Background: Ponatinib is a tyrosine kinase inhibitor (TKI) indicated for the treatment of Ph+ chronic myeloid leukemia (CML) or acute lymphocytic leukemia (ALL) in the absence of other appropriate TKI therapies or presence of the T315I BCR-ABL mutation. Hematologic toxicity can result in dose reductions, interruptions and discontinuation of drug therapy. In the following analysis, we summarize the hematologic safety profile of single agent ponatinib reported in 468 patients from 2 trials. The primary objective is to evaluate the number and percent of patients with hematologic toxicities based on previously published data. Methods: Data reported from patients treated with ponatinib in trials 10-201 and 07-101 was included in the analysis. Ponatinib was dosed at 45 mg orally once daily. Hematologic adverse effects analyzed included thrombocytopenia, neutropenia, anemia and arterial thrombotic events. Results: See Table below for summary of events. Thrombocytopenia, neutropenia and anemia were more frequently associated with patients in blast or accelerated phase CML and Ph+ ALL. Dose reductions and interruptions secondary to any adverse reaction were measured in 449 patients with an incidence of 55% (n=247) and 67% (n=301). Arterial thrombotic events were measured in 449 patients and had a frequency of 16% (n=70). Of these patients, the majority had a history of ischemic disease or a minimum of one risk factor prior to enrollment. Conclusions: The frequency of hematologic toxicities was comparable to previously approved TKIs, with the exception of arterial thrombotic events. These occurred in a larger number of patients although the significance of ponatinib's role is difficult to interpret due to the high number of cardiovascular risk factors. In summary, this analysis supports the use of ponatinib in heavily pre-treated CML or Ph+ALL or patients with the T315I BCR-ABL mutation with stringent monitoring and safety measures for arterial thrombotic events.