Long-Term Bosutinib (Bos) For Philadelphia Chromosome-Positive (Ph Plus ) Advanced (Adv) Chronic Myeloid Leukemia (Cml) After Prior Tyrosine Kinase Inhibitor (Tki) Failure.

7068 Background: ADV Ph+ CML pts have worse outcomes vs chronic CML pts. In this first report of BOS activity in this cohort as fully enrolled, we evaluate long-term efficacy and safety of BOS in ADV pts ≥4 vs ≥1 y from last enrolled pt. Methods: Ongoing phase 1/2 BOS study in 79 accelerated (AP) and 64 blast phase (BP) pts with prior TKI failure Results: For AP and BP pts, 18% and 3% remained on BOS at 4 y (vs 48%; 13% at 1 y; 1 y = 48 wk); 57% and 28% newly attained or maintained baseline overall hematologic response (OHR) by 4 y (most by 12 mo); 40% and 37% attained/maintained major cytogenetic response (MCyR) by 4 y (most by 12 mo). Kaplan-Meier (KM) probabilities of maintaining OHR in responders at 4 vs 1 y were 49% vs 78% (AP) and 19% vs 28% (BP); KM MCyR probabilities at 4 vs 1 y were 49% vs 65% (AP) and 21% vs 21% (BP). AP and BP pts were treated for median 10.2 (range, 0.1–88.6); 2.8 (0.03–55.9) mo. Most common AEs were gastrointestinal (AP, 96%; BP, 83%), primarily diarrhea (85%; 64%), which was...