Background: The final 5-year analysis of the PACE trial, which evaluated use of PON in pts with refractory chronic myeloid leukemia (CML) and Ph+ acute lymphoblastic leukemia, identified a 25% incidence of AOEs (Cortes, Blood 2018) from a search utilizing > 400 preferred terms (PTs) defined by MedDRA and related to vascular ischemia or thrombosis. We performed a retrospective review using an independent Endpoint Adjudication Committee (EAC) to better understand clinically relevant AOE rates in PACE. Methods: The EAC consisted of 3 cardiologists, 1 hematologist, and 1 neurologist to review AOEs (identified using > 500 terms) in PACE using American College of Cardiology/American Heart Association (ACC/AHA) definitions for major adverse cardiovascular events (MACE), and to review pt profiles including event, severity, concomitant medication, and hospitalization data. These results were compared with MedDRA PT search results. The EAC was blind to dose, dose modification, and investigator causality opinion. Results: The PACE review included 449 heavily pretreated pts with Ph+ leukemia (median age, 59 y; 47% female; 93% ≥2 tyrosine kinase inhibitors). With median follow-up 37.3 mo in all pts, AOEs were identified by MedDRA PT search in 25% of pts and EAC-verified in 17% (Table). In each category listed in the table, the EAC verification identified fewer AOEs and serious AOEs. Serious AOEs were identified by MedDRA PT search in 20% of pts and EAC-verified in 16%. Events that were not associated with a cardiovascular etiology or failed to meet the MACE definition set forth by the ACC/AHA were determined by the EAC not to be an AOE. Conclusions: The independent EAC review showed a lower rate of clinically relevant AOEs than was reported in PACE, suggesting an earlier possible overestimation that may not accurately reflect the risk of AOEs with PON. The ongoing PON dose-ranging OPTIC study will further evaluate the PON risk:benefit profile. Clinical trial information: NCT01207440.

CP-CML, chronic-phase CML; EAC, EAC-verified AOE; PT, AOE identified by broad PT search. ^aExcludes hypertension AEs.