Recent Advances in the Biology and CD123-Directed Treatment of Blastic Plasmacytoid Dendritic Cell Neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an aggressive myeloid malignancy of the dendritic cell lineage that affects patients of all ages, though the incidence appears to be highest in patients over the age of 60 years. Diagnosis is based on the presence of plasmacytoid dendritic cell precursors expressing CD123, the interleukin-3 (IL-3) receptor alpha, and a distinct histologic appearance. Timely diagnosis remains a challenge, due to lack of disease awareness and overlapping biologic and clinical features with other hematologic malignancies. Prognosis is poor with a median overall survival of 8 to 14 months, irrespective of disease presentation pattern. Historically, the principal treatment was remission induction therapy followed by a stem cell transplant (SCT) in eligible patients. However, bridging to SCT is often not achieved with induction chemotherapy regimens. The discovery that CD123 is universally expressed in BPDCN and is considered to have a pathogenetic role in its development paved the way for the successful introduction of tagraxofusp, a recombinant human IL-3 fused to a truncated diphtheria toxin payload, as an initial treatment for BPDCN. Tagraxofusp was approved in 2018 by the United States Food and Drug Administration for the treatment of patients aged 2 years and older with newly diagnosed and relapsed/refractory BPDCN, and by the European Medicines Agency in 2021 for first-line treatment of adults. The advent of tagraxofusp has opened a new era of precision oncology in the treatment of BPDCN. Herein, we present an overview of BPDCN biology, its diagnosis, and treatment options, illustrated by clinical cases.

Phase 1b trial of tagraxofusp in combination with azacitidine with or without venetoclax in acute myeloid leukemia

ABSTRACT

CD123, a subunit of the interleukin-3 receptor, is expressed on ∼80% of acute myeloid leukemias (AMLs). Tagraxofusp (TAG), recombinant interleukin-3 fused to a truncated diphtheria toxin payload, is a first-in-class drug targeting CD123 approved for treatment of blastic plasmacytoid dendritic cell neoplasm. We previously found that AMLs with acquired resistance to TAG were re-sensitized by the DNA hypomethylating agent azacitidine (AZA) and that TAG-exposed cells became more dependent on the antiapoptotic molecule BCL-2. Here, we report a phase 1b study in 56 adults with CD123-positive AML or high-risk myelodysplastic syndrome (MDS), first combining TAG with AZA in AML/MDS, and subsequently TAG, AZA, and the BCL-2 inhibitor venetoclax (VEN) in AML. Adverse events with 3-day TAG dosing were as expected, without indication of increased toxicity of TAG or AZA+/-VEN in combination. The recommended phase 2 dose of TAG was 12 μg/kg/day for 3 days, with 7-day AZA +/- 21-day VEN. In an expansion cohort of 26 patients (median age 71) with previously untreated European LeukemiaNet adverse-risk AML (50% TP53 mutated), triplet TAG-AZA-VEN induced response in 69% (n=18/26; 39% complete remission [CR], 19% complete remission with incomplete count recovery [CRi], 12% morphologic leukemia-free state [MLFS]). Among 13 patients with TP53 mutations, 7/13 (54%) achieved CR/CRi/MLFS (CR = 4, CRi = 2, MLFS = 1). Twelve of 17 (71%) tested responders had no flow measurable residual disease. Median overall survival and progression-free survival were 14 months (95% CI, 9.5-NA) and 8.5 months (95% CI, 5.1-NA), respectively. In summary, TAG-AZA-VEN shows encouraging safety and activity in high-risk AML, including TP53-mutated disease, supporting further clinical development of TAG combinations. The study was registered on ClinicalTrials.gov as #NCT03113643.

MPN-467 Findings From an Observational, Multicenter, Retrospective Analysis of Patients With Blastic Plasmacytoid Dendritic Cell Neoplasm Treated With Tagraxofusp in the European Expanded Access Program

CONTEXT

Blastic plasmacytoid dendritic cell neoplasm (BPDCN), an aggressive hematologic malignancy with poor prognosis, is characterized by clonal expansion of plasmacytoid dendritic tumor cells expressing specific markers including the interleukin-3 receptor alpha (CD123). Tagraxofusp (TAG) is a CD123-targeted therapy approved by the FDA and EMA. A global expanded access program (EAP) was implemented prior to TAG's EMA authorization to provide access to patients in real-world practice.

OBJECTIVE

Main objectives were rates of complete response and incidence/severity of capillary leak syndrome (CLS). Key secondary objectives included rate of patients bridged to transplantation, survival, safety, number of cycles administered.

DESIGN

Non-interventional, retrospective analysis of BPDCN patients enrolled in the European EAP from 08.2019-12.2021.

SETTING

57 European centers (Germany, France, Italy, Switzerland, United Kingdom, Spain, Austria).

PATIENTS

76 adult (median age 64 years, range 21-85 years) and 4 pediatric patients with BPDCN confirmed by hematopathology with established marker panels (including CD123).

INTERVENTIONS

TAG 12 mcg/kg was administered intravenously once daily on days 1-5 (up to day 10 allowed) of a 21-day cycle. Hospitalization was required for the first cycle (subsequent cycles allowed outpatient administration).

MAIN OUTCOME MEASURES

Review of case report forms and individual records of patients who met criteria for TAG prior to regulatory approval.

RESULTS

Most patients were male (78%), representing real-world distribution. Sixty-three patients received TAG first-line and 17 patients as second/or further line of treatment. The median number of cycles was 2.5 (range 1-8) in first-line and 2.6 (range 1-13) in second-line/further, respectively. No deaths due to CLS were reported. Adverse events (AEs) mainly occurred in cycle 1, with similar rates and severity in older vs younger patients. Analysis is ongoing; data on safety, efficacy, transplantation, and time-related parameters will be reported.

CONCLUSIONS

The is the largest retrospective analysis of real-world clinical practice outside of a clinical trial in BPDCN patients treated with TAG. Adherence to the EAP and multidisciplinary training is thought to have positively affected prevention and management of CLS and other grade 3-4 AEs. These preliminary results confirm the feasibility and safety of TAG, including in elderly patients, with manageable safety.

Precision Medicine in Hematology 2021: Definitions, Tools, Perspectives, and Open Questions

During the past few years, our understanding of molecular mechanisms and cellular interactions relevant to malignant blood cell disorders has improved substantially. New insights include a detailed knowledge about disease-initiating exogenous factors, endogenous (genetic, somatic, epigenetic) elicitors or facilitators of disease evolution, and drug actions and interactions that underlie efficacy and adverse event profiles in defined cohorts of patients. As a result, precision medicine and personalized medicine are rapidly growing new disciplines that support the clinician in making the correct diagnosis, in predicting outcomes, and in optimally selecting patients for interventional therapies. In addition, precision medicine tools are greatly facilitating the development of new drugs, therapeutic approaches, and new multiparametric prognostic scoring models. However, although the emerging roles of precision medicine and personalized medicine in hematology and oncology are clearly visible, several questions remain. For example, it remains unknown how precision medicine tools can be implemented in healthcare systems and whether all possible approaches are also affordable. In addition, there is a need to define terminologies and to relate these to specific and context-related tools and strategies in basic and applied science. To discuss these issues, a working conference was organized in September 2019. The outcomes of this conference are summarized herein and include a proposal for definitions, terminologies, and applications of precision and personalized medicine concepts and tools in hematologic neoplasms. We also provide proposals aimed at reducing costs, thereby making these applications affordable in daily practice.

Analytical Validation of a Hybrid Capture-Based Next-Generation Sequencing Clinical Assay for Genomic Profiling of Cell-Free Circulating Tumor DNA

Genomic profiling of circulating tumor DNA derived from cell-free DNA (cfDNA) in blood can provide a noninvasive method for detecting genomic biomarkers to guide clinical decision making for cancer patients. We developed a hybrid capture–based next-generation sequencing assay for genomic profiling of circulating tumor DNA from blood (FoundationACT). High-sequencing coverage and molecular barcode–based error detection enabled accurate detection of genomic alterations, including short variants (base substitutions, short insertions/deletions) and genomic re-arrangements at low allele frequencies (AFs), and copy number amplifications. Analytical validation was performed on 2666 reference alterations. The assay achieved >99% overall sensitivity (95% CI, 99.1%–99.4%) for short variants at AF >0.5%, >95% sensitivity (95% CI, 94.2%–95.7%) for AF 0.25% to 0.5%, and 70% sensitivity (95% CI, 68.2%–71.5%) for AF 0.125% to 0.25%. No false positives were detected in 62 samples from healthy volunteers. Genomic alterations detected by FoundationACT demonstrated high concordance with orthogonal assays run on the same clinical cfDNA samples. In 860 routine clinical FoundationACT cases, genomic alterations were detected in cfDNA at comparable frequencies to tissue; for the subset of cases with temporally matched tissue and blood samples, 75% of genomic alterations and 83% of short variant mutations detected in tissue were also detected in cfDNA. On the basis of analytical validation results, FoundationACT has been approved for use in our Clinical Laboratory Improvement Amendments–certified/College of American Pathologists–accredited/New York State–approved laboratory.

Distinct age-associated molecular profiles in acute myeloid leukemia defined by comprehensive clinical genomic profiling

Large scale comprehensive genomic profiling (CGP) has led to an improved understanding of oncogenic mutations in acute myeloid leukemia (AML), as well as identification of alterations that can serve as targets for potential therapeutic intervention. We sought to gain insight into age-associated variants in AML through comparison of extensive DNA and RNA-based GP results from pediatric and adult AML. Sequencing of 932 AML specimens (179 pediatric (age 0-18), 753 adult (age ≥ 19)) from diagnostic, relapsed, and refractory times points was performed. Comprehensive DNA (405 genes) and RNA (265) sequencing to identify a variety of structural and short variants was performed. We found that structural variants were highly prevalent in the pediatric cohort compared to the adult cohort (57% vs. 30%; p < 0.001), with certain structural variants detected only in the pediatric cohort. Fusions were the most common structural variant and were highly prevalent in AML in very young children occurring in 68% of children < 2 years of age. We observed an inverse trend in the prevalence of fusions compared to the average number of mutations per patient. In contrast to pediatric AML, adult AML was marked by short variants and multiple mutations per patient. Mutations that were common in adult AML were much less common in the adolescent and young adult cohort and were rare or absent in the pediatric cohort. Clinical CGP demonstrates the biologic differences in pediatric vs. adult AML that have significant therapeutic impacts on prognosis, therapeutic allocation, disease monitoring, and the use of more targeted therapies.

Next-generation sequencing of idiopathic multicentric and unicentric Castleman disease and follicular dendritic cell sarcomas

Castleman disease (CD) is a rare lymphoproliferative disorder subclassified as unicentric CD (UCD) or multicentric CD (MCD) based on clinical features and the distribution of enlarged lymph nodes with characteristic histopathology. MCD can be further subtyped based on human herpes virus 8 (HHV8) infection into HHV8-associated MCD, HHV8-/idiopathic MCD (iMCD), and polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin change (POEMS)-associated MCD. In a subset of cases of UCD, an associated follicular dendritic cell sarcoma (FDCS) may be seen. Although numerous reports of the clinical and histologic features of UCD, MCD, and FDCS exist, an understanding of the genetic and epigenetic landscape of these rare diseases is lacking. Given this paucity of knowledge, we analyzed 15 cases of UCD and 3 cases of iMCD by targeted next-generation sequencing (NGS; 405 genes) and 3 cases of FDCS associated with UCD hyaline vascular variant (UCD-HVV) by whole-exome sequencing. Common amplifications of ETS1, PTPN6, and TGFBR2 were seen in 1 iMCD and 1 UCD case; the iMCD case also had a somatic DNMT3A L295Q mutation. This iMCD patient also showed clinicopathologic features consistent with a specific subtype known as Castleman-Kojima disease (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly [TAFRO] clinical subtype). Additionally, 1 case of UCD-HVV showed amplification of the cluster of histone genes on chromosome 6p. FDCS associated with UCD-HVV showed mutations and copy number changes in known oncogenes, tumor suppressors, and chromatin structural-remodeling proteins.

Loss of heterozygosity as a marker of homologous repair deficiency in multiple myeloma: a role for PARP inhibition?

PARP inhibitors can induce synthetic lethality in tumors characterized by homologous recombination deficiency (HRD), which can be detected by evaluating genome-wide loss of heterozygosity (LOH). Multiple myeloma (MM) is a genetically unstable tumor and we hypothesized that HRD-related LOH (HRD-LOH) could be detected in patient samples, supporting a potential role for PARP inhibition in MM. Using results from targeted next-generation sequencing studies (FoundationOne^® Heme), we analyzed HRD-LOH in patients at all disease stages (MGUS (n = 7), smoldering MM (SMM, n = 30), newly diagnosed MM (NDMM, n = 71), treated MM (TRMM, n = 64), and relapsed MM (RLMM, n = 234)) using an algorithm to identify HRD-LOH segments. We demonstrated HRD-LOH in MM samples, increasing as disease progresses. The extent of genomic HRD-LOH correlated with high-risk disease markers. Outcome of RLMM patients, the biggest clinical group, was analyzed and patients with HRD-LOH above the third quartile (≥5% HRD-LOH) had significantly worse progression-free and overall survival than those with lower levels (p < 0.001). Mutations in key homologous recombination genes account for some, but not all, of the cases with an excess of HRD-LOH. These data support the further evaluation of PARP inhibitors in MM patients, particularly in the relapsed setting with a high unmet need for new treatments.

The varied distribution and impact of RAS codon and other key DNA alterations across the translocation cyclin D subgroups in multiple myeloma

We examined a set of 805 cases that underwent DNA sequencing using the FoundationOne Heme (F1H) targeted sequencing panel and gene expression profiling. Known and likely variant calls from the mutational data were analyzed for significant associations with gene expression defined translocation cyclin D (TC) molecular subgroups. The spectrum of KRAS, NRAS, and BRAF codon mutations varied across subgroups with NRAS mutations at Q61 codon being common in hyperdiploid (HRD) and t(11;14) myeloma while being rare in MMSET and MAF. In addition, the presence of RAS-RAF mutations was inversely associated with NFκB pathway activation in all subgroups excluding MAF. In the MMSET subgroup, cases with low FGFR3 expression frequently had RAS-RAF mutations. Conditional inference tree analysis determined that mutation and homozygous deletion of TP53, CDKN2C, and RB1 were key prognostic factors associated with adverse outcome in a non-relapse clinical setting. In conclusion, this study highlights the heterogeneity in the distribution and clinical outcomes of RAS codon and other mutations in multiple myeloma dependent upon primary molecular subgroup.

Unraveling the genetic underpinnings of myeloproliferative neoplasms and understanding their effect on disease course and response to therapy: proceedings from the 6th International Post-ASH Symposium

Immediately after the annual scientific meeting of the American Society of Hematology (ASH), a select group of clinical and laboratory investigators in myeloproliferative neoplasms (MPN) is summoned to a post-ASH conference on chronic myeloid leukemia and the BCR-ABL1-negative MPN. The 6th such meeting occurred on December 13–14,2011, in La Jolla, California, USA, under the direction of its founder,Dr. Tariq Mughal. The current document is the first of two reports on this post-ASH event and summarizes the most recent preclinical and clinical advances in polycythemia vera, essential thrombocythemia,and primary myelofibrosis.

Mutations with epigenetic effects in myeloproliferative neoplasms and recent progress in treatment: Proceedings from the 5th International Post-ASH Symposium

Immediately following the 2010 annual American Society of Hematology (ASH) meeting, the 5th International Post-ASH Symposium on Chronic Myelogenous Leukemia and BCR-ABL1-Negative Myeloproliferative Neoplasms (MPNs) took place on 7–8 December 2010 in Orlando, Florida, USA. During this meeting, the most recent advances in laboratory research and clinical practice, including those that were presented at the 2010 ASH meeting, were discussed among recognized authorities in the field. The current paper summarizes the proceedings of this meeting in BCR-ABL1-negative MPN. We provide a detailed overview of new mutations with putative epigenetic effects (TET oncogene family member 2 (TET2), additional sex comb-like 1 (ASXL1), isocitrate dehydrogenase (IDH) and enhancer of zeste homolog 2 (EZH2)) and an update on treatment with Janus kinase (JAK) inhibitors, pomalidomide, everolimus, interferon-α, midostaurin and cladribine. In addition, the new ‘Dynamic International Prognostic Scoring System (DIPSS)-plus' prognostic model for primary myelofibrosis (PMF) and the clinical relevance of distinguishing essential thrombocythemia from prefibrotic PMF are discussed.

The Ph-positive and Ph-negative myeloproliferative neoplasms: some topical pre-clinical and clinical issues

This review focuses on topical issues in the biology and treatment of the myeloproliferative neoplasms (MPNs). Studies in transgenic mice suggest that BCR-ABL1 reduces the fraction of self-renewing 'leukemic' stem cells in the bone marrow but that some of these cells survive treatment with imatinib. This also seems to operate in humans. Data from models also strongly support the notion that JAK2(V617F) can initiate and sustain MPNs in mice; relevance to disease in humans is less clear. These data also support the hypothesis that level of JAK2(V617F) expression influences the MPN phenotype: higher levels favor erythrocytosis whereas lower levels favor thrombocytosis. Although TET2-mutations were thought to precede JAK2(V617F) in some persons with MPNs, it now appears that TET2 mutations may occur after JAK2(V617F). Further understanding of signal-transduction pathways activated in chronic myeloid leukemia suggests various possible targets for new therapies including the WNT/beta catenin, notch and hedgehog pathways. Finally, the clinical role of the new JAK2- and BCR-ABL1-inhibitors is considered. Much further progress is likely in several of these areas soon.

Chronic myeloproliferative diseases with and without the Ph chromosome: some unresolved issues

Ph-positive chronic myeloid leukemia (CML) and Ph-negative chronic myeloproliferative diseases (MPDs), characterized in many cases by the presence of the JAK2(V617F) mutation, have many features in common and yet also show fundamental differences. In this review, we pose five discrete and related questions relevant to both categories of hematological malignancy, namely: What are the mechanisms that underlie disease progression from a relatively benign or chronic phase? By what therapeutic methods might one target residual leukemia stem cells in CML? Is JAK2(V617F) the original molecular event in MPD? What epigenetic events must have a role in dictating disease phenotype in MPDs? And finally, Will the benefits conferred by current or future JAK2(V617F) inhibitors equal or even surpass the clinical success that has resulted from the use of tyrosine kinase inhibitors in CML? These and others questions must be addressed and in some cases should be answered in the foreseeable future.

Optimal management of patients with newly diagnosed chronic phase chronic myeloid leukemia in 2007

Chronic myeloid leukemia cells contain a Bcr-Abl oncoprotein with an enhanced tyrosine kinase activity, which is considered to be the principal cause of the leukemia. The use of the first-generation tyrosine kinase inhibitor imatinib to inhibit the dysregulated kinase activity has proved remarkably successful, and imatinib as a single-agent is now considered to be the best initial treatment for the majority of adult patients in chronic phase. For patients who develop resistance to imatinib, the Bcr-Abl signaling pathway is often re-activated, second generation tyrosine kinase inhibitors, such as dasatinib or nilotinib, might restore the kinase inhibition. Allogeneic stem cell transplantation is now generally offered to older patients in whom imatinib therapy, and perhaps dasatinib or nilotinib also, have failed; efforts to establish firm criteria for the selection of second-line therapies after imatinib failure continue. At this time, children and younger adults should probably be considered for transplantation as first-line treatment.

The changing face of HIV-associated lymphoma: what can we learn about optimal therapy inl the post highly active antiretroviral therapy era?

Epidemiological data indicate that the risk of developing non-Hodgkin lymphoma (NHL) in HIV positive individuals is related to age and CD4 count (i.e. degree of immunosuppression). The prognosis of patients with HIV-NHL has been shown to be linked to several features including age, stage, modified IPI, prior AIDS diagnosis, CD4 count, immunoblastic pathology, LDH, and HAART use. These features are, as would be expected, a mixture of prognostic factors relating to both the HIV, and to the NHL. Population studies indicate that the incidence of associated (HIV-NHL) may be reducing with the advent of HAART, although not all studies concur. However, most population-based studies have not as yet shown a significant improvement in the survival of patients with HIV-NHL with HAART. The optimal chemotherapy for these patients is unknown, although it is generally accepted that CNS prophylaxis is mandatory. There is currently no good evidence of any survival benefit with increased dose intensity from large RCT. However, it must be borne in mind that the large randomised studies comparing differing dose intensities were undertaken before the advent of effective HAART. There is some evidence that there may be a subset of good prognosis patients who may benefit from more intensive therapy. Given that the prognosis of patients with HIV can now be considerably improved with HAART, we cannot necessarily assume that the same results would apply with regard to chemotherapy dose intensity. There is some evidence that there is a survival benefit from the addition of HAART to chemotherapy, although this is retrospective. It is likely, however, that the reason for this is that the HAART improves the prognosis of the patients from their HIV, and therefore reduces the number of patients dying from other HIV-related illnesses whilst in remission from their lymphoma, as was seen in large numbers of patients in the earlier chemotherapy trials. It must not be forgotten that the prognosis of the patient's NHL is intimately linked to their prognosis with respect to the HIV. Although the number of patients with HIV-NHL is currently few, there is a need for more trials of chemotherapy, particularly now in the HAART era, when the prognosis from the point of view of the HIV has improved so much. In particular, the issue of dose intensity needs revisiting for patients whose overall prognosis can be improved by commencing HAART. Patients with HIV-NHL should be managed at specialist centres, and where possible should be managed as part of RCT.

Neoadjuvant vinorelbine/epirubicin (VE) versus standard adriamycin/cyclophosphamide (AC) in operable breast cancer: analysis of response and tolerability in a randomised phase III trial (TOPIC 2)

BACKGROUND

Vinorelbine is active and well tolerated against advanced breast cancer but there are no published efficacy studies in early breast cancer. We have therefore carried out a randomised phase III neoadjuvant trial in operable breast cancer.

PATIENTS AND METHODS

Patients with > or =3 cm operable breast carcinoma were randomised to receive either vinorelbine 25 mg/m(2) on days 1 and 8 and epirubicin 60 mg/m(2) on day 1, 3 weekly for six cycles (VE) or doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) i.v. on day 1, 3 weekly for six cycles (AC), prior to standard local therapy, and adjuvant endocrine therapy as appropriate.

RESULTS

A total of 451 patients were randomised. Results for AC and VE, respectively, were: overall clinical response 73% and 74%, complete clinical remission 20% and 24%, pathological complete remission 12% and 12%, mastectomy rate 52% and 55%. None of these differences were significant. Dose reduction was required in 8% for AC and 20% for VE (P <0.001) (GSCF support not used). Significantly more grade 3/4 toxicity for nausea, vomiting and alopecia (despite scalp cooling) was seen for AC compared with VE but significantly less grade 3/4 thrombophlebitis and neuropathy.

CONCLUSIONS

Neoadjuvant VE is as effective as AC in early breast cancer and was better tolerated except for thrombophlebitis and neuropathy.

Methicillin resistant Staphylococcus aureus: a multicentre study

OBJECTIVE

To determine the frequency of Methicillin resistance Staphylococcus aureus infection in major cities of Pakistan.

SETTING

Various laboratories of the country with one as the central Laboratory.

MATERIALS AND METHODS

Seven hundred and ninety two consecutive clinical isolates of Staphylococcus aureus were collected from 8 laboratories all over Pakistan i.e. Karachi, Peshawar, Lahore, Sukkhur, Islamabad, Quetta, and Mirpur, Azad Kashmir. Antibiotic sensitivity was done by Kirby Bauer disc diffusion method and MIC of Vancomycin was determined by 'E' test.

RESULTS

Forty two percent of the isolates were found to be Methicillin resistant staphylococcus aureus (MRSA) while no Vancomycin resistance was encountered.

CONCLUSION

Methicillin resistant Staphylococcus aureus (MRSA) are seen in the local population with frequencies varying between 2-61% highest incidence is seen in the major cities of the country. Fortunately no Vancomycin resistant Staphylococcus has been isolated from any of the major cities.

Interferon-alpha facilitates renal transplantation in hemodialysis patients with chronic viral hepatitis

Interferon-alpha has not been used previously in hemodialysis patients with chronic hepatitis B and C. This uncontrolled report evaluates the biochemical and/or histologic profile resulting from the administration of interferon-alpha in seven hemodialysis patients, two with chronic hepatitis B and five with hepatitis C. Biochemical improvement was noted in all patients. Histologic progression did not occur in the two cases in which such assessment was made, and five of them were subsequently transplanted without recurrence of disease.

Autografting for patients with chronic myeloid leukemia--the Hammersmith experience

The optimal approach for curing patients with chronic myeloid leukemia (CML) in chronic phase (CP) is an allogeneic bone marrow transplant (BMT). However, this approach is not available to the majority of patients. Autografting, using either purged or unpurged bone marrow or peripheral blood stem cells (PBSC), could be beneficial for patients who are not eligible for BMT. Between 1984 and 1992, 21 patients with CML in CP were autografted using unmanipulated PBSC harvested either at diagnosis or thereafter. Ten of 21 patients survived at a median of 84 months following autografting (range: 12-108 months). Eleven patients died, seven of blast transformation and four from other causes. The timing of the autograft or the harvest does not appear to have a bearing on survival.

Late relapse after allogeneic bone marrow transplantation for Philadelphia-positive acute lymphoblastic leukaemia

Late relapse of leukaemia is rare in patients with chronic myeloid leukaemia (CML) subjected to allogeneic bone marrow transplantation in chronic phase. Herein, we report a patient who presented with acute lymphoblastic leukaemia who after chemotherapy developed a picture consistent with CML in chronic phase. He then received an allograft from an HLA-identical sister and remained in complete remission for 4 years, before he eventually relapsed with features of myeloid transformation of CML. We speculate that the same population of already transformed leukaemic progenitor cells may have given rise to the original lymphoid blast cells and the myeloid blast cells that characterized the terminal relapse.

Chronic leukaemias: can they be cured? Part 1: Chronic myeloid leukaemia

Chronic myeloid leukaemia, a clonal myeloproliferative disorder with a biphasic nature, is characterised by a specific chromosomal aberration, the Philadelphia (Ph) chromosome. The Ph chromosome is the result of a reciprocal translocation between chromosomes 9 and 22 and involves the ABL and BCR genes resulting in a chimeric mRNA encoding a specific protein, termed P210. At present, there is no convincing evidence that to maintain the leucocyte count within the normal range prolongs the duration of the stable chronic phase or of survival, and the objectives of treatment are simply to alleviate symptoms or to delay their onset. It has, however, become clear that bone marrow transplantation performed during the chronic phase using an HLA-identical sibling donor offers the best chance of a cure.