Induction chemotherapy and post-remission imatinib therapy for de Novo BCR-ABL-positive AML

Clinical and genomic characterization of patients diagnosed with the provisional entity acute myeloid leukemia with BCR-ABL1, a Swedish population-based study

Acute myeloid leukemia (AML) with t(9;22)(q34;q11), also known as AML with BCR-ABL1, is a rare, provisional entity in the WHO 2016 classification and is considered a high-risk disease according to the European LeukemiaNet 2017 risk stratification. We here present a retrospective, population-based study of this disease entity from the Swedish Acute Leukemia Registry. By strict clinical inclusion criteria we aimed to identify genetic markers further distinguishing AML with t(9;22) as a separate entity. Twenty-five patients were identified and next-generation sequencing using a 54-gene panel was performed in 21 cases. Interestingly, no mutations were found in NPM1, FLT3, or DNMT3A, three frequently mutated genes in AML. Instead, RUNX1 was the most commonly mutated gene, with aberrations present in 38% of the cases compared to around 10% in de novo AML. Additional mutations were identified in genes involved in RNA splicing (SRSF2, SF3B1) and chromatin regulation (ASXL1, STAG2, BCOR, BCORL1). Less frequently, mutations were found in IDH2, NRAS, TET2, and TP53. The mutational landscape exhibited a similar pattern as recently described in patients with chronic myeloid leukemia (CML) in myeloid blast crisis (BC). Despite the concomitant presence of BCR-ABL1 and RUNX1 mutations in our cohort, both features of high-risk AML, the RUNX1-mutated cases showed a superior overall survival compared to RUNX1 wildtype cases. Our results suggest that the molecular characteristics of AML with t(9;22)/BCR-ABL1 and CML in myeloid BC are similar and do not support a distinction of the two disease entities based on their underlying molecular alterations.

Acute Myeloid Leukemia with Philadelphia Chromosome, Near-tetraploidy, and 5q Deletion

A 49-year-old male presented to his physician with three weeks of dyspnea, dry cough, and fever. He did not respond to antibiotics and corticosteroids. He presented to the emergency department with worsening symptoms, where blood work revealed severe anemia, leukocytosis, thrombocytopenia, and 61% blasts on peripheral smear. Bone marrow biopsy showed acute myeloid leukemia (AML). While the results of other studies were awaited, treatment was begun with 7+3 induction (cytarabine and daunorubicin). Karyotyping returned positive for the BCR-ABL1 fusion gene (Philadelphia chromosome), near-tetraploidy, and 5q deletion. Follow-up bone marrow biopsy revealed residual disease (12% blasts). Re-induction was initiated with 5+2 cytarabine and daunorubicin with the addition of dasatinib. Subsequent bone marrow biopsies revealed minimal residual disease and BCR-ABL on polymerase chain reaction (PCR). The patient was placed on dasatinib maintenance and later switched to nilotinib. This case demonstrates the simultaneous presence of rare cytogenetic abnormalities in AML. It also discusses the successful utilization of tyrosine kinase inhibitors (TKIs) in the treatment of BCR-ABL-positive AML, as there are no established guidelines.

Clinical implications of molecular markers in acute myeloid leukemia

The recently updated World Health Organization (WHO) Classification of myeloid neoplasms and leukemia reflects the fact that research in the underlying pathogenic mechanisms of acute myeloid leukemia (AML) has led to remarkable advances in our understanding of the disease. Gene mutations now allow us to explore the enormous diversity among cytogenetically defined subsets of AML, particularly the large subset of cytogenetically normal AML. Despite the progress in unraveling the tumor genome, only a small number of recurrent mutations have been incorporated into risk-stratification schemes and have been proven to be clinically relevant, targetable lesions. We here discuss the utility of molecular markers in AML in prognostication and treatment decision making, specifically highlighting the aberrations included in the current WHO classification.

Relatively favorable outcome after allogeneic stem cell transplantation for BCR-ABL1-positive AML: A survey from the acute leukemia working party of the European Society for blood and marrow transplantation (EBMT)

The aim of the study was to assess the role of allogeneic stem cell transplantation (SCT) in patients diagnosed with BCR-ABL1-positive acute myeloid leukemia (AML). Fifty-seven patients (median age, 48 years, range: 19-67) with BCR-ABL1 positive AML undergoing SCT were identified. The majority of the patients (70%) received a TKI before the transplant. At SCT 48 patients were in CR (45 in CR1), while 9 patients were transplanted in a more advanced stage of the disease. MRD was negative (BCR-ABL1/ABL < 10⁴ ) at time of SCT in 36.1% (14/40). After SCT, 16 (61.5%) out of 26 patients with MRD positive at transplantation reached MRD negativity. After a median follow-up of 6.3 years (0.7-14.2), NRM, RI, LFS, OS, and GRFS at 5 years were 18.1%, 37%, 44.2%, 53.8%, and 32.1%, respectively. The cumulative incidence of acute GvHD grade II-IV was 16.4%, incidence of chronic GvHD 24.9%, and of extensive cGvHD 21.4%, respectively. In patients who received SCT in CR1, 5-yr NRM, RI, LFS, OS, and GRFS were 15.9%, 36.4%, 46.5%, 59.4%, and 34.9%, respectively. Univariate analysis showed that age (<50 vs. ≥50 years) was associated with RI (5-yr: 22.7 vs. 50%), LFS (5-yr: 61.9 vs. 31.8%), and GRFS (5-yr: 52.4 vs. 18.2%), whereas MRD-negative status before SCT was associated with an improved GRFS (38.9 vs. 16.7%). We conclude that the outcome of patients <50 years of age with BCR-ABL1-positive AML receiving allogeneic SCT in CR is relatively favorable, possibly reflecting the beneficial effect of the use of TKI.

Philadelphia chromosome with acute myeloid leukemia and concurrent large B cell lymphoma of different origins: A case report

Philadelphia chromosome with de novo acute myeloid leukemia (Ph + AML) arising from t(9;22) is an uncommon occurrence. Ph + AML is known to respond poorly to conventional chemotherapy. To the best of our knowledge, simultaneous diagnosis of de novo Ph + AML and lymphoma in a single patient has not yet been reported. The present study reports the case of a 37-year-old female patient who presented with bone pain, fever and lymphadenopathy, and was diagnosed as Ph + AML with concurrent diffuse large B cell lymphoma. Combined chemotherapy regimen covering AML and lymphoma was administered, achieving short-term response. However, the therapy soon failed and the patient succumbed to the disease. The present study reports the first case of Ph + AML occurring concurrently with diffuse large B cell lymphoma, and discusses certain differences between Ph + AML and chronic myelogenous leukemia in the myeloid blast crisis phase, as well as the appropriate therapeutic modalities for Ph + AML. In addition, the potential association between Ph + AML and diffuse large B cell lymphoma in this patient was investigated.

Rare but authentic Philadelphia-positive acute myeloblastic leukemia: two case reports and a literature review of characteristics, treatment and outcome

The Philadelphia chromosome (Ph+), corresponding to translocation t(9;22), is found in chronic myeloid leukemia (CML) and acute lymphoblastic leukemia. Several cases of Ph+ acute myeloid leukemia (AML) have been reported in the literature. A retrospective study of Ph+ AML between 2001 and 2012 was conducted through a review of the literature. Among 400 AML patients, two cases of Ph+ AML (0.5%) were identified and treated with conventional chemotherapy with or without tyrosine kinase inhibitors (TKIs), followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). One patient had a complex karyotype including 7 monosomy (-7) and p190 BCR-ABL fusion transcript. Both patients remain in complete molecular remission. To date, 21 Ph+ AML cases treated with TKIs have been described in the literature with a median overall survival of 18months. One-third of the patients had additional karyotypic abnormalities, and 14% had -7. Molecular analysis showed 59% p210 and 41% p190 fusion protein. Relapse rate was observed in 38% of patients with p190 compared to 10% in patients with p210. Allo-HSCT was performed in eight patients; two relapsed (25%). Cytogenetic (-7) and molecular features help to distinguish Ph+ AML from CML. Survival improved with TKIs, particularly in association with conventional chemotherapy and allo-HSCT. Further studies of Ph+ AML patients are needed to better define this entity, its prognostic value, and therapeutic strategy.

Prolonged survival with imatinib mesylate combined with chemotherapy and allogeneic stem cell transplantation in de novo Ph+ acute myeloid leukemia

BACKGROUND

De novo Philadelphia chromosome-positive (Ph+) acute myeloid leukemia (AML) is a rare disease with a poor prognosis. Imatinib mesylate (IM) is the standard treatment for Ph+ chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia; however, its role in Ph+ AML has not been extensively investigated.

METHODS

Two patients aged of 46 and 19 years were diagnosed with de novo Ph+ AML according to the WHO Classification of Myeloid Neoplasms (2002) and the French-American-British (FAB) classification systems (1989). Cytogenetic analysis confirmed the presence of t(9;22). Standard RT-PCR was used to detect expression of the BCR-ABL1 fusion gene. Minimal residual disease was monitored by RQ-PCR for the BCR-ABL1/ABL ratio. Both patients received initial IM therapy combined with daunorubicin-based chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) and IM maintenance treatment after allo-HSCT.

RESULTS

Both patients achieved long-term disease-free survival with complete hematologic response, complete molecular response, and complete cytogenetic response for 44 and 48 months, respectively.

CONCLUSIONS

Our cases indicate that IM combined with daunorubicin-based chemotherapy followed by allo-HSCT and IM maintenance treatment is associated with a favorable outcome for de novo Ph+ AML, especially when IM is used in an early phase of AML.

Philadelphia chromosome-positive acute myeloid leukemia (Ph + AML) treated with imatinib mesylate (IM): a report with IM plasma concentration and bcr-abl transcripts

We studied the efficacy and pharmacokinetics of imatinib mesylate (IM) and bcr-abl expression in a Philadelphia chromosome-positive acute myeloid leukemia (Ph + AML) patient, a rare disease with a poor prognosis. Although sufficient IM trough concentrations were maintained, bcr-abl transcripts revealed only one-log reduction with IM monotherapy, suggesting a resistance against IM, and this patient required additional chemotherapy. Despite the resistance against IM at induction therapy, the patient has been in complete molecular response for more than 6 months with IM maintenance monotherapy. Our experience suggests that IM might have a positive role in consolidation and/or maintenance therapy in remission Ph + AML patients.

Successful interim therapy with imatinib prior to allogeneic stem cell transplantation in Philadelphia chromosome-positive acute myeloid leukemia

OBJECTIVES

Imatinib (Glivec, STI571) has been successfully used in patients with chronic myelogenous leukemia and acute lymphoblastic leukemia with the Philadelphia chromosome (Ph). We used imatinib interim therapy for four consecutive patients with newly diagnosed Ph+ acute myeloid leukemia (AML). We monitored the patient status for minimal residual disease by real-time quantitative polymerase chain reaction.

METHODS AND RESULTS

Imatinib was administered on an interim schedule after each chemotherapy course. After the first imatinib cycle, all patients remained in sustained complete hematologic remission (CHR) with a decrease in the breakpoint cluster region of the Abelson oncogene locus transcript. All patients received a second imatinib cycle following consolidation and showed sustained CHR, including two cases with complete molecular remission. All cases underwent hematopoietic stem cell transplantation (HSCT) in favorable condition, and are still alive with a leukemia-free status at 6, 6, 9, and 25 months after HSCT.

CONCLUSIONS

As a first-line interim therapy, imatinib appears to be a useful treatment strategy to provide a bridge to HSCT in patients with Ph+ AML. Further studies with a larger patient population and longer follow-up are needed for accurate assessment of the impact of imatinib on the long-term outcome of transplantation for patients with Ph+ AML.