance of cytogenetic abnormalities and clinical remission during
therapy with 13-cis-retinoic acid in a patient with myelodysplastic
syndrome: inhibition of growth of the patient's malignant monocytoid clone
J Abrahm, EC Besa, M Hyzinski, J Finan and P Nowell
Median survival is as little as 6 months for patients with refractory
anemia with excess blasts who demonstrate an abnormal karyotype in the
majority of marrow cells. We treated a patient who presented with 29%
marrow blasts and 90% abnormal metaphases with 13-cis-retinoic acid. He
achieved a complete clinical and cytogenetic remission during therapy. To
determine the mechanism of the response, serial studies were done of the
effects of 13-cis-retinoic acid and dexamethasone on in vitro growth of his
marrow cells. During clinical remission, when the drug was not
administered, marrow growth remained significantly depressed. During
relapse, the remission growth pattern was replaced by overgrowth of the
karyotypically abnormal monocytoid clone. Clonal growth occurred in
cultures containing colony-stimulating activity or dexamethasone but was
absent in cultures containing concentrations of 13-cis-retinoic acid
achieved in vivo. After the drug was reinstituted, a second clinical
stabilization developed. Since 13-cis-retinoic acid inhibits normal
monocyte colony growth, we postulate that the patient's unusual clinical
responses to the drug were due to in vivo growth inhibition of the
malignant monocytoid clone.
Volume 67,
Issue 5,
pp. 1323-1327,
05/01/1986
Copyright © 1986 by The American Society of Hematology
