Optimal approach to treatment of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: how to best use all the available tools

Comparison of autologous and allogeneic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

Objectives: To analyze the outcomes of patients who received autologous stem cell transplantation (auto-SCT), matched sibling donor stem cell transplantation (MSD-SCT) and haploidentical stem cell transplantation (haplo-SCT) and provide the basis for the choice of transplantation method in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Methods: We retrospectively investigated the outcomes of 119 adult patients with Ph+ ALL in our center. The overall survival (OS) rate, leukemia-free survival (LFS) rate, cumulative incidence of relapse (CIR) rate, non-relapse mortality (NRM) rate and the impact of achievement of complete molecular response (CMR) within 3 months and sustaining CMR up to transplantation (s3CMR) on transplantation method were explored. Results: The estimated OS, LFS, CIR and NRM rates at 3 years were not significantly different among three groups (p = 0.960, 0.917, 0.375 and 0.096, respectively). For the 65 patients who achieved s3CMR, there was no significant difference in OS (84.5% vs 72.5% vs 100%, p = 0.374), LFS (75.2% vs 64.5% vs 83.3%, p = 0.668), CIR (17.2% vs 8.1% vs 16.7%, p = 0.583) and NRM (3.1% vs 23.4% vs 0%, p = 0.055) among auto-SCT group, MSD-SCT group and haplo-SCT group. However, in patients who did not achieve s3CMR, auto-SCT recipients tended to have higher CIR (60% vs 33.2% vs 24.0%, p = 0.013) than the allo-HSCT group. Conclusions: Auto-SCT with maintenance therapy after HSCT appears to be an attractive treatment option for patients with Ph+ ALL especially for those whose s3CMR was kept up to transplantation. For non-s3CMR patients, allogeneic transplantation may be more effective from lower relapse.

[Comparison of autologous versus matched sibling donor stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia]

目的

比较自体造血干细胞移植（auto-HSCT）和同胞全相合造血干细胞移植（MSD-HSCT）治疗费城染色体阳性急性淋巴细胞白血病（Ph⁺ ALL）的疗效，为患者移植方式的选择提供依据。

方法

回顾性总结2008年1月至2017年12月于中国医学科学院血液病医院行auto-HSCT（31例）及MSD-HSCT（47例）的78例Ph⁺ ALL患者的临床特征，比较不同移植方式患者的总生存（OS）率、无白血病生存（LFS）率、累积复发率（CIR）及非复发死亡率（NRM），并观察是否3个月内实现完全分子学缓解并持续至移植（s3CMR）条件下不同移植方式对预后的影响。

结果

auto-HSCT组、MSD-HSCT组粒细胞植入的中位时间分别为12（10～29）d、14（11～24）d（P＝0.006），血小板植入的中位时间分别为17.5（10～62）d、17（10～33）d（P＝0.794）。MSD-HSCT组中，Ⅱ～Ⅳ度和Ⅲ～Ⅳ度急性移植物抗宿主病（GVHD）的发生率分别为27.7%（13/47）和8.5%（4/47），局限型和广泛型慢性GVHD的发生率为17.0%（8/47）和12.8%（6/47）。auto-HSCT组、MSD-HSCT组3年CIR、NRM、LFS率差异均无统计学意义（P值均>0.05）。在达到s3CMR的44例患者中，auto-HSCT组和MSD-HSCT组的3年OS率［（84.0±8.6）%对（78.0±8.7）%，P＝0.612］、LFS率［（70.3±10.3）%对（68.2±10.1）%，P＝0.970］、CIR［（24.9±10.0）%对（14.4±8.0）%，P＝0.286］和NRM［（4.7±4.7）%对（17.4±8.1）%，P＝0.209］差异均无统计学意义；未达到s3CMR的34例患者中，auto-HSCT组与MSD-HSCT组相比，3年CIR明显升高［（80.0±14.7）%对（39.6±10.9）%，P＝0.057］。

结论

对于化疗后达s3CMR的Ph⁺ ALL患者，auto-HSCT是一种有效的巩固治疗选择，与MSD-HSCT疗效相当；对于未达到s3CMR的患者，MSD-HSCT复发率更低。

Identification of novel MECOM gene fusion and personalized therapeutic targets through integrative clinical sequencing in secondary acute myeloid leukemia in a patient with severe congenital neutropenia: a case report and literature review

Severe congenital neutropenia (SCN) is a rare hematologic disorder characterized by defective myelopoiesis and a high incidence of malignant transformation to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). SCN patients who develop MDS/AML have excessive toxicities to traditional chemotherapy, and safer therapies are needed to improve overall survival in this population. In this report, we outline the use of a prospective integrative clinical sequencing trial (PEDS-MIONCOSEQ) in a patient with SCN and AML to help identify oncogenic targets for less toxic agents. Integrative sequencing identified two somatic cis-mutations in the colony stimulating factor 3 receptor (CSF3R) gene, a p.T640N mutation in the transmembrane region and a p.Q768* truncation mutation in the cytoplasmic domain. A somatic mutation p.H105Y, in the runt homology domain (RHD) of runt-related transcription factor 1 (RUNX1), was also identified. In addition, sequencing discovered a unique in-frame EIF4A2-MECOM (MDS1 and ectopic viral integration site 1 complex) chromosomal translocation with high MECOM expression. His mutations in CSF3R served as potential targets for tyrosine kinase inhibition and therefore provided an avenue to avoid more harmful therapy. This study highlights the utility of integrative clinical sequencing in SCN patients who develop leukemia and outlines a strategy on how to approach these patients in a future clinical sequencing trial to improve historically poor outcomes. A thorough review of leukemia in SCN and the role of CSF3R mutations in oncologic therapy are provided to support a new strategy on how to approach MDS/AML in SCN.

Immunological effects of nilotinib prophylaxis after allogeneic stem cell transplantation in patients with advanced chronic myeloid leukemia or philadelphia chromosome-positive acute lymphoblastic leukemia

Allogeneic stem cell transplantation remains the standard treatment for resistant advanced chronic myeloid leukemia and Philadelphia chromosome–positive acute lymphoblastic leukemia. Relapse is the major cause of treatment failure in both diseases. Post-allo-SCT administration of TKIs could potentially reduce relapse rates, but concerns regarding their effect on immune reconstitution have been raised. We aimed to assess immune functions of 12 advanced CML and Ph+ ALL patients who received post-allo-SCT nilotinib. Lymphocyte subpopulations and their functional activities including T-cell response to mitogens, NK cytotoxic activity and thymic function, determined by quantification of the T cell receptor (TCR) excision circles (TREC) and TCR repertoire, were evaluated at several time points, including pre-nilotib-post-allo-SCT, and up to 365 days on nilotinib treatment. NK cells were the first to recover post allo-SCT. Concomitant to nilotinib administration, total lymphocyte counts and subpopulations gradually increased. CD8 T cells were rapidly reconstituted and continued to increase until day 180 post SCT, while CD4 T cells counts were low until 180−270 days post nilotinib treatment. T-cell response to mitogenic stimulation was not inhibited by nilotinib administration. Thymic activity, measured by TREC copies and surface membrane expression of 24 different TCR Vβ families, was evident in all patients at the end of follow-up after allo-SCT and nilotinib treatment. Finally, nilotinib did not inhibit NK cytotoxic activity. In conclusion, administration of nilotinib post allo-SCT, in attempt to reduce relapse rates or progression of Ph+ ALL and CML, did not jeopardize immune reconstitution or function following transplantation.

The clonal evolution of two distinct T315I-positive BCR-ABL1 subclones in a Philadelphia-positive acute lymphoblastic leukemia failing multiple lines of therapy: a case report

BACKGROUND

The treatment of Philadelphia chromosome-positive Acute Lymphoblastic Leukemia (Ph+ ALL) patients who harbor the T315I BCR-ABL1 mutation or who have two or more mutations in the same BCR-ABL1 molecule is particularly challenging since first and second-generation Tyrosine Kinase Inhibitors (TKIs) are ineffective. Ponatinib, blinatumomab, chemotherapy and transplant are the currently available options in these cases.

CASE PRESENTATION

We here report the case of a young Ph+ ALL patient who relapsed on front-line dasatinib therapy because of two independent T315I-positive subclones, resulting from different nucleotide substitutions -one of whom never reported previously- and where additional mutant clones outgrew and persisted despite ponatinib, transplant, blinatumomab and conventional chemotherapy. Deep Sequencing (DS) was used to dissect the complexity of BCR-ABL1 kinase domain (KD) mutation status and follow the kinetics of different mutant clones across the sequential therapeutic approaches.

CONCLUSIONS

This case presents several peculiar and remarkable aspects: i) distinct clones may acquire the same amino acid substitution via different nucleotide changes; ii) the T315I mutation may arise also from an 'act' to 'atc' codon change; iii) the strategy of temporarily replacing TKI therapy with chemo or immunotherapy, in order to remove the selective pressure and deselect aggressive mutant clones, cannot always be expected to be effective; iv) BCR-ABL1-mutated sub-clones may persist at very low levels (undetectable even by Deep Sequencing) for long time and then outcompete BCR-ABL1-unmutated ones becoming dominant even in the absence of any TKI selective pressure.

Efficacy and prognostic factors of imatinib plus CALLG2008 protocol in adult patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia

A CALLG2008 protocol was developed by the Chinese Acute Lymphoblastic Leukemia Cooperative Group for adult acute lymphoblastic leukemia (ALL). We retrospectively analyzed 153 newly diagnosed adult patients with Philadelphia chromosome (Ph)-positive ALL enrolled into imatinib (400 mg/d) plus CALLG2008 regimen between 2009 and 2015. The median age was 40 years (range, 18-68 years), with 81 (52.3%) males. The overall hematologic complete remission (CR) rate was 96.7% after induction. With a median follow-up of 24.2 months, the estimated 3-year overall survival (OS) and event-free survival (EFS) rates were 49.5%(95%confidence interval (CI): 38.5%-59.5%) and 49.2% (95% CI: 38.3%-59.2%), respectively. Fifty-eight (36 with haploidentical donor) patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in first CR. Among the patients in CR1 after induction, both the 3-year OS and EFS were significantly better in the allo-HSCT group than in the without allo-HSCT group (73.2%, 95% CI: 58.3%-83.5% vs. 22.2%, 95% CI: 8.7%-39.6% and 66.5%, 95% CI: 50.7%-78.2% vs. 16.1%, 95% CI: 5.1%-32.7%, respectively). Multivariate analysis showed that allo-HSCT and achievement of major molecular response were associated with favorable OS or EFS independently. Interestingly, in the allo-HSCT cohort, the donor type (haploidentical versus matched donors) had no significant impact on EFS or OS. All these results suggested that imatinib plus CALLG2008 was an effective protocol for Ph-positive ALL. Haploidentical donors can also be a reasonable alternative expedient donor pool.

[Characteristics and clinical outcome of T315I mutation in Philadelphia chromosome-positive acute lymphoblastic leukemia and chronic myeloid leukemia]

目的

分析伴T315I突变的Ph染色体阳性急性淋巴细胞白血病(Ph⁺ALL)和慢性髓性白血病(CML)的特征及疗效。

方法

收集2014年3月至2015年6月于郑州大学附属肿瘤医院行ABL激酶区突变检测并对酪氨酸激酶抑制剂(TKI)耐药的23例Ph⁺ ALL患者和95例CML患者的临床资料。采用R显带法进行染色体分析，实时定量PCR方法检测BCR-ABL融合基因，TRIzol法提取总RNA，直接测序法检测ABL激酶区突变。

结果

ABL激酶区突变发生率在TKI耐药Ph⁺ ALL和CML中分别为60.9%(14/23)、41.1%(39/95)，其中T315I突变发生率分别为34.8%(8/23)和5.3%(5/95)，差异具有统计学意义(χ²=13.586，P<0.01)。CML慢性期患者ABL激酶区突变发生率为38.8%(19/49)，加速期、急变期分别为47.1%(8/17)、41.4%(12/29)，差异无统计学意义(χ²=0.360，P=0.835)。Ph⁺ ALL、CML患者自开始TKI治疗至发生T315I突变的中位时间分别为10和19个月，T315I突变发生至死亡或随访终止的中位时间分别为2和3个月，中位血液学缓解持续时间分别为10和16个月，中位总生存时间分别为13和42个月。

结论

Ph⁺ ALL较CML更易出现T315I突变，但两者自开始TKI治疗至发生T315I突变的中位时间相近，在现有方案治疗下，两者血液学缓解持续时间、总生存时间相近。

Minimal Residual Disease Monitoring in Adult ALL to Determine Therapy

Almost 90 % of children and 50 % of adults with acute lymphoblastic leukemia (ALL) are cured by modern treatment regimens, with significant variations due to several disease- and host-related characteristics. The attainment of an early remission and the avoidance of relapse and treatment-related mortality are the fundamental therapeutic steps. In remission patients, the assessment of the disease response to early intensive therapy through the detection and monitoring of minimal residual disease (MRD) can accurately refine the individual prognosis and is increasingly used to support a risk-oriented treatment strategy. In this way, only the patients with an unfavorable MRD response are preferably selected for allogeneic stem cell transplantation, irrespective of their clinical risk class. This choice spares transplant-related toxicities to MRD responsive cases. Further advancement is expected by integrating the MRD analysis with improved pediatric-type regimens and novel targeting agents for ALL subsets at higher risk of relapse.

Blinatumomab for the treatment of acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is a potentially fatal disease that involves clonal expansion of early lymphoid progenitor cells. Much of drug development for ALL treatment involves targeting antigens of the clonal cell surface. Blinatumomab belongs to an emerging class of anti-cancer therapeutics referred to as bispecific T-cell engaging antibodies. The Food and Drug Administration approved its use in relapsed or refractory adult Philadelphia chromosome-negative B-cell precursor ALL in December of 2014.

MECHANISM OF ACTION AND PHARMACODYNAMICS

Blinatumomab contains both an anti-CD3 and anti-CD19 arm, allowing for the juxtaposition of CD3+ T-cells to malignant CD19+ B-cells, thereby resulting in granzyme- and perforin-mediated B-cell apoptosis.

PRECLINICAL PHARMACOLOGY

Preclinical studies suggest that blinatumomab's efficacy is related to the effector-to-target ratio and to the difference between its affinity for CD19 and CD3.

PHARMACOKINETICS AND METABOLISM

Preclinical and early phase clinical studies have allowed for the characterization of the pharmacokinetics of blinatumomab, including the determination of its short half-life. The metabolic pathway has not been fully characterized but is thought to be similar to that of other antibodies.

CLINICAL STUDIES

Phase I and II studies led to the identification of an ideal stepwise dose, involving long-term continuous intravenous infusion (CIVI), to optimize its efficacy and reduce the risk of certain toxicities. A high remission rate and duration were noted among a relapsed/refractory population of patients.

SAFETY

The results of clinical trials have identified cytokine release syndrome and neurotoxicity, among others, as serious drug-related toxicities, leading to the institution of a Risk Evaluation and Mitigation Strategy.

DISCUSSION AND CONCLUSIONS

Blinatumomab represents a significant addition to the treatment options for ALL, but it is not without its limitations, of which are its short-half life, necessitating long-term CIVI, and the eventual emergence of CD19-negative clones. Continual development of the agent involves assessing its role in the frontline setting and in combination with chemotherapy.

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.

[In vitro study of BRD4 inhibitor GSK525762A against primary adult common B-cell acute lymphoblastic leukemia cells in vitro]

OBJECTIVE

To investigate the effects of bromodomain-containing protein 4 (BRD4) inhibitor GSK525762A on the proliferation and apoptosis of primary common B-cell acute lymphoblastic leukemia (common B-ALL) cells from adult patients, then to further explore the possible mechanisms.

METHODS

Purified leukemia cells from 14 common B-ALL adult patients (4 Ph⁺ and 10 Ph⁻ cases) were obtained by flow cytometry sorting, and maintained in a mimic bone marrow microenvironment culture system for short-term culture. Leukemia cells were treated with various concentrations of GSK525762A. The inhibitory effects of BRD4 inhibitor on common B-ALL leukemia cells were measured by CCK-8 assay and the apoptosis of those cells was determined by AnnexinⅤ/7-AAD staining using flow cytometry. The transcripts of c-MYC, CDK6 and Bcl-2 were detected by quantitative RT-PCR, and the expression of c-MYC, CDK6 and Bcl-2 proteins were detected via Western blot.

RESULTS

GSK525762A could inhibit the proliferation of leukemia cells from all 14 common B-ALL patients in a dose-dependent manner, the median value of IC50 was 256.25 (90.64-1 378.39)nmol/L. GSK525762A could promote cells apoptosis of B-ALL leukemia cells in a dose-dependent manner, the median apoptosis rates respectively were 45.17%(9.38%-70.91%), 66.02% (24.36%-96.34%) and 89.29% (39.29%-99.37%) after treated by 500, 1 000 and 2 500 nmol/L GSK525762A. GSK525762A has a similar effect on Ph⁺ ALL and Ph⁻ B-ALL, but the effect of proliferation inhibition and apoptosis enhancement on Ph+ B-ALL is weaker than that on Ph⁻ B-ALL. Compared with vehicle control group, the levels of c-MYC, Bcl-2 and CDK6 transcripts in leukemic cells were reduced after treatment for 24 h and 48 h by 1 000 nmol/L GSK525762A, and there are no significant differences in the downregulation of c-MYC and CDK6 mRNA between Ph⁺ and Ph⁻ B-ALL; however, the inhibitory effect on Bcl-2 transcription was weaker in Ph⁺ B-ALL cells than that in Ph⁻ B-ALL cells. Moreover, c-MYC, Bcl-2 and CDK6 protein levels decreased in GSK525762A treated group.

CONCLUSION

GSK525762A could strongly inhibit the proliferation of common B-ALL and trigger apoptosis; meanwhile it has certain effects against Ph⁺ ALL in vitro. The effect may be achieved by down-regulation of c-MYC, CDK6 and Bcl-2 expression.

Prognostic impact of minimal residual disease in adult acute lymphoblastic leukemia

SUMMARY 

While adult acute lymphoblastic leukemia (ALL) is curable in 40–50% of the patients, the individual prognosis is rather unpredictable due to associated biological and clinical risk factors. In both B- and T-precursor ALL, minimal residual disease (MRD) represents the most sensitive prognostic marker, useful to support critical treatment decisions, ranging from allogeneic stem cell transplantation in patients with inadequate MRD response to chemotherapy only in MRD responsive ones. This optimized risk-adapted strategy allows to spare transplant-associated morbidity and mortality in patients curable by chemotherapy. Further progress is expected from the integration of the MRD-based strategy with improved pediatric-type regimens and novel targeting agents for discrete ALL subsets. These changes are increasing the cure rate to above 50%.

Susceptibility of Ph-positive all to TKI therapy associated with Bcr-Abl rearrangement patterns: a retrospective analysis

Background

Tyrosine kinase inhibitors (TKIs) have demonstrated success in the treatment of acute lymphoblastic leukemia (ALL) in patients that express BCR-ABL rearrangements (Philadelphia chromosome [Ph]). The current study aimed to assess the efficacy of TKIs and prognostic factors in the treatment of adults with Ph+-ALL.

Methods

In this multicenter retrospective study, the relationship between Ph+-ALL and treatment outcomes among Chinese patients receiving TKI-containing induction/consolidation chemotherapy was examined. A total of 86 Ph+-ALL patients were included and followed for 3.85 (0.43–9.30) years. Overall survival (OS) and event-free survival (EFS) were analyzed.

Results

A total of 86 Ph+-ALL patients (40 females and 46 males; median age: 34.0 years) were enrolled, including those with BCR/ABL transcripts 190 (n = 52), 210 (n = 25), and 230 (n = 2); BCR/ABL isoform determination was not available for 7 patients. Mortality was influenced by variable BCR/ABL transcripts and TKI administration, and BCR/ABL transcripts, hematopoietic stem cell transplantation (HSCT), and TKI administration were associated with the occurrence of events. The OS rate in the TKI administration group during steady state was significantly higher compared with those patients who did not receive TKI administration (P = 0.008), the EFS rate in the TKI administration group during steady state was significantly higher compared with those patients who did not receive TKIs (P = 0.012), and also higher than those with TKI salvage administration (P = 0.004). BCR/ABL transcripts 210 showed preferable OS and EFS compared with BCR/ABL transcripts 190 and 230 (P<0.05 for each).

Conclusions

The susceptibility of Ph+-ALL to TKI associated with the patterns of BCR-ABL rearrangement is demonstrated for the first time, thus adding another risk-stratifying molecular prognostic tool for the management of patients with Ph+-ALL.

Phase 1/2 study of nilotinib prophylaxis after allogeneic stem cell transplantation in patients with advanced chronic myeloid leukemia or Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND

Allogeneic stem cell transplantation (SCT) remains the standard treatment for advanced chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL). Relapsed disease is the major cause of treatment failure, especially when SCT is given in the setting of advanced disease. Tyrosine kinase inhibitors can be given after transplantation prophylactically or after the detection of minimal residual disease (MRD) to reduce the relapse risk.

METHODS

Posttransplant nilotinib was started after the achievement of sustained engraftment and the resolution of transplant-related toxicities. Nilotinib was continued until progression or unacceptable toxicity.

RESULTS

Twenty-two patients with advanced CML (n = 15) or Ph(+) ALL (n = 7) underwent SCT with human leukocyte antigen-matched siblings (n = 11), unrelated donors (n = 7), or alternative donors (n = 4). Sixteen patients were given prophylactic nilotinib maintenance, which was started at a median of 38 days after transplantation. Six patients stopped the treatment because of toxicities (mostly gastrointestinal and hepatic). After nilotinib maintenance, 11 patients achieved (n = 9) or maintained (n = 2) a complete molecular response (CMR), and only 1 of them later relapsed. Four of the 5 patients not achieving CMR relapsed. At a median follow-up of 46 months, 9 patients were alive, and 13 had died. The 2-year overall and progression-free survival rates were 55% (95% confidence interval [CI], 34%-75%) and 45% (95% CI, 25%-66%), respectively. Among the 16 nilotinib recipients, the rates were 69% (95% CI, 46%-92%) and 56% (95% CI, 32%-81%), respectively. The 2-year nonrelapse mortality and relapse rates for all patients were 32% (95% CI, 17%-58%) and 23% (95% CI, 11%-49%), respectively.

CONCLUSIONS

Nilotinib is relatively safe and effective prophylactic therapy for the prevention of relapse after SCT. It may control MRD and convert patients to CMR, which is associated with prolonged survival. These observations merit further study in larger scale studies.

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.

Impact of tyrosine kinase inhibitors on minimal residual disease and outcome in childhood Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND

Breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 (BCR-ABL1) tyrosine kinase inhibitors (TKIs) improve the outcome of patients with childhood Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) when they are incorporated into postremission induction chemotherapy. To date, no data are available on the impact of TKIs on minimal residual disease (MRD) at the end of induction therapy among patients who have a poor early response to 2 weeks of induction therapy that does not include TKIs.

METHODS

The authors analyzed the early response to TKIs during remission induction in children with Ph-positive ALL who were treated at St. Jude Children's Research Hospital. MRD was measured on days 15 and 42 of induction. TKIs were incorporated into induction therapy on day 22 in the post-TKI era.

RESULTS

TKIs produced a marked drop in MRD levels: at the end of remission induction, 9 of 11 patients who received imatinib or dasatinib and conventional induction chemotherapy achieved MRD-negative status compared with only 2 of 16 patients who received chemotherapy alone (P < .001). The 5-year event-free survival rate (± standard deviation) was 68.6% ± 19.2% for the 11 patients who received TKIs versus 31.6% ± 9.9% for the 19 patients who did not (P = .022); notably, 2 of the former group underwent hematopoietic stem cell transplantation versus 15 of the latter group (P = .002). MRD levels and outcomes did not differ significantly among 498 patients with standard-risk/high-risk, Ph-negative ALL who were treated in the pre-TKI or post-TKI eras.

CONCLUSIONS

TKIs administered in the early phases of therapy can dramatically reduce MRD and improve the outcome of childhood Ph-positive ALL.

Novel targeted therapies in acute lymphoblastic leukemia

Chemotherapy alone cures only 25-45% of adult patients with acute lymphoblastic leukemia (ALL), making novel treatment agents and strategies desperately needed. The addition of monoclonal antibodies (rituximab, alemtuzumab, epratzumab) to chemotherapy has demonstrated encouraging results in patients with newly diagnosed and relapsed ALL. The anti-CD22 immunoconjugate, inotuzumab ozogamicin, and the anti-CD19 BiTE(®) antibody, blinatumomab, have demonstrated impressive single agent activity in patients with relapsed or refractory B-ALL. Early reports of chimeric antigen receptor therapies have been promising in patients with relapsed ALL. Other agents targeting NOTCH1, FLT3, the proteasome and DNA methylation are early in development. These new agents hope to improve the outcome of ALL therapy with less toxicity. The challenge going forward will be to find safe and effective combinations and determine where in the treatment schema these agents will be most effective in ALL therapy.

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.