An effective chemotherapy-free regimen of ponatinib plus venetoclax for relapsed/refractory Philadelphia chromosome-positive acute lymphoblastic leukemia

A review of immunotargeted therapy for Philadelphia chromosome positive acute lymphoblastic leukaemia: making progress in chemotherapy-free regimens

Philadelphia chromosome-positive acute lymphoblastic leukemia (PH + ALL) is the most common cytogenetic abnormality of B-ALL in adults and is associated with poor prognosis. Previously, the only curative treatment option in PH + ALL was allogeneic hematopoietic stem cell transplantation (Allo-HSCT). Since 2000, targeted therapy combined with chemotherapy, represented by the tyrosine kinase inhibitor Imatinib, has become the first-line treatment for PH + ALL. Currently, the remission rate and survival rate of Imatinib are superior to those of simple chemotherapy, and it can also improve the efficacy of transplantation. More recently, some innovative immune-targeted therapy greatly improved the prognosis of PH + ALL, such as Blinatumomab and Inotuzumab Ozogamicin. For patients with ABL1 mutations and those who have relapsed or are refractory to other treatments, targeted oral small molecule drugs, monoclonal antibodies, Bispecific T cell Engagers (BiTE), and chimeric antigen receptor (CAR) T cells immunotherapy are emerging as potential treatment options. These new therapeutic interventions are changing the treatment landscape for PH + ALL. In summary, this review discusses the current advancements in targeted therapeutic agents shift in the treatment strategy of PH + ALL towards using more tolerable chemotherapy-free induction and consolidation regimens confers better disease outcomes and might obviate the need for HSCT.

Decitabine, venetoclax, and ponatinib for advanced phase chronic myeloid leukaemia and Philadelphia chromosome-positive acute myeloid leukaemia: a single-arm, single-centre phase 2 trial

BACKGROUND

Advanced phase Philadelphia chromosome-positive myeloid disease-consisting of chronic myeloid leukaemia in the myeloid blast phase and in the accelerated phase, and Philadelphia chromosome-positive acute myeloid leukaemia-is associated with poor outcomes. Although previous studies have suggested the benefit of chemotherapy and BCR::ABL1 tyrosine kinase inhibitor combinations, the optimal regimen is uncertain and prospective studies for this rare group of diseases are scant. Preclinical and retrospective clinical data suggest possible synergy between the BCL-2 inhibitor venetoclax and BCR::ABL1 tyrosine kinase inhibitors. We therefore aimed to design a study to evaluate the safety and activity of a novel combination of decitabine, venetoclax, and the third-generation BCR::ABL1 tyrosine kinase inhibitor ponatinib in advanced phase Philadelphia chromosome-positive myeloid diseases.

METHODS

For this phase 2 study, patients aged 18 years or older with previously untreated or relapsed or refractory myeloid chronic myeloid leukaemia-blast phase, chronic myeloid leukaemia-accelerated phase, or advanced phase Philadelphia chromosome-positive acute myeloid leukaemia, and an Eastern Cooperative Oncology Group performance status of 0-3 were eligible. Patients were eligible regardless of the number of previous lines of therapy received or previous receipt of ponatinib. Cycle 1 (induction) consisted of a 7-day lead-in of ponatinib 45 mg orally daily (days 1-7), followed by combination therapy with decitabine 20 mg/m2 intravenously on days 8-12, venetoclax orally daily with ramp-up to a maximum dose of 400 mg on days 8-28, and ponatinib 45 mg orally daily on days 8-28. Cycles 2-24 consisted of decitabine 20 mg/m2 intravenously on days 1-5, venetoclax orally 400 mg on days 1-21, and ponatinib orally daily on days 1-28. Response-based dosing of ponatinib was implemented in consolidation cycles, with reduction to 30 mg daily in patients who reached complete remission or complete remission with an incomplete haematological recovery and a reduction to 15 mg daily in patients with undetectable BCR::ABL1 transcripts. The primary endpoint was the composite rate of complete remission or complete remission with incomplete haematological recovery in the intention-to-treat population. Safety was assessed in the intention-to-treat population. This trial was registered with ClinicalTrials.gov (NCT04188405) and is still ongoing.

RESULTS

Between July 12, 2020, and July 8, 2023, 20 patients were treated (14 with chronic myeloid leukaemia-blast phase, four with chronic myeloid leukaemia-accelerated phase, and two with advanced phase Philadelphia chromosome-positive acute myeloid leukaemia). The median age was 43 years (IQR 32-58); 13 (65%) patients were male and seven (35%) were female; and 12 (60%) were White, three (15%) were Hispanic, four (20%) were Black, and one (5%) was Asian. 12 (60%) patients had received 2 or more previous BCR::ABL1 tyrosine kinase inhibitors, and 14 (70%) patients had at least one high-risk additional chromosomal abnormality or complex karyotype. The median duration of follow-up was 21·2 months (IQR 14·1-24·2). The complete remission or complete remission with an incomplete haematological recovery rate was 50% (10 of 20 patients); complete remission in one [5%] patient and complete remission with incomplete haematological recovery in nine [45%]). An additional six (30%) patients had a morphologic leukaemia-free state. The most common grade 3-4 non-haematological adverse events were febrile neutropenia in eight (40%) patients, infection in six (30%), and alanine or aspartate transaminase elevation in five (25%). Eight (40%) patients had at least one cardiovascular event of any grade. There were three on-study deaths, none of which was considered related to the study treatment and all from infections in the setting of refractory leukaemia.

INTERPRETATION

The combination of decitabine, venetoclax, and ponatinib is safe and shows promising activity in patients with advanced phase chronic myeloid leukaemia, including those with multiple previous therapies or high-risk disease features. Further studies evaluating chemotherapy and venetoclax-based combination strategies using newer-generation BCR::ABL1 tyrosine kinase inhibitors are warranted.

FUNDING

Takeda Oncology, the National Institutes of Health, and the National Cancer Institute Cancer Center.

A phase 1 trial of venetoclax in combination with liposomal vincristine in patients with relapsed or refractory B-cell or T-cell acute lymphoblastic leukemia: Results from the ECOG-ACRIN EA9152 protocol

Introduction

Relapsed or refractory (r/r) acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) remains a therapeutic challenge. Preclinical data in both B- and T-ALL suggests synergy of venetoclax (VEN) with vincristine (VCR). We designed a phase I/II trial (EA9152) of the combination of L-VCR and VEN for patients with r/r B-or T-cell ALL or LL. Here, we report the safety and efficacy outcomes of the phase I portion of this trial (NCT03504644).

Methods

In a 3+3 dose escalation design, r/r ALL subjects were given single-agent VEN doses reaching 400, 600, or 800 mg for the three respective dose levels. Weekly L-VCR at 2.25 mg/m2 IV was started on D15 of cycle 1. The primary phase I objective was to determine the maximum tolerated dose (MTD) of the combination.

Results

Among the 18 patients in phase I, grade ≥ 3 treatment-related adverse events were reported in 89% of treated patients. Two patients (two of three) at dose level 3 experienced dose-limiting toxicities. Therefore, the MTD of the combination was determined to be dose level 2 (VEN 600 mg). Twenty-two percent of evaluable patients (N = 4) achieved a complete response, with two of them showing no evidence of measurable residual disease (MRD).

Conclusion

The combination of VEN and L-VCR was found to be safe for patients with r/r ALL and encouraging preliminary efficacy, including MRD negative responses. With the removal of L-VCR from the US market, the phase 2 portion of this trial is actively enrolling with vincristine sulfate.

Mitochondria and Acute Leukemia: A Clinician's Perspective

Acute leukemia is a group of aggressive hematological malignancies, with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) being the most common types. The biology of acute leukemia involves complex genetic and epigenetic alterations that lead to uncontrolled cell proliferation and resistance to apoptosis. Mitochondrial dysfunction is a feature of acute leukemia that results in altered energy production, unregulated cell death pathways, and increased cancer cell survival. Apoptosis, particularly via the mitochondrial pathway, is crucial for cellular homeostasis and cancer prevention. In acute leukemia, disruption of apoptosis is pivotal in disease development and progression, with elevated levels of anti-apoptotic proteins conferring a survival advantage to leukemia cells and promoting resistance to conventional therapies. Targeting mitochondrial apoptosis using BH3 mimetics and anti-apoptotic protein inhibitors is a viable therapeutic strategy. Alterations in the mitochondrial membrane potential, metabolism, and dynamics also contribute to the pathogenesis of acute leukemia. Continued research is vital for developing novel therapies and enhancing survival outcomes in patients with acute leukemia while minimizing the long-term adverse effects of treatment. In this narrative review, we provide a birds-eye view of the available scientific literature on the importance of mitochondria in acute leukemia, and discuss the role of BH3 mimetics in targeting the mitochondrial internal apoptotic machinery.

Philadelphia-chromosome positive acute lymphoblastic leukemia: ten frequently asked questions

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) constitutes a distinctive cytogenetic entity associated with challenging outcomes, particularly in adult patients. Current upfront chemotherapy-tyrosine kinase inhibitor (TKI)-based therapies include first, second and third-generation TKIs that have revolutionized patient outcomes including molecular remission and overall survival. Chemotherapy-free regimens such as blinatumomab-dasatinib or blinatumomab-ponatinib offer exciting possibilities, yet challenges arise, particularly in preventing central nervous system relapse. Monitoring measurable residual disease is now a cornerstone particularly using next-generation sequencing (NGS)-Clonoseq for accurate assessment. Controversy regarding the ability to omit consolidation with allogeneic stem cell transplantation, specifically for patients achieving early molecular remission, is related to the excellent survival achieved with novel combinations in the upfront setting, however challenged by the lower disease control when transplant is utilized beyond first remission. Post-transplant maintenance introduces new dilemmas: the optimal TKI, dosing, and duration of therapy are open questions. Meanwhile, a myriad of new combinations and cellular therapies are used for relapsed Ph+ ALL, prompting us to unravel the optimal sequencing of these promising regimen. In this review, we delve into the breakthroughs and controversies in Ph+ ALL with ten commonly asked questions.

Novel Biomarkers and Molecular Targets in ALL

PURPOSE OF REVIEW

Acute lymphoblastic leukemia (ALL) is a widely heterogeneous disease in terms of genomic alterations, treatment options, and prognosis. While ALL is considered largely curable in children, adults tend to have higher risk disease subtypes and do not respond as favorably to conventional chemotherapy. Identifying genomic drivers of leukemogenesis and applying targeted therapies in an effort to improve disease outcomes is an exciting focus of current ALL research. Here, we review recent updates in ALL targeted therapy and present promising opportunities for future research.

RECENT FINDINGS

With the utilization of next-generation sequencing techniques, the genomic landscape of ALL has greatly expanded to encompass novel subtypes characterized by recurrent chromosomal rearrangements, gene fusions, sequence mutations, and distinct gene expression profiles. The evolution of small molecule inhibitors and immunotherapies, and the exploration of unique therapy combinations are some examples of recent advancements in the field. Targeted therapies are becoming increasingly important in the treatment landscape of ALL to improve outcomes and minimize toxicity. Significant recent advancements have been made in the detection of susceptible genomic drivers and the use of novel therapies to target them.

Multilineage Lymphoblastic Lymphoma as an Initial Presentation of Mixed Phenotype Acute Leukemia

Mixed phenotype acute leukemia (MPAL) is characterized by leukemic blasts that express markers of multiple lineages. Compared with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), MPAL is considered to have a poor treatment outcome. We report a case of MPAL T/myeloid not otherwise specified that was initially presented as multilineage lymphoblastic lymphoma and subsequently developed into leukemic MPAL. An acute lymphoblastic leukemia-based treatment regimen was ineffective, but azacitidine and venetoclax therapy resulted in hematological complete remission. Our case suggests that multilineage lymphoblastic lymphoma should be considered to be the same disease as MPAL, albeit with different clinical presentations. Optimal treatment for MPAL has not been established yet, but azacitidine and venetoclax therapy may be a potential approach.

Ph+ ALL in 2022: is there an optimal approach?

Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) carried a very poor prognosis prior to the advent of tyrosine kinase inhibitors (TKIs) that block the activity of the BCR-ABL1 oncoprotein. With improvements in TKI efficacy and allogeneic hematopoietic cell transplantation (HCT), survival has improved over the past 3 decades, and the role of chemotherapy and allogeneic HCT is now changing. Better risk stratification, the application of the third-generation TKI ponatinib, and the use of immunotherapy with the CD19-CD3 bifunctional T-cell engaging antibody blinatumomab in place of chemotherapy has made therapy for Ph+ ALL more tolerable and arguably more efficacious, especially for older patients who comprise most patients with Ph+ ALL.

Modern Management Options for Ph+ ALL

Simple Summary

The use of tyrosine kinase inhibitors has represented a major step forward in the therapy of Philadelphia chromosome positive acute lymphoblastic leukemia. Recent improvements in the therapy are focused on early use of third generation tyrosine kinase inhibitors, their combination with immunotherapy, the refined indication of allogeneic hematopoietic stem cell transplantation, the optimal use and duration of maintenance therapy, and the management of patients with molecular or hematological relapse with combination of targeted therapies and immunotherapy, including cellular therapies. Improvements in the assessment of measurable residual disease and in the detection of mutations in the ABL1 domain are contributing to the better selection of the therapy for newly diagnosed as well as for relapsed or refractory patients.

Abstract

Impressive advances have been achieved in the management of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) since the initial concurrent use of imatinib and standard chemotherapy. The attenuation of chemotherapy has proven to be equally effective and less toxic, the use of third generation TKI upfront has improved the frequency of complete molecular response and the survival rate, and the combination of tyrosine kinase inhibitors with immunotherapy has further increased the rate of molecular response to 70–80% after consolidation, which has been translated into a survival rate of 75–90% in recent trials. As a result of these improvements, the role of allogeneic hematopoietic stem cell transplantation is being redefined. The methodology of measurable residual disease assessment and the detection of ABL1 mutations are also improving and will contribute to a more precise selection of the treatment for newly diagnosed and relapsed or refractory (R/R) patients. Finally, new compounds combined with immunotherapeutic approaches, including cellular therapy, are being used as rescue therapy and will hopefully be included in first line therapy in the near future. This article will review and update the modern management of patients with Ph+ ALL.

The Emerging Role of Venetoclax-Based Treatments in Acute Lymphoblastic Leukemia

Venetoclax, a B-cell lymphoma (BCL-2) inhibitor, in combination with hypomethylating agents has become the new standard of care in elderly and unfit patients with acute myeloid leukemia, with significantly improved overall survival and quality of life. Studies of venetoclax combined with high-dose chemotherapy are emerging with evidence of higher rates of molecular remission. Recently, a growing number of publications bring forth the use of venetoclax in patients with acute lymphoblastic leukemia (ALL). In the current review, we present the biological rationale of BCL-2 inhibition in ALL, how the interplay of BH3 proteins modulate the response and the current clinical experience with various combinations.

Targeting Apoptosis in ALL

PURPOSE OF REVIEW

While the treatment of acute lymphoblastic leukemia (ALL) has improved significantly over the last 30 years, the majority of adult patients will have their disease relapse. The BCL-2 gene was initially discovered from follicular lymphoma research; however, the BH3 family of proteins has is emerging to be crucial in patients with ALL due to their reliance on the balance of these pro-apoptotic and anti-apoptotic proteins in the BH3 family. We discuss apoptosis in ALL, the reliance mechanisms, drug development in this space, and areas for future research.

RECENT FINDINGS

The first drugs that were developed to inhibit the BCL-2 pathway include both venetoclax (BCL-2 specific inhibitor) and navitoclax (BCL-2, BCL-XL, and BCL-W). These drugs show promise and have obtained complete remissions, minimal residual disease negative status, and have been used as a bridge to allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia and chronic lymphocytic leukemia. There are multiple ongoing clinical trials looking to assess the use of BCL-2 inhibition with chemotherapy, targeted therapies, and bi-specific T-cell engager therapies not only in both frontline and relapsed refractory ALL but also in consolidation and maintenance phases. There is still a large need for improvement of ALL outcomes in adult patients. Research has shown that ALL depends on the BCL-2 family of proteins for cell survival and proliferation. Targeting this pathway with BCL-2 inhibition has led to encouraging results, and future research is aimed at incorporating this targeted therapy into current treatment paradigms.

Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia in Adults

Simple Summary

Outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) dramatically improved during the past 20 years with the advent of tyrosine kinase inhibitors and monoclonal antibodies. Their great efficacy in young and fit patients led to question our reliance on chemotherapy and allogeneic hematopoietic stem cell transplantation. Moreover, these well-tolerated treatments can be safely administrated even in the elderly that represent the majority of Ph+ ALL patient. This review will focus on the recent changes of paradigm in the management of Ph+ ALL patients and the development of novel therapeutic strategies.

Abstract

Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) is the most common subtype of B-ALL in adults and its incidence increases with age. It is characterized by the presence of BCR-ABL oncoprotein that plays a central role in the leukemogenesis of Ph+ ALL. Ph+ ALL patients traditionally had dismal prognosis and long-term survivors were only observed among patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first complete remission (CR1). However, feasibility of allo-HSCT is limited in this elderly population. Fortunately, development of increasingly powerful tyrosine kinase inhibitors (TKIs) from the beginning of the 2000′s dramatically improved the prognosis of Ph+ ALL patients with complete response rates above 90%, deep molecular responses and prolonged survival, altogether with good tolerance. TKIs became the keystone of Ph+ ALL management and their great efficacy led to develop reduced-intensity chemotherapy backbones. Subsequent introduction of blinatumomab allowed going further with development of chemo free strategies. This review will focus on these amazing recent advances as well as novel therapeutic strategies in adult Ph+ ALL.

INCB84344-201: Ponatinib and steroids in frontline therapy of unfit patients with Ph+ acute lymphoblastic leukemia

In patients with newly diagnosed Ph⁺ ALL, ponatinib and prednisone therapy resulted in long molecular remissions and few resistance mutations.

The observed high rates of discontinuation and dose modification suggest that a lower dose may be more appropriate in older/unfit patients.

Tyrosine kinase inhibitors have improved survival for patients with Philadelphia chromosome–positive (Ph⁺) acute lymphoblastic leukemia (ALL). However, prognosis for old or unfit patients remains poor. In the INCB84344-201 (formerly GIMEMA LAL 1811) prospective, multicenter, phase 2 trial, we tested the efficacy and safety of ponatinib plus prednisone in newly diagnosed patients with Ph⁺ ALL ≥60 years, or unfit for intensive chemotherapy and stem cell transplantation. Forty-four patients received oral ponatinib 45 mg/d for 48 weeks (core phase), with prednisone tapered to 60 mg/m²/d from days-14-29. Prophylactic intrathecal chemotherapy was administered monthly. Median age was 66.5 years (range, 26-85). The primary endpoint (complete hematologic response [CHR] at 24 weeks) was reached in 38/44 patients (86.4%); complete molecular response (CMR) in 18/44 patients (40.9%) at 24 weeks. 61.4% of patients completed the core phase. As of 24 April 2020, median event-free survival was 14.31 months (95% CI 9.30-22.31). Median overall survival and duration of CHR were not reached; median duration of CMR was 11.6 months. Most common treatment-emergent adverse events (TEAEs) were rash (36.4%), asthenia (22.7%), alanine transaminase increase (15.9%), erythema (15.9%), and γ-glutamyltransferase increase (15.9%). Cardiac and vascular TEAEs occurred in 29.5% (grade ≥3, 18.2%) and 27.3% (grade ≥3, 15.9%), respectively. Dose reductions, interruptions, and discontinuations due to TEAEs occurred in 43.2%, 43.2%, and 27.3% of patients, respectively; 5 patients had fatal TEAEs. Ponatinib and prednisone showed efficacy in unfit patients with Ph⁺ ALL; however, a lower ponatinib dose may be more appropriate in this population. This trial was registered at www.clinicaltrials.gov as #NCT01641107.

Optimizing the treatment of acute lymphoblastic leukemia in younger and older adults: new drugs and evolving paradigms

In the past decade, the available treatments for patients with acute lymphoblastic leukemia (ALL) have rapidly expanded, in parallel with an increased understanding of the genomic features that impact the disease biology and clinical outcomes. With the development of the anti-CD22 antibody-drug conjugate inotuzumab ozogamicin, the CD3-CD19 bispecific T-cell engager antibody blinatumomab, CD19 chimeric antigen receptor T-cell therapy, and the potent BCR-ABL1 tyrosine kinase inhibitor ponatinib, the outlook of ALL in both younger and older adults has substantially improved. The availability of highly effective drugs raised important questions concerning the optimal combination and sequence of these agents, their incorporation into frontline regimens, and the role of hematopoietic stem cell transplantation. In this review, we discuss the rapidly evolving paradigms in the treatment of ALL, highlighting both established and effective regimens, as well as promising new therapies that are being evaluated in ongoing clinical trials. We specifically focus on novel combination regimens in both the frontline and salvage settings that are leading to new standards of care in the treatment of ALL.

Impact of frontline treatment approach on outcomes of myeloid blast phase CML

Background

The natural course of untreated chronic myeloid leukemia (CML) is progression to an aggressive blast phase. Even in the current era of BCR-ABL1 tyrosine kinase inhibitors (TKIs), the outcomes of blast phase CML remain poor with no consensus frontline treatment approach.

Methods

We retrospectively analyzed the response rates and survival outcomes of 104 consecutive patients with myeloid blast phase CML (CML-MBP) treated from 2000 to 2019 based on 4 different frontline treatment approaches: intensive chemotherapy (IC) + TKI (n = 20), hypomethylating agent (HMA) + TKI (n = 20), TKI alone (n = 56), or IC alone (n = 8). We also evaluated the impact of TKI selection and subsequent allogeneic stem cell transplant (ASCT) on patient outcomes.

Results

Response rates were similar between patients treated with IC + TKI and HMA + TKI. Compared to treatment with TKI alone, treatment with IC/HMA + TKI resulted in a higher rate of complete remission (CR) or CR with incomplete count recovery (CRi) (57.5% vs 33.9%, p < 0.05), a higher complete cytogenetic response rate (45% vs 10.7%, p < 0.001), and more patients proceeding to ASCT (32.5% vs 10.7%, p < 0.01). With a median follow-up of 6.7 years, long-term outcomes were similar between the IC + TKI and HMA + TKI groups. Combination therapy with IC/HMA + TKI was superior to therapy with TKI alone, including when analysis was limited to those treated with a 2nd/3rd-generation TKI. When using a 2nd/3rd-generation TKI, IC/HMA + TKI led to lower 5-year cumulative incidence of relapse (CIR; 44% vs 86%, p < 0.05) and superior 5-year event-free survival (EFS; 28% vs 0%, p < 0.05) and overall survival (OS; 34% vs 8%, p = 0.23) compared to TKI alone. Among patients who received IC/HMA + TKI, EFS and OS was superior for patients who received a 2nd/3rd generation TKI compared to those who received imatinib-based therapy. In a landmark analysis, 5-year OS was higher for patients who proceeded to ASCT (58% vs 22%, p = 0.12).

Conclusions

Compared to patients treated with TKI alone for CML-MBP, treatment with IC + TKI or HMA + TKI led to improved response rates, CIR, EFS, and OS, particularly for patients who received a 2nd/3rd-generation TKI. Combination therapy with IC + TKI or HMA + TKI, rather than a TKI alone, should be considered the optimal treatment strategy for patients with CML-MBP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-021-01106-1.