Allogeneic hematopoietic cell transplantation for adult Philadelphia-positive acute lymphoblastic leukemia in the era of tyrosine kinase inhibitors

Clinico-hematological and immunophenotypic profile of acute leukemia of ambiguous lineage: A four year experience from a single tertiary care centre of West India

Background

: Acute leukemia of ambiguous lineage (ALAL) is a heterogeneous group of rare leukemias that lacks definite evidence of differentiation along one lineage. It includes acute undifferentiated leukemia and mixed-phenotype acute Leukaemia (MPAL).

Aims

The present study highlighted the clinicohematological and immunophenotypic profile of ALAL cases diagnosed in the tertiary care centre of western India.

Study Design

Retrospective observational study.

Methods and Materials

Patients diagnosed with acute leukemia, preferably their bone marrow aspirate samples, were collected in ethylene diamine tetra-acetic acid-vial. The immunophenotypic study was done using the Fluorescence Activated Cell Sorting (FACS) Canto Eight color flow cytometer and a broad panel of monoclonal antibodies. The patients were diagnosed for ALAL, based on the World Health Organization (WHO) 2017 classification.

Statistical Analysis Used

Descriptive statistics with categorical and continuous variables.

Results

Overall incidence of ALAL was about 2.1%, and singly MPAL and AUL were 1.8%, and 0.3%, in frequency, respectively. The age range was 4 to 57 (median age 21 years), of which 11 (57.9%) were adults and eight were children (42.1%). There was male predominance with Male: Female ratio of 5.3:1. On immunophenotyping, B/myeloid MPAL (42.1%) was the commonest among the ALAL. Translocation t(9;22) was the most common cytogenetic abnormality found mainly in B/myeloid MPAL. Two cases were of chronic myeloid leukemia in a mixed phenotypic blast crisis. Over all prognosis of ALAL was poor.

Conclusion

ALAL is overall associated with poor prognosis as both their diagnosis and treatment decisions are difficult owing to the lack of optimum treatment data and the rarity of the disease. Hence, A careful diagnosis with the help of immunophenotyping is crucial.

Multiparametric Flow Cytometry in Mixed Phenotype Acute Leukemia

Mixed phenotype acute leukaemia (MPAL) is a diverse group of leukemia of ambiguous lineage diagnosed when blasts in peripheral blood and/or bone marrow have antigens of more than one lineage or a mosaic of blasts belonging to more than one lineage. Retrospective analysis of 218 consecutive cases of acute leukaemia diagnosed by multiparametric flow cytometry (FCM) was done. MPAL cases were identified in accordance with European Group for the Immunological Classification of Leukaemias Criteria and World Health Organization 2008/2016 guidelines for lineage assignment. Nine out of 218 (4.1%) cases were classified as MPAL. Eight out of nine patients (88.8%) were male and 4/9 (44.4%) were < 20 years of age. There were three cases of B/T and T/myeloid MPAL each. Two cases were B/myeloid MPAL and one case was chronic myeloid leukaemia (CML) in B/myeloid blast crisis. B/myeloid MPAL and CML in B/myeloid blast crisis cases were Philadelphia chromosome positive. The latter case had a complex karyotype as well. Seven cases were treated with acute lymphoblastic leukaemia treatment regimen; two of them achieved complete remission (CR). The patient with CML in B/myeloid blast crisis was treated with imatinib based regimen, attained CR, underwent allogenic bone marrow stem cell transplantation, but developed graft versus host disease. Five patients died due to complications of febrile neutropenia early in the course of treatment (62.5%). The last patient (B/T MPAL) refused therapy and was lost to follow-up. Early accurate diagnosis of MPAL requires FCM. It may be misdiagnosed if a limited panel of antibodies is used.

Mixed-phenotype acute leukemia: state-of-the-art of the diagnosis, classification and treatment

Mixed-phenotype acute leukemia (MPAL) is a heterogeneous group of hematopoietic malignancies in which blasts show markers of multiple developmental lineages and cannot be clearly classified as acute myeloid or lymphoblastic leukemias. Historically, various names and classifications were used for this rare entity accounting for 2-5% of all acute leukemias depending on the diagnostic criterias used. The currently valid classification of myeloid neoplasms and acute leukemia published by the World Health Organization (WHO) in 2016 refers to this group of diseases as MPAL. Because adverse cytogenetic abnormalities are frequently present, MPAL is generally considered a disease with a poor prognosis. Knowledge of its treatment is limited to retrospective analyses of small patient cohorts. So far, no treatment recommendations verified by prospective studies have been published. The reported data suggest that induction therapy for acute lymphoblastic leukemia followed by allogeneic hematopoietic cell transplantation is more effective than induction therapy for acute myeloid leukemia or consolidation chemotherapy. The establishment of cooperative groups and international registries based on the recent WHO criterias are required to ensure further progress in understanding and treatment of MPAL. This review summarizes current knowledge on the diagnosis, classification, prognosis and treatment of MPAL patients.

Normal karyotype CALLA-positive adult pre-B ALL: dismal outcome with chemotherapy for patients with loss/gain of ABL1 and/or BCR FISH signals

BACKGROUND

Diagnostic karyotype and molecular studies represent the most powerful prognostic indicators in acute myeloid leukemia and provide the framework for risk stratification. Risk stratification in ALL has also a vital role in predicting outcome and identifying patients at higher risk of relapse with multiagent chemotherapy, but the role of diagnostic karyotype and molecular markers in adult ALL is limited to few well recognized cytogenetic abnormalities.

PATIENTS AND METHODS

We report a case series of 6 adult ALL patients with a characteristic molecular abnormality that have done poorly with chemotherapy. Between April 2004 and November 2009, 72 adult ALL patients (Pre-B-cell 61; T-cell 11) were referred to and treated at the Leukemia/BMT Program of BC in Vancouver, Canada. FISH for BCR-ABL fusion was positive in 12 of 61 Pre-B cell ALL patients. An additional 6 patients were negative for this typical fusion but had FISH abnormalities related to BCR and/or ABL1.

RESULTS

In this report, we describe the clinical and hematopathologic characteristics of these 6 patients and their poor outcome. We review the literature where only 2 similar cases with normal karyotype Pre-B ALL and associated FISH BCR/ABL1 numerical abnormalities were found.

CONCLUSION

We recommend screening all adult pre-B ALL patients with normal karyotype for this clonal abnormality and suggest classifying these ALL patients into the high-risk category.

Reduced-intensity conditioning followed by peripheral blood stem cell transplantation for adult patients with high-risk acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) with high-risk features has a poor prognosis in adults despite aggressive chemotherapy. Reduced-intensity conditioning (RIC) is a lower toxicity alternative for high-risk patients requiring hematopoietic cell transplantation (HCT); however, it has not been widely used for ALL. We conducted a retrospective study of 24 high-risk adult ALL patients who received an RIC regimen of fludarabine (Flu)/melphalan (Mel) prior to allogeneic peripheral blood stem cell transplantation (PBSCT) between 6/14/02 and 6/15/07 at the City of Hope. Indications for the RIC regimen were: (1) aged 50 years or older (42%), (2) compromised organ function (54%), or (3) recipient of a previous HCT (37.5%). Patients had a median age of 47.5 years and the median follow-up was 28.5 months for living patients. Both overall survival (OS) and disease-free survival (DFS) at 2 years was 61.5%. Relapse incidence was 21.1% and nonrelapse mortality (NRM) was 21.5% at 2 years. Chronic graft-versus-host (cGVHD) developed in 86% of evaluable patients. In this series, no significant correlations were made between outcomes and patient age, presence of Philadelphia chromosome, relatedness of donor source, or prior HCT. These high survival rates for high-risk ALL patients following RIC HCT may offer a promising option for patients not eligible for a standard myeloablative transplant.