A multicenter total therapy strategy for de novo adult Philadelphia chromosome positive acute lymphoblastic leukemia patients: final results of the GIMEMA LAL1509 protocol

Management of Adult Acute Lymphoblastic Leukemia: A Review

Importance

Research in acute lymphoblastic leukemia (ALL) is translating into rapid changes in therapy and outcomes. Historically, adult ALL was treated with intensive chemotherapy extending over 2.5 to 3 years. This established tradition, accepted because of the high cure rates in childhood ALL, has been challenged by the development of highly active targeted therapies.

Observation

Treatment modalities, combined with less and shorter chemotherapy durations, have produced better results than chemotherapy. The novel therapies include using the more potent BCR::ABL1 tyrosine kinase inhibitors (eg, ponatinib, dasatinib) with the bispecific CD3-CD19 T-cell engager antibody blinatumomab in Philadelphia chromosome-positive ALL and combining blinatumomab and/or inotuzumab (CD22 antibody drug conjugate) with standard chemotherapy in B-cell ALL. These have been associated with improved 4-year survival rates of 85% to 90% in Philadelphia chromosome-positive ALL and 80% to 85% in B-cell ALL.

Conclusions and Relevance

The management of ALL is changing rapidly. Investigators have evaluated frontline and later-line regimens with combinations of tyrosine kinase inhibitors and immunotherapies with less or no chemotherapy. Future research will evaluate CD19, CD20, and CD22 multitargeting antibodies and chimeric antigen receptor T-cell therapies, new antibody formulations, and less intensive/shorter regimens.

Integrating Blinatumomab in the Frontline Treatment in B-Cell Acute Lymphoblastic Leukemia: A New Era in Therapeutic Management

Blinatumomab, a bispecific T-cell engager (BiTE), has shown substantial efficacy in treating both relapsed/refractory (R/R) Philadelphia chromosome (Ph)-positive and Ph-negative acute lymphoblastic leukemia (ALL). With its targeted mechanism of action, favorable safety profile, and ability to induce deep molecular remissions, blinatumomab is increasingly incorporated into frontline treatment regimens for B-ALL. Recently, the Food and Drug Administration (FDA) has approved its use in the frontline setting for Ph-negative ALL. In Ph-negative ALL, combining blinatumomab with intensive chemotherapy has resulted in superior measurable residual disease (MRD) clearance and improved long-term outcomes. In Ph-positive ALL, combination therapies involving tyrosine kinase inhibitors (TKIs), particularly ponatinib and blinatumomab, are challenging the traditional approach of allogeneic hematopoietic stem cell transplantation (allo-SCT). This review explores the current evidence supporting the frontline use of blinatumomab in newly diagnosed adults with B-ALL, its impact on treatment paradigms, and potential future directions, including novel combination therapies and the role of emerging immunotherapeutic approaches.

Tyrosine Kinase Inhibitor Post-Allogeneic Stem Cell Transplantation in Adult Philadelphia-Positive B-Acute Lymphoblastic Leukemia: State of the Art and Future Directions

In a scenario characterized by continuous improvement in outcomes, Philadelphia chromosome-positive (Ph+) ALL, once considered a biologically defined subtype with one of the poorest prognoses, now includes patients achieving long-term survival even without allogeneic stem cell transplantation. First-line therapy is increasingly adopting a chemo-free approach, combining tyrosine kinase inhibitors (TKIs) with immunotherapy-specifically blinatumomab-which has resulted in high rates of complete molecular responses and improved survival outcomes. Within this paradigm shift, the allocation to transplantation is becoming increasingly selective and genomically oriented, focusing on patients with particularly unfavorable prognostic and predictive factors. For patients undergoing transplantation, maintenance therapy with TKIs has emerged as one of the most important strategies to reduce the risk of relapse. However, there remains considerable uncertainty regarding which patients benefit most from this approach, the optimal TKI agents, dosing strategies, and the duration of maintenance therapy. In this review, we aim to consolidate the available evidence on this topic, analyzing it in the context of the most recent clinical experiences.

Asciminib plus dasatinib and prednisone for Philadelphia chromosome-positive acute leukemia

ABSTRACT

Dasatinib is an effective treatment for Philadelphia chromosome-positive (Ph+) acute leukemia, but some patients develop resistance. Combination treatment with dasatinib and asciminib, an allosteric inhibitor of BCR::ABL1, may deepen responses and prevent the emergence of dasatinib-resistant clones. In this phase 1 study (NCT03595017), 24 adults with Ph+ acute lymphoblastic leukemia (ALL; n = 22; p190, n = 16; p210, n = 6) and chronic myeloid leukemia in lymphoid blast crisis (n = 2) were treated with escalating daily doses of asciminib in combination with dasatinib 140 mg daily plus prednisone 60 mg/m2 daily to determine the maximum tolerated dose. After a 28-day induction, dasatinib and asciminib were continued indefinitely or until hematopoietic stem cell transplant. The median age was 64.5 years (range, 33-85; 50% aged ≥65 years). The recommended phase 2 dose of asciminib was 80 mg daily in combination with dasatinib and prednisone. The dose limiting toxicity at 160 mg daily was asymptomatic grade 3 pancreatic enzyme elevation without symptomatic pancreatitis. There were no vaso-occlusive events. Among patients with de novo ALL, the complete hematologic remission rates at days 28 and 84 were 84% and 100%, respectively. At day 84, 100% of patients achieved complete cytogenetic remission, 89% achieved measurable residual disease negativity (<0.01%) by multicolor flow cytometry, and 74% and 26% achieved BCR::ABL1 reverse transcription quantitative polymerase chain reaction <0.1% and <0.01%, respectively. Dual BCR::ABL1 inhibition with dasatinib and asciminib is safe with encouraging activity in patients with de novo Ph+ ALL. This trial was registered at www.clinicaltrials.gov as #NCT02081378.

How I treat adult Ph+ ALL

ABSTRACT

The Philadelphia (Ph) chromosome is one of the few genetic aberrations in which a casualty has been proven and, as such, represents a success in the history of medicine. This is also evident in the setting of Ph+ acute lymphoblastic leukemia (ALL), the most frequent genetic subgroup in adult ALL, whose incidence increases with age and whose prognosis, before the advent of tyrosine kinase inhibitors (TKIs), was particularly poor. The outcome and management of patients with Ph+ ALL have greatly improved since the incorporation of first-, second-, and third-generation TKIs in the therapeutic backbone and is further changing with the more recent introduction of immunotherapy. This allows for long-term survival rates currently ranging between 75% and 80%. The clinical scenario of adult Ph+ ALL has thus changed profoundly, and new challenges are emerging. In this article, illustrative clinical cases are used to discuss the current role of systemic chemotherapy and allogeneic stem cell transplant, the difficulty in treating central nervous system relapses and, more in general, relapses in the current therapeutic era, and the possibility of stopping TKIs. Finally, the challenges related to an optimal management of these patients are discussed.

IKZF1 in acute lymphoblastic leukemia: the rise before the fall?

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children and adolescents and in recent decades, the survival rates have risen to >90% in children largely due the introduction of risk adapted therapy. Therefore, knowledge of factors influencing risk of relapse is important. The transcription factor IKAROS is a regulator of lymphocyte development and alterations of its coding gene, IKZF1, are frequent in ALL and are associated with higher relapse risk. This concise review will discuss the normal function of IKAROS together with the effect of gene alterations in ALL such as relieved energy restriction and altered response to anti-leukemic drugs. Besides the biology, the clinical impact of gene alterations in the different subtypes of ALL will be discussed. Finally, possibilities for treating ALL with IKZF1 alterations will be considered including novel therapies like cell signaling inhibitors and immunotherapy.

Efficacy of Chemotherapy-Free Regimens in the Treatment of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: A Systematic Review and Meta-Analysis

INTRODUCTION

The historical standard of care for Ph+ ALL is chemotherapy plus a tyrosine kinase inhibitor (TKI). Recently chemotherapy-free regimens have shown promising efficacy. We performed a meta-analysis to compare the efficacy of chemotherapy-free regimens for Ph+ ALL.

METHODS

We searched PubMed and Embase for chemotherapy-free regimens for Ph+ ALL published between January 2000 and October 2023. Of the 5,348 articles screened, 9 nonrandomized clinical trials enrolling 413 patients were included. Two trials (N = 117) included treatment with 3 agents (blinatumomab, TKI, and steroid) and 7 trials (N = 248) included treatment with 2 agents (TKI and steroids). R software was used to conduct the meta-analysis (PROSPERO registration no. CRD42023482439).

RESULTS

The pooled complete molecular response (CMR) rate of patients receiving a TKI, blinatumomab, and steroids was 81% (95%CI, 69%-89%). TKIs plus blinatumomab were nearly 6 times as likely to have CMR (odds ratio [OR], 5.98; 95%CI, 2.99-11.96) and more than 5 times as likely to be alive at 1-year (OR, 5.1; 95%CI, 1.74-14.9) as compared to TKIs alone. Patients receiving ponatinib were about twice as likely as those receiving dasatinib to achieve CMR (OR, 2.51; 95%CI, 0.72-8.72).

CONCLUSION

Adding blinatumomab to TKIs and steroids significantly improved Ph+ ALL patients' response and survival rates. Regimens with ponatinib elicited higher molecular response rates than those with other TKIs. The high response and survival rates achieved with blinatumomab plus TKIs and steroids suggest that further studies are required to assess the need for intensive treatments such as chemotherapy or stem cell transplant in these patients.

Center effect on allogeneic hematopoietic stem cell transplantation outcomes for B-cell acute lymphoblastic leukemia

This nationwide study retrospectively examined the center effect on allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult B-cell acute lymphoblastic leukemia. The cohort analyses were separated into Philadelphia chromosome (Ph)-positive and -negative cases. The patients were divided into low- and high-volume groups according to the number of allo-HSCTs at each facility. The primary endpoint was 5-year overall survival (OS). This study included 1156 low-volume and 1329 high-volume Ph-negative and 855 low-volume and 926 high-volume Ph-positive cases. In Ph-negative cases, 5-year OS was significantly higher in the high-volume centers at 52.7% (95% confidence interval [CI]: 49.9-55.5) versus 46.8% (95% CI: 43.8-49.7) for the low-volume centers (P < 0.01). Multivariate analysis identified high volume as a favorable prognostic factor (hazard ratio [HR]: 0.81 [95% CI: 0.72-0.92], P < 0.01). Subgroup analysis in Ph-negative cases revealed that the center effects were more evident in patients aged ≥40 years (HR: 0.72, 95% CI: 0.61-0.86, P < 0.01) and those receiving cord blood transplantation (HR: 0.62, 95% CI: 0.48-0.79, P < 0.01). In Ph-positive cases, no significant difference was observed between the high and low-volume centers for 5-year OS (59.5% [95% CI: 56.2-62.7] vs. 54.9% [95% CI: 51.3-58.3], P = 0.054). In multivariate analysis, center volume did not emerge as a significant prognostic indicator. This study showed center effects on survival in Ph-negative but not in Ph-positive cases, highlighting the heterogeneity of the center effect in allo-HSCT for B-cell acute lymphoblastic leukemia. Collaborative efforts among transplant centers and further validation are essential to improve outcomes.

A critical review of management of allogeneic transplant-eligible adults with Ph+ acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) in 20%-30% of adult patients contains the Philadelphia (Ph+) chromosome. Historically, Ph+ ALL denoted a markedly inferior outcome and long-term survival in the absence of an allograft was uncommon. However, the advent of targeted therapy directed against the BCR::ABL1 fusion protein with various tyrosine kinase inhibitors (TKIs) has markedly improved the prognosis, resulting in a number of treatment controversies in allograft-eligible patients. Which is the best TKI to use in induction? What is the clinical relevance of the subdivision of Ph+ ALL into multilineage vs lymphoid types? Do all patients in first morphological complete remission (CR1) after induction and consolidation with chemotherapy/TKI require an allograft? If not, what risk factors predict a poor outcome without an allograft? Can chemotherapy-free approaches, such as blinatumomab in conjunction with more potent TKIs, obviate the need for an allograft in high-risk patients? What is the best strategy to deal with persistent or emerging minimal residual disease both pre- and post-transplant? Is maintenance TKI indicated in all patients post allograft? Can salvage therapy and a subsequent allograft cure patients who relapse after not being transplanted in CR1? This manuscript reviews the latest data influencing contemporary management and discusses these controversies.

[The progress in classification and prognosis evaluation of BCR::ABL1 positive acute lymphoblastic leukemia]

The application of tyrosine kinase inhibitors and targeted immunotherapy has revolutionized the therapeutic strategies and clinical outcome for BCR::ABL1-positive B-cell acute lymphoblastic leukemia (BCR::ABL1(+) B-ALL). The classification was updated successively by the World Health Organization and the International Consensus Classification in 2022. The risk stratification of this entity, for the first time, was modified by the National Comprehensive Cancer Network in 2023, both minimal residual disease assessment and IKZF1(plus) genotyping recognized as critical prognostic factors. These important updates would have significant implications for clinical management. Therefore, this review focused on the latest advances in the classification and prognostic evaluation of BCR::ABL1(+) B-ALL.

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.

Nilotinib with or without cytarabine for Philadelphia-positive acute lymphoblastic leukemia

ABSTRACT

We previously demonstrated that a reduced-intensity chemotherapy schedule can safely replace hyper-CVAD (cyclophosphamide-vincristine-doxorubicin [Adriamycin]-dexamethasone) cycle 1 when combined with imatinib in adults with Philadelphia-positive acute lymphoblastic leukemia. In the present randomized GRAAPH-2014 trial, we used nilotinib and addressed the omission of cytarabine (Ara-C) in consolidation. The primary objective was the major molecular response (MMR) rate measured by BCR::ABL1 quantification after cycle 4 (end of consolidation). All patients were eligible for allogeneic stem cell transplant (SCT), whereas those in MMR could receive autologous SCT, followed by 2-year imatinib maintenance in both cases. After the enrollment of 156 of 265 planed patients, the data and safety monitoring board decided to hold the randomization because of an excess of relapse in the investigational arm. Among the 155 evaluable patients, 76 received Ara-C during consolidation (arm A) and 79 did not (arm B). Overall, 133 patients (85%) underwent SCT, 93 allogeneic and 40 autologous. The noninferiority end point regarding MMR was reached with 71.1% (arm A) and 77.2% (arm B) of patients reaching MMR. However, the 4-year cumulative incidence of relapse was higher in arm B compared with arm A (31.3% [95% confidence interval {CI}, 21.1%-41.9%] vs 13.2% [95% CI, 6.7%-21.9%]; P = .017), which translated to a lower relapse-free survival. With a median follow-up of 3.8 years, 4-year overall survival was 79.0% (95% CI, 70.6%-89.3%) in arm A vs 73.4% (95% CI, 63.9%-84.4%) in arm B (P = .35). Despite a noninferior rate of MMR, more relapses were observed when ARA-C was omitted without impact on survival. ClinicalTrials.gov ID, NCT02611492.

Ponatinib vs Imatinib in Frontline Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: A Randomized Clinical Trial

Importance

In newly diagnosed Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), disease progression due to acquired resistance to first- or second-generation BCR::ABL1 tyrosine kinase inhibitors is common. Ponatinib inhibits BCR::ABL1 and all single-mutation variants, including T315I.

Objective

To compare frontline ponatinib vs imatinib in adults with newly diagnosed Ph+ ALL.

Design, Setting, and Participants

Global registrational, phase 3, open-label trial in adults aged 18 years or older with newly diagnosed Ph+ ALL. From January 2019 to May 2022, eligible patients at 77 sites were randomized 2:1 to ponatinib (30 mg/d) or imatinib (600 mg/d) with reduced-intensity chemotherapy, followed by single-agent ponatinib or imatinib after the cycle 20 phase of the trial. The last date of follow-up for this analysis was August 12, 2022.

Intervention

Patients received ponatinib, 30 mg/d, or imatinib, 600 mg/d, with reduced-intensity chemotherapy, followed by single-agent ponatinib or imatinib after cycle 20. The ponatinib dose was reduced to 15 mg on achievement of minimal residual disease-(MRD) negative complete remission.

Main Outcomes and Measures

The primary end point of this interim analysis was MRD-negative complete remission (≤0.01% BCR::ABL1 [MR4] centrally assessed by reverse transcriptase-quantitative polymerase chain reaction), with complete remission maintained for at least 4 weeks at the end of cycle 3. The key secondary end point was event-free survival.

Results

Of 245 patients randomized (median age, 54 years; 133 [54.3%] female), 232 (ponatinib, n = 154; imatinib, n = 78) who had p190 or p210 dominant isoforms verified by the central laboratory were analyzed for the primary end point. The MRD-negative complete remission rate (primary end point) was significantly higher with ponatinib (34.4% [53/154]) vs imatinib (16.7% [13/78]) (risk difference, 0.18 [95% CI, 0.06-0.29]; P = .002). At the data cutoff, event-free survival had not met the prespecified number of events. Median event-free survival was not reached in the ponatinib group and was 29 months in the imatinib group. The most common adverse events were similar between treatment groups. Arterial occlusive events were infrequent and comparable between groups (ponatinib, 2.5%; imatinib, 1.2%).

Conclusions and Relevance

Ponatinib demonstrated a superior rate of MRD-negative complete remission at the end of induction vs imatinib when combined with reduced-intensity chemotherapy in adults with newly diagnosed Ph+ ALL. The safety profile of ponatinib was comparable with imatinib.

Trial Registration

ClinicalTrials.gov Identifier: NCT03589326.

Transcriptome analysis of primary adult B-cell lineage acute lymphoblastic leukemia identifies pathogenic variants and gene fusions, and predicts subtypes for in depth molecular diagnosis

BACKGROUND

B-cell acute lymphoblastic leukemia (B-ALL) is classified into subgroups based on known driver oncogenes and molecular lesions, including translocations and recurrent mutations. However, the current diagnostic tests do not identify subtypes or oncogenic lesions for all B-ALL samples, creating a heterogeneous B-ALL group of unknown subtypes.

METHODS

We sorted primary adult B-ALL cells and performed transcriptome analysis by bulk RNA sequencing (RNA-seq).

RESULTS

Transcriptomic analysis of an adult B-ALL cohort allowed the classification of four patient samples with subtypes that were not previously revealed by standard gene panels. The leukemia of two patients were of the DUX4 subtype and two were CRLF2+ Ph-like B-ALL. Furthermore, single nucleotide variant analysis detected the oncogenic NRAS-G12D, KRAS-G12D, and KRAS-G13D mutations in three of the patient samples, presenting targetable mutations. Additional oncogenic variants and gene fusions were uncovered, as well as multiple variants in the PDE4DIP gene across five of the patient samples.

CONCLUSION

We demonstrate that RNA-seq is an effective tool for precision medicine in B-ALL by providing comprehensive molecular profiling of leukemia cells, identifying subtype and oncogenic lesions, and stratifying patients for appropriate therapy.

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.

Case Report: CAR-T cells and subsequent maintenance with ponatinib in an adult Philadelphia acute lymphoblastic leukemia patient with hematological and extramedullary relapse after allogeneic stem cell transplantation

Relapsed or refractory (r/r) Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) still represent an unmet clinical need despite the new immune therapies available for these patients. We report the case of a Ph + ALL relapsed one year after allogeneic stem cell transplant. After one DLI was started CAR-T program with brexucabtageneautoleucel, using as bridging treatment ponatinib, vincristine and prednisone. Brexu-cel infusion was performed in 2023, without CRS or ICANS onset. One month after Brexu-cel infusion BM aspirate and CT-PET showed recovery of full donor chimerism, MRD negativity and complete metabolic remission. Subsequently was started maintenance with ponatinib: at last follow-up, the patient persisted in leukemia-free status. CAR-T cells represent the most powerful treatment for r/r Ph + ALL but there is no consensus about the optimal bridging strategy and also regarding the management algorithm during "post CAR-T phase". Here, we report the efficacy of ponatinib as a bridge to anti-CD19 CAR-T cell therapy and as post CAR-T maintenance. Our experience suggests that a preserving approach with TKI associated to low-dose chemotherapy can be the optimal bridging therapy prior to CAR-T and that an "MRD-guided" and "TKI-based" maintenance strategy can represent the best choice for Ph + ALL which satisfactorily responds to CAR-T.

How to Manage Philadelphia-Positive Acute Lymphoblastic Leukemia in Resource-Constrained Settings

Recent studies have indicated that more than half of adult patients newly diagnosed with Ph+ ALL can now achieve a cure. However, determining the most suitable protocol for less-resourced settings can be challenging. In these situations, we must consider the potential for treatment toxicity and limited access to newer agents and alloSCT facilities. Currently, it is advisable to use less intensive induction regimens for Ph+ ALL. These regimens can achieve high rates of complete remission while causing fewer induction deaths. For consolidation therapy, chemotherapy should remain relatively intensive, with careful monitoring of the BCR-ABL1 molecular transcript and minimal residual disease. AlloSCT may be considered, especially for patients who do not achieve complete molecular remission or have high-risk genetic abnormalities, such as IKZF1-plus. If there is a loss of molecular response, it is essential to screen patients for ABL mutations and, ideally, change the TKI therapy. The T315I mutation is the most common mechanism for disease resistance, being targetable to ponatinib. Blinatumomab, a bispecific antibody, has shown significant synergy with TKIs in treating this disease. It serves as an excellent salvage therapy, aside from achieving outstanding results when incorporated into the frontline.

Low-Intensity and Chemo-Free Treatments in Ph+ ALL: Progression-Free Survival Based on Indirect Comparisons

In Philadelphia chromosome-positive B-cell (Ph+) acute lymphoblastic leukemia (LLA), growing evidence has accumulated regarding the efficacy of low-intensity and chemo-free regimens. Our objective was to analyze all recent trials evaluating these treatments and to compare them in terms of efficacy. We applied the Shiny method, an artificial intelligence technique, to analyze Kaplan-Meier curves and reconstruct patient-level data. Reconstructed patient data were then evaluated through standard survival statistics and subjected to indirect head-to-head treatment comparisons. The endpoint was progression-free survival (PFS). Based on 432 reconstructed patients, eight trials were analyzed. The survival data from these trials were pooled into three types of treatments: (i) treatments based on tyrosine kinase inhibitors (TKIs) combined with reduced-intensity chemotherapy (denoted as TKICHE); (ii) TKIs associated with steroids with no chemotherapy (TKISTE); (iii) chemotherapy-free combinations of blinatumomab plus TKIs (TKIBLI). According to the Shiny method, the three PFS curves were reported in a single Kaplan-Meier graph and subjected to survival statistics. In terms of PFS, TKIBLI ranked first, TKICHE second, and TKISTE third; the differences between these three regimens were statistically significant. This multi-treatment Kaplan-Meier graph, generated through the Shiny method, summarized the current evidence on these treatments in both qualitative and quantitative terms.

Moving away from chemotherapy in newly diagnosed Philadelphia chromosome-positive B-cell acute lymphoblastic leukaemia

Chemotherapy-free regimens are reshaping the treatment landscape of Philadelphia chromosome-positive acute lymphoblastic leukaemia. The report by Xie et al. suggests that the combination of dasatinib and prednisone is effective as induction and early consolidation. Survival was improved in patients who subsequently underwent allogeneic stem cell transplantation. Commentary on: Xie et al. Dasatinib plus prednisone as induction and consolidation for adults with Ph-positive acute lymphoblastic leukaemia: A single-arm, multicentre, phase 2 trial. Br J Haematol 2023;202:1119-1126.

Frontline combination of ponatinib and hyper-CVAD in Philadelphia chromosome-positive acute lymphoblastic leukemia: 80-months follow-up results

The combination of ponatinib, a third-generation BCR::ABL1 tyrosine kinase inhibitor, with hyper-CVAD chemotherapy resulted in high rates of complete molecular remissions and survival, without the need for stem cell transplantation (SCT) in most patients with Philadelphia chromosome(Ph)-positive acute lymphocytic leukemia (ALL). Confirming these results in a large cohort of patients with longer follow-up would establish this regimen as a new standard of care. Adults with newly diagnosed Ph-positive ALL were treated with the hyper-CVAD regimen. Ponatinib was added as 45 mg daily × 14 during induction, then 45 mg daily continuously (first 37 patients) or 30 mg daily continuously, with dose reduction to 15 mg daily upon achievement of a complete molecular response (CMR; absence of a detectable BCR::ABL1 transcript by quantitative reverse transcription polymerase-chain reaction at a sensitivity of 0.01%). Maintenance therapy consisted of daily ponatinib and vincristine-prednisone monthly for 2 years, followed by daily ponatinib indefinitely. Twelve intrathecal injections of cytarabine alternating with methotrexate were given as central nervous system prophylaxis. The trial is registered on clinicaltrials.gov with the identifier NCT01424982. Eighty-six patients were treated. Their median age was 46 years (range, 21-80). All 68 patients with active disease at the initiation of therapy achieved complete response (CR) The cumulative CMR rate was 86%. Twenty- patients (23%) underwent allogeneic SCT. With a median follow-up of 80 months (range, 16-129 months), the estimated 6-year event-free survival rate was 65% and the overall survival rate was 75%. There was no difference in outcome by performance of allogeneic SCT in first CR. Common grade 3-5 adverse events included infection (n = 80, 93%), increased liver transaminases (n = 26, 31%) and total bilirubin (n = 13, 15%), hypertension (n = 15, 17%), pancreatitis (n = 13, 15%), hemorrhage (n = 12, 13%), and skin rash (n = 9, 10%). Two ponatinib-related deaths from myocardial infarction (3%; at months 2.6 and 4.3, respectively; both in CR) in the first 37 patients treated led to the ponatinib dose-modifications mentioned earlier, with no further ponatinib-related deaths observed. The long-term results of ponatinib and hyper-CVAD continue to demonstrate excellent outcome results and acceptable safety data, indicating that this strategy is another standard of care approach in frontline Ph-positive ALL.

Treatment de-escalation in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia: the emerging role of chemotherapy-free regimens

The management of Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) has witnessed major progress over the past two decades. Initially, the incorporation of the first-generation BCR::ABL1 tyrosine kinase inhibitor (TKI) imatinib into intensive chemotherapy regimens improved outcomes compared with chemotherapy alone. The combinations of chemotherapy with second- or third-generation TKIs further improved outcomes, with higher rates of complete molecular remission (CMR) and superior survival. The combination of ponatinib plus chemotherapy resulted in durable remissions and prolonged long-term survival, even in patients who did not receive allogeneic stem cell transplantation (SCT). The promising results seen with later-generation TKIs have caused many to re-evaluate the role of allogeneic SCT for patients who achieve CMR with potent TKI regimens. Recently, the chemotherapy-free combinations of blinatumomab plus TKIs were shown to be safe and effective in newly diagnosed Ph-positive ALL, sparing patients the toxicities associated with intensive chemotherapy. In particular, encouraging early results have been seen with the combination of blinatumomab plus ponatinib, suggesting that this regimen may represent a chemotherapy-free and SCT-sparing strategy for patients with Ph-positive ALL. Herein, we discuss the current evidence for frontline therapies of Ph-positive ALL, the treatment de-escalation strategies over time, and the role of allogeneic SCT in view of the emergence of newer chemotherapy-free regimens using potent TKIs.

Intensity of induction regimen and outcomes among adults with Ph+ALL undergoing allogeneic hematopoietic stem cell transplantation

Tyrosine kinase inhibitors (TKIs) are essential for the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and have allowed for effective, low intensity induction regimens including no or minimal chemotherapy. Whether the use of low intensity induction regimens impacts outcomes after allogeneic hematopoietic stem cell transplant (alloHCT) is less understood. We identified consecutive adult patients with Ph+ ALL undergoing alloHCT in first complete remission (CR1) at our center from 2010 to 2021 and examined the impact of pre-transplant induction intensity on outcomes. Among the 87 identified patients, 44 (51%) received low intensity induction and 43 (49%) received induction with high intensity chemotherapy. Patients receiving low intensity induction were older (median age 60 vs. 47 years, p < 0.01). Following induction, measurable residual disease (MRD) negativity by BCR::ABL1 RT-PCR was similar in the low and high intensity induction cohorts (54% and 52% respectively). Receipt of reduced intensity transplant conditioning was not associated with intensity of induction regimen (39% vs. 19% in low vs. high, respectively, p = 0.06). At a median follow-up of 21 months from transplant, there was no difference between low and high intensity induction with respect to 2-year disease-free survival (58% vs. 56%), 2-year overall survival (62% vs. 63%), 2-year cumulative incidence of relapse (9% vs. 17%), and 2-year non-relapse mortality (33% vs. 29%). We also found no difference in outcomes when patients were segmented by both induction and conditioning regimen intensities. Our retrospective analysis suggests that induction intensity does not impact post-transplant outcomes among patients with Ph+ ALL transplanted in CR1.

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.

Changing Landscape in the Treatment of Adult Acute Lymphoblastic Leukemia (ALL)

Acute lymphoblastic leukemia (ALL) is a rare hematological malignancy characterized by proliferation and accumulation of premature lymphoid blasts. Depending on risk factors, the survival of acute lymphoblastic leukemia has significantly improved over the last decades. During the last years, measurable residual disease (MRD) assessment has evolved into one of the most sensitive markers for prognosis and risk of relapse. For this reason, measurable residual disease detection and monitoring count as standard evaluation in patients with acute lymphoblastic leukemia. Allogeneic stem cell transplantation is still the recommended treatment option for patients with high and highest risk profiles as well as for relapsed or refractory settings. The increased understanding of the pathomechanism and heterogeneity of acute lymphoblastic leukemia has led to the development of several novel therapeutic opportunities such as tyrosine-kinase inhibitors, antibody-based therapies and CAR-T cells with the aim of improving clinical outcomes. Furthermore, the major advances in disease understanding of ALL have led to the identification of different subgroups and better disease stratification. Even though novel therapy targets are constantly developed, acute lymphoblastic leukemia remains a challenging and life-threatening disease. To improve the historically unsatisfying result in therapy of adult acute lymphoblastic leukemia many clinical trials have recently been initiated to determine the optimum combination regimens of novel and old agents for adult acute lymphoblastic leukemia.

Prognostic significance of copy number variation in B-cell acute lymphoblastic leukemia

Copy number variations (CNVs) are widespread in both pediatric and adult cases of B-cell acute lymphoblastic leukemia (B-ALL); however, their clinical significance remains unclear. This review primarily discusses the most prevalent CNVs in B-ALL to elucidate their clinical value and further personalized management of this population. The discovery of the molecular mechanism of gene deletion and the development of targeted drugs will further enhance the clinical prognosis of B-ALL.

Treatment of Adults With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia-From Intensive Chemotherapy Combinations to Chemotherapy-Free Regimens: A Review

Importance

With the advent of potent BCR::ABL1 tyrosine kinase inhibitors (TKIs), Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL) is now a relatively favorable-risk acute leukemia. In this review, we discuss the current evidence for frontline therapies of Ph-positive ALL, the major principles that guide therapy, and the progress with chemotherapy-free regimens.

Observations

Incorporating TKIs into the chemotherapy regimens of patients with newly diagnosed Ph-positive ALL has led to improved remission rates, higher probability of reaching allogeneic stem cell transplantation (SCT), and longer survival compared with chemotherapy alone. Early achievement of a complete molecular remission (CMR) is an important end point in Ph-positive ALL and identifies patients who have excellent long-term survival and may not need allogeneic SCT. Second-generation TKIs combined with intensive or low-intensity chemotherapy resulted in higher CMR rates compared with imatinib-based regimens. This translated into better outcomes, with less reliance on allogeneic SCT. To further improve the outcomes, the potent third-generation TKI ponatinib was added to chemotherapy. The combination of hyper-CVAD and ponatinib resulted in an overall CMR rate of 84% and a 5-year survival rate of 73% and 86% among patients who did and did not undergo allogeneic SCT, respectively, suggesting that allogeneic SCT may not be needed with this regimen. The recent chemotherapy-free combination of dasatinib and blinatumomab was safe and effective in patients with newly diagnosed Ph-positive ALL and resulted in an estimated 3-year OS rate of 80%; 50% of patients underwent allogeneic SCT. The chemotherapy-free regimen of ponatinib and blinatumomab resulted in a CMR rate of 86% and a 2-year survival rate of 93%, with no relapses or leukemia-related deaths, and with only 1 patient proceeding to allogeneic SCT.

Conclusions and Relevance

The promising results obtained with the chemotherapy-free regimens of blinatumomab plus TKIs question the role of allogeneic SCT in first remission. Patients with Ph-positive ALL who achieve early and deep molecular responses have excellent long-term outcomes and may not benefit from allogeneic SCT.

The current treatment approach to adolescents and young adults with acute lymphoblastic leukemia (AYA-ALL): challenges and considerations

INTRODUCTION

AYA-ALL differs from pediatric ALL in terms of clinical, biological, psychosocial factors and access to care and has an inferior outcome. It is now being recognized that pediatric-inspired protocols are superior to adult protocols for this cohort, but given the lack of randomized trials, several questions remain unanswered.

AREAS COVERED

In this review, we discuss how AYA-ALL is different from the pediatric ALL population, compare AYA ALL with ALL in middle and older age adults, review the studies that have enrolled the AYA cohort, summarize risk-stratified and response-adapted approaches, describe the biological subtypes, and review the novel agents/approaches under evaluation.

EXPERT OPINION

AYA-ALL is a complex and challenging disease that needs multidisciplinary and focused care. Well-designed clinical trials that focus on this cohort are needed to further improve the outcomes.

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.

Distinct outcomes, ABL1 mutation profile, and transcriptome features between p190 and p210 transcripts in adult Philadelphia-positive acute lymphoblastic leukemia in the TKI era

BACKGROUND

The differential signaling and outcome of patients with p190 or p210 transcripts of BCR-ABL1 have been systematically investigated in chronic myeloid leukemia rather than in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL).

METHODS

We analyzed the outcomes and ABL1 mutation profiles in 305 consecutive adult patients with Ph⁺ ALL treated with chemotherapy plus tyrosine kinase inhibitors. We also studied transcriptome features in two newly diagnosed patients with p190 and p210 using single-cell RNA sequencing (scRNA-seq).

RESULTS

P190 and p210 were found in 199 (65%) and 106 (35%) patients, respectively. Compared to patients with p190, a higher white blood cell count (p = 0.05), platelet count (p = 0.047), BCR-ABL1 transcript level (p < 0.001), and lower bone marrow blasts (p = 0.003) were found in patients with p210. Patients with p210 had fewer types of ABL1 mutations (4 vs. 16) and a higher prevalence of T315I and E225K/V mutations (91.3% vs. 68.6%; p = 0.031). Patients with p210 had a similar complete remission rate (91.0% vs. 90.1%; p = 0.805) but a lower complete molecular remission rate at 1 month (9.9% vs. 22.0%; p = 0.031) compared with p190. Patients with p210 had lower 3-year overall survival (OS) and disease-free survival (DFS) rates than those with p190 (3-year DFS: 10.4% vs. 9.2%, p = 0.069, 3-year OS: 44.3% vs. 38.2%, p = 0.018, respectively). Multivariate analysis revealed that p210 was independently associated with worse OS [HR 1.692 (95% CI 1.009-2.838), p = 0.046]. Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) was associated with a better prognosis in patients with p210 (p < 0.0001). In addition, scRNA-seq data showed distinct molecular and cellular heterogeneity between bone marrow cells of the two transcripts.

CONCLUSIONS

Ph⁺ ALL patients with p190 and p210 had different clinical characteristics, outcomes, ABL1 mutation profiles, and transcriptome features. Allo-HSCT could improve the outcomes of patients with p210.

Applicability of droplet digital polymerase chain reaction for minimal residual disease monitoring in Philadelphia-positive acute lymphoblastic leukaemia

In Ph+ acute lymphoblastic leukaemia (Ph+ ALL), minimal residual disease (MRD) is the most relevant prognostic factor. Currently, its evaluation is based on quantitative real‐time polymerase chain reaction (Q‐RT‐PCR). Digital droplet PCR (ddPCR) was successfully applied to several haematological malignancies. We analyzed 98 samples from 40 Ph+ ALL cases, the majority enrolled in the GIMEMA LAL2116 trial: 10 diagnostic samples and 88 follow‐up samples, mostly focusing on positive non‐quantifiable (PNQ) or negative samples by Q‐RT‐PCR to investigate the value of ddPCR for MRD monitoring. DdPCR BCR/ABL1 assay showed good sensitivity and accuracy to detect low levels of transcripts, with a high rate of reproducibility. The analysis of PNQ or negative cases by Q‐RT‐PCR revealed that ddPCR increased the proportion of quantifiable samples (p < 0.0001). Indeed, 29/54 PNQ samples (53.7%) proved positive and quantifiable by ddPCR, whereas 13 (24.1%) were confirmed as PNQ by ddPCR and 12 (22.2%) proved negative. Among 24 Q‐RT‐PCR‐negative samples, 13 (54.1%) were confirmed negative, four (16.7%) resulted PNQ and seven (29.2%) proved positive and quantifiable by ddPCR. Four of 5 patients, evaluated at different time points, who were negative by Q‐RT‐PCR and positive by ddPCR experienced a relapse. DdPCR appears useful for MRD monitoring in adult Ph+ ALL.

Emerging tyrosine kinase inhibitors for the treatment of adult acute lymphoblastic leukemia

Introduction: The broadening of targeted and immunotherapeutic strategies markedly impacted on the management of acute lymphoblastic leukemia (ALL). The advent of tyrosine kinase inhibitors (TKIs) changed the history of Philadelphia-chromosome positive (Ph+) ALL. Nowadays, almost all Ph+ ALL patients treated with TKIs achieve a complete hematologic response, and most become minimal residual disease negative. In Ph- ALL, genomic profiling studies have identified a subtype associated with a high relapse risk and a transcriptional profile similar to that of Ph+ ALL, the so-called Ph-like ALL. Given the high prevalence of kinase-activating lesions in this subset, there is compelling evidence from experimental models and clinical observations favoring TKI administration.Areas covered: We discuss the main findings exploring the efficacy of TKIs in ALL.Expert opinion: The use of more potent TKIs will further enhance the inhibitory activity on leukemia cells and increase the possibility of eradicating the disease at a molecular level. In the future, 'combined' approaches of different inhibitors may be considered to prevent/avoid resistance and/or mutations. A rapid identification of Ph-like ALL patients is needed to propose early TKI-based intervention. Several questions remain open, including the initial TKI choice in Ph+ ALL and whether Ph-like ALL patients might benefit from immunotherapy.

The impact of tyrosine kinase inhibitors on allogeneic hematopoietic stem cell transplantation for adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In the tyrosine kinase inhibitor (TKI) era, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still the most potential approach for cure of adult patients with Philadelphia chromosome-positive acute lymphocytic leukemia (Ph⁺ ALL). TKI plus chemotherapy has strikingly increased response rates and depth of response, and facilitated allo-HSCT, which decreases relapse and improves survival eventually. Meanwhile, for those with older age or comorbidities at diagnosis, TKI in combination with reduced-intensity chemotherapy or chemotherapy-free strategy reduces treatment-related mortality, deferred intensive chemotherapy increases molecular responses and reduced-intensity conditioning (RIC) allo-HSCT improves survival finally. Of note, according to minimal residual disease (MRD) and BCR/ABL1 kinase domain mutation screening, prophylactic or preemptive maintenance therapy with a sensitive TKI decreases relapse further. Regarding transplantation-related mortality and impaired quality of life related to complications of allo-HSCT, autologous-HSCT (auto-HSCT) among those with early and persistent molecular remission and the most potent TKI ponatinib plus intensive chemotherapy has exhibited non-inferior survival to allo-HSCT. Even so, risk-adapted strategy isn't available now. Lastly, outcomes of relapse after allo-HSCT are dismal due to TKIs exposure, and new therapeutic interventions combined with TKIs shed light on this thorny problem.