Gautam Borthakur

Phase I/II Study of Combination Therapy With Sorafenib, Idarubicin, and Cytarabine in Younger Patients With Acute Myeloid Leukemia

PURPOSE To determine the efficacy and toxicity of the combination of sorafenib, cytarabine, and idarubicin in patients with acute myeloid leukemia (AML) younger than age 65 years. PATIENTS AND METHODS In the phase I part of the study, 10 patients with relapsed AML were treated with escalating doses of sorafenib with chemotherapy to establish the feasibility of the combination. We then treated 51 patients (median age, 53 years; range, 18 to 65 years) who had previously untreated AML with cytarabine at 1.5 g/m(2) by continuous intravenous (IV) infusion daily for 4 days (3 days if > 60 years of age), idarubicin at 12 mg/m(2) IV daily for 3 days, and sorafenib at 400 mg orally twice daily for 7 days. RESULTS Overall, 38 (75%) patients have achieved a complete remission (CR), including 14 (93%) of 15 patients with mutated FMS-like tyrosine kinase-3 (FLT3; the 15th patient had complete remission with incomplete platelet recovery [CRp]) and 24 (66%) of 36 patients with FLT3 wild-type (WT) disease (three additional FLT3-WT patients had CRp). FLT3-mutated patients were more likely to achieve a CR than FLT3-WT patients (P = .033). With a median follow-up of 54 weeks (range, 8 to 87 weeks), the probability of survival at 1 year is 74%. Among the FLT3-mutated patients, 10 have relapsed and five remain in CR with a median follow-up of 62 weeks (range, 10 to 76 weeks). Plasma inhibitory assay demonstrated an on-target effect on FLT3 kinase activity. CONCLUSION Sorafenib can be safely combined with chemotherapy, produces a high CR rate in FLT3-mutated patients, and inhibits FLT3 signaling.

Pegylated Interferon Alfa-2a Yields High Rates of Hematologic and Molecular Response in Patients With Advanced Essential Thrombocythemia and Polycythemia Vera

PURPOSE We conducted a phase II study of pegylated interferon alfa-2a (PEG-IFN-alpha-2a) in patients with essential thrombocythemia (ET) and polycythemia vera (PV). PATIENTS AND METHODS Seventy-nine patients (40 with PV and 39 with ET) have been treated. Median time from diagnosis to PEG-IFN-alpha-2a was 54 months in patients with PV and 33 months in patients with ET. Eighty-one percent of patients had received prior therapy. The first three patients received PEG-IFN-alpha-2a at 450 microg weekly. As a result of poor tolerance, this dose was decreased in a stepwise manner to a current starting dose of 90 microg weekly. Seventy-seven patients are evaluable and have been observed for a median of 21 months. RESULTS The overall hematologic response rate was 80% in PV and 81% in ET (complete in 70% and 76% of patients, respectively). The JAK2(V617F) mutation was detected in 18 patients with ET and 38 patients with PV; sequential measurements by a pyrosequencing assay were available in 16 patients with ET and 35 patients with PV. The molecular response rate was 38% in ET and 54% in PV, being complete (undetectable JAK2(V617F)) in 6% and 14%, respectively. The JAK2(V617F) mutant allele burden continued to decrease with no clear evidence for a plateau. The tolerability of PEG-IFN-alpha-2a at 90 microg weekly was excellent. CONCLUSION PEG-IFN-alpha-2a resulted in remarkable clinical activity, high rates of molecular response, and acceptable toxicity in patients with advanced ET or PV. The ability of PEG-IFN-alpha-2a to induce complete molecular responses suggests selective targeting of the malignant clone.

First report of phase 2 study of dasatinib with hyper-CVAD for the frontline treatment of patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia.

The combination of cytotoxic chemotherapy and imatinib has improved the outcome for patients with Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL). Dasatinib has significant clinical activity in patients with imatinib resistance. We examined the efficacy and safety of combining chemotherapy with dasatinib for patients with Ph(+) ALL. Newly diagnosed patients received dasatinib 50 mg by mouth twice per day (or 100 mg daily) for the first 14 days of each of 8 cycles of alternating hyper-CVAD, and high-dose cytarabine and methotrexate. Patients in complete remission received maintenance daily dasatinib and monthly vincristine and prednisone for 2 years, followed by dasatinib indefinitely. Thirty-five patients with untreated Ph(+) ALL with a median age of 53 years (range, 21-79 years) were treated; 33 patients (94%) achieved complete remission. Two patients died of infections before response assessment. Grade 3 and 4 adverse events included hemorrhage and pleural and pericardial effusions. With a median follow-up of 14 months (range, 4-37 months), the median disease-free survival and median overall survival have not been reached, with an estimated 2-year survival of 64%. The combination of chemotherapy with dasatinib is effective in achieving long-term remissions in patients with newly diagnosed Ph(+) ALL. This study was registered at www.ClinicalTrials.gov as NCT00390793.

Nilotinib As Front-Line Treatment for Patients With Chronic Myeloid Leukemia in Early Chronic Phase

PURPOSE Although most patients with chronic myeloid leukemia (CML) in chronic phase respond well to front-line therapy with imatinib, some patients do not achieve the desirable end point, and others may eventually lose response or are intolerant. PATIENTS AND METHODS Patients with newly diagnosed CML in chronic phase were treated with nilotinib 400 mg twice daily on an empty stomach as initial therapy. RESULTS Among 51 patients in chronic phase observed for at least 3 months, 50 (98%) achieved a complete cytogenetic remission (CCyR), and 39 (76%) achieved a major molecular response (MMR). Responses occurred rapidly, with 96% of patients achieving CCyR by 3 months and 98% achieving CCyR by 6 months. The projected event-free survival at 24 months is 90%, and all patients are alive after a median follow-up time of 17 months. Grade >or= 3 neutropenia occurred in 12% of patients, and thrombocytopenia in occurred 11%. Nonhematologic toxicity was usually grade 1 to 2 and manageable. The actual median dose at 12 months was 800 mg (range, 200 to 800 mg). CONCLUSION Nilotinib is an effective option for the initial management of CML in early chronic phase, producing high rates of CCyR and MMR, with most patients reaching these responses early during their therapy.

Results of Dasatinib Therapy in Patients With Early Chronic-Phase Chronic Myeloid Leukemia

PURPOSE Dasatinib is effective therapy for chronic myeloid leukemia (CML) after imatinib failure. In this study, we investigate the efficacy of dasatinib as initial therapy for patients with CML in early chronic phase. PATIENTS AND METHODS Patients with newly diagnosed CML in early chronic phase were randomly assigned to receive dasatinib 100 mg once daily or 50 mg twice daily as initial therapy. RESULTS Among 50 patients observed for at least 3 months, 49 patients (98%) achieved a complete cytogenetic response (CCyR), and 41 patients (82%) achieved a major molecular response (MMR). Responses occurred rapidly, with 94% of patients achieving CCyR by 6 months. There was no difference in response rate by treatment arm. The projected event-free survival rate at 24 months is 88%, and all patients are alive after a median follow-up time of 24 months. Grade >or= 3 neutropenia and thrombocytopenia occurred in 21% and 10% of patients, respectively. Nonhematologic toxicity was usually grade 1 to 2. There was no significant difference in toxicity between the two arms, and the actual median dose at 12 months was 100 mg (range, 20 to 100 mg). CONCLUSION Dasatinib is an effective agent for the initial management of CML in early chronic phase, producing high rates of CCyR and MMR.

Phase 2 study of azacytidine plus sorafenib in patients with acute myeloid leukemia and FLT-3 internal tandem duplication mutation

Patients received 5-azacytidine (AZA) 75 mg/m(2) intravenously daily for 7 days and sorafenib 400 mg orally twice daily continuously; cycles were repeated at ~1-month intervals. Forty-three acute myeloid leukemia (AML) patients with a median age of 64 years (range, 24-87 years) were enrolled; 37 were evaluable for response. FMS-like tyrosine kinase-3 (FLT3)-internal tandem duplication (ITD) mutation was detected in 40 (93%) patients, with a median allelic ratio of 0.32 (range, 0.009-0.93). They had received a median of 2 prior treatment regimens (range, 0-7); 9 had failed prior therapy with a FLT3 kinase inhibitor. The response rate was 46%, including 10 (27%) complete response with incomplete count recovery (CRi), 6 (16%) complete responses (CR), and 1 (3%) partial response. The median time to achieve CR/CRi was 2 cycles (range, 1-4), and the median duration of CR/CRi was 2.3 months (range, 1-14.3 months). Sixty-four percent of patients achieved adequate (defined as >85%) FLT3 inhibition during their first cycle of therapy. The degree of FLT3 inhibition correlated with plasma sorafenib concentrations. FLT3 ligand levels did not rise to levels seen in prior studies of patients receiving cytotoxic chemotherapy. The combination of AZA and sorafenib is effective for patients with relapsed AML and FLT-3-ITD. This trial was registered at clinicaltrials.gov as #NCT01254890.

Selective BCL-2 Inhibition by ABT-199 Causes On-Target Cell Death in Acute Myeloid Leukemia

B-cell leukemia/lymphoma 2 (BCL-2) prevents commitment to programmed cell death at the mitochondrion. It remains a challenge to identify those tumors that are best treated by inhibition of BCL-2. Here, we demonstrate that acute myeloid leukemia (AML) cell lines, primary patient samples, and murine primary xenografts are very sensitive to treatment with the selective BCL-2 antagonist ABT-199. In primary patient cells, the median IC50 was approximately 10 nmol/L, and cell death occurred within 2 hours. Our ex vivo sensitivity results compare favorably with those observed for chronic lymphocytic leukemia, a disease for which ABT-199 has demonstrated consistent activity in clinical trials. Moreover, mitochondrial studies using BH3 profiling demonstrate activity at the mitochondrion that correlates well with cytotoxicity, supporting an on-target mitochondrial mechanism of action. Our protein and BH3 profiling studies provide promising tools that can be tested as predictive biomarkers in any clinical trial of ABT-199 in AML.

A randomized study of clofarabine versus clofarabine plus low-dose cytarabine as front-line therapy for patients aged 60 years and older with acute myeloid leukemia and high-risk myelodysplastic syndrome

We previously reported the feasibility of clofarabine and cytarabine combinations in AML. Questions remain as to (1) the therapeutic advantage of this combination and (2) the role of lower doses of clofarabine and cytarabine in older patients. We have conducted an adaptively randomized study of lower-dose clofarabine with or without low-dose cytarabine in previously untreated patients with AML aged 60 years and older. Patients received 30 mg/m(2) clofarabine intravenously daily for 5 days with or without 20 mg/m(2) cytarabine subcutaneously daily for 14 days as induction. Consolidation consisted of 3 days of clofarabine with or without 7 days of cytarabine. Seventy patients were enrolled. The median age was 71 years (range, 60-83 years). Sixteen patients received clofarabine and 54 the combination. Overall, 56% achieved complete remission (CR). CR rate was significantly higher with the combination (63% vs 31%; P = .025). Induction mortality was 19% with the combination versus 31% with clofarabine alone (P = .276). The combination showed better event-free survival (7.1 months vs 1.7 months; P = .04), but not overall survival (11.4 months vs 5.8 months; P = .1). Clofarabine plus low-dose cytarabine has a higher response rate than clofarabine alone with comparable toxicity. This trial is registered at www.clinicaltrials.gov as no. NCT00088218.

Phase I Study of Quizartinib Administered Daily to Patients With Relapsed or Refractory Acute Myeloid Leukemia Irrespective of FMS-Like Tyrosine Kinase 3–Internal Tandem Duplication Status

PURPOSE FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations in acute myeloid leukemia (AML) are associated with early relapse and poor survival. Quizartinib potently and selectively inhibits FLT3 kinase activity in preclinical AML models. PATIENTS AND METHODS Quizartinib was administered orally at escalating doses of 12 to 450 mg/day to 76 patients (median age, 60 years; range, 23 to 86 years; with a median of three prior therapies [range, 0 to 12 therapies]), enrolled irrespective of FLT3-ITD mutation status in a phase I, first-in-human study in relapsed or refractory AML. RESULTS Responses occurred in 23 (30%) of 76 patients, including 10 (13%) complete remissions (CR) of any type (two CRs, three CRs with incomplete platelet recovery [CRp], five CRs with incomplete hematologic recovery [CRi]) and 13 (17%) with partial remissions (PRs). Of 17 FLT3-ITD-positive patients, nine responded (53%; one CR, one CRp, two CRis, five PRs); of 37 FLT3-ITD-negative patients, five responded (14%; two CRps, three PRs); of 22 with FLT3-ITD-indeterminate/not tested status, nine responded (41%; one CR, three CRis, five PRs). Median duration of response was 13.3 weeks; median survival was 14.0 weeks. The most common drug-related adverse events (> 10% incidence) were nausea (16%), prolonged QT interval (12%), vomiting (11%), and dysgeusia (11%); most were ≤ grade 2. The maximum-tolerated dose was 200 mg/day, and the dose-limiting toxicity was grade 3 QT prolongation. FLT3-ITD phosphorylation was completely inhibited in an in vitro plasma inhibitory assay. CONCLUSION Quizartinib has clinical activity in patients with relapsed/refractory AML, particularly those with FLT3-ITD, and is associated with an acceptable toxicity profile.

Improved survival in chronic myeloid leukemia since the introduction of imatinib therapy: a single-institution historical experience

A total of 1569 patients with chronic myeloid leukemia (CML) referred to our institution within 1 month of diagnosis since 1965 were reviewed: 1148 chronic phase (CP), 175 accelerated phase (AP), and 246 blastic phase (BP). The median survival was 8.9 years in CP, 4.8 years in AP, and 6 months in BP. In CP, the 8-year survival was ≤ 15% before 1983, 42%-65% from 1983-2000, and 87% since 2001. Survival was worse in older patients (P = .004), but this was less significant since 2001 (P = .07). Survival by Sokal risk was significantly different before 2001 (P < .001), but not since 2001 (P = .4). In AP, survival improved over time (P < .001); the 8-year survival in patients treated since 2001 was 75%. Survival by age was not different in years < 2001 (P = .09), but was better since 2001 in patients ≤ 70 years of age (P = .004). In BP, the median survival improved over time (P < .001), although it has been only 7 months since 2001. In summary, survival in CML has significantly improved since 2001, particularly so in CP-AML and AP-CML. Imatinib therapy minimized the impact of known prognostic factors and Sokal risk in CP-CML and accentuated the impact of age in AP- and BP-CML.