Differentiation of blasts from patients in myeloid crisis of chronic myelogenous leukemia by in-vivo and in-vitro plicamycin treatment.

Two cases in myeloid blast phase of chronic myelogenous leukemia (CML) responded to treatment with plicamycin alone. Their total white blood cell (WBC) count and immature myeloid cells fell in one case rapidly and in the other gradually. Approximately two to three weeks after initiation of plicamycin their total WBC count began to rise again, whereas the mature myeloid cells remained constant throughout the treatment. These results suggest that plicamycin may be effective in suppressing proliferation of blasts and promoting their maturation in the myeloid blast phase of CML, but that plicamycin alone may not be effective enough to sustain duration of response.