Efficacy and Safety of Ponatinib in CP-CML Patients By Number of Prior Tyrosine Kinase Inhibitors: 4-Year Follow-up of the Phase 2 PACE Trial
Authors: Hochhaus Andreas , Cortes Jorge E. , Kim Dong-Wook , Pinilla-Ibarz Javier , le Coutre Philipp D. , Paquette Ronald , Chuah Charles , Nicolini Franck E. , Apperley Jane F. , Khoury H. Jean , Talpaz Moshe , DeAngelo Daniel J. , Abruzzese Elisabetta , Rea Delphine , Baccarani Michele , Muller Martin C. , Gambacorti-Passerini Carlo , Lustgarten Stephanie , Conlan Maureen , Rivera Victor M. , Guilhot Francois , Deininger Mochael W. , Hughes Timothy P. , Shah Neil P. , Kantarjian Hagop M. 
Published: October 2019

Introduction: Ponatinib is a potent oral tyrosine kinase inhibitor (TKI) approved for use in patients with refractory CML and Ph+ ALL, including patients with the resistant BCR-ABLT315I mutation. To evaluate whether patient characteristics and outcomes with ponatinib differed by extent of pretreatment with other TKIs, this post hoc analysis examines results among CP-CML patients enrolled in the phase 2 PACE trial (NCT01207440) according to the number of TKIs received prior to study entry. Updated data with 4 years of follow-up will be presented.

Methods: Patients with CML or Ph+ ALL who were resistant or intolerant to dasatinib or nilotinib or who had the T315I mutation were enrolled (N=449). Ponatinib was initiated at 45 mg once daily. CP-CML patients were evaluated based on previous treatment with 1, 2, 3, or 4 prior TKIs approved for use in CP-CML (ie, imatinib, dasatinib, nilotinib, and bosutinib). Data reported in this abstract are as of February 2, 2015.

Results: Overall, 270 CP-CML patients were enrolled and treated in PACE. Patient characteristics and disposition varied by number of prior TKIs (Table 1). Both median age and median time from diagnosis increased with number of prior TKIs; median dose intensity was highest in patients who had received only 1 prior TKI. The most common reasons for discontinuation across groups were adverse events (AEs) and withdrawal by patient request. Responses by number of prior TKIs are shown in Table 2. Rates of cytogenetic and molecular response to ponatinib were higher with fewer prior TKIs. While the frequency of individual AEs did not follow a consistent trend, the incidence of grade ≥3 AEs appeared to increase with the number of prior TKIs received (68%, 86%, 89%, and 100%, respectively); grade ≥3 AEs in ≥10% of CP-CML patients overall were thrombocytopenia (35%), neutropenia (17%), hypertension (13%), increased lipase (12%), and abdominal pain (10%). A similar frequency pattern was observed for serious AEs, which occurred in 58%, 53%, 62%, and 92% of patients who had previously received 1, 2, 3, and 4 approved TKIs, respectively. Serious AEs in ≥5% of CP-CML patients overall were pancreatitis (7%), angina pectoris (5%), and pneumonia (5%). The frequency of arterial occlusive events (AOEs) was 32% (6/19), 26% (25/98), 28% (39/141), and 42% (5/12) by increasing number of prior TKIs; exposure-adjusted incidence rates of new AOEs were 11.75, 10.4, 12.6, and 33.3 events per 100 patient-years, respectively.

Conclusions: With 4 years of follow-up, ponatinib continues to provide benefit to ongoing CP-CML patients in the PACE trial. Analysis by treatment history indicates that patients who had received fewer TKIs prior to study entry appear to exhibit better efficacy and safety profiles. However, treatment decisions should be primarily guided by individual patient and disease factors, including mutation status, and physicians should weigh both the benefits and risks of prescribing ponatinib.

Table 1. Patient Characteristics and Disposition by Number of Prior TKIs 1 TKI (n=19) 2 TKIs (n=98) 3 TKIs (n=141) 4 TKIs (n=12) Median age at baseline, years 52 58 63 67 Median time from diagnosis to first dose, years 2.8 5.2 7.9 12.4 Median dose intensity, mg/d 34.0 28.7 29.9 31.0 Mutations detected at baseline, % 68 51 43 75 T315I mutation detected at baseline, % 63 31 16 0 Prior TKI exposure, %, imatinib/dasatinib/nilotinib/bosutinib 68/21/5/5 97/66/36/1 100/96/96/7 100/100/100/100 Remain on study, % 53 48 40 8 Discontinued, % 47 52 60 92 Primary reason for discontinuation, % AE 16 18 17 33 Withdrawal by patient request 5 11 11 25 Disease progression 16 5 13 0 Lack of efficacy 0 2 9 8 Death 0 2 3 17 Othera 11 13 8 8 Median follow-up, months 42.3 42.9 42.1 28.2 aIncludes noncompliance, physician decision, protocol violation, and other reasons

Table 2 Responses to Ponatinib by Number of Prior TKIs 1 TKI (n=16a) 2 TKIs (n=98) 3 TKIs (n=141) 4 TKIs (n=12) MCyR 12 (75) 69 (70) 69 (49) 7 (58) CCyR 12 (75) 63 (64) 63 (45) 4 (33) MMR 10 (63) 41 (42) 51 (36) 1 (8) MR4 6 (38) 30 (31) 38 (27) 1 (8) MR4.5 4 (25) 22 (22) 34 (24) 1 (8) All responses are n (%) a16/19 patients were evaluable for efficacy

Disclosures

Hochhaus: Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding. Cortes:ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role, Research Funding. Pinilla-Ibarz:Novartis: Consultancy, Other: Consulting & Advisory Role, Research Funding; ARIAD Pharmaceuticals, Inc.: Consultancy, Other: Consulting & Advisory Role, Research Funding; Teva: Consultancy, Speakers Bureau; Pfizer: Consultancy, Other: Consulting & Advisory Role, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Other: Consulting & Advisory Role, Speakers Bureau. le Coutre:Novartis: Honoraria; BMS: Honoraria; ARIAD Pharmaceuticals Inc.: Honoraria; Pfizer: Honoraria. Paquette:ARIAD Pharmaceuticals Inc.: Honoraria; BMS: Honoraria; Novartis: Honoraria. Chuah:Children International: Honoraria; Novartis: Honoraria; Bristol Meyers Squibb: Honoraria. Nicolini:Ariad Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Apperley:BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ARIAD: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Talpaz:Pfizer: Other: CONSULTING OR ADVISORY ROLE; Novartis: Other: CONSULTING OR ADVISORY ROLE; ARIAD Pharmaceutical Inc.: Other: CONSULTING OR ADVISORY ROLE; Pfizer: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Novartis: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; ARIAD Pharmaceutical Inc.: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Incyte: Other: TRAVEL, ACCOMODATIONS, EXPENSES, Research Funding; Sanofi: Research Funding. DeAngelo:Incyte: Other: Consulting or Advisory Role; Pfizer: Other: Consulting or Advisory Role; Novartis: Other: Consulting or Advisory Role; BMS: Other: Consulting or Advisory Role; ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role; Amgen: Other: Consulting or Advisory Role. Abruzzese:BMS: Other: Consulting or Advisory Role; ARIAD Pharmaceuticals Inc.: Other: Consulting & Advisory Role; Novartis: Other: Consulting or Advisory Role; Pfizer: Other: Consulting or Advisory Role. Rea:Bristol-Myers Squibb: Honoraria; Novartis: Honoraria; Pfizer: Honoraria; Ariad: Honoraria. Baccarani:Pfizer: Other: Travel, Accommodations, Expenses; BMS: Other: Travel, Accommodations, Expenses; Novartis: Other: Travel, Accommodations, Expenses; ARAID Pharmaceutical Inc.: Other: Consulting or Advisory Role, Speakers Bureau; Pfizer: Honoraria, Other: Consulting or Advisory Role, Speakers Bureau; Novartis: Honoraria, Other: Consulting or Advisory Role, Speakers Bureau; BMS: Honoraria, Speakers Bureau; ARIAD Pharmaceutical Inc.: Other: Travel, Accommodations, Expenses. Muller:ARIAD Pharmaceuticals Inc.: Honoraria, Other: Consulting & Advisory Role, Research Funding; Novartis: Honoraria, Other: Consulting or Advisory Role, Research Funding; BMS: Honoraria, Other: Consulting or Advisory Role, Research Funding. Lustgarten:ARIAD Pharmaceuticals Inc.: Employment, Equity Ownership, Other: Stock. Conlan:ARIAD Pharmaceuticals Inc.: Other: Stock. Rivera:ARIAD Pharmaceuticals Inc.: Employment, Other: Full-time Employee & Shareholder (self-managed). Guilhot:Celgene: Consultancy, Other: CONSULTING OR ADVISORY ROLE; Pfizer: Honoraria; Novartis: Honoraria, Other: TRAVEL, ACCOMODATIONS, EXPENSES. Deininger:Incyte: Consultancy, Honoraria, Other: Consulting or Advisory Role; Pfizer: Consultancy, Honoraria, Other: Consulting or Advisory Role; ARIAD Pharmaceutical Inc.: Consultancy, Honoraria, Other: Consulting or Advisory Role; Gilead: Research Funding; Celgene: Research Funding; Novartis: Consultancy, Honoraria, Other: Consulting or Advisory Role, Research Funding; BMS: Consultancy, Honoraria, Other: Consulting & Advisory Role, Research Funding. Hughes:Bristol-Myers Squibb: Honoraria, Research Funding; ARIAD: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Shah:Pfizer: Research Funding; Bristol-Myers Squibb: Research Funding; Plexxikon Inc.: Research Funding. Kantarjian:Novartis: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Amgen: Research Funding.