Ellen K. Ritchie

Efficacy and safety of dasatinib in imatinib-resistant or -intolerant patients with chronic myeloid leukemia in blast phase

Dasatinib is an inhibitor of BCR-ABL and SRC-family kinases for patients with imatinib-resistant or -intolerant chronic myelogenous leukemia (CML). In this international phase II trial, dasatinib was administered orally (70 mg twice daily) to patients with myeloid blast phase (MBP, n=109) or lymphoid blast phase (LBP, n=48) CML. After a minimum follow-up of 12 months (range 0.03–20.7 months), major hematologic responses were induced in 34% (MBP-CML) and 35% (LBP-CML) of patients. Major cytogenetic responses were attained in 33% (MBP-CML) and 52% (LBP-CML) of patients and complete cytogenetic responses were attained in 26 and 46%, respectively. Median progression-free survival was 6.7 (MBP-CML) and 3.0 (LBP-CML) months. Median overall survival was 11.8 (MBP-CML) and 5.3 (LBP-CML) months. Overall, dasatinib had acceptable tolerability. Fluid retention events were more frequent in the MBP-CML than the LBP-CML cohort: pleural effusion occurred in 36 and 13% (all grades) and 15 and 6% (grades 3/4), respectively. Other non-hematologic side effects were primarily grade 1/2; grade 3/4 events were recorded in ⩽6% of patients, except febrile neutropenia (15%). Cytopenias were noted in the majority of patients, and were manageable with dose interruptions/reductions. Dasatinib is associated with a promising rate of response in this high-risk population.

First-In-Man Study of CPX-351: A Liposomal Carrier Containing Cytarabine and Daunorubicin in a Fixed 5:1 Molar Ratio for the Treatment of Relapsed and Refractory Acute Myeloid Leukemia

PURPOSE This phase I dose-escalation trial was performed to determine the maximum-tolerated dose, dose-limiting toxicities, and pharmacokinetics of CPX-351. PATIENTS AND METHODS CPX-351 induction was administered on days 1, 3, and 5 by 90-minute infusion to 48 relapsed or refractory patients with acute myeloid leukemia (AML) or high-risk myelodysplasia. Doses started at 3 units/m(2) with dose doublings in single-patient cohorts until a pharmacodynamic effect (treatment-related adverse events or reduction in bone marrow cellularity or blast count) was observed, followed by 33% escalations in three patient cohorts until dose-limiting toxicity (DLT) occurred. RESULTS The maximum-tolerated dose was 101 units/m(2). DLTs consisted of hypertensive crisis, congestive heart failure, and prolonged cytopenias. Adverse events were consistent with cytarabine and daunorubicin treatment. Response occurred at doses as low as 32 units/m(2). Of 43 patients with AML, nine had complete response (CR) and one had CR with incomplete platelet recovery; of patients with acute lymphoblastic leukemia, one of three had CR. Eight CRs were achieved among the 31 patients with prior cytarabine and daunorubicin treatment. CR in AML occurred in five of 26 patients age ≥ 60 years and in five of 17 patients younger than age 60 years. Median half-life was 31.1 hours (cytarabine) and 21.9 hours (daunorubicin), with both drugs and their metabolites detectable > 7 days after the last dose. The targeted 5:1 molar ratio was maintained at all dose levels for up to 24 hours. CONCLUSION The recommended dose of CPX-351 for phase II study is 101 units/m(2). Further exploration of efficacy and safety is ongoing in phase II trials in newly diagnosed and first-relapse patients with AML.

Phase 1 study of epigenetic priming with decitabine prior to standard induction chemotherapy for patients with AML

We conducted an open-label phase 1 study exploring the feasibility, safety, and biologic activity of epigenetic priming with decitabine before standard induction chemotherapy in patients with less-than-favorable risk of acute myelogenous leukemia (AML). We directly compared the clinical and DNA-hypomethylating activity of decitabine delivered at 20 mg/m² by either a 1-hour infusion (Arm A) or a continuous infusion (Arm B) for 3, 5, or 7 days before a single, standard induction with infusional cytarabine (100 mg/m² for 7 days) and daunorubicin (60 mg/m² × 3 doses). Toxicity was similar to that of standard induction chemotherapy alone. Although we did not identify a maximum tolerated dose, there was more gastro-intestinal toxicity with 7 days of decitabine priming. Decitabine induced DNA hypomethylation at all dose levels and there was a trend toward greater hypomethylation in CD34(+) bone marrow cells when decitabine was delivered by a short pulse (Arm A). Twenty-seven subjects (90%) responded to therapy: 17 with complete remission (57%) and 10 with partial remission (33%). Of the patients with partial remission to protocol treatment, 8 achieved remission to their next therapy, bringing the overall complete remission rate to 83%. We conclude that epigenetic priming of intensive chemotherapy can be safely delivered in an attempt to improve response rates. This trial was registered at www.clinicaltrials.gov as NCT00538876.

Decitabine in patients with newly diagnosed and relapsed acute myeloid leukemia.

Abstract Treatment options for older patients with acute myeloid leukemia (AML) and for patients with relapsed/refractory AML are limited, and outcomes are poor. Decitabine, a hypomethylating agent, is active in patients with myelodysplastic syndrome (MDS) and AML, but its optimal dose and schedule are unknown. We report the efficacy and safety of repeated 10-day cycles of decitabine 20 mg/m2 administered intravenously over 1 h in 52 newly diagnosed and 102 relapsed/refractory patients. Repeated 10-day cycles of decitabine produced a complete response (CR) in 40% of newly diagnosed older patients with AML, many of whom had adverse prognostic features. The median overall survival (OS) was 318 days but there was prolonged survival in responders of 481 days. Relapsed/refractory patients had a CR rate of 15.7% with a median OS of 177 days. Extramedullary toxicity was mild and the regimen was well tolerated for ongoing post-remission, outpatient maintenance cycles. Responses were durable for over 1 year.

Vosaroxin plus cytarabine versus placebo plus cytarabine in patients with first relapsed or refractory acute myeloid leukaemia (VALOR): a randomised, controlled, double-blind, multinational, phase 3 study.

BACKGROUND Safe and effective treatments are urgently needed for patients with relapsed or refractory acute myeloid leukaemia. We investigated the efficacy and safety of vosaroxin, a first-in-class anticancer quinolone derivative, plus cytarabine in patients with relapsed or refractory acute myeloid leukaemia. METHODS This phase 3, double-blind, placebo-controlled trial was undertaken at 101 international sites. Eligible patients with acute myeloid leukaemia were aged 18 years of age or older and had refractory disease or were in first relapse after one or two cycles of previous induction chemotherapy, including at least one cycle of anthracycline (or anthracenedione) plus cytarabine. Patients were randomly assigned 1:1 to vosaroxin (90 mg/m(2) intravenously on days 1 and 4 in a first cycle; 70 mg/m(2) in subsequent cycles) plus cytarabine (1 g/m(2) intravenously on days 1-5) or placebo plus cytarabine through a central interactive voice system with a permuted block procedure stratified by disease status, age, and geographical location. All participants were masked to treatment assignment. The primary efficacy endpoint was overall survival and the primary safety endpoint was 30-day and 60-day all-cause mortality. Efficacy analyses were done by intention to treat; safety analyses included all treated patients. This study is registered with ClinicalTrials.gov, number NCT01191801. FINDINGS Between Dec 17, 2010, and Sept 25, 2013, 711 patients were randomly assigned to vosaroxin plus cytarabine (n=356) or placebo plus cytarabine (n=355). At the final analysis, median overall survival was 7·5 months (95% CI 6·4-8·5) in the vosaroxin plus cytarabine group and 6·1 months (5·2-7·1) in the placebo plus cytarabine group (hazard ratio 0·87, 95% CI 0·73-1·02; unstratified log-rank p=0·061; stratified p=0·024). A higher proportion of patients achieved complete remission in the vosaroxin plus cytarabine group than in the placebo plus cytarabine group (107 [30%] of 356 patients vs 58 [16%] of 355 patients, p<0·0001). Early mortality was similar between treatment groups (30-day: 28 [8%] of 355 patients in the vosaroxin plus cytarabine group vs 23 [7%] of 350 in the placebo plus cytarabine group; 60-day: 70 [20%] vs 68 [19%]). Treatment-related deaths occurred at any time in 20 (6%) of 355 patients given vosaroxin plus cytarabine and in eight (2%) of 350 patients given placebo plus cytarabine. Treatment-related serious adverse events occurred in 116 (33%) and 58 (17%) patients in each group, respectively. Grade 3 or worse adverse events that were more frequent in the vosaroxin plus cytarabine group than in the placebo plus cytarabine group included febrile neutropenia (167 [47%] vs 117 [33%]), neutropenia (66 [19%] vs 49 [14%]), stomatitis (54 [15%] vs 10 [3%]), hypokalaemia (52 [15%] vs 21 [6%]), bacteraemia (43 [12%] vs 16 [5%]), sepsis (42 [12%] vs 18 [5%]), and pneumonia (39 [11%] vs 26 [7%]). INTERPRETATION Although there was no significant difference in the primary endpoint between groups, the prespecified secondary analysis stratified by randomisation factors suggests that the addition of vosaroxin to cytarabine might be of clinical benefit to some patients with relapsed or refractory acute myeloid leukaemia. FUNDING Sunesis Pharmaceuticals.

Active oral regimen for elderly adults with newly diagnosed acute myelogenous leukemia: a preclinical and phase 1 trial of the farnesyltransferase inhibitor tipifarnib (R115777, Zarnestra) combined with etoposide

The farnesyltransferase inhibitor tipifarnib exhibits modest activity against acute myelogenous leukemia. To build on these results, we examined the effect of combining tipifarnib with other agents. Tipifarnib inhibited signaling downstream of the farnesylated small G protein Rheb and synergistically enhanced etoposide-induced antiproliferative effects in lymphohematopoietic cell lines and acute myelogenous leukemia isolates. We subsequently conducted a phase 1 trial of tipifarnib plus etoposide in adults over 70 years of age who were not candidates for conventional therapy. A total of 84 patients (median age, 77 years) received 224 cycles of oral tipifarnib (300-600 mg twice daily for 14 or 21 days) plus oral etoposide (100-200 mg daily on days 1-3 and 8-10). Dose-limiting toxicities occurred with 21-day tipifarnib. Complete remissions were achieved in 16 of 54 (30%) receiving 14-day tipifarnib versus 5 of 30 (17%) receiving 21-day tipifarnib. Complete remissions occurred in 50% of two 14-day tipifarnib cohorts: 3A (tipifarnib 600, etoposide 100) and 8A (tipifarnib 400, etoposide 200). In vivo, tipifarnib plus etoposide decreased ribosomal S6 protein phosphorylation and increased histone H2AX phosphorylation and apoptosis. Tipifarnib plus etoposide is a promising orally bioavailable regimen that warrants further evaluation in elderly adults who are not candidates for conventional induction chemotherapy. These clinical studies are registered at www.clinicaltrials.gov as #NCT00112853.

Phase II trial of panobinostat, an oral pan‐deacetylase inhibitor in patients with primary myelofibrosis, post–essential thrombocythaemia, and post–polycythaemia vera myelofibrosis

Myelofibrosis (MF) is a Philadelphia chromosome–negative stem cell myeloproliferative neoplasm (MPN) associated with cytopenias, splenomegaly, constitutional symptoms, and poor prognosis. MF patients commonly express JAK2 V617F mutation and activation of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling. Agents targeting the JAK/STAT pathway have demonstrated efficacy in patients with MF. This study evaluated panobinostat, a pan‐deacetylase inhibitor that depletes JAK2 V617F levels and JAK/STAT signalling in MPN cells, in patients with primary MF, post–essential thrombocythaemia MF, and post–polycythaemia vera MF. Patients received panobinostat 40 mg administered three times per week. Dose reductions were permitted for toxicities. The primary endpoint was response rate at 6 months using International Working Group for Myelofibrosis Research and Treatment (IWG‐MRT) consensus criteria. Analyses of peripheral blood cells from treated patients revealed that panobinostat inhibited JAK/STAT signalling, decreased inflammatory cytokine levels, and decreased JAK2 V617F allelic burden. However, panobinostat was poorly tolerated at the dose and schedule evaluated, and only 16 of 35 patients completed ≥2 cycles of treatment. One patient (3%) achieved an IWG‐MRT response. Common adverse events were thrombocytopenia (71·4%) and diarrhoea (80·0%). Although molecular correlative analyses suggested that panobinostat inhibits key intracellular targets, limited clinical activity was observed because of poor tolerance.

Complete hematologic and molecular response in adult patients with relapsed/refractory philadelphia chromosome-positive B-precursor acute lymphoblastic leukemia following treatment with blinatumomab: results from a phase II, single-arm, multicenter study

Purpose Few therapeutic options are available for patients with Philadelphia chromosome-positive (Ph+) B-precursor acute lymphoblastic leukemia (ALL) who progress after failure of tyrosine kinase inhibitor (TKI) -based therapy. Here, we evaluated the efficacy and tolerability of blinatumomab in patients with relapsed or refractory Ph+ ALL. Patients and Methods This open-label phase II study enrolled adults with Ph+ ALL who had relapsed after or were refractory to at least one second-generation or later TKI or were intolerant to second-generation or later TKIs and intolerant or refractory to imatinib. Blinatumomab was administered in 28-day cycles by continuous intravenous infusion. The primary end point was complete remission (CR) or CR with partial hematologic recovery (CRh) during the first two cycles. Major secondary end points included minimal residual disease response, rate of allogeneic hematopoietic stem-cell transplantation, relapse-free survival, overall survival, and adverse events (AEs). Results Of 45 patients, 16 (36%; 95% CI, 22% to 51%) achieved CR/CRh during the first two cycles, including four of 10 patients with the T315I mutation; 88% of CR/CRh responders achieved a complete minimal residual disease response. Seven responders (44%) proceeded to allogeneic hematopoietic stem-cell transplantation, including 55% (six of 11) of transplantation-naïve responders. Median relapse-free survival and overall survival were 6.7 and 7.1 months, respectively. The most frequent AEs were pyrexia (58%), febrile neutropenia (40%), and headache (31%). Three patients had cytokine release syndrome (all grade 1 or 2), and three patients had grade 3 neurologic events, one of which (aphasia) required temporary treatment interruption. There were no grade 4 or 5 neurologic events. Conclusion Single-agent blinatumomab showed antileukemia activity in high-risk patients with Ph+ ALL who had relapsed or were refractory to TKIs. AEs were consistent with previous experience in Ph- ALL.

Selective inhibition of FLT3 by gilteritinib in relapsed or refractory acute myeloid leukaemia: a multicentre, first-in-human, open-label, phase 1–2 study

Background Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations are common in acute myeloid leukemia (AML) and are associated with rapid relapse and short survival. In relapsed/refractory (R/R) AML, the clinical benefit of FLT3 inhibitors has been limited by rapid generation of resistance mutations, especially FLT3-D835. Gilteritinib is a potent, highly selective oral FLT3/AXL inhibitor with preclinical activity against FLT3-ITD and FLT3-D835 mutations. The aim of this Phase 1/2 study was to assess the safety, tolerability, and pharmacokinetic (PK) effects of gilteritinib in FLT3 mutation-positive (FLT3mut+) R/R AML. Methods This ongoing pharmacodynamic-driven Phase 1/2 trial (NCT02014558) enrolled subjects from October 2013 to August 2015 who were aged ≥18 years and were either refractory to induction therapy or had relapsed after achieving remission with prior therapy. Subjects were enrolled in one of seven dose-escalation or dose-expansion cohorts that were assigned to receive once-daily doses of oral gilteritinib (20, 40, 80, 120, 200, 300, or 450 mg). Cohort expansion was based on safety/tolerability, FLT3 inhibition in correlative assays, and antileukemic activity; the 120 and 200 mg dose cohorts were further expanded to include FLT3mut+ patients only. Safety and tolerability, and PK effects were the primary endpoints; antileukemic response was the main secondary endpoint. Safety and tolerability were assessed by monitoring dose-limiting toxicities and treatment-emergent adverse events, and safety assessments (eg, clinical laboratory evaluations, electrocardiograms) in the Safety Analysis Set. Findings A total of 252 adults with R/R AML, including 58 with wild-type FLT3 and 194 with FLT3 mutations (FLT3-ITD, n=162; FLT3-D835, n=16; FLT3-ITD and -D835, n=13; other, n=3), received oral gilteritinib (20–450 mg) once daily in one of seven dose-escalation (n=23) or dose-expansion (n=229) cohorts. Gilteritinib was well tolerated in this heavily pretreated population; Grade 3 diarrhea and hepatic transaminase elevation limited dosing above 300 mg/d. The most common Grade 3/4 adverse events were febrile neutropenia (39%; n=97/252), anemia (24%; n=61/252), thromobocytopenia (13%; n=33/252), sepsis (11%; n=28/252), and pneumonia (11%; n=27/252). Serious adverse events in ≥5% of patients were febrile neutropenia (31%; n=78/252), progressive disease (17%; n=43/252), sepsis (14%; n=36/252), pneumonia (11%; n=27/252), and acute renal failure (10%; n=25/252), pyrexia (8%; n=21/252), bacteremia (6%; n=14/252), and respiratory failure (6%; n=14/252). Gilteritinib demonstrated consistent, potent inhibition of FLT3 phosphorylation at doses ≥80 mg/d in correlative assays. While responses were observed across all dose levels regardless of FLT3 mutation status (overall response rate [ORR]=40%), response rate was improved in FLT3mut+ patients at doses ≥80 mg/d (ORR=52%). Among patients with FLT3-ITD, the additional presence of FLT3-D835 did not alter response rate; patients with only FLT3-D835 responded less frequently. Interpretation Gilteritinib had a favorable safety profile and generated potent FLT3 inhibition leading to high rates of antileukemic responses in patients with FLT3mut+ R/R AML. These findings confirm that FLT3 is a high-value target in R/R AML and that long-term success of therapeutic FLT3 inhibition in AML is optimized by agents with potent, selective, and sustained activity against FLT3-ITD mutations and FLT3 tyrosine kinase domain mutations. Funding This study was funded by Astellas Pharma, Inc., by a National Cancer Institute Leukemia Specialized Program of Research Excellence grant (CA100632) awarded to Drs Mark Levis and Jorge Cortes, and by Associazione Italiana Ricerca sul Cancro awarded to Professor Giovanni Martinelli.

Arsenic trioxide and low-dose cytarabine in older patients with untreated acute myeloid leukemia, excluding acute promyelocytic leukemia.

Acute myeloid leukemia (AML) carries a dismal prognosis in older patients. In this study, the authors evaluated the safety and efficacy of arsenic trioxide combined with low‐dose cytarabine in untreated patients aged ≥60 years with AML.