MULTIPLE MYELOMA. III. EFFECT OF URETHANE THERAPY ON PLASMA CELL GROWTH, ABNORMAL SERUM PROTEIN COMPONENTS AND BENCE JONES PROTEINURIA 1

Abstract

Admn. of 90-300 g. of urethane (ethyl carbamate) during 6-10 weeks to patients with multiple myeloma reduces the percentage of abnormal plasma cells in the marrow of most patients, and produces morphologic changes indicative of arrested or retarded growth. The relationship of plasma cell proliferation to the abnormal serum proteins and to Bence-Jones proteinuria in mutiple myeloma was studied during urethane therapy. 60 electrophoretic analyses of the serum proteins were made in 11 patients followed 3-28 mos. 6 patients had tall, sharp peaks of protein with the mobility of gamma globulin. 3 of these had virtually normal patterns 2-4 mos. after therapy. Slight homogeneity remained in the gamma globulin. In a 4th patient the abnormal protein was reduced 50%. In 2 patients there was no change in serum proteins or in plasma cell growth. One patient with a virtually normal electrophoretic pattern initially developed an "M" peak during an exacerbation of his disease 17 mos. later. As plasma cell growth is inhibited by urethane in multiple myeloma, abnormal serum protein components, even those generally found not to represent Bence-Jones proteinemia, are reduced or may virtually disappear. This change parallels the reduction or disappearance of Bence-Jones proteinuria. During prolonged continuous admn. of urethane myeloma cells may become dependent on the chemical. It is postulated that urethane may suppress the growth of cells by serving as a competitive metabolite.