- Most CML patients who have a suboptimal response to imatinib have low OCT-1 activity: higher doses of imatinib may overcome the negative impact of low OCT-1 activity. White, D.L., Saunders, V.A., Dang, P., Engler, J., Venables, A., Zrim, S., Zannettino, A., Lynch, K., Manley, P.W., Hughes, T. Blood (2007)