Plasma spermidine concentrations as early indication of response to therapy in human myeloma

Eighteen patients with melphalan refractory myeloma were treated with vindesine and prednisone. Plasma spermidine concentrations were measured by radioimmunoassay before and after a single vindesine injection. Seven patients showed a significant rise of plasma spermidine after vindesine and five of these showed a clinical response on further evaluation. Of the 11 patients who did not show raised spermidine concentrations, 10 did not respond to the therapy. The correlation between clinical response/rise of spermidine and between non-response/no rise of spermidine was statistically significant (p less than 0.05). Pretreatment spermidine concentrations did not distinguish those who responded to treatment nor did they differ in patients and controls.