Final Report Of Single-Center Study Of Chemotherapy Plus Dasatinib For The Initial Treatment Of Patients With Philadelphia-Chromosome Positive Acute Lymphoblastic Leukemia

Background The dual Src and Abl inhibitor dasatinib has significant in vitro kinase inhibition against wild-type and mutant BCR-ABL, and significant clinical activity in patients with imatinib-resistant lymphoid blast phase CML (CML-LB) and Philadelphia-chromosome positive (Ph+) acute lymphoblastic leukemia (ALL). Aim To determine the long-term efficacy of the combination of the hyperCVAD regimen with dasatinib for treating patients with Ph+ ALL. Methods In this phase II trial, patients with newly diagnosed Ph+ ALL received dasatinib 50 mg po bid (or 100 mg daily) for the first 14 days of each of 8 cycles of alternating hyperCVAD and high dose cytarabine and methotrexate (induction/consolidation cycles). After 42 patients, the protocol was amended to give dasatinib 100 mg daily in the first 14 days of the first cycle and then 70 mg daily continuously from the second cycle. Patients in complete remission (CR) continued to receive maintenance dasatinib 50 mg po bid (or 100 mg daily) and vincristine and prednisone monthly for 2 years followed by dasatinib indefinitely. Patients eligible for allogeneic stem cell transplant proceeded to it in first CR. Results 63 patients with untreated Ph+ ALL and 9 patients with 1 or 2 prior cycles of chemotherapy (before Ph+/BCR-ABL+ status was known) have been enrolled in the study from September 2006 to March 2012. Patients have received a median of 6 cycles (range 1-8) of induction/consolidation. Median age is 55 years (range 21 – 80); 46 patients were older than 50 years, Median WBC at diagnosis was 12 x 109/L (range, 0.4 - 658.1 x 109/L). Ten patients had CNS involvement at presentation. All patients are evaluable for assessment of response to induction; 69 (96%) achieved CR after first cycle or were CR at start. 3 patients died before response assessment from infections. 57 of 69 (83%) evaluable patients achieved cytogenetic (CG) CR after 1 cycle; 5 had a major CG response (4 had 5% and one had 15% Ph+), 2 had insufficient metaphases, and 5 are unknown (no CG exam on day 21 marrow). To date, 45 patients (65%) have achieved complete molecular remission (CMR) and another 19 (28%) have achieved a major (but not complete) molecular response (MMR) at a median of 4 weeks from initiation of treatment (range, 2 – 38 weeks). Minimal residual disease assessment by flow cytometry is negative in 65 (94 %) patients at a median of 3 weeks (range, 2-37 weeks). The median time to neutrophil and platelet recovery for cycle 1 is 18 and 22 days and for subsequent cycles is 15 and 20 days. Grade 3 and 4 adverse events have included bleeding (GI, GU, soft tissue and subdural hematomas), pleural effusions, pericardial effusions, reversible rise in creatinine, deep vein thromboses, pulmonary emboli, as well as diarrhea, infections, hypophosphatemia, hypokalemia, hypocalcemia, hyperglycemia, and elevated transaminases. With a median follow up of 48 months in the surviving patients (range 16.5 - 81.5), 36 patients (50%) are alive and 31 (43%) are in CR. Twelve patients have undergone an allogeneic stem cell transplant. Thirty six patients have died [3 at induction, 16 after relapse, 7 post stem cell transplant performed in CR1, and 10 in CR (6 from infections, 1 from unrelated cardiac event, 1 from unrelated cancer, and 2 from an unknown cause)]. The median disease free survival is 31 months (range, 0.3 to 81) and the median overall survival is 44 months (range, 0.2 to 82). Twenty-one patients have relapsed with a median response duration of 16 months (range, 5 - 62) and 16 of them have died. In 6 patients morphological relapse was preceded by flow and molecular relapse. Six relapsed patients had ABL mutations (4 T315I, 1 F359V, and 1 V299L). Conclusion Combination of chemotherapy with dasatinib is effective in achieving long term remissions in patients with newly diagnosed Ph+ ALL. Disclosures: Ravandi: Bristol Myers Squibb: Honoraria, Research Funding. Off Label Use: Use of dasatinib for the frontline therapy of Ph+ ALL. O'Brien:Pharmacyclics: Research Funding. Jabbour:Bristol Myers Squibb: Consultancy, Honoraria. Cortes:Bristol Myers Squibb: Research Funding. Kantarjian:Bristol Myers Squibb: Research Funding.