Effect of imatinib and PSC833 on imatinib-resistant primary CML cells.

Progenitor cell colony formation after 14 days in quadruplicate methylcellulose cultures in the presence or absence of 1 μM imatinib or 1 μM PSC833 or both. Results represent the mean ± SE of the average colony counts in samples from 6 patients with CML and are expressed as a percentage of the control, untreated cultures.