Successful Treatment with Imatinib Mesylate in a Case of Minor BCR-ABL-Positive Acute Myelogenous Leukemia

Precision medicine in acute myeloid leukemia: where are we now and what does the future hold?

INTRODUCTION

Precision medicine has revolutionized the diagnostic and therapeutic management of acute myeloid leukemia (AML), from standardized schemes based on chemotherapy to tailored approaches according to molecular and genetic profile and targeted therapy.

AREAS COVERED

The main topics of precision medicine in AML were reviewed in MEDLINE, EMBASE, and Cochrane Central Register databases, and future directions in this therapeutic area were addressed. This review included targeted therapies, drug-sensitivity tests and predictive biomarkers, and genetic studies employing pharmacogenetic and deep sequencing strategies.

EXPERT OPINION

Precision medicine has opened the door to personalized therapy for specific AML patient populations with promising results. Several targeted therapies have been approved or are being tested for specific mutations (i.e. FLT3, IDH, BCL-2, TP53), obtaining improvements in clinical outcomes and less toxicity as compared with intensive treatment, allowing potential combination therapy. Ongoing trials and real data will establish the role of these molecules in monotherapy or combined in different AML settings (front-line, relapsed/refractory, or post-transplant). Experience in drug-sensitivity predictors and pharmacogenetic biomarkers is encouraging and could be useful tools in the next years, but we need a better understanding of AML biology and pathogenesis as well as confirmatory studies to demonstrate the utility in clinical practice.

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.

Emerging treatment strategies for acute myeloid leukemia (AML) in the elderly

Acute myeloid leukemia (AML) is more prevalent in older adults, with an incidence in the United States of 17.6 per 100,000 for those 65 years of age, compared with an incidence of 1.8 per 100,000 for those <65 years of age. While there have been improvements in survival during the last decade for younger patients, prognosis in elderly patients is still poor; approximately 50% achieve complete responses, but many of them relapse. With increasing age, more patients are suboptimal candidates for standard induction chemotherapy due to poor performance status, pre-existing myelodysplasia, unfavorable cytogenetics, treatment-related AML, multidrug resistance protein expression, and CD34 positivity, which are often characteristic of this patient population. In addition, the presence of comorbid conditions make many treatment options less tolerable for elderly patients. Several investigators have described subgroups showing no benefit after intensive treatment approaches in recent years. However, several novel agents have been developed to treat elderly AML patients. These include new chemotherapeutic agents, such as nucleoside analogs, as well as targeted therapies like farnesyltransferase inhibitors, tyrosine kinase inhibitors, epigenetic drugs, and antibodies. On the other hand new insights into the biology of the disease lead to a better understanding of its heterogeneity. Thus, with a variety of novel substances at hand it is increasingly important to introduce a risk-adapted approach for the optimal management of patients. This review will identify subgroups not likely to benefit from intensive chemotherapy and highlight the efficacy and tolerability of new agents in the treatment of AML.

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.

Targeting receptor tyrosine kinase signaling in acute myeloid leukemia

Acute myeloid leukemia (AML) is a quickly progressing, heterogeneous clonal disorder of hematopoietic progenitor cells. Significant progress in understanding the pathogenesis of AML has been achieved in the past few years. Two major types of genetic events are thought to give rise to leukemic transformation: alterations in the activity of transcription factors controlling hematopoietic differentiation and activation of components of receptor tyrosine kinase (RTK) signaling pathways. This has led to the development of promising new therapeutic strategies for the disease. In this article, we will discuss recent developments in the field of molecularly targeted therapies for AML, which involve RTKs such as FMS-like tyrosine kinase 3 (Flt3), c-Kit and signal transduction via the phosphoinositide 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways. Initial results imply that targeting RTKs is a very promising approach for AML and that other receptors, such as the insulin-like growth factor receptor (IGF-IR), could also represent new targets in the future.

Long-term remission in BCR/ABL-positive AML-M6 patient treated with Imatinib Mesylate

BCR/ABL-positive acute myeloid leukemia (AML) is a rare disease, characterized by a poor prognosis, with resistance to induction chemotherapy and frequent relapses in responsive patients. Here we report a case of BCR/ABL-positive AML-M6 who, after relapse, was treated with Imatinib Mesylate (600 mg/die) and within 4 months achieved a cytogenetic and molecular complete response. After more than 4 years of continuous Imatinib therapy, nested RT-PCR for BCR/ABL is persistently negative. The case reported shows that the response obtained with Imatinib Mesylate in BCR/ABL-positive AML may be long lasting, offering a chance of successful treatment for this poor prognosis group of patients.

Acute monocytic leukemia with coexpression of minor BCR-ABL1 and PICALM-MLLT10 fusion genes along with overexpression of HOXA9

The t(9;22)(q34;q11) translocation occurs in chronic myeloid leukemia (CML) and adult B-cell acute lymphoblastic leukemia (ALL), leading to fusion of BCR to ABL1 and constitutive activation of ABL1 tyrosine kinase activity. The main BCR-ABL1 breakpoints result in P190 BCR-ABL1 or P210 BCR-ABL1 fusion proteins. The latter is found in almost all cases of CML and in one third of the cases of t(9;22)-positive adult B-ALL. P190 BCR-ABL1 is found in the remaining two thirds of t(9;22)-positive adult B-ALL cases but only exceptionally in CML. We describe here the first case of t(9;22)(q34;q11) associated with t(10;11)(p13;q14) in acute monocytic leukemia. The recurrent t(10;11)(p13;q14) translocation, usually found in acute myeloid leukemia (AML) and T-ALL, merges PICALM to MLLT10. RT-PCR enabled identification of PICALM-MLLT10 and BCR-ABL1 e1-a2 fusion transcripts; in the context of chronic and acute myeloid leukemia, the latter usually has a monocytic presentation. We also identified overexpression of HOXA9, a gene essential to myeloid differentiation that is expressed in PICALM-MLLT10 and MLL-rearranged acute leukemias. This case fits with and extends a recently proposed multistage AML model in which constitutive activation of tyrosine kinases by mutations (BCR-ABL1) are associated with deregulation of transcription factors central to myeloid differentiation (HOXA9 secondary to PICALM-MLLT10).