Alberto Catalano

All-trans-retinoic acid, idarubicin, and IV arsenic trioxide as initial therapy in acute promyelocytic leukemia (APML4)

The treatment of acute promyelocytic leukemia has improved considerably after recognition of the effectiveness of all-trans-retinoic acid (ATRA), anthracycline-based chemotherapy, and arsenic trioxide (ATO). Here we report the use of all 3 agents in combination in an APML4 phase 2 protocol. For induction, ATO was superimposed on an ATRA and idarubicin backbone, with scheduling designed to exploit antileukemic synergy while minimizing cardiotoxicity and the severity of differentiation syndrome. Consolidation comprised 2 cycles of ATRA and ATO without chemotherapy, followed by 2 years of maintenance with ATRA, oral methotrexate, and 6-mercaptopurine. Of 124 evaluable patients, there were 4 (3.2%) early deaths, 118 (95%) hematologic complete remissions, and all 112 patients who commenced consolidation attained molecular complete remission. The 2-year rate for freedom from relapse is 97.5%, failure-free survival 88.1%, and overall survival 93.2%. These outcomes were not influenced by FLT3 mutation status, whereas failure-free survival was correlated with Sanz risk stratification (P[trend] = .03). Compared with our previously reported ATRA/idarubicin-based protocol (APML3), APML4 patients had statistically significantly improved freedom from relapse (P = .006) and failure-free survival (P = .01). In conclusion, the use of ATO in both induction and consolidation achieved excellent outcomes despite a substantial reduction in anthracycline exposure. This trial was registered at the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12605000070639.

Response of myeloma to the proteasome inhibitor bortezomib is correlated with the unfolded protein response regulator XBP-1

Background Multiple myeloma, a malignancy of the antibody-secreting plasma cells, remains incurable by current therapy. However, the proteasome inhibitor bortezomib and other new drugs are revolutionizing its treatment. It remains unclear why myelomas are peculiarly sensitive to bortezomib, or what causes primary or acquired resistance. The ‘unfolded protein response’ is necessary for folding and assembly of immunoglobulin chains in both normal and malignant plasma cells, as well as for the disposal of incorrectly folded or unpaired chains via the ubiquitin-proteasome pathway. We tested the hypothesis that levels of transcription factor XBP-1, a major regulator of the unfolded protein response, predict response to bortezomib. Design and Methods Expression of XBP-1 and other regulators of the unfolded protein response were measured in myeloma and other cancer cell lines and two cohorts of patients with refractory myeloma and correlated with sensitivity/response to bortezomib. Bortezomib-resistant myeloma cell lines were derived and the effects on expression of unfolded protein response regulators, immunoglobulin secretion, proteasome activity and cross-resistance to cytotoxic drugs and tunicamycin determined. The consequences of manipulation of XBP-1 levels for sensitivity to bortezomib were tested. Results Low XBP-1 levels predicted poor response to bortezomib, both in vitro and in myeloma patients. Moreover, myeloma cell lines selected for resistance to bortezomib had down-regulated XBP-1 and immunoglobulin secretion. Expression of ATF6, another regulator of the unfolded protein response, also correlated with bortezomib sensitivity. Direct manipulation of XBP-1 levels had only modest effects on sensitivity to bortezomib, suggesting it is a surrogate marker of response to bortezomib rather than a target itself. Conclusions The unfolded protein response may be a relevant target pathway for proteasome inhibitors in the treatment of myeloma and its regulator XBP-1 is a potential response marker. (The BIR study was registered with Australian Clinical Trial Registry Number 12605000770662)

Use of arsenic trioxide in remission induction and consolidation therapy for acute promyelocytic leukaemia in the Australasian Leukaemia and Lymphoma Group (ALLG) APML4 study: a non-randomised phase 2 trial

BACKGROUND Initial treatment of acute promyelocytic leukaemia traditionally involves tretinoin (all-trans retinoic acid) combined with anthracycline-based risk-adapted chemotherapy, with arsenic trioxide being the treatment of choice at relapse. To try to reduce the relapse rate, we combined arsenic trioxide with tretinoin and idarubicin in induction therapy, and used arsenic trioxide with tretinoin as consolidation therapy. METHODS Patients with previously untreated genetically confirmed acute promyelocytic leukaemia were eligible for this study. Eligibilty also required Eastern Cooperative Oncology Group performance status 0-3, age older than 1 year, normal left ventricular ejection fraction, Q-Tc interval less than 500 ms, absence of serious comorbidity, and written informed consent. Patients with genetic variants of acute promyelocytic leukaemia (fusion of genes other than PML with RARA) were ineligible. Induction comprised 45 mg/m(2) oral tretinoin in four divided doses daily on days 1-36, 6-12 mg/m(2) intravenous idarubicin on days 2, 4, 6, and 8, adjusted for age, and 0·15 mg/kg intravenous arsenic trioxide once daily on days 9-36. Supportive therapy included blood products for protocol-specified haemostatic targets, and 1 mg/kg prednisone daily as prophylaxis against differentiation syndrome. Two consolidation cycles with tretinoin and arsenic trioxide were followed by maintenance therapy with oral tretinoin, 6-mercaptopurine, and methotrexate for 2 years. The primary endpoints of the study were freedom from relapse and early death (within 36 days of treatment start) and we assessed improvement compared with the 2 year interim results. To assess durability of remission we compared the primary endpoints and disease-free and overall survival at 5 years in APML4 with the 2 year interim APML4 data and the APML3 treatment protocol that excluded arsenic trioxide. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12605000070639. FINDINGS 124 patients were enrolled between Nov 10, 2004, and Sept 23, 2009, with data cutoff of March 15, 2012. Four (3%) patients died early. After a median follow-up of 4·2 years (IQR, 3·2-5·2), the 5 year freedom from relapse was 95% (95% CI 89-98), disease-free survival was 95% (89-98), event-free survival was 90% (83-94), and overall survival was 94% (89-97). The comparison with APML3 data showed that hazard ratios were 0·23 (95% CI 0·08-0·64, p=0·002) for freedom from relapse, 0·21 (0·07-0·59, p=0·001) for disease-free survival, 0·34 (0·16-0·69, p=0·002) for event-free survival, and 0·35 (0·14-0·91, p=0·02) for overall survival. INTERPRETATION Incorporation of arsenic trioxide in initial therapy induction and consolidation for acute promyelocytic leukaemia reduced the risk of relapse when compared with historical controls. This improvement, together with a non-significant reduction in early deaths and absence of deaths in remission, translated into better event-free and overall survival. FUNDING Phebra.

Results of the APML3 trial incorporating all-trans-retinoic acid and idarubicin in both induction and consolidation as initial therapy for patients with acute promyelocytic leukemia

Background Initial therapy for patients with acute promyelocytic leukemia most often involves the combination of all-trans-retinoic acid with anthracycline-based chemotherapy. The role of non-anthracycline drugs in induction and consolidation is less well-established and varies widely between different cooperative group protocols. Design and Methods In an attempt to minimize relapse and maximize survival for patients with newly diagnosed acute promyelocytic leukemia, the Australasian Leukaemia and Lymphoma Group utilized all-trans-retinoic acid and idarubicin as anti-leukemic therapy for both induction and consolidation. The protocol (known as APML3) was subsequently amended to incorporate maintenance with all-trans-retinoic acid, methotrexate and 6-mercaptopurine. Results Eight (8%) of 101 patients died within 30 days, and 91 (90%) achieved complete remission. With a median estimated potential follow-up of 4.6 years, 4-year overall survival was 84%, and 71% of the patients remained in remission at 4 years. The cumulative incidence of all relapses was 28.1%, with 15 of the 25 relapses initially identified as an isolated molecular relapse. Both FLT3 mutations (internal tandem duplications and codon 835/836 kinase domain mutations) and increased white cell count at diagnosis were associated with inferior overall survival, but in multivariate analyses only FLT3 mutations remained significant (hazard ratio 6.647, P=0.005). Maintenance therapy was significantly associated with improved remission duration (hazard ratio 0.281, P<0.001) and disease-free survival (hazard ratio 0.290, P<0.001). Conclusions The combination of all-trans-retinoic acid and just two cycles of idarubicin followed by triple maintenance produced durable remissions in most patients, but patients with high-risk disease, especially those with FLT3 mutations, require additional agents or alternative treatment approaches. The significant reduction in relapse seen after the addition of maintenance to the protocol supports a role for maintenance in the context of relatively low chemotherapy exposure during consolidation. (actr.org.au identifier: ACTRN12607000410459)

Molecular biology of lymphoma in the microarray era

Summary This review will focus on the molecular biology of lympho‐proliferative disorders with emphasis on lymphomas. The spectrum of known recurrent gene rearrangements found in lymphomas will be outlined and their relevance to diagnosis and subclassification of disease will be discussed. Finally, a survey of the current trends in gene expression profiling of lymphomas by microarray technology will be presented with reference to implications for diagnosis, classification, prognosis and treatment.Abbreviations: ALL, acute lymphoblastic leukaemia; ALCL, anaplastic large cell lymphoma; ABC, activated B‐cells; D, diversity genes; DLBCL, diffuse large B‐cell lymphoma; FL, follicular lymphoma; GCB, germinal centre B cell; GEP, gene expression profiling; HL, Hodgkin lymphoma; IGH, immunoglobulin heavy chain; J, joining genes; LBL, lymphoblastic lymphomas; MALT, mucosa‐associated lymphoid tissue; MCL, mantle cell lymphoma; RSS, recombination signal sequences; TCR, T‐cell receptor; V, variable genes.

Concomitant FIP1L1-PDGFRA fusion gene and T-cell clonality in a case of chronic eosinophilic leukemia with clonal evolution and an incomplete response to imatinib

Hypereosinophilic syndromes (HES) are rare heterogeneous hematological disorders, characterized by sustained (unexplained) eosinophil overproduction, in which tissue infiltration and mediator release can cause end-organ damage [1]. A specific molecular or immunologic defect can be identified in around 20% of cases, with at least two distinct, and previously assumed mutually exclusive, categories described [1]. Chronic eosinophilic leukemia (CEL) with myeloproliferative features (increased serum vitamin B12 and tryptase, circulating myeloid precursors, hepatosplenomegaly) is characterized by clonal abnormalities—in particular, an interstitial deletion of chromosome 4q12 resulting in the FIP1L1– PDGFRA fusion gene (F/P) with constitutive tyrosine kinase (TK) activity [1,2]. The ‘lymphocytic’ variant (L-HES) is characterized by expansion of a clonal interleukin-5 (IL-5; and other T-helper cell type 2 [Th2] cytokine) producing T-cell population [3]. Recent reports on the frequency of T-cell clonality in HES note that it is rarely seen in addition to F/P [4–6]. The coexistence, however, may add insight to the complex pathogenesis and disease heterogeneity. We report a 65-year-old man with CEL and concomitant expression of F/P and T-cell clonality who has sustained a complete hematological response (CHR) to imatinib. However, a complete molecular response (CMR) has never been achieved, which we postulate is due to clonal evolution of the F/P and acquired impaired imatinib sensitivity. In December 2002, he presented with an isolated and sustained eosinophilia (5.56 10/L), hepatosplenomegaly, lethargy, and sweats but no clinical end-organ dysfunction. The marrow demonstrated myeloproliferation with a prominent (27%) eosinophilia and increased reticulin (MF-1). The karyotype was diploid, and fluorescence in situ hybridization (FISH) for BCR–ABL was negative; flow cytometric and polymerase chain reaction (PCR) studies for Tcell clonality and F/P were not performed at that time. He commenced hydroxycarbamide, adjusted to his eosinophil count, and prednisolone (25 mg/day, tapered over 8 weeks). He responded within 2 weeks, with sustained normalization of his eosinophil count. In December 2005, he was referred to our institution with cytologically confirmed eosinophilic pericardial and pleural effusions, peripheral blood eosinophilia (5.36 10/L), and splenomegaly. Hydroxycarbamide proved ineffective, with a rising eosinophil count (106 10/L). Bone marrow

Sensitive monitoring of acute promyelocytic leukemia by PML-RARA DNA Q-PCR

Ivar O. Kommers, Paul A. Bartley, Bradley Budgen, Sue Latham, Ashanka Beligaswatte, Shane G. Supple, Alberto Catalano, Harry J. Iland, Alexander A. Morley and David M. Ross Department of Clinical and Molecular Medicine, Flinders University and Medical Centre, Adelaide, Australia; VU University Medical Center, Amsterdam, The Netherlands; Institute of Haematology, Royal Prince Alfred Hospital, Sydney, Australia; Sydney Medical School, University of Sydney, Sydney, Australia; School of Medicine, University of Adelaide, Adelaide, Australia

Using digital polymerase chain reaction to detect minimal residual disease in myeloma by identifying FGFR3 up-regulation.

As new therapies increase the incidence of stringent complete remission (sCR) and overall survival (OS) of patients with multiple myeloma (MM), there is a growing demand for a sufficiently sensitive monitoring method to detect low levels of residual disease. Traditional monitoring using bone marrow (BM) morphology and M-protein requires a substantial plasma cell burden to be present before a positive signal can be detected. Such methods, although important for defining response, are becoming increasingly irrelevant in the context of an emerging need to detect lower levels of measurable residual disease (MRD). MRD in MM has been detected using allele-specific