Treatment of Philadelphia chromosome-positive acute lymphoblastic leukaemia with imatinib combined with a paediatric-based protocol

Is intensive chemotherapy and allogeneic stem cell transplantation mandatory for curing Philadelphia chromosome-positive acute lymphoblastic leukemia in young patients in the era of multitarget agents?

INTRODUCTION

The treatment outcomes for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) have improved with various tyrosine kinase inhibitors (TKIs) and bispecific T-cell engagers. Although allogeneic stem cell transplantation (allo-SCT) is the standard treatment for young patients with Ph+ALL, its role remains debatable in the era of TKIs and blinatumomab.

AREAS COVERED

There are some issues regarding Ph+ALL. First, do young patients require intensive chemotherapy (IC) in the era of multitarget agents? Second, which TKI is preferred for frontline therapy? Third, should allo-SCT be performed in patients achieving complete remission with ponatinib and IC? Fourth, can chemo-free treatment lead to a cure without allo-SCT? We searched relevant literature from the last 30 years on PubMed; reviewed the role of chemo-free therapies and combinations of ponatinib and IC; and assessed the necessity of allo-SCT in young patients with Ph+ALL.

EXPERT OPINION

Allo-SCT may not be needed, even in young patients with Ph+ALL treated with ponatinib-based IC or combined ponatinib and blinatumomab as frontline therapy. When adopting a ponatinib-based chemo-minimized regimen for induction, allo-SCT is needed with posttransplant ponatinib maintenance. Continuous exposure to ponatinib at pre- or post-transplant is regarded as one of the most important factor for the success of treatment.

Long-Term Results of the Dasatinib-Blinatumomab Protocol for Adult Philadelphia-Positive ALL

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.We report the long-term results of the frontline trial with dasatinib and blinatumomab in induction/consolidation (GIMEMA LAL2116, D-ALBA) for adult Philadelphia-positive ALL (Ph+ ALL), which enrolled 63 patients of all ages. At a median follow-up of 53 months, disease-free survival, overall survival, and event-free survival are 75.8%, 80.7%, and 74.6%, respectively. No events have occurred among early molecular responders. A significantly worse outcome was recorded for IKZF1plus patients. Twenty-nine patients-93.1% being in molecular response (ie, complete molecular response or positive nonquantifiable) after dasatinib/blinatumomab-never received chemotherapy/transplant and continued with a tyrosine kinase inhibitor only; 28 patients remain in long-term complete hematologic response (CHR). An allogeneic transplant was carried out in first CHR mainly in patients with persistent minimal residual disease; 83.3% of patients are in continuous CHR. The transplant-related mortality was 12.5% for patients transplanted in first CHR and 13.7% overall. Nine relapses and six deaths have occurred. ABL1 mutations were found in seven cases. The final analysis of the D-ALBA study shows that a chemotherapy-free induction/consolidation regimen on the basis of a targeted strategy (dasatinib) and immunotherapy (blinatumomab) is effective in inducing durable long-term hematologic and molecular responses in adult Ph+ ALL, paving the way for a new era in the management of these patients.

Comparison of allogeneic hematopoietic stem cell transplantation and TKI combined with chemotherapy for adult philadelphia chromosome positive acute lymphoblastic leukemia: a systematic review and meta-analysis

OBJECTIVE

This study seeks to clarify whether allogeneic hematopoietic stem cell transplantation (allo-HSCT) is necessary for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) in post-remission based on a comparison with tyrosine kinase inhibitor (TKI) combined with chemotherapy.

METHODS

We searched the Pubmed, Embase, and Web of Science databases and limited the date range for the studies from January 2010 to August 2020. A hazard ratio (HR) with a 95% confidence interval (CI) was employed to assess overall survival (OS) and relapse-free survival (RFS), and an odds ratio (OR) with a 95% CI was used to evaluate the ratio of non-relapsed mortality (NRM) and non-relapsed survival (NRS). All analyses were conducted with Stata software 16.0 and Revman 5.3.

RESULTS

Fifteen studies, totaling 959 patients, were included in our analysis. Among those patients, 473 underwent allo-HSCT, and 486 received TKI plus chemotherapy. The pooled results showed no difference in OS between outcomes for patients receiving TKI plus chemotherapy and those treated with allo-HSCT (HR = 0.76, 95% CI [0.51-1.12], p = 0.16). Patients undergoing allo-HSCT did better than those receiving TKI plus chemotherapy regarding RFS (HR = 0.48, 95% CI [0.37-0.63], p = 0.00), and NRS (OR = 2.64, 95% CI [1.25-5.57], p = 0.00). The NRM rate of the TKI plus chemotherapy group was significantly lower than the allo-HSCT group (OR = 2.33, 95% CI [1.51-3.59], p = 0.00).

CONCLUSION

TKI combined with chemotherapy can be considered a post-remission treatment option for adult Ph+ ALL patients who are ineligible for allo-HSCT. However, more prospective studies with large sample sizes should be carried out in the future.

Risk of Thrombosis in Adult Philadelphia-Positive ALL Treated with an Asparaginase-Free ALL Regimen

BACKGROUND

venous thromboembolism (VTE) is a well-known complication in adults with acute lymphoblastic leukemia (ALL), especially in patients treated with asparaginase (ASNase)-including regiments. However, VTE risk in adult Philadelphia-positive ALL (Ph+ve ALL) patients treated with non-hyperCVAD chemotherapy is unclear. In this study, we examined VTE incidence in adult Ph+ve ALL patients treated with imatinib plus a pediatric-inspired asparaginase (ASNase)-free regimen modified from the Dana Farber Cancer Institute (DFCI) ALL protocol.

METHODS

a single centre retrospective review of Ph+ve ALL patients treated at Princess Margaret Cancer Center (PMCC) from 2008-2019 with imatinib plus modified DFCI protocol was conducted.

RESULTS

of the 123 patients included, 30 (24.3%) had at least 1 radiology confirmed VTE event from diagnosis to the end of maintenance therapy. 86.7% (26/30) of the VTE events occurred during active treatment. Of all VTE events, the majority (53.3%) were DVT and/or PE while another significant portion were catheter-related (40.0%). Major bleeding was observed in 1 patient on VTE treatment with low molecular weight heparin (LMWH).

CONCLUSION

a high VTE incidence (24.3%) was observed in adults Ph+ve ALL patients treated with imatinib plus an ASNase-free modified DFCI pediatric ALL protocol, suggesting prophylactic anticoagulation should be considered for all adult Ph+ve ALL patients including those treated with ASNase-free regimens.

Dasatinib-Blinatumomab for Ph-Positive Acute Lymphoblastic Leukemia in Adults

BACKGROUND

Outcomes in patients with Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) have improved with the use of tyrosine kinase inhibitors. Molecular remission is a primary goal of treatment.

METHODS

We conducted a phase 2 single-group trial of first-line therapy in adults with newly diagnosed Ph-positive ALL (with no upper age limit). Dasatinib plus glucocorticoids were administered, followed by two cycles of blinatumomab. The primary end point was a sustained molecular response in the bone marrow after this treatment.

RESULTS

Of the 63 patients (median age, 54 years; range, 24 to 82) who were enrolled, a complete remission was observed in 98%. At the end of dasatinib induction therapy (day 85), 29% of the patients had a molecular response, and this percentage increased to 60% after two cycles of blinatumomab; the percentage of patients with a molecular response increased further after additional blinatumomab cycles. At a median follow-up of 18 months, overall survival was 95% and disease-free survival was 88%; disease-free survival was lower among patients who had an IKZF1 deletion plus additional genetic aberrations (CDKN2A or CDKN2B, PAX5, or both [i.e., IKZF1 ^plus]). ABL1 mutations were detected in 6 patients who had increased minimal residual disease during induction therapy, and all these mutations were cleared by blinatumomab. Six relapses occurred. Overall, 21 adverse events of grade 3 or higher were recorded. A total of 24 patients received a stem-cell allograft, and 1 death was related to transplantation (4%).

CONCLUSIONS

A chemotherapy-free induction and consolidation first-line treatment with dasatinib and blinatumomab that was based on a targeted and immunotherapeutic strategy was associated with high incidences of molecular response and survival and few toxic effects of grade 3 or higher in adults with Ph-positive ALL. (Funded by Associazione Italiana per la Ricerca sul Cancro and others; GIMEMA LAL2116 D-ALBA EudraCT number, 2016-001083-11; ClinicalTrials.gov number, NCT02744768.).

Treatment and monitoring of Philadelphia chromosome-positive leukemia patients: recent advances and remaining challenges

The Philadelphia (Ph) chromosome, resulting from the t(9;22)(q34;q11) translocation, can be found in chronic myeloid leukemia (CML) as well as in a subset of acute lymphoblastic leukemias (ALL). The deregulated BCR-ABL1 tyrosine kinase encoded by the fusion gene resulting from the translocation is considered the pathogenetic driver and can be therapeutically targeted. In both CML and Ph-positive (Ph+) ALL, tyrosine kinase inhibitors (TKIs) have significantly improved outcomes. In the TKI era, testing for BCR-ABL1 transcript levels by real-time quantitative polymerase chain reaction (RQ-PCR) has become the gold standard to monitor patient response, anticipate relapse, and guide therapeutic decisions. In CML, key molecular response milestones have been defined that draw the ideal trajectory towards optimal long-term outcomes. Treatment discontinuation (treatment-free remission, TFR) has proven feasible in a proportion of patients, and clinical efforts are now focused on how to increase this proportion and how to best select TFR candidates. In Ph+ ALL, results of trials with second- and third-generation TKIs are challenging the role of intensive chemotherapy and even that of allogeneic stem cell transplantation. Additional weapons are offered by the recently introduced monoclonal antibodies. In patients harboring mutations in the BCR-ABL1 kinase domain, prompt therapeutic reassessment and individualization based on mutation status are important to regain response and prevent disease progression. Next-generation sequencing is likely to become a precious tool for mutation testing because of the greater sensitivity and the possibility to discriminate between compound and polyclonal mutations. In this review, we discuss the latest advances in treatment and monitoring of CML and Ph+ ALL and the issues that still need to be addressed to make the best use of the therapeutic armamentarium and molecular testing technologies currently at our disposal.

Efficacy of Ponatinib Versus Earlier Generation Tyrosine Kinase Inhibitors for Front-line Treatment of Newly Diagnosed Philadelphia-positive Acute Lymphoblastic Leukemia

INTRODUCTION

Complete molecular response (CMR) and 2- and 3-year overall survival (OS) were compared for patients with newly diagnosed Philadelphia-positive acute lymphoblastic leukemia (Ph⁺ ALL) who had undergone front-line combination chemotherapy plus ponatinib versus combination therapy plus earlier generation tyrosine kinase inhibitors (TKIs; imatinib, dasatinib, and nilotinib).

PATIENTS AND METHODS

We identified 26 Ph⁺ ALL studies: 25 of earlier generation TKIs and 1 of ponatinib. The outcomes from studies of combination chemotherapy plus earlier generation TKIs were summarized using pooled estimates with 95% confidence intervals (CIs) from a random-effects meta-analysis. A binomial distribution was assumed to calculate the 95% CIs for the results from the single-arm combination chemotherapy plus ponatinib trial. Adjusted logistic meta-regression analyses were used to compare the outcomes between the TKI groups.

RESULTS

The percentage of patients achieving a CMR was greater with combination chemotherapy plus ponatinib (79%) than the pooled percentage of patients achieving a CMR with combination chemotherapy plus earlier generation TKIs (34%). Greater OS was observed with ponatinib compared with the pooled OS for earlier generation TKIs (2-year, 83% vs. 58%; 3-year, 79% vs. 50%). Odds ratios for ponatinib versus earlier generation TKIs were 6.09 (95% CI, 1.16-31.90; P = .034) for CMR, 3.70 (95% CI, 0.93-14.73; P = .062) for 2-year OS, and 4.49 (95% CI, 1.00-20.13; P = .050) for 3-year OS.

CONCLUSION

Ponatinib plus chemotherapy might be associated with better outcomes than chemotherapy with earlier generation TKIs in patients with newly diagnosed Ph⁺ ALL.

A sequential approach with imatinib, chemotherapy and transplant for adult Ph+ acute lymphoblastic leukemia: final results of the GIMEMA LAL 0904 study

In the GIMEMA LAL 0904 protocol, adult Philadelphia positive acute lymphoblastic leukemia patients were treated with chemotherapy for induction and consolidation, followed by maintenance with imatinib. The protocol was subsequently amended and imatinib was incorporated in the induction and post-remission phase together with chemotherapy. Due to the toxicity of this combined approach, the protocol was further amended to a sequential scheme based on imatinib plus steroids as induction, followed by consolidation with chemotherapy plus imatinib and, when applicable, by a hematopoietic stem cell transplant. Fifty-one patients (median age 45.9 years) were enrolled in the final sequential protocol. At the end of induction (day +50), 96% of evaluable patients (n=49) achieved a complete hematologic remission; after consolidation, all were in complete hematologic remission. No deaths in induction were recorded. Overall survival and disease-free survival at 60 months are 48.8% and 45.8%, respectively. At day +50 (end of imatinib induction), a more than 1.3 log-reduction of BCR-ABL1 levels was associated with a significantly longer disease-free survival (55.6%, 95%CI: 39.0-79.3 vs. 20%, 95%CI: 5.8-69.1; P=0.03), overall survival (59.1%, 95%CI: 42.3-82.6 vs. 20%, 95%CI: 5.8-69.1; P=0.02) and lower incidence of relapse (20.5%, 95%CI: 7.2-38.6 vs. 60.0%, 95%CI: 21.6-84.3; P=0.01). Mean BCR-ABL1 levels remained significantly higher in patients who subsequently relapsed. Finally, BCR-ABL1^p190 patients showed a significantly faster molecular response than BCR-ABL1^p210 patients (P=0.023). Though the study was not powered to evaluate the role of allogeneic stem cell transplant, allografting positively impacted on both overall and disease-free survival. In conclusion, a sequential approach with imatinib alone in induction, consolidated by chemotherapy plus imatinib followed by a stem cell transplant is a feasible, well-tolerated and effective strategy for adult Philadelphia positive acute lymphoblastic leukemia, leading to the best long-term survival rates so far reported. (clinicaltrials.gov identifier: 00458848).

Management of adult Ph-positive acute lymphoblastic leukemia

Philadelphia-positive acute lymphoblastic leukemia (Ph+ ALL) has been regarded for decades as the ALL subgroup with the worse outcome. It represents the most frequent genetic subtype of adult ALL, and increases progressively with age. The introduction of tyrosine kinase inhibitors (TKIs) has enabled to obtain complete hematologic remissions (CHRs) in virtually all patients, including the elderly, to improve disease-free survival and overall survival, as well as to increase the percentage of patients who can undergo an allogeneic stem cell transplant (allo-SCT).

The current management of adult Ph+ ALL patients relies on the use of a TKI with or without chemotherapy followed by an allo-SCT, which still remains the only curative option. Minimal residual disease screening is permitting not only a better stratification of patients, but has also allowed to reconsider the role of autologous stem cell transplant for a set of patients who do not have a donor or are not eligible for an allo-SCT. At present, clinical challenges are represented by the emergence of resistant mutations, particularly the gatekeeper T315I, for which alternative approaches, comprising novel TKIs or therapies based on the combination of TKI with immunotherapeutic strategies, are being considered in order to overcome resistance.

Mixed Phenotype Acute Leukemia with Two Immunophenotypically Distinct B and T Blasts Populations, Double Ph (+) Chromosome and Complex Karyotype: Report of an Unusual Case

Mixed phenotype acute leukemia (MPAL) is considered as a rare type of leukemia with an incidence of less than 4% of all acute leukemia based on the most recent 2008 WHO classification. Common subtypes are the B/myeloid and T/myeloid; B/T and trilineage MPAL being extremely rare. We present a case of a male in his 20s, whose peripheral blood smears showed 34% blast cells and bone marrow with 70% blasts. Immunophenotyping by multiparametric flow cytometry showed two populations of blasts, the major one with B-lineage and the minor one with T-lineage. Conventional karyotyping revealed complex karyotype with the presence of double Philadelphia chromosome (Ph⁺). BCR/ABL1 rearrangement was confirmed by fluorescent in situ hybridization (FISH) analysis. The BCR/ABL1 ES probe on interphase cells indicated p190 minor m-BCR/ABL fusion in 46% and a second abnormal clone with double Ph⁺ in 16% of the cells analyzed confirmed by reverse transcription-PCR (RT-PCR). The case was diagnosed as MPAL with double Philadelphia chromosome Ph⁺. The patient was treated with dasatinib, four cycle hyper CVAD/methotrexate cytarabin protocol, and allogeneic transplant. He is still alive in complete hematological, cytogenetic, and molecular remission. Mixed phenotype B/T acute leukemia is an extremely rare disease, particularly those with double Philadelphia chromosomes and clinically presents challenges in diagnosis and treatment.

Favorable outcome of haploidentical hematopoietic stem cell transplantation in Philadelphia chromosome-positive acute lymphoblastic leukemia: a multicenter study in Southwest China

Background

Since the introduction of tyrosine kinase inhibitors (TKIs) into combination chemotherapy regimens, the majority of newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) patients have achieved complete remission (CR). However, without allogeneic hematopoietic stem cell transplantation (HSCT), long-term outcomes in adults remain unsatisfactory. Indeed, haploidentical HSCT has become a common treatment for adult patients who lack an HLA-matched donor, though limited data are available on the efficacy of haploidentical HSCT in Ph+ ALL patients.

Methods

We analyzed the clinical outcomes of 82 Ph+ ALL patients who underwent haploidentical HSCT (n = 47) or HLA-matched HSCT (n = 35). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to assess BCR-ABL expression. All of the patients were treated with an imatinib-based regimen before undergoing HSCT. Imatinib treatment was resumed in the patients’ posttransplantation following detection of BCR-ABL transcripts.

Results

All of the patients achieved neutrophil and platelet engraftment, with the exception of five patients who died prior to engraftment. Haploidentical HSCT was associated with higher incidences of acute graft-versus-host disease (GVHD) (51.1 vs. 25.7 %, p < 0.05) and chronic GVHD (48.9 vs. 25.7 %, p < 0.05) compared with HLA-matched HSCT, but there was no difference in the incidence of either grades III–IV acute GVHD or extensive chronic GVHD. The incidence of cytomegalovirus (CMV) infection was significantly higher in the patients treated with haploidentical HSCT than in those treated with HLA-matched HSCT (38.3 vs. 14.3 %, p < 0.05). Haploidentical HSCT was associated with a significantly lower relapse rate compared with HLA-matched HSCT (44.8 vs. 19.1 %, p < 0.05). There were no differences in non-relapse mortality (NRM), leukemia-free survival (LFS), or overall survival (OS) between the patients who received HLA-matched HSCT and those who underwent haploidentical HSCT.

Conclusions

Our data indicate that the incidence of NRM after HSCT is similar between the patients who receive HLA-matched donor cells and those who receive haploidentical donor cells and that haploidentical HSCT reduces the relapse rate. Haploidentical HSCT represents an encouraging treatment option for Ph+ ALL patients who lack a suitable HLA-matched donor.

Evidence-based guidelines for the use of tyrosine kinase inhibitors in adults with Philadelphia chromosome-positive or BCR-ABL-positive acute lymphoblastic leukemia: a Canadian consensus

Adult Philadelphia chromosome-positive (Ph+) or BCR-ABL-positive (BCR-ABL+) acute lymphoblastic leukemia (all) is an acute leukemia previously associated with a high relapse rate, short disease-free survival, and poor overall survival. In adults, allogeneic hematopoietic cell transplant in first remission remains the only proven curative strategy for transplant-eligible patients. The introduction of tyrosine kinase inhibitors (tkis) in the treatment of patients with Ph+ or BCR-ABL+ all has significantly improved the depth and duration of complete remission, allowing more patients to proceed to transplantation. Although tkis are now considered a standard of care in this setting, few randomized trials have examined the optimal use of tkis in patients with Ph+ all. Questions of major importance remain, including the best way to administer these medications, the choice of tki to administer, and the schedule and the duration to use. We present the results of a systematic review of the literature with consensus recommendations based on the available evidence.

Philadelphia chromosome-positive acute lymphoblastic leukemia with extramedullary and meningeal relapse after allogeneic hematopoietic stem cell transplantation that was successfully treated with dasatinib

Central nervous system (CNS) relapse is a critical issue while treating Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL). A 58-year-old woman with Ph-positive ALL who relapsed after bone marrow transplantation for meningeal leukemia was treated with high-dose methotrexate, which resulted in remission. She underwent allogeneic cord blood transplantation followed by reduced intensity conditioning chemotherapy with imatinib; however, she experienced CNS relapse and developed an extramedullary mass on the right side of the temporal region. We treated 40 mg of dasatinib once daily, which had to be temporarily discontinued because she developed grade 2 pleural effusion and grade 2 hematemesis. After reinitiation of dasatinib, the extramedullary mass disappeared and meningeal leukemia ameliorated almost immediately. With 40 mg dasatinib administered once daily, its trough level and cerebrospinal fluid (CSF) concentration were 32 ng/mL and below the sensitivity threshold of 1 ng/mL, respectively. Treatment was continued, and the patient remained in complete remission until she died of pneumonia 7 years after the initial diagnosis of ALL. Dasatinib can be an effective treatment for Ph-positive ALL with CNS relapse. Although the concentration in the CSF seems low, it may be sufficient to exert anti-leukemic effects in the human CNS.

Current and future management of Ph/BCR-ABL positive ALL

Following the introduction of targeted therapy with tyrosine kinase inhibitors (TKI) at the beginning of the past decade, the outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) has dramatically improved. Presently, the use of refined programs with first/second generation TKI's and chemotherapy together with allogeneic stem cell transplantation allow up to 50% of all patients to be cured. Further progress is expected with the new TKI ponatinib, overcoming resistance caused by T315I point mutation, other targeted therapies, autologous transplantation in molecularly negative patients, therapeutic monoclonal antibodies like inotuzumab ozogamicin and blinatumomab, and chimeric antigen receptor-modified T cells. Ph+ ALL could become curable in the near future even without allogeneic stem cell transplantation, minimizing the risk of therapy-related death and improving greatly the quality of patients' life.

Novel agents and biomarkers for acute lymphoid leukemia

New genetic markers for adult acute lymphoblastic leukemia (ALL) have been found to have prognostic impact, such as the lymphoid transcription factor gene IKZF1 alterations, which are associated with a high rate of leukemic relapse in B-ALL. Although complete remission rates by induction chemotherapy in ALL are now high, the long-term survival is still disappointing. Improvements in the survival outcome of ALL have been observed in young adults as a result of the use of pediatric inspired regimens and the broadening of the number of patients who are eligible for allogeneic SCT. Development of new and less toxic agents also provide promise to improve the outcome in adult ALL, such as tyrosine kinase inhibitors in Ph-positive ALL, rituximab in CD20-positive disease, blinatumomab in precursor B-ALL and nelarabine in T-lineage ALL. Challenges for the future are to implement genomic profiling into the clinical setting to guide risk stratification and providing novel targets for tailored therapies.

Outcomes of adult patients with relapsed acute lymphoblastic leukemia following frontline treatment with a pediatric regimen

We analyzed the outcome of 46 patients with acute lymphoblastic leukemia (ALL) who relapsed following treatment with a pediatric-based protocol; 34 received intensive re-induction chemotherapy, with a CR2 rate of 62%, median overall survival (OS) 7.8 months, median relapse-free survival 5.2 months and one year OS 19%. Allogeneic HSCT was performed in 8 patients in CR2/3, with a median OS 2.2 months. OS was superior in patients who relapsed after completion of chemotherapy, compared to those relapsing on treatment. The outcome of adult ALL relapsing after treatment was therefore poor, and novel salvage strategies are needed to improve outcomes.