Ponatinib In Patients (pts) With Chronic Myeloid Leukemia (CML) and Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ ALL) Resistant Or Intolerant To Dasatinib Or Nilotinib, Or With The T315I BCR-ABL Mutation: 2-Year Follow-Up Of The PACE Trial

Ponatinib is a potent, oral, pan-BCR-ABL inhibitor with activity against native and mutant forms of BCR-ABL, including the tyrosine kinase inhibitor (TKI)-resistant T315I mutant. The efficacy and safety of ponatinib (45 mg orally QD) were evaluated in the phase 2, international, open-label clinical trial (PACE) in pts with CML or Ph+ ALL.

449 pts resistant or intolerant (R/I) to dasatinib or nilotinib or with the T315I mutation confirmed at entry were enrolled. Five pts (3 CP-CML, 2 AP-CML) without confirmed T315I and not R/I to dasatinib or nilotinib were treated, but not assigned to a cohort; they were included in safety analyses only. The primary endpoint was major cytogenetic response (MCyR) at any time within 12 mos for CP-CML, major hematologic response (MaHR) at any time within 6 mos for advanced Ph+ leukemia. Data are as of 1 April 2013, with a median follow-up of 19 (0.1-30) mos, and 18 mos minimum follow-up for pts remaining on study.

Median age was 59 (18-94) yrs; 53% were male. Median time from diagnosis to ponatinib was 6 (0.3-28) yrs. Pts were heavily pretreated: 96% received prior imatinib, 84% dasatinib, 65% nilotinib, 7% bosutinib; 58% received ≥3 TKIs. In pts previously treated with dasatinib or nilotinib (N=427), 88% had a history of resistance, 12% were purely intolerant to dasatinib or nilotinib. Best prior response to most recent dasatinib or nilotinib was 26% MCyR or better in CP-CML, 23% MaHR or better in advanced Ph+ leukemia. The most common BCR-ABL mutations at baseline were 29% T315I, 8% F317L, 4% E255K, 4% F359V, 3% G250E. No mutations were detected in 44% of pts (Sanger sequencing). At the time of analysis, 46% of pts remained on study (60% CP-CML). The most common reasons for discontinuation: progressive disease (20%), adverse events (AEs; 13%; most common was thrombocytopenia, 4%). Response rates are shown in the table. Response rates were higher in CP-CML T315I vs R/I cohorts, however, a post-hoc multivariate analysis previously showed that T315I was not an independent predictor of MCyR. Other features, especially higher dose intensity and younger age in T315I pts, may explain the higher response rates. In CP-CML, responses were deep and durable; 91%, 91%, and 75% of pts with MCyR, CCyR, or MMR, respectively, were estimated to remain in response at 12 mos; progression-free survival (PFS) and overall survival (OS) were estimated to be 80% (median 27 mos) and 94% at 12 mos, respectively; progression to AP/BP occurred in 3 CP-CML pts , 2 other pts with a history of AP re-entered AP. 49% of AP-CML pts with MaHR were estimated to remain in response at 12 mos (median 12 mos); PFS and OS were estimated to be 56% (median 14 mos) and 84% at 12 mos. 36% of BP-CML pts with MaHR were estimated to remain in response at 12 mos (median 5 mos); PFS and OS were estimated to be 18% (median 4 mos) and 30% (median 7 mos) at 12 mos. 8% of Ph+ ALL pts with MaHR were estimated to remain in MaHR at 12 mos (median 3 mos); PFS and OS were estimated to be 7% (median 3 mos) and 39% (median 8 mos) at 12 mos. The most common drug-related AEs (>30%) were thrombocytopenia (37%), rash (34%), and dry skin (32%). Pancreatitis was the most common drug-related serious AE (5%); it occurred early and was primarily managed with dose modification, 1 pt discontinued. Serious cardiovascular, cerebrovascular, and peripheral vascular AEs occurred in 6%, 3%, and 2% of pts (drug-related: 2%, 1%, 1%).

Ponatinib has substantial activity in these heavily pretreated Ph+ leukemia pts who have limited available treatment options, with a safety profile reflective of the population. Updated data with a minimum follow-up of 2 yrs will be presented.

Cortes: Ariad, Pfizer, Teva: Consultancy; Ariad, BMS, Novartis, Pfizer, Teva: Research Funding. Kim:BMS, Novartis, IL-Yang: Consultancy; BMS, Novartis, Pfizer, ARIAD, IL-Yang: Research Funding; BMS, Novartis, Pfizer, IL-Yang: Honoraria; BMS, Novartis, Pfizer: Speakers Bureau; BMS, Pfizer: Membership on an entity’s Board of Directors or advisory committees. Pinilla-Ibarz:Novartis, Ariad: Research Funding; Novartis, Ariad, BMS and Pfizer: Speakers Bureau. le Coutre:Novartis: Research Funding; Novatis, BMS, Pfizer: Honoraria. Paquette:ARIAD, BMS, Novartis: Consultancy, Honoraria, Speakers Bureau. Chuah:Novartis, Bristol-Myers Squibb: Honoraria. Nicolini:Novartis, Ariad, Teva, Pfizer: Membership on an entity’s Board of Directors or advisory committees; Novartis, BMS, Teva: Speakers Bureau; Novartis, BMS, Teva, Pfizer, Ariad: Honoraria; Novartis & Bristol Myers Squibb: Research Funding; Novartis, Ariad and Teva: Consultancy. Apperley:Novartis: Research Funding; Ariad, Bristol Myers Squibb, Novartis, Pfizer, Teva: Honoraria. Talpaz:Ariad, BMS, Sanofi, INCYTE: Research Funding; Ariad, Novartis: Speakers Bureau; Ariad, Sanofi, Novartis: Membership on an entity’s Board of Directors or advisory committees. DeAngelo:Araid, Novartis, BMS: Consultancy. Abruzzese:BMS, Novartis: Consultancy. Rea:BMS, Novartis, Pfizer, Ariad, Teva: Honoraria. Baccarani:Ariad, Novartis, BMS: Consultancy; Ariad, Novartis, BMS, Pfizer, Teva: Honoraria, Speakers Bureau. Müller:Novartis, BMS, Ariad: Consultancy, Honoraria; Novartis, BMS: Research Funding. Gambacorti-Passerini:Pfizer: Research Funding; Pfizer, BMS: Honoraria. Lustgarten:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Rivera:ARIAD: Employment. Clackson:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Turner:ARIAD: Employment. Haluska:ARIAD: employees of and own stock/stock options in ARIAD Pharmaceuticals, Inc Other, Employment. Deininger:BMS, ARIAD, NOVARTIS: Consultancy; BMS, NOVARTIS, CELGENE, GILEAD: Research Funding; ARIAD, NOVARTIS: Advisory Boards, Advisory Boards Other. Hochhaus:Ariad, Novartis, BMS, MSD, Pfizer: Research Funding; Novartis, BMS, Pfizer: Honoraria. Hughes:Novartis, BMS, ARIAD: Honoraria, Research Funding. Goldman:Ariad: Honoraria. Shah:Ariad, Bristol-Myers Squibb: Consultancy, Research Funding. Kantarjian:ARIAD, Novartis, BMS, Phizer: Research Funding.