The 2-cyanaziridin derivative,
azimexon (E), has previously been shown to have certain immunomodulatory properties. In particular, the induction of
leukocytosis, the stimulation of delayed-type
hypersensitivity reactions and the synergistic effect of
azimexon and
antibiotics in the control of lethal bacterial and
fungal infections in mice prompted us to test
azimexon as an adjuvant to
chemotherapy in 14 myeloma patients. In a randomized double-blind cross-over study 3 X 600 mg of
azimexon were added to one of two consecutive, identical
chemotherapy courses consisting of
melphalan/
prednisone (MP) or
vincristine/
cyclophosphamide/
melphalan/
prednisone (VCMP).
Chemotherapy was given during days 1-4 and
azimexon or placebo were added on days 6, 10 and 14. Blood counts and natural killer (NK) cell testing were performed on days 0 and 21 of each course. With the exception of a transient taste irritation in two patients,
azimexon caused no subjective side-effects. White blood cell counts were not altered by the drug; red blood cells and
hemoglobin showed a borderline depression after
azimexon. NK activities measured against three target cell lines (K562, IGR3, L1210) tended to increase after
azimexon treatment. When added in vitro to NK assays
azimexon caused a slight increase of NK activity at concentrations of 0.01-0.25 mu/ml, whereas concentrations above 1 microgram/ml were inhibitory. The increase of NK activity by
azimexon was not due to the induction of
interferon in the effector lymphocyte population.