Effects of interleukin-3 following chemotherapy of non-Hodgkin's lymphoma. A prospective, controlled phase I/II study.

The effect of rhIL-3 was investigated in 32 patients with newly diagnosed non-Hodgkin lymphoma in a phase I/II trial. All patients received 6 cycles of standard CHOP chemotherapy, and each patient was his own control where rhIL-3 was given as a daily s.c. injection for 14 days (day 2-15) in cycle 2 and 4, while cycle 1 and 3 were control cycles. Five dose levels were examined (0.5 - 1 - 5 - 7.5 - 10 micrograms/kg). Compared to the other more lineage-specific hemopoietic growth factors G- and GM-CSF, the effect of rhIL-3 on the hemopoiesis was less dramatic and more delayed, i.e. the most apparent effect was observed in the 2 weeks of treatment. Thus, the neutrophil counts from days 15 to 22 following CHOP were significantly raised and the duration of neutropenia was shorter (significantly only at 10 micrograms/kg), while the nadir values were unaffected. Platelet recovery from days 12-22 was significantly increased and nadir values occurred earlier compared to control cycles, but were only increased in some subsets. Other cell populations affected moderately in the recovery period were eosinophils and monocytes. Reticulocytes increased, but no effect on hemoglobin or RBC transfusion requirement was noted. Only moderate adverse reactions occurred such as fever, chills, flushing of the face and flu-like symptoms. There was no evidence of stimulation of tumor growth. Most significant, the rhIL-3 treatment at all but the lowest dose levels led to an improved tolerance to chemotherapy, as indicated by a decline in number of delayed cycles. A conclusion concerning the role of rhIL-3 as post-chemotherapy adjuvant should await studies using rhIL-3 in combination with more lineage-restricted hemopoietic growth factors.