Background: The tyrosine kinase inhibitor (TKI) ponatinib has potent activity against native and mutant BCR-ABL1 and is approved for use in pts with relapsed/intolerant CML or Ph+ ALL, or with BCR-ABL1/T315I. Methods: In the pivotal PACE study (NCT01207440), ponatinib (starting dose 45 mg/d) was assessed in pts with CML or Ph+ ALL resistant/intolerant to dasatinib or nilotinib, or with T315I. In Oct ’13, dose reductions were implemented due to observed arterial occlusive events (AOEs). Efficacy and safety at 5 yrs (data as of 3 Oct ’16) for CP-CML pts are reported. Results: Of 270 CP-CML pts in the safety population, 60% received ≥3 prior TKIs. At initiation of study closure, 99 pts were ongoing; among these pts, minimum follow-up was 52 months, and most (78%) had 15 mg/d as their last dose. In all CP-CML pts (n = 267, efficacy evaluable), cumulative response rates were: MCyR, 60%; CCyR, 54%; MMR, 40%; and MR^4.5, 24%. Among pts who achieved MCyR (n = 148) or MMR (n = 108), the Kaplan-Meier (KM) estimated probability of remaining in response at 5 yrs was 74% (95% CI, 62 – 83) and 61% (95% CI, 51 – 70), respectively. Regardless of dose reduction in Oct ’13, maintenance of response was high (Table). KM estimated 5-yr rate for PFS/OS was 49%/77%. TEAEs in ≥45% of CP-CML pts were rash 47%, abdominal pain 46%, and thrombocytopenia 46%. Most newly occurring AEs were observed within the first year. The incidence of any AOEs/serious AOEs for CP-CML pts was 29%/23%. Among CP-CML pts with no prior AOEs who had a prospective dose reduction, 17% (11/63) had a first AOE occurring after Oct ‘13. Conclusions: Long-term (5-yr) results from PACE demonstrate that ponatinib continues to show clinical benefit, irrespective of dose reductions, with deep and lasting responses in heavily pretreated CP-CML pts. Safety results were consistent with the safety profile across the ponatinib clinical program. Clinical trial information: NCT01207440

^aExcludes pts who lost response before Oct ’13; ^bAt last assessment up to Oct ‘16.