Results of ponatinib as frontline therapy for chronic myeloid leukemia in chronic phase.

BACKGROUND: Ponatinib is a third-generation BCR::ABL1 tyrosine kinase inhibitor (TKI) with robust activity in Philadelphia chromosome-positive leukemias. Herein, we report the long-term follow-up of the phase 2 trial of ponatinib in chronic myeloid leukemia in chronic phase. METHODS: Patients received ponatinib 30 to 45 mg/day. The primary end point was the rate of 6-month complete cytogenetic response (CCyR). The study was held in June 2014 because of the risk of cardiovascular toxicity, requiring patients to change TKI. RESULTS: Fifty-one patients were treated with ponatinib (median dose, 45 mg/day). Median age was 48 years (range, 21-75); 30 (59%) had baseline cardiovascular comorbidities. Median treatment duration was 13 months (range, 2-25). Fourteen patients (28%) discontinued ponatinib because of toxicities, 36 (71%) after the Food and Drug Administration warning/study closure, and one for noncompliance. Dasatinib was the most frequently chosen second-line TKI (n = 34; 66%). Among 46 patients evaluable at 6 months, 44 (96%) achieved CCyR, 37 (80%) major molecular response, 28 (61%) MR4, and 21 (46%) MR4.5. The cumulative 6-month rates of CCyR, major molecular response, MR4, and MR4.5 were 96%, 78%, 50%, and 36%, respectively. Durable MR4 ≥24 or ≥60 months was observed in 67% and 51% of patients, respectively. The 24-month event-free survival rate was 97%. After a median follow-up of 128 months, the 10-year overall survival rate was 90%. Eight patients (16%) had serious grade 2 to 3 cardiovascular adverse events, leading to permanent discontinuation in five (10%). CONCLUSION: Ponatinib yielded high cytogenetic and molecular responses in newly diagnosed chronic myeloid leukemia in chronic phase. Its use in the frontline setting is hindered by arterio-/vaso-occlusive and other severe toxicities.

The outcomes of patients with chronic myeloid leukemia treated with third-line BCR::ABL1 tyrosine kinase inhibitors.

The BCR::ABL1 tyrosine kinase inhibitors (TKIs) have improved the outcomes of patients with chronic myeloid leukemia (CML). After failing second-generation TKI (2G-TKI), the optimal third-line therapy in chronic phase CML (CML-CP) is not well established. We analyzed 354 patients with CML-CP treated with a third-line BCR::ABL1 TKI at our institution, and in the PACE and OPTIC trials, and evaluated the outcome after alternate 2G-TKIs or ponatinib. We performed a propensity score matching analysis to compare outcomes and multivariate analysis to identify variables associated with survival. One hundred seventy-three (49%) patients received 2G-TKIs and 181 (51%) ponatinib. Patients in the ponatinib group had more cardiovascular risk factors (34% versus 19%) and higher disease burden (BCR::ABL1 transcript levels >1%, 165/175 [94%] versus 75/135 [55%]; p < .001) compared with the 2G-TKI group. Among the 173 evaluable patients treated with ponatinib, 89 (52%) achieved 2 + -log reduction of baseline transcripts (20% 2-log reduction and 32% 3 + -log reduction). Among the 128 evaluable patients treated with 2G-TKIs, 44 (34%) achieved 2 + -log reduction of baseline transcripts (13% 2-log reduction and 21% 3 + -log reduction). With a median follow-up of 46 months, the 3-year progression-free survival was 59% (60% before matching) with 2G-TKI and 83% (81% before matching) with ponatinib (p < .001). The 3-year survival was 83% (81% before matching) with 2G-TKI and 87% (89% before matching) with ponatinib (p = .03). By multivariate analysis, third-line therapy with ponatinib was the only independent factor associated with better survival (p = .003). In conclusion, ponatinib is an optimal treatment for patients with CML-CP failing two prior TKIs.

Low-dose dasatinib 50 mg/day versus standard-dose dasatinib 100 mg/day as frontline therapy in chronic myeloid leukemia in chronic phase: A propensity score analysis.

Low-dose dasatinib is safe and effective in patients with chronic myeloid leukemia in chronic phase (CML-CP). No randomized trials have compared the outcome with standard-dose dasatinib. This study aims to compare the outcome of patients with CML-CP treated with frontline dasatinib 50 versus 100 mg/day. We analyzed 233 patients with newly diagnosed CML-CP treated with low-dose dasatinib (N = 83) or standard-dose dasatinib (N = 150). Propensity score analysis with 1:1 matching was performed and identified 77 patients in each cohort without significant baseline differences. Response rates were reported as the cumulative incidences of complete cytogenetic response, major molecular response (MMR), molecular response (MR)4, and MR4.5. Failure-free survival (FFS), event-free survival (EFS), transformation-free survival (TFS), and overall survival (OS) were also compared. Patients on low-dose dasatinib with suboptimal response by European LeukemiaNet (ELN) 2013 criteria had the option to increase the dose to 100 mg/day. The overall median follow-up time was 60 months. The 3-year MMR rates were 92% and 84% for low-dose and standard-dose dasatinib, respectively (p = .23). Dasatinib 50 mg/day induced higher cumulative incidence of MR4 (77% vs. 66%; p = .04) and MR4.5 (77% vs. 62%; p = .02) at 3 years. The 4-year FFS, EFS and OS rates were 89% versus 77% (p = .04), 95% versus 92% (p = .06), and 97% versus 96% (p = .78) with low-dose and standard-dose dasatinib, respectively. The rate of any grade pleural effusion was 5% with dasatinib 50 mg/day compared to 21% with 100 mg/day. Dasatinib 50 mg/day is at least as effective as 100 mg/day with a better safety profile and drug exposure.

Long-term follow-up of lower dose dasatinib (50 mg daily) as frontline therapy in newly diagnosed chronic-phase chronic myeloid leukemia.

BACKGROUND: Dasatinib, a potent Bcr-Abl tyrosine kinase inhibitor, is approved for the treatment of chronic-phase chronic myeloid leukemia (CML-CP) in the frontline and salvage settings. Notable side effects include pleural effusions and myelosuppression. Dasatinib at 50 mg daily has previously been reported to be active and better tolerated than the approved 100-mg daily dose. The aim of this study was to update the long-term follow-up results of dasatinib at 50 mg daily as frontline therapy for CML-CP. METHODS: Eighty-three patients with newly diagnosed CML-CP received dasatinib at 50 mg daily. Eligibility and response criteria were standards used in previous protocols. RESULTS: After a minimum follow-up of 12 months, 81 patients were evaluable. Two patients came off the study in less than 3 months. The rates of BCR-ABL1 transcript levels (International Standard) at ≤10% and ≤1% at 3 months were 96% and 77%, respectively. The cumulative rates for a complete cytogenetic response by 6 and 12 months were 77% and 95%, respectively. The cumulative rates for a major molecular response, a molecular response with a 4.0-log reduction, and a molecular response with a 4.5-log reduction by 12 months were 81%, 55%, and 49%, respectively. Twenty-one patients (25%) had treatment interruptions for a median of 13 days (range, 4-64 days). Five patients (6%) developed pleural effusions; 4 of these patients (80%) required a dose reduction. Two patients (2%) failed to achieve any cytogenetic or molecular response and were taken off the study. At a median follow-up of 24 months, none of the patients had disease transformation to an accelerated or blastic phase. The 2-year event-free and overall survival rates were 100%. CONCLUSIONS: These updated results continue to support 50 mg of dasatinib daily as an effective and safe dose for early CML-CP.

Long-term results of frontline dasatinib in chronic myeloid leukemia.

BACKGROUND: Dasatinib is a second-generation tyrosine kinase inhibitor that, when used as frontline therapy, produces more and faster cytogenetic and molecular responses compared with imatinib. The authors report the long-term follow-up from the first study using dasatinib as initial therapy for chronic-phase chronic myeloid leukemia. METHODS: Between November 2005 and August 2014, patients were randomly assigned to receive 100 mg daily or 50 mg twice daily. After June 2009, all patients started with 100 mg daily. RESULTS: With a median follow-up of 6.5 years, 94 of 149 treated patients (63%) were still receiving dasatinib on study. The median patient age was 48 years (interquartile range, 37-55 years), and 9% of patients had a high risk Sokal risk score. The cumulative complete cytogenetic response rate at 11 years was 92.6%, the major molecular response (MR) rate was 88.2%, and the MR4.5 rate (indicating a ≥4.5-log reduction in BCR-ABL1 transcripts) was 79.5%. The median time to a major MR and MR4.5 was 6 and 23 months, respectively. A sustained MR4.5 (≥2 years) was achieved in 82 patients (55%). The 10-year overall survival, transformation-free survival, event-free survival, and failure-free survival rates were 89%, 95%, 86%, and 65%, respectively. Univariate analysis showed that the achievement of a complete MR was associated with improved overall survival. The most common reasons for treatment discontinuation were toxicity and elective discontinuation. The most common treatment-emergent grade 3 and 4 adverse events were fatigue, thrombocytopenia, and infections. CONCLUSIONS: After this long-term follow-up, dasatinib continues to show an excellent safety profile and produces rapid cytogenetic responses and MRs, durable deep MRs, and excellent long-term survival outcomes in patients with chronic-phase chronic myeloid leukemia.

Long-term results of a phase 2 trial of nilotinib 400 mg twice daily in newly diagnosed patients with chronic-phase chronic myeloid leukemia.

BACKGROUND: Nilotinib is a potent, second-generation inhibitor of BCR-ABL1 tyrosine kinase and has been approved as frontline and salvage therapy for patients with chronic-phase chronic myeloid leukemia (CP-CML). METHODS: In this single-institution, phase 2 study, 122 patients with newly diagnosed CP-CML received nilotinib 400 mg twice daily. The median follow-up on study was 78.3 months (interquartile range, 58.4-96.5 months). RESULTS: Fifty-six percent of patients remained on therapy at the last follow-up. Both the complete cytogenetic response rate and the major molecular response (MR) rate were 91%. Seventy-five percent and 59% of patients achieved a ≥4.5-log reduction in BCR-ABL1 transcripts (MR4.5) and a sustained MR4.5 beyond 2 years, respectively. The estimated event-free survival and overall survival rates at 5 years were 89% and 93%, respectively, and the corresponding rates at 10 years were 85% and 88%, respectively. Treatment discontinuation due to toxicity occurred in 19% of patients, mostly because of cardiovascular events (10%) and biochemical abnormalities (6%). The top 3 nonhematologic toxicities were rash (55%), elevated bilirubin (57%), and elevated aminotransferases (48%). Hematologic toxicity was transient and mild. Ischemic cardiovascular adverse events occurred in 8% of patients. Four patients (3%) progressed to accelerated or blast phase while on therapy, and 7 patients (6%) died on study. CONCLUSIONS: The current data confirm the long-term efficacy of nilotinib 400 mg twice daily in patients with CP-CML. A majority of patients can achieve sustained MR4.5.

The clinical impact of time to response in de novo accelerated-phase chronic myeloid leukemia.

We aimed to describe the impact of time to response on the outcomes of 75 patients with accelerated-phase chronic myeloid leukemia (CML-AP) at diagnosis. Patients had at least 1 feature of AP: blasts ≥15% (n = 2), basophils ≥20% (n = 19), platelets <100 × 109 /L (n = 7), cytogenetic clonal evolution (n = 34), or more than one factor (n = 13). Thirty-three patients received imatinib; 42 received a second-generation tyrosine kinase inhibitor (2GTKI) (19 dasatinib and 23 nilotinib). We used chi-square and Kaplan-Meier analyses to determine the impact of various degrees of molecular and cytogenetic response at early time points (3 and 6 months) on rates of overall cytogenetic and molecular response, overall survival (OS), event-free survival (EFS), transformation-free survival (TFS), and failure-free survival (FFS). After a median follow-up of 96 months (range: 18-224 months), the overall rate of complete cytogenetic response was 79%, of major molecular response, 71%, and of molecular reponse (MR)4.5, 59%. Patients who achieved a major cytogenetic response (MCyR) (n = 49) at 3 months had significantly better 3-year OS (94% vs 75%; P = .002), TFS (98% vs 73%; P < .001), EFS (93% vs 42%; P < .001), and FFS (83% vs 25%; P < .001) rates than patients who did not have MCyR at 3 months. Most (67%) who eventually achieved sustained MR4.5 had achieved MCyR at 3 months. In de novo CML-AP, early response at 3 and 6 months is a strong determinant of long-term outcome.

Clonal chromosomal abnormalities appearing in Philadelphia chromosome-negative metaphases during CML treatment.

Clonal chromosomal abnormalities in Philadelphia chromosome-negative (CCA/Ph-) metaphases emerge as patients with chronic phase chronic myeloid leukemia (CP-CML) are treated with tyrosine kinase inhibitors (TKIs). We assessed the characteristics and prognostic impact of 598 patients with CP-CML treated on clinical trials with various TKIs. CCA/Ph- occurred in 58 patients (10%); the most common were -Y in 25 (43%) and trisomy 8 in 7 patients (12%). Response to TKI therapy was similar for patients with CCA/Ph- and those without additional chromosomal abnormalities (ACAs). We further categorized CCA/Ph- into those in which -Y was the only clonal abnormality, and all others. We found that patients with non -Y CCA/Ph- had worse failure-free survival (FFS), event-free survival (EFS), transformation-free survival (TFS), and overall survival (OS) compared with those without ACAs with the following 5-year rates: FFS (52% vs 70%, P = .02), EFS (68% vs 86%, P = .02), TFS (76% vs 94%, P < .01), and OS (79% vs 94%, P = .03). In a multivariate analysis, non -Y CCA/Ph- increased the risk of transformation or death when baseline characteristics were considered with a hazard ratio of 2.81 (95% confidence interval, 1.15-6.89; P = .02). However, this prognostic impact was not statistically significant when achieving BCR-ABL <10% at 3 months was included in the analysis. In conclusion, non -Y CCA/Ph- are associated with decreased survival when emerging in patients with chronic-phase CML across various TKIs. This trial was registered at www.clinicaltrials.gov as #NCT00048672, #NCT00038649, and #NCT00050531 (imatinib); #NCT00254423 (dasatinib); #NCT00129740 (nilotinib); and NCT01570868 (ponatinib).

Prognostic factors and survival outcomes in patients with chronic myeloid leukemia in blast phase in the tyrosine kinase inhibitor era: Cohort study of 477 patients.

BACKGROUND: Outcomes in patients with chronic myeloid leukemia in blast phase (CML-BP) are historically dismal. Herein, the authors sought to analyze the characteristics, prognostic factors, and survival outcomes in patients with CML-BP in the tyrosine kinase inhibitor (TKI) era. METHODS: A total of 477 patients with CML-BP were treated with a TKI at some point during the course of their CML. Cox proportional hazard models identified characteristics that were predictive of survival. Overall survival and failure-free survival were assessed. Optimal cutoff points for specific parameters were identified using classification and regression tree (CART) analysis. RESULTS: The median age of the patients was 53 years (range, 16-84 years) and 64% were male. Approximately 80% of patients initially were diagnosed in the chronic phase of CML at a median of 41 months (range, 0.7-298 months) before transformation to CML-BP. De novo CML-BP occurred in 71 patients. Approximately 72% of patients received TKI therapy before CML-BP. The initial therapy for CML-BP included a TKI alone (35%), a TKI with chemotherapy (46%), and non-TKI therapies (19%). The median overall survival was 12 months and the median failure-free survival was 5 months. In multivariate analysis, myeloid immunophenotype, prior TKI, age ≥58 years, lactate dehydrogenase level ≥1227 IU/L, platelet count < 102 K/µL, no history of stem cell transplantation, transition to BP from chronic phase/accelerated phase, and the presence of chromosome 15 aberrations predicted for a significantly increased risk of death. Achievement of major hematologic response and/or complete cytogenetic response to first-line treatment was found to be predictive of better survival. The combination of a TKI with intensive chemotherapy followed by stem cell transplantation appeared to confer the best outcome. CONCLUSIONS: Patients with CML-BP continue to pose a therapeutic challenge, have dismal outcomes, and require newer treatment approaches. Cancer 2017;123:4391-402. © 2017 American Cancer Society.

A propensity score matching analysis of dasatinib and nilotinib as a frontline therapy for patients with chronic myeloid leukemia in chronic phase.

BACKGROUND: Both dasatinib and nilotinib are approved frontline therapy for chronic myeloid leukemia in chronic phase (CML-CP) based on randomized trials compared with imatinib. However, no head-to-head comparison of dasatinib and nilotinib has been conducted in patients with newly diagnosed CML-CP. METHODS: The authors conducted a propensity score (PS) matched comparison of patients with CML-CP who received frontline therapy with either dasatinib (N = 102) or nilotinib (N = 104) under the respective phase 2 trials conducted in parallel. RESULTS: PS matching resulted in 87 patients from each trial being matched for pretreatment characteristics. The 3-month BCR-ABL1/ABL1 ratio <10% rate was 93% with dasatinib and 94% with nilotinib (P = .25); the rates of major molecular response at 12 months were 77% and 85%, respectively (P = .13); and the rates of molecular response with 4.5-log reduction in the ratio at 36 months were 66% and 64%, respectively (P = .96). All other clinically relevant responses were similar between the 2 treatment cohorts. The 3-year probability of event-free survival was 89% among the patients who received dasatinib and 87% among those who received nilotinib (P = .99), and the corresponding 3-year overall survival probabilities were 99% and 93%, respectively (P = .95). No statistical difference was observed between the dasatinib and nilotinib groups in any of the other survival endpoints. The treatment discontinuation rate also was similar between the 2 cohorts (dasatinib group, 18%; nilotinib group, 19%; P = .82). CONCLUSIONS: In a PS-matched cohort of patients with newly diagnosed CML-CP, dasatinib and nilotinib offer similar response and survival outcomes. Both drugs can be considered reasonable standard-of-care options as first-line therapy for patients with CML-CP. Cancer 2016;122:3336-3343. © 2016 American Cancer Society.

Analysis of 2013 European LeukaemiaNet (ELN) responses in chronic phase CML across four frontline TKI modalities and impact on clinical outcomes.

This study assessed the relevance of 2013 European LeukaemiaNet (ELN) response categories on patients treated with common frontline tyrosine kinase inhibitors (TKI) in chronic myeloid leukaemia in chronic phase (CML-CP). Four hundred and eighty-seven patients treated with imatinib (400 mg; IM 400, n = 70; 800 mg; IM800, n = 201), dasatinib (n = 107) or nilotinib (n = 109) were analysed. Intention to treat (ITT) analysis indicated that the proportion of patients falling into optimal, warning and failure ELN categories were 89%, 6%, 6% at 3 months, 78%, 17% and 6% at 6 months, and 75%, 13% and 13% at 12 months, respectively. Rates of optimal response at 3 months were 75% for IM400, 90% for IM800, 89% for dasatinib and 97% for nilotinib; 41%, 80%, 86% and 89% at 6 months; and 47%, 77%, 76% and 87% at 12 months, respectively. Patients achieving optimal response had longer eventfree (EFS), failurefree (FFS), transformationfree (TFS) and overall survival (OS) compared to warning and failure responses at all-time points. Treatment with imatinib 800, dasatinib or nilotinib predicted for achieving an optimal response. Optimal response predicted for significantly longer EFS, FFS, TFS and OS at 3, 6 and 12 months, irrespective of the TKI modality used. ELN response categories reliably predicted outcomes in CML patients receiving commonly used TKIs.

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.

Life after ponatinib failure: outcomes of chronic and accelerated phase CML patients who discontinued ponatinib in the salvage setting.

Ponatinib is a pan-tyrosine kinase inhibitor (TKI) with efficacy in multirefractory CML patients who have failed other TKIs. Despite excellent response rates, resistance or intolerance may develop. We conducted a retrospective review of the outcome of patients with chronic (CP) and accelerated (AP) phase CML refractory to prior TKI who discontinued ponatinib for resistance or intolerance. Nineteen CP patients, discontinued due to resistance (n = 13), toxicity (n = 5) and to pursue stem cell transplantation (n = 1). At discontinuation, 14 were still in CP, three had progressed to AP and two to blast phase (BP). Three CP patients improved their cytogenetic response (CyR) to complete CyR (CCyR), two after SCT and one on omacetaxine. None of the 12 patients, without a major cytogenetic response at ponatinib discontinuation, including all patients treated with subsequent TKIs, responded to therapy. Seventeen AP patients, stopped ponatinib due to resistance (n = 15) or intolerance (n = 2). At discontinuation, 14 were still in AP and three had progressed to BP. Four patients were treated with SCT and one achieved major molecular response. None of the 12 patients treated with non-SCT approaches responded to subsequent therapy. Median survival for all patients was 16.6 months after ponatinib discontinuation (31, 9 and 13 months for patients in CP, AP and BP, respectively). Median survival was 60 months for patients who discontinued ponatinib for toxicity and 11 months for those who discontinued for resistance. Long-term outcome of patients with ponatinib failure are poor with estimated one-year OS and EFS rates of 54% and 40%, respectively. New treatment options are required for this subset of patients.

Characteristics and outcome of chronic myeloid leukemia patients with E255K/V BCR-ABL kinase domain mutations.

Kinase domain (KD) mutations of ABL1 represent the most common resistance mechanism to tyrosine kinase inhibitors (TKI) in CML. Besides T315I, mutations in codon 255 are highly resistant mutations in vitro to all TKI. We aimed to study the incidence, prognosis, and response to treatment in patients with E255K/V. We evaluated 976 patients by sequencing of BCR-ABL1 fusion transcript for ABL1 KD mutations. We identified KD mutations in 381 (39%) patients, including E255K/V in 48 (13% of all mutations). At mutation detection, 14 patients (29%) were in chronic phase (CP), 12 (25%) in accelerated phase (AP), and 22 (46%) in blast phase (BP). 9/14 CP patients responded to treatment (best response complete hematologic response-CHR-4; complete cytogenetic response-CCyR-1; major molecular response-MMR-4); only 4/12 AP patients (CHR 3; MMR 1) and 7/22 BP patients responded (CCyR 2; MMR 2; partial cytogenetic response-PCyR-3). After a median follow-up of 65 months from mutation detection, 36 patients (75%) died: 9/14 (64%) in CP, 9/12 (75%) in AP, and 18/22 (82%) in BP (p = 0.003); median overall survival was 12 months. Patients with E255K/V mutation have a poor prognosis, regardless of the stage of the disease at detection.

A phase I/II study of the Janus kinase (JAK)1 and 2 inhibitor ruxolitinib in patients with relapsed or refractory acute myeloid leukemia.

BACKGROUND: Ruxolitinib is a potent and specific JAK1/JAK2 inhibitor recently approved for the treatment of myelofibrosis. PATIENTS AND METHODS: We conducted a single-center phase I/II clinical study testing 3 dose levels (50 mg b.i.d. [n = 4], 100 mg b.i.d. [n = 5], and 200 mg b.i.d. [n = 18]). We enrolled 27 patients older than 14 years with relapsed or refractory acute myeloid leukemia (n = 26) or acute lymphoid leukemia (n = 1). RESULTS: The median age was 66 (range, 25-88) years. Thirteen patients were evaluable for dose-limiting toxicities. The most common Grade 3 or 4 nonhematologic event was infection (n = 26 events; most frequently pneumonia; 15 of 26; 58%). One patient with multiple relapses after 7 lines of therapy had a CRp at a ruxolitinib dose of 200 mg b.i.d. CONCLUSION: In this cohort of heavily pretreated patients with relapsed or refractory acute leukemias, ruxolitinib was overall reasonably well tolerated, with 1 patient achieving CRp.

Long-term molecular and cytogenetic response and survival outcomes with imatinib 400 mg, imatinib 800 mg, dasatinib, and nilotinib in patients with chronic-phase chronic myeloid leukaemia: retrospective analysis of patient data from five clinical trials.

BACKGROUND: Several tyrosine kinase inhibitors (TKIs) are available for treatment of patients with chronic myeloid leukaemia in chronic phase (CML-CP). We analysed long-term molecular and cytogenetic response and survival outcomes for four TKI modalities used as frontline therapy for CML-CP. METHODS: In a retrospective cohort analysis, we included data from patients with CML-CP treated in prospective clinical trials with frontline TKI modalities at a single institution between July 31, 2000, and Sept 10, 2013. The main aim of the study was to determine whether achievement of complete cytogenetic response or major molecular response had similar prognostic implications irrespective of the frontline TKI modality used. We analysed each TKI modality for response assessment and analysed survival endpoints (event-free, failure-free, transformation-free, and overall survival) with the Kaplan-Meier method. Univariate and multivariate analyses were done with Cox proportional hazard regression. FINDINGS: Our analysis included 482 patients who were treated with imatinib 400 mg daily (n=68), imatinib 800 mg daily (n=200), dasatinib 50 mg twice daily or 100 mg daily (n=106), or nilotinib 400 mg twice daily (n=108). More patients receiving imatinib 800 mg or second-generation TKIs (ie, dasatinib or nilotinib) achieved complete cytogenetic response (58 [87%] of 67 for imatinib 400 mg vs 180 [90%] of 199 for imatinib 800 mg, vs 100 [96%] of 104 for dasatinib vs 99 [93%] of 107 for nilotinib), major molecular response (51 [76%] vs 171 [86%] vs 93 [90%] vs 97 [91%]), and 4·5 log or higher reduction in BCR-ABL transcripts (MR(4·5) response 38 [57%] vs 148 [74%] vs 76 [71%] vs 76 [71%]). This finding was consistent over time (3-60 months). 5-year event free survival significantly differed between the imatinib 400 mg group and the other TKI groups (imatinib 800 mg p=0·029, dasatinib p=0·003, nilotinib p=0·031). There was no significant difference in 5-year failure-free survival (p=0·32, p=0·075, p=0·332), transformation-free survival (p=0·053, p=0·038, p=0·493), or overall survival (p=0·563, p=0·162, p=0·981). Multivariate analysis showed that therapy with imatinib 800 mg (HR 0·51, 95% CI 0·29-0·88, p=0·016), dasatinib (0·28, 0·12-0·66, p=0·004), or nilotinib (0·42, 0·20-0·89, p=0·024) predicted for better event-free survival compared with imatinib 400 mg, but that failure-free, transformation-free, and overall survival were similar irrespective of the TKI used. 28 (41%) patients receiving imatinib 400 mg, 85 (43%) receiving imatinib 800 mg, 23 (21%) receiving dasatinib, and 27 (25%) receiving nilotinib discontinued treatment for any reason. INTERPRETATION: Treatment with imatinib 800 mg or the second-generation TKIs dasatinib or nilotinib resulted in superior and deeper responses than did standard-dose imatinib, which were maintained after 5 years of follow-up. Results with imatinib 800 mg were similar to those with second-generation TKIs, although more patients discontinued therapy. FUNDING: MD Anderson Cancer Center, National Cancer Institute.