Efficacy and safety of ponatinib in management of chronic myeloid leukaemia: Experience from Kenya.

Abstract

e19067 Background: BCR-ABL tyrosine kinase inhibitors imatinib, nilotinib, bosutinib, and dasatinib, are used upfront in the management of chronic myeloid leukaemia (CML). In terms of resistance, ponatinib is the most potent tyrosine kinase inhibitor used in CML. It is however not used as first line therapy because of the fear of cardiovascular toxicity. However, because of a lot of inconsistency in the way oncology and cardiovascular trials define adverse events, this risk is not well defined. Methods: To document the efficacy and safety of ponatinib among CML patients treated at the Max Access Solutions Clinic at the Nairobi Hospital retrospectively. Results: Fourty-five patients were included between 02-10-2017 and 03-12-2022; males 23(51.1%) and females 22 (48.9%). All patients took imatinib first line. Ponatinib was taken second line by 10 (22.2%), third line by 18 (40%) and 4th line by 17 (37.8%). Of these, 25 (55.6%) were in chronic phase, 10(22.2%) accelerated and 9(20%) blastic phases. Of 22 evaluable cases in chronic phase, 1 (4.5%) died after 9 months on ponatinib, the rest are on follow-up for 1 – 60 months with a mean of 16.8 months and median of 10 months. Of 8 evaluable in accelerated phase, one (12.5%) died after 36 months. The range of follow-up is 2-36 months and mean 19.4 months. Of 9 evaluable in blastic phase, two (22.2%) are still alive after 6 and 41 months respectively. Seven (77.8%) died after follow-up ranging from 2-18 months, mean of 9.3 months. Interquartile range (IQR) for total white blood cell (wbc) count dropped from 9.08 x 109/litre to 4.82 x 109/litre on ponatinib, absolute neutrophil count dropped from 6.70 x 109/litre to 2.29 x 109/litre and platelets IQR rose from 114 x 109/litre -163 x 109/litre. Adverse events were registered in 6 (13.3 %), mainly grade 1-2, none of which was cardiovascular. Conclusions: Ponatinib is an active in all phases of CML with manageable side effect profile.