Nilotinib after imatinib first-line: a real-life longitudinal cohort of patients with chronic myeloid leukaemia in chronic phase

Prognosis in Chronic Myeloid Leukemia: Baseline Factors, Dynamic Risk Assessment and Novel Insights

The introduction of tyrosine kinase inhibitors (TKIs) has changed the treatment paradigm of chronic myeloid leukemia (CML), leading to a dramatic improvement of the outcome of CML patients, who now have a nearly normal life expectancy and, in some selected cases, the possibility of aiming for the more ambitious goal of treatment-free remission (TFR). However, the minority of patients who fail treatment and progress from chronic phase (CP) to accelerated phase (AP) and blast phase (BP) still have a relatively poor prognosis. The identification of predictive elements enabling a prompt recognition of patients at higher risk of progression still remains among the priorities in the field of CML management. Currently, the baseline risk is assessed using simple clinical and hematologic parameters, other than evaluating the presence of additional chromosomal abnormalities (ACAs), especially those at "high-risk". Beyond the onset, a re-evaluation of the risk status is mandatory, monitoring the response to TKI treatment. Moreover, novel critical insights are emerging into the role of genomic factors, present at diagnosis or evolving on therapy. This review presents the current knowledge regarding prognostic factors in CML and their potential role for an improved risk classification and a subsequent enhancement of therapeutic decisions and disease management.

Patterns of Tyrosine Kinase Inhibitor Utilization in Newly Treated Patients With Chronic Myeloid Leukemia: An Exhaustive Population-Based Study in France

We analyzed demographic characteristics, comorbidities and patterns of treatment with tyrosine kinase inhibitors (TKIs) in a cohort of 3,633 incident cases of chronic myeloid leukemia (CML) identified across France from 1 January 2011 to 31 December 2014. Patients were identified through a specific algorithm in the French Healthcare Data System and were followed up 12 months after inclusion in the cohort. The estimated incidence rate of CML for this period in France was 1.37 per 100,000 person-years (95% Confidence Interval 1.36-1.38) and was higher in men, with a peak at age 75-79 years. At baseline, the median age of the cohort was 60 years (Inter Quartile Range 47-71), the Male/Female ratio was 1.2, and 25% presented with another comorbidity. Imatinib was the first-line TKI for 77.6% of the patients, followed by nilotinib (18.3%) and dasatinib (4.1%). Twelve months after initiation, 86% of the patients remained on the same TKI, 13% switched to another TKI and 1% received subsequently three different TKIs. During the follow-up, 23% discontinued and 52% suspended the TKI. Patients received a mean of 16.7 (Standard Deviation (SD) 9.6) medications over the first year of follow-up, and a mean of 2.7 (SD 2.3) concomitant medications on the day of first TKI prescription: 24.4% of the patients received allopurinol, 6.4% proton pump inhibitors (PPI) and 6.5% antihypertensive agents. When treatment with TKI was initiated, incident CML patients presented with comorbidities and polypharmacy, which merits attention because of the persistent use of these concomitant drugs and the potential increased risk of drug-drug interactions.

Dasatinib treatment long-term results among imatinib-resistant/intolerant patients with chronic phase chronic myeloid leukemia are favorable in daily clinical practice

To evaluate long-term real-life results of dasatinib therapy among chronic phase chronic myeloid leukemia patients resistant or intolerant to imatinib, we retrospectively analyzed data of 118 patients treated in centers participating in the database INFINITY. With median follow-up of 37 months, estimated 5-year cumulative incidences of complete cytogenetic and major molecular responses were 78% and 68%, respectively. The estimated 5-year probability of overall survival (OS) and event-free survival (EFS) were 86% and 83%, respectively. Both OS and EFS were significantly improved among patients with BCR-ABL1 transcript level ≤10% at 3 months. Dasatinib toxicity was tolerable however persistent in almost half our patients, even after years of therapy. Pleural effusion occurred in 29% of patients and was responsible for 30% of dasatinib discontinuations. Our results confirmed very good efficacy and acceptable toxicity of dasatinib in second line setting and support the evidence and importance of high-quality real-life CML patient management.

Purinostat Mesylate Is a Uniquely Potent and Selective Inhibitor of HDACs for the Treatment of BCR-ABL-Induced B-Cell Acute Lymphoblastic Leukemia

PURPOSE

This study was to perform preclinical evaluation of a novel class I and IIb HDAC-selective inhibitor, purinostat mesylate, for the treatment of Ph⁺ B-cell acute lymphoblastic leukemia (B-ALL).

EXPERIMENTAL DESIGN

Biochemical assays were used to test enzymatic activity inhibition of purinostat mesylate. Ph⁺ leukemic cell lines and patient cells were used to evaluate purinostat mesylate activity in vitro. BL-2 secondary transplantation Ph⁺ B-ALL mouse model was used to validate its efficacy, mechanism, and pharmacokinetics properties in vivo. BCR-ABL(T315I)-induced primary B-ALL mouse model and PDX mouse model derived from relapsed Ph⁺ B-ALL patient post TKI treatment were used to determine the antitumor effect of purinostat mesylate for refractory or relapsed Ph⁺ B-ALL. Long-term toxicity and hERG blockade assays were used to safety evaluation of purinostat mesylate.

RESULTS

Purinostat mesylate, a class I and IIb HDAC highly selective inhibitor, exhibited robust antitumor activity in hematologic cancers. Purinostat mesylate at low nanomolar concentration induced apoptosis, and downregulated BCR-ABL and c-MYC expression in Ph⁺ leukemia cell lines and primary Ph⁺ B-ALL cells from relapsed patients. Purinostat mesylate efficiently attenuated Ph⁺ B-ALL progression and significantly prolonged the survival both in BL-2 secondary transplantation model with clinical patient symptoms of Ph⁺ B-ALL, BCR-ABL(T315I)-induced primary B-ALL mouse model, and PDX model derived from patients with relapsed Ph⁺ B-ALL post TKI treatment. In addition, purinostat mesylate possesses favorable pharmacokinetics and low toxicity properties.

CONCLUSIONS

Purinostat mesylate provides a new therapeutic strategy for patients with Ph⁺ B-ALL, including those who relapse after TKI treatment.

Tyrosine Kinase Inhibitor Sequencing in Patients with Chronic Myeloid Leukemia

The management of chronic myeloid leukemia (CML) has been revolutionized by the discovery of tyrosine kinase inhibitors (TKIs) against BCR-ABL1 oncogenic fusion protein. Imatinib, the first BCR-ABL1 TKI, was introduced into clinical practice in the early 2000s. In the following years, the so-called second-generation TKIs (2GTKIs)—dasatinib, nilotinib, and bosutinib were approved, initially for patients resistant to imatinib, and subsequently for front-line treatment. With multiple TKIs available, selection of first-line therapy is challenging. CML risk, patient characteristics and potential toxicities of different TKIs play a fundamental role, in particular when deciding between imatinib and 2GTKIs as frontline treatment. So, when deciding front-line therapy for a patient with CML in the chronic phase (CML-CP), clinicians must consider both the long-term outcomes, such as overall survival and progression-free survival, as well as safety, tolerance and possible treatment discontinuation. This paper offers a practical algorithmic approach for the sequential use of commercially available TKIs in patients with CML-CP along with the data available in the literature.

SIGNIFICANCE OF ADDITIONAL CHROMOSOMAL ABNORMALITIES FOR THE OUTCOMES AFTER THE SECOND LINE NILOTINIB THERAPY IN THE CHRONIC MYELOID LEUKEMIA PATIENTS

Background. There is limited information about impact of additional chromosome aberrations (ACA) on the efficacy of the 2nd line nilotinib therapy. Objective. The aim of the study was to analyze significance of ACAs for the outcome after second line tyrosine kinase inhibitors (TKI) therapy with nilotinib in the chronic myeloid leukemia (CML) patients, who experienced previous imatinib therapy failure. Methods. The CML patients in chronic phase treated with nilotinib after imatinib failure were analyzed for outcomes. Results. Among a total of 114 patients, 18 patients (15.8%) had ACAs at the beginning of the 2nd line therapy with nilotinib. Seven patients (38.9%) of 18 had variant translocations and 11 patients (61.1%) had other chromosomal abnormalities in addition to t(9;22), known as clonal evolution. Complete cytogenetic response (CCR) at 12 months was achieved in 37.5%, 42.8% and 45.5% (p=0.842) of patients with classic t(9;22) translocation, variant translocations and ACAs respectively. In the patients with variant translocations t(9;V;22) or clonal evolution treated with nilotinib after the imatinib failure, the CCR and major molecular response (MMR), event free survival (EFS), progression free survival (PFS) and overall survival (OS) rates did not differ from those in the CML patients with t(9;22) only. At the same time quantitative characteristics of leukemic and ACA clones had prognostic value for CCR. The increased number of Ph-positive cells and the number of cells with the ACA at the start of nilotinib therapy reduced the probability of CCR. Conclusions. Higher nilotinib inhibitory activity compare with imatinib allows us to overcome imatinib resistance in the CML patients regardless of the ACA presence at the beginning of nilotinib therapy.