Real-Life Outcomes of Ponatinib Treatment in Patients with Chronic Myeloid Leukemia (CML) and Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph+ ALL): Data from a Nationwide Belgian Registry
Authors: Devos Timothy , Havelange Violaine , Theunissen Koen , Meers Stef , Benghiat Fleur Samantha , Gadisseur Alain , Vanstraelen Gaëtan , André Marc , Bailly Benjamin , Granacher Nikki , Lewalle Philippe , De Becker Ann , Van Eygen Koen , Lejeune Marie , Deeren Dries , Nifosi Gianfilippo , Triffet Agnes , Vrelust Inge , Bekaert Julie , Beck Michael , Selleslag Dominik 
Published: November 2019

Background
Iclusig (ponatinib) is a third-generation tyrosine kinase inhibitor (TKI) indicated for adult patients with chronic, accelerated or blast phase CML resistant or intolerant to nilotinib or dasatinib or with Ph+ ALL resistant or intolerant to dasatinib or for patients with the T315I mutation. Long-term efficacy and safety of ponatinib have been demonstrated in clinical trials, but real-world data are still limited. Here, we report the data on ponatinib use in CML and Ph+ ALL patients in routine clinical practice collected over 3 years in Belgium.
Methods
This ongoing prospective registry (NCT03678454) is conducted in Belgium and includes patients ≥18 years of age eligible for ponatinib treatment per product label. Data on demographics, medical history, disease characteristics, treatment patterns, treatment outcomes and safety were collected for patients enrolled from 1 March 2016 (ponatinib reimbursement in Belgium) onwards. Median follow-up was 15 and 4.5 months for CML and Ph+ ALL patients, respectively. All analyses were descriptive. The study received Ethics Committee approval and patients' consents were collected as per Helsinki Declaration.
Results
In total, 50 patients (33 CML and 17 Ph+ ALL) were enrolled from 20 hospitals. The median age of CML and Ph+ ALL patients was 58 and 56 years, respectively. 91% of CML and 94% of Ph+ ALL patients had received ≥2, and 54% of CML and 29% of Ph+ ALL patients had received ≥ 3 prior TKIs. Potential risk factors for TKI cardiovascular toxicity were observed: hypertension (17 patients), history of cardiovascular disease (19), smoking (13), hypercholesterolemia (6), hyperlipidemia (5) and diabetes (8).
The reasons for starting ponatinib were: intolerance to previous TKIs (20, 40%), refractoriness to previous TKIs (14, 28%), disease progression (8, 16%) or T315I mutation (8, 16%). At entry, 22 patients (44%; 11 CML and 11 Ph+ ALL) had a confirmed BCR-ABL mutation. Of these, 12 (55%; 6 CML and 6 Ph+ ALL) had the T315I mutation. Starting doses of ponatinib in CML patients were: 45 mg (70%), 30 mg (12%) and 15 mg (15%) once daily. One patient with CML started with 15 mg every 2 days. Starting doses in Ph+ ALL patients were: 45 mg (76%), 30 mg (12%) and 15 mg (12%).
The median treatment duration was 380 days (range 15-2777) for CML patients and 123 days (range 13-2114) for Ph+ ALL patients, which included recently enrolled patients. Major molecular response (MMR) was achieved as best response in 19 (58%) CML patients and 7 (41%) Ph+ ALL patients; while 2 (6%) of CML and 3 (18%) of Ph+ ALL patients achieved complete cytogenetic response (CCyR) as best response. Of patients who started ponatinib due to intolerance to previous TKIs, 9 CML (64%) and 4 Ph+ ALL (67%) achieved MMR.
There were 57 cases (38 in CML and 19 in Ph+ ALL) of dose reduction or interruption, due to AEs (74%), to prevent AEs (25%) and other reason (2%). There were 24 cases (19 in CML and 5 in Ph+ ALL) of dose increase: due to good tolerance of treatment (54%) and absent or low response (46%). At time of analysis, 29 patients (15 CML and 14 Ph+ ALL) had discontinued treatment, for the following reasons: AEs (34%), planned allogeneic transplantation (21%), disease progression (14%), intolerance (3%) and other reasons (28%).
Treatment-related adverse events (AEs) were reported in 34 patients (68%); the most common were rash (26%) and dry skin (10%). Six (12%) patients reported ≥1 treatment-related serious AE (SAE): thrombocytopenia (2), palpitations (1), hypertension (1), pneumonia (1), coeliac artery stenosis (1), cholecystitis (1) and hyponatremia (1). One patient, with a history of congenital cardiomyopathy and aortic prosthesis, reported 3 serious cardiovascular events; these were considered as not related to ponatinib by the investigator.
Conclusion
Results from this real-world Belgian registry support the use of ponatinib in CML and Ph+ ALL patients who are resistant or intolerant to previous TKIs or have the T315I mutation. Most CML and a large proportion of Ph+ ALL patients obtained deep molecular responses. No new safety signals emerged with ponatinib treatment. The obtained results were in line with those of the PACE clinical trial, with the frequency of cardiovascular events apparently lower, possibly due to selection or improved monitoring of patients, or possible under-reporting vs clinical trial. Longer follow-up will be done to assess the long-term clinical efficiency in this real-life population.

Disclosures
André: Celgene: Other: Travel grants, Research Funding; Chugai: Research Funding; Takeda Millenium: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers-Squibb: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Other: Travel grants, Research Funding; Amgen: Other: Travel grants, Research Funding; Johnson & Johnson: Research Funding. Bailly:Incyte Biosciences: Other: Local PI of the Study. De Becker:Celgene: Other: ad hoc member of advisory board; Pfizer: Other: ad hoc member of advisory board; Sanofi Pasteur: Other: ad hoc member of advisory board; Incyte: Other: ad hoc member of advisory board. Deeren:Alexion, Amgen, Janssen, Roche, Sunesis, Takeda, Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bekaert:Incyte Biosciences: Employment. Beck:Incyte Biosciences: Employment. Selleslag:INCYTE: Consultancy, Other: Travel Expenses.