Allogeneic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia

Indications for Allogeneic HCT in Adults with Acute Lymphoblastic Leukemia in First Complete Remission

OPINION STATEMENT

Acute lymphoblastic leukemia (ALL) in adults is associated with poor outcomes as compared to children when treated with chemotherapy, leading to a considerably inferior cure rate. Historically, consolidation with allogeneic hematopoietic cell transplant (alloHCT) was routinely recommended for eligible adults with ALL in first complete remission (CR1) if a donor was available, since randomized studies showed superiority over continuing chemotherapy. With the increasing use of pediatric-inspired frontline regimens in young adults with ALL and the availability of novel salvage agents for relapsed/refractory B-cell ALL that have high potential in inducing a second CR, the role of early alloHCT in the treatment paradigm for ALL needs to be reevaluated, and the decision should be individualized for each patient. Simultaneously, alloHCT has evolved considerably lately, and historical randomized studies that have proven the benefit of alloHCT in adults with ALL in CR1 did not included the increasing use of reduced intensity conditioning and haploidentical transplants, and therefore, data may not entirely apply. Nowadays, detectable minimal residual disease (MRD) is the most prognostic determinant of ALL outcome and should be a major consideration in the decision to perform alloHcT in CR1. Nonetheless, other biological and clinical factors remain relevant and can support the complex decision-making. Such factors include high-risk leukemia genetics, the type of administered chemotherapy regimen and the ability of the patient to tolerate all key components of the regimen, and the availability of effective salvage therapies that allow alloHCT to be performed in CR2 in case of relapse after chemotherapy.

Targeting BCL-2 and ABL/LYN in Philadelphia chromosome-positive acute lymphoblastic leukemia

Treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+)ALL) remains a challenge. Although the addition of targeted tyrosine kinase inhibitors (TKIs) to standard cytotoxic therapy has greatly improved upfront treatment, treatment-related morbidity and mortality remain high. TKI monotherapy provides only temporary responses and renders patients susceptible to the development of TKI resistance. Thus, identifying agents that could enhance the activity of TKIs is urgently needed. Recently, a selective inhibitor of B cell lymphoma 2 (BCL-2), ABT-199 (venetoclax), has shown impressive activity against hematologic malignancies. We demonstrate that the combination of TKIs with venetoclax is highly synergistic in vitro, decreasing cell viability and inducing apoptosis in Ph(+)ALL. Furthermore, the multikinase inhibitors dasatinib and ponatinib appear to have the added advantage of inducing Lck/Yes novel tyrosine kinase (LYN)-mediated proapoptotic BCL-2-like protein 11 (BIM) expression and inhibiting up-regulation of antiapoptotic myeloid cell leukemia 1 (MCL-1), thereby potentially overcoming the development of venetoclax resistance. Evaluation of the dasatinib-venetoclax combination for the treatment of primary Ph(+)ALL patient samples in xenografted immunodeficient mice confirmed the tolerability of this drug combination and demonstrated its superior antileukemic efficacy compared to either agent alone. These data suggest that the combination of dasatinib and venetoclax has the potential to improve the treatment of Ph(+)ALL and should be further evaluated for patient care.

Long-term follow-up of allogeneic hematopoietic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: impact of tyrosine kinase inhibitors on treatment outcomes

The introduction of tyrosine kinase inhibitors (TKI) has revolutionized therapy for patients with acute lymphoblastic leukemia (ALL) who have the Philadelphia (Ph) chromosome. A retrospective analysis was conducted on 102 adults and 11 children who received a first-matched related (n = 60), matched unrelated (n = 40), mismatched cord blood (n = 12), or haploidentical (n = 1) allogeneic hematopoietic stem cell transplantation (HSCT) for Ph-positive (Ph+) ALL in first complete remission (n = 71), second complete remission (n = 11), or with active disease (n = 31) between 1990 and 2009. Sixty-seven patients received TKI with upfront ALL therapy, and 32 patients received TKI maintenance following HSCT. With median follow-up of 5 years among survivors (range: 1.1-20.4 years), overall survival (OS) was significantly better for patients transplanted in first remission compared with HSCT in advanced disease: 43% versus 16%, P = .002. Disease stage and age at time of HSCT, the development of acute graft-versus-host disease (aGVHD), and decade of HSCT were found to significantly impact OS, progression-free survival (PFS), and nonrelapse mortality (NRM) in multivariate analyses. Allogeneic HSCT provides durable remission for patients with Ph+ ALL in first remission. Neither TKI use pre- nor post-HSCT were found to significantly impact transplant outcomes in univariate and multivariate analyses.

Long-term Follow-up of 14 Patients with Philadelphia Chromosome—Positive Acute Lymphoblastic Leukemia following Autologous Bone Marrow Transplantation in First Complete Remission

We describe the clinical outcome of autologous bone marrow transplantation (ABMT) for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL). Between 1985 and 2000, 14 patients in first complete remission underwent transplantation. In all cases, harvested marrow was purged with a cocktail of complement and monoclonal antibodies to common acute lymphoblastic leukemia antigen (CALLA). Eight patients died following BMT: 2 patients from interstitial pneumonia and 6 from disease recurrence. For the 6 surviving patients in continuous remission, the median follow-up period was 96 months. The probability of disease-free survival and the rate of relapse at 5 years were 41.7% and 51.4%, respectively. Minimal residual disease (MRD) was assayed quantitatively with patient-specific D-JH probes in 6 of 14 cases. A higher residual tumor burden at marrow harvest was associated with subsequent relapse. Efforts to reduce the MRD burden before harvesting stem cells should improve the clinical outcome of ABMT.

Die Bedeutung der Stammzelltherapie in der Hämatologie und Onkologie

The transplantation of hematopoietic stem cells (HSCT) is an established part of the therapy of hematologic neoplasia and certain solid tumors. In the allogeneic approach hematopoietic stem cells are harvested from healthy donors, while in the autologous setting preparations originating from the patient himself are being used. Both therapies use high dose cytotoxic medication for the induction of higher remission rates in malignant diseases. While autologous HSCT rescues hematopoiesis after high dose chemotherapy, in allogeneic HSCT donor immune cells exert an additional allo-reactivity towards recipient tissue and residual malignant cells. Autologous HSCT is mainly used in relapsed malignant high-grade lymphoma. Allogeneic HSCT results in cure from acute leukemia with unfavorable prognosis in a high percentage of patients. Recent developments target the expansion of the donor pool for allogeneic stem cells and want to reduce chemotherapeutic toxicity of allogeneic transplantation with sustained anti-leukemia efficacy.

Allogeneic hematopoietic cell transplantation for patients with high-risk acute lymphoblastic leukemia in first or second complete remission using fractionated total-body irradiation and high-dose etoposide: a 15-year experience

OBJECTIVE

The rationale for this retrospective study was to identify the long-term overall and event-free survival, relapse, and treatment-related mortality rates of high-risk pediatric and adult first (CR1) and second remission (CR2) patients with acute lymphoblastic leukemia (ALL) who were treated with a single preparatory regimen consisting of fractionated total-body irradiation (FTBI) and high-dose etoposide (VP-16) prior to allogeneic hematopoietic cell transplantation.

PATIENTS AND METHODS

Over a 15-year period at Stanford University Medical Center, 85 consecutive high-risk pediatric (up to age 17 years; n=41) and adult (age 18-55 years; n=44); patients with leukemia (ALL) in CR1 (n=55) and CR2 (n=30) received HLA-matched sibling allogeneic bone marrow or peripheral blood progenitor grafts after being treated with FTBI (1320 cGy) and high-dose VP-16 (60 mg/kg) as their preparatory regimen. The majority of patients transplanted in CR1 (n=45) had high-risk features, including age above 30 years, white blood cell count at presentation exceeding 25000/microL, extramedullary disease, need for more than 4 weeks of induction chemotherapy to achieve CR, or high-risk chromosomal translocations. Most patients transplanted in CR1 were adults (n=39), whereas patients in CR2 were primarily children or adolescents (n=25).

RESULTS

The 10-year Kaplan-Meier estimates of relapse were significantly (p=0.05) lower in CR1 patients (15%+/-10%) than in CR2 patients (33%+/-20%). Relapse was the most common cause of treatment failure in patients transplanted in CR2. There was a significantly (p=0.05) higher rate of chronic graft-vs-host disease in CR1 (32%+/-14%) compared with CR2 (9%+/-11%) patients; however, overall survival for patients transplanted in CR1 (66%+/-14%) was comparable (p=0.67) to that of patients transplanted in CR2 (62%+/-19%). Event-free survival rates also were similar (p=0.53) between CR1 (64%+/-14%) and CR2 (61%+/-18%) patients. Treatment-related mortality rates were equivalent (p=0.51) between CR1 and CR2, as well as between Philadelphia chromosome (Ph) positive (Ph(+))and Ph(-) (p=0.23) ALL patients.

CONCLUSION

Overall, FTBI/VP-16 is a highly effective preparatory regimen that provides durable remissions for patients receiving allogeneic hematopoietic cell transplantation for high-risk ALL in CR1 or CR2.

A potential graft-versus-leukemia effect after allogeneic hematopoietic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: results from the French Bone Marrow Transplantation Society

SUMMARY

Philadelphia chromosome (Ph) acute lymphoblastic leukemia-positive (ALL) is a subgroup of ALL with a poor prognosis. We sought to evaluate the results of allogeneic hematopoietic stem cell transplantation (HSCT) in this situation. From 1992 to 2000, 121 patients with Ph- positive ALL enrolled in one of the three main French prospective ALL chemotherapy trials and receiving allogeneic HSCT were reported to the registry of the French Society of Bone Marrow Transplantation (SFGM-TC). The median age was 35 years (range, 1-53). In all, 76 patients received HSCT in first complete remission and 45 in a more advanced disease stage. Minimal residual disease was evaluated just before the graft: 35 patients of the 52 patients in first remission had persistent BCR-ABL transcript detectable while 17 had no detectable minimal residual disease. Bone marrow and/or peripheral blood samples from 94 patients were submitted for reverse transcriptase polymerase chain reaction analysis at variable points after transplantation. Estimated 2-year survival and relapse rate for patients in CR1 were 50 and 37%, respectively, significantly better than for patients with more advanced disease (P=0.0001 and 0.01, respectively). There was no difference in survival or in relapse rates in terms of the donor used. Relapse was the most common cause of treatment failure. Hematological status at the time of transplant and the occurrence of acute graft-versus-host disease (GvHD) were the only two prognostic factors identified for relapse (P=0.02 and 0.02, respectively). Detection of BCR-ABL transcripts after transplantation had a predictive value on relapse occurrence. Finally, donor lymphocyte infusions were successfully used to treat some relapses. The graft-versus-leukemia effect of HSCT in Ph-positive ALL appears to be supported by (1) the lack of prognostic significance of pretransplant BCR-ABL transcript detection, (2) the efficacy of donor lymphocyte infusions in cases of relapse, and (3) the role of GvHD as protecting against relapse.

Bone marrow transplant in Ph+ ALL patients

Although the outcome for Philadelphia positive (Ph+) acute lymphoblastic leukemia (ALL) with conventional chemotherapy is poor, the outcome after a sibling-matched allogeneic bone marrow transplantation (BMT) seems to be significantly better. The surprising success of allogeneic BMT may be because of disease response to high-dose chemotherapy combined with a graft-versus-leukemia effect. However, less than 30% of patients have a matched related donor available, and some of them will be too old/not fit for conventional BMT. While young patients who do not have a matched related donor should be considered for matched unrelated donor (MUD) transplant, older patients may be treated with autologous stem cell transplantation (ASCT) or rarely considered for a low-intensity MUD transplant. The efficacy of autologous BMT compared with chemotherapy is still debatable, although the new tyrosine kinase inhibitor Imatinib may be used for pretransplant purging/post-transplant therapy, aiming to improve autologous and allogeneic BMT results. The advantage of low-intensity sib/MUD allograft compared with chemotherapy is not proven either and is currently under investigation. However, if shown to be curative, low-intensity allograft may significantly improve the outcome of older Ph+ ALL patients, who are not eligible for conventional allograft.

Perspectives on the treatment of chronic phase and advanced phase CML and Philadelphia chromosome positive ALL(1)

Chronic myeloid leukaemia (CML) is a malignant disease of the bone marrow characterised by the presence of the Philadelphia (Ph) chromosome. About 20% of acute lymphoblastic leukaemia (ALL) patients also show this genetic abnormality. A new drug, imatinib (Glivec, Novartis Pharma AG, Basel, Switzerland, and formerly STI571) is having a profound effect on the treatment and management of all stages of CML and Philadelphia chromosome positive (Ph+) ALL. New treatment algorithms are being developed. Should imatinib replace or be combined with existing therapies? To address this question, we review the pros and cons of therapy with interferon-alpha (IFN-alpha), allogeneic transplantation, autologous transplantation, imatinib, and in the case of Ph+ ALL, chemotherapy and experimental approaches. Conservative and aggressive treatments will be discussed and new molecular methods of monitoring cytogenetic response and their significance will also be reviewed.

Stem cell transplantation in adult ALL patients

Less than 40% of adult acute lymphocytic leukaemia (ALL) patients will still be alive at 5 years post-diagnosis. Ways to improve patients' outcome, using high-dose therapy followed by autologous/allogeneic stem cell transplantation (SCT) in first complete remission (CR1) rather than consolidation/maintenance chemotherapy, have been investigated. However, prospective studies are small and results are inconclusive. The largest prospective trial ever being performed in adult ALL patients, the ongoing UKALL 12/ECOG 2993 trial, is assigning all patients who have a sibling donor to receive allogeneic SCT (alloSCT) in CR1, whereas all other patients are randomized to continue chemotherapy versus autologous SCT. An interim analysis of this trial seems to support an alloSCT in first CR in adult ALL patients (reflected by a significantly reduced relapse rate with an improved disease-free survival). However, less than 30% of the patients have a matched sibling donor, the majority of the patients are over 40 years old, which makes them less suitable for conventional allograft, and even in those who have a matched sibling donor and are young and fit enough to receive it the treatment-related mortality (TRM) is about 20%. Strategies for expanding donor availability, meanwhile, to reduce the TRM, remain challenges. Data regarding the efficacy of reduced-intensity regimens in ALL patients are still scanty. Another way of improving patient outcome is to select patients for allograft more carefully. There are enough data to suggest now that children who achieved a clinical remission but failed to obtain a molecular/immunological remission are more prone to relapse. Similar data have recently been published for adult ALL. However, data are still limited, and the significance of minimal residual disease (MRD) has never been studied prospectively in adult ALL patients. A reasonable approach is to assign all patients with a matched related donor who has failed to achieve a molecular/immunological remission to receive a conventional alloSCT, whereas all others might be randomized to receive alloSCT versus chemotherapy/autologousSCT. However, patients with Ph(+) ALL who have a donor should receive an alloSCT in CR1, regardless of their MRD results. It appears that alloSCT provides the best chance for cure. However, by improving our ability to select those who have the highest risk for relapse, unnecessary toxicity/mortality might be prevented and the general outcome might improve.

Philadelphia chromosome-positive acute lymphoblastic leukemia- current concepts and future perspectives

Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) is diagnosed rarely in children, but constitutes the most frequent cytogenetic abnormality in adults with ALL. In contrast to chronic myeloid leukemia (CML), patients with Ph-positive ALL usually demonstrate expression of a truncated version of the BCR-ABL protein called p190bcr-abl. Irrespective of age and breakpoint location, Ph-positive ALL carries a poor prognosis. Although remission rates are identical to those of Ph-negative ALL, relapse is almost universal and long-term survival remains rare. Given the poor outcome with current chemotherapy consolidation programs, stem cell transplantation is usually recommended for these patients in first remission or as soon as feasible. Even with transplantation the impact on outcome is limited and new therapeutic concepts are urgently needed. One of the most promising developments in recent years has been the introduction of the tyrosine kinase inhibitors such as STI571. An overview of current treatment modalities in Ph-positive ALL will be provided and the rationale for new therapies will be discussed.

Intensified and shortened cyclical chemotherapy for adult acute lymphoblastic leukemia

PURPOSE

To assess the efficacy and toxicity of a new treatment program of intensified and shortened cyclical chemotherapy (protocol 8707) in adults with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Previously untreated adults < or = 60 years old with ALL were treated with a four-agent induction chemotherapy regimen. This was followed by cyclical postremission therapy with high-dose cytarabine/etoposide; high-dose methotrexate/6-mercaptopurine; and daunorubicin, vincristine, prednisone, and asparaginase. Maintenance chemotherapy with oral methotrexate and 6-mercaptopurine was continued for 30 months. CNS prophylaxis was given with intrathecal methotrexate in addition to the systemic chemotherapy indicated above.

RESULTS

Seventy-eight of 84 patients (93%) achieved complete remission. With a median follow-up of 5.6 years, 5-year event-free survival (EFS) of all remission patients is 52%. Patients with high-risk features including adverse cytogenetics, failure to achieve remission with the first cycle of chemotherapy, and B-precursor disease with WBC counts more than 100,000/microL all relapsed unless taken off study for transplantation. For patients without these high-risk features, 5-year EFS was 60%. Compared with our previous treatment regimen, results appear to be improved for patients with standard-risk B-precursor disease (5-year EFS, 66% v 34%; P =.01).

CONCLUSION

Intensified and shortened chemotherapy may improve the outcome for patients with ALL with B-precursor disease lacking high-risk features. Further trials of this regimen are warranted.