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2158 Efficacy and Safety of Bosutinib By Age and Charlson Comorbidity Index in Previously Treated Patients with Chronic Myeloid Leukemia: Results from the Phase 4 Byond StudyClinically Relevant Abstract

Program: Oral and Poster Abstracts
Session: 632. Chronic Myeloid Leukemia: Therapy: Poster II
Hematology Disease Topics & Pathways:
Biological, Diseases, CML, Therapies, Myeloid Malignancies, TKI
Sunday, December 6, 2020, 7:00 AM-3:30 PM

Gianantonio Rosti, MD1*, Tim H Brümmendorf, MD2, Bjorn T. Gjertsen, MD, PhD3, Pilar Giraldo, PhD4, Ulla Olsson-Strömberg, MD, PhD5*, Fausto Castagnetti, MD, PhD6, Carlo Gambacorti-Passerini, MD7, Andrea Viqueira8*, Eric Leip9*, Simon Purcell10*, Francis J. Giles, MD, FRCPI, FRCPath11 and Andreas Hochhaus, MD12

1University of Bologna, Bologna, Italy
2Universitätsklinikum RWTH Aachen, Aachen, Germany
3Haukeland University Hospital, Bergen, Norway
4CIBER Enfermedades Raras (CIBERER), Miguel Servet University Hospital, Zaragoza, Spain
5Department of Hematology, University Hospital Uppsala, Uppsala, Sweden
6University Hospital, University of Bologna, Bologna, Italy
7Dept of Medicine and Surgery, University of Milano Bicocca, Monza, MB, Italy
8Pfizer SLU, Madrid, Spain
9Pfizer Inc., Cambridge, MA
10Pfizer Ltd, London, GBR
11Developmental Therapeutics Consortium, Chicago, IL
12Klinik für Innere Medizin II, Jena, Germany

Introduction: Bosutinib is approved for use in patients with Philadelphia chromosome–positive (Ph+) chronic myeloid leukemia (CML) resistant or intolerant to prior therapy and in patients with newly diagnosed Ph+ chronic phase (CP) CML.

Methods: In the ongoing BYOND trial (NCT02228382), patients with pretreated CML received bosutinib at a starting dose of 500 mg/day. Here we report efficacy and safety of bosutinib in 156 patients with Ph+ CP CML by i.) age: ≥65 (n=61) vs <65 years (n=95) and ≥75 (n=28) vs <75 years (n=128), and ii.) comorbidities. Charlson Comorbidity Index scores (without the age component; mCCI) were derived from baseline data and patients grouped by mCCI score 2 (n=100), 3 (n=27), and ≥4 (n=29). Data are reported at ≥1 year after the last enrolled patients, and median follow-up time was 30.4 months; approximately 85% of patients had a minimum follow-up of 2 years.

Results: Median duration of treatment was 23 vs 24 months for patients ≥65 vs <65 years as well as for patients ≥75 vs <75 years; respective median dose intensity was 304 vs 343 mg/day and 265 vs 340 mg/day. Cumulative response rates according to age group are shown in the table. Grade 3/4 treatment-emergent adverse event (TEAE) rates were 82% vs 68% for patients ≥65 vs <65 years, and 89% vs 70% for patients ≥75 vs <75 years. Bosutinib was permanently discontinued by 56% vs 36% of patients ≥65 vs <65 years, and 61% vs 40% of patients ≥75 vs <75 years, most commonly due to adverse events (AEs; 33% vs 20% and 36% vs 23%, respectively). Deaths occurred in 10 vs 0 patients ≥65 vs <65 years, and 4 vs 6 patients ≥75 vs <75 years.

Median treatment duration for patients with mCCI 2, 3, and ≥4 was 24, 24 and 18 months; respective median dose intensity was 344, 299 and 304 mg/day. Cumulative response rates across mCCI are shown in the table. Grade 3/4 TEAE rates were 73%, 70%, and 79% for patients with mCCI 2, 3, and ≥4. Bosutinib was permanently discontinued by 38%, 44% and 62% of patients with mCCI 2, 3, and ≥4, most commonly due to AEs (22%, 26%, and 35%, respectively). Deaths occurred in 4, 3, and 3 patients with mCCI 2, 3, and ≥4.

Conclusions: Bosutinib efficacy was demonstrated across age groups and mCCI scores. Older patients (≥65 or ≥75 years) and those with high comorbidity burden (mCCI ≥4) showed a trend towards higher rates of TEAEs and discontinuations due to AEs and may require more careful monitoring.

Disclosures: Rosti: Novartis: Speakers Bureau; Pfizer: Research Funding, Speakers Bureau; Incyte: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau. Brümmendorf: Merck: Consultancy; Pfizer: Consultancy, Honoraria, Other: Travel, Accommodation, Expenses, Research Funding; Novartis: Consultancy, Honoraria, Other: travel, accommodation, expenses, Patents & Royalties, Research Funding; Takeda: Consultancy; Janssen: Consultancy. Gjertsen: KinN Therapeutics AS: Current equity holder in private company; Alden Cancer Therapy AS: Current equity holder in private company; Pfizer Inc: Consultancy; BerGenBio AS: Consultancy, Research Funding; Novartis: Consultancy. Olsson-Strömberg: Pfizer: Research Funding. Castagnetti: Bristol Myers Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Gambacorti-Passerini: Bristol-Myers Squibb: Consultancy; Pfizer: Honoraria, Research Funding. Viqueira: Pfizer: Current Employment, Current equity holder in publicly-traded company. Leip: Pfizer: Current Employment, Current equity holder in publicly-traded company. Purcell: Pfizer: Current Employment, Current equity holder in publicly-traded company. Giles: Novartis: Consultancy, Research Funding; Pfizer: Research Funding; Actuate Therapeutics Inc: Consultancy. Hochhaus: MSD: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Incyte: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Takeda: Honoraria.

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