European Journal of Haematology 93 (455–468)
REVIEW ARTICLE
Anaplastic lymphoma kinase-positive anaplastic large cell lymphoma: current and future perspectives in adult and paediatric disease Toby A. Eyre1, Dalia Khan1, Georgina W. Hall2, Graham P. Collins1 1
Department of Haematology, Oxford University Hospitals NHS Trust, Churchill Hospital, Oxford; 2Paediatric & Adolescent Haematology/ Oncology Unit, Oxford University Hospitals NHS Trust, Children’s Hospital, John Radcliffe Hospital, Oxford, UK
Abstract Anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma seen in both adults and children. ALCL is associated with a characteristic chromosomal translocation, t(2;5)(p23;35) which fuses the anaplastic lymphoma kinase (ALK) gene on chromosome 2 with the nucleophosmin (NPM) gene on chromosome 5, resulting in a NPM-ALK fusion protein, ALK over-expression and constitutive tyrosine kinase activity. This aggressive lymphoma is more prevalent in males and can present with extranodal involvement (lung, skin and marrow infiltration) and haemophagocytic lymphohistocytosis. The long-term overall survival is approximately 70–90% in children and over 70% in adults. Staging systems and prognostic risk factors are different in both childhood and adult ALCL. Treatment in adults is typically anthracycline-based, with autologous stem cell transplantation (ASCT) salvaging patients in relapsed disease. There is evidence for ALL-like therapy or intensive, pulsed anthracycline-based induction in children. ASCT, allogeneic SCT and vinblastine maintenance are all considered reasonable options in relapsed childhood disease. The antiCD30 immunoconjugate Brentuximab Vedotin and the specific ALK inhibitor Crizotinib are changing the treatment paradigm in ALCL (ALK-positive or negative) and ALK-positive ALCL respectively. Both agents have shown encouraging responses in relapsed ALCL. It remains to be seen how these novel agents are used, but it is very possible that they may improve overall responses and survival in both children and adults. This review highlights the presentation, histopathological features, prognostic factors, and evidence-based treatment approaches in the first line and relapsed setting in ALK-positive ALCL. The review concludes by discussing the novel approaches using Brentuximab and Crizotinib which are being tested in clinical trials. Key words anaplastic large cell lymphoma; anaplastic lymphoma kinase; stem cell transplantation; Brentuximab; Crizotinib; vinblastine Correspondence Toby A. Eyre, Lymphoma Clinical Research Fellow, Department of Haematology and Early Phase Trials Unit, Churchill Hospital, Oxford OX3 7LE, UK. Tel: +44 (0) 1865 235886; Fax: +44 (0) 1865 235260; e-mail: [email protected] Accepted for publication 21 April 2014
Anaplastic large cell lymphomas (ALCL) are a subgroup of Peripheral T-Cell Lymphomas (PTCL) thought to derive from cytotoxic T cells. The 2008 WHO classification identifies three separate biological entities: (1) primary systemic ALK-positive ALCL (ALK-positive ALCL), primary systemic ALK-negative ALCL and primary cutaneous ALCL (2, 3). ALK-positive ALCL, by definition overexpresses an ALK-fusion gene, typically via t(2;5)(p23;35) which fuses the anaplastic lymphoma kinase (ALK) gene on chromosome 2 with the nucleophosmin (NPM) gene on chromosome 5,
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
doi:10.1111/ejh.12360
resulting in a NPM-ALK chimeric protein with constitutive tyrosine kinase activity (4, 5). Anaplastic large cell lymphomas presents at any age. Characterised by extranodal presentation and male predominance, ALCL is typically a chemo-sensitive disease with long-term OS rate of approximately 70–90% in both adults and children despite different treatment approaches. Although relapsed, refractory disease remains a challenge, impressive novel targeted therapy has made a huge impact and is likely to change the treatment paradigm in ALCL.
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Future perspective for ALK-positive ALCL
Laboratory investigations
There is a spectrum of morphological heterogeneity, but cells are often large, with ‘horse-shoe’ or ‘kidney-bean’ shaped nuclei with a prominent nucleolus and dispersed chromatin. Other subtypes such as small cell type and lymphohistocytic cell type are described (6). Although 90% of cases show T-cell receptor (TCR) clonal rearrangements, typical malignant T cells often have a ‘null’ phenotype. It is common for the neoplastic cells to lack CD3 and other commonly expressed T-cell surface markers are often underexpressed. Neoplastic cells strongly express CD30, lack CD15, and most express epithelial membrane antigen (EMA). Cytotoxic granule-associated antigen expression (TIA-1, Perforin, Granzyme) and a golgi pattern of reactivity for clusterin is often seen (7). The cytoplasmic and nuclear pattern of ALK expression depends on the nature of the ALK translocation. Typically, the classical NPM1-ALK translocation leads to nuclear and cytoplasmic ALK staining (8), although this specific translocation is not seen in 10–15% of cases (9). There are no clearly defined prognostic differences in tumours with variant ALK translocations. The ALK gene can be translocated onto other chromosomes, leading to different fusion proteins and various immunohistochemical patterns of ALK expression. For example in t(1;2)(q25;p23) (10) or inv(2) (p23;q35), (11) the ALK protein accumulates only in the cytoplasm. Moreover, in two large studies (6, 9) up to 20% of ALK-positive ALCL displayed cytoplasmic-only expression. Although it is possible to make the diagnosis by immunohistochemical assessment of ALK, EMA, CD30 and T-cell markers, the most sensitive test for ALK-positive ALCL is fluorescence in-situ hybridization (FISH) using an ALK-gene break-apart probe. If the precise ALK translocation is known, patients can also be assessed by real-time polymerase chain reaction (RT-PCR). Recently, gene expression profiling (GEP) has shown that ALK-positive ALCL, ALKnegative ALCL and PTCL-NOS are all distinct molecular entities (12). Lymph nodes typically display diffusely effaced architecture or sinusoidal and/or perivascular tumour involvement. The bone marrow is infiltrated in 10–30% of cases. Extranodal tissue infiltration can also provide the diagnosis. Diagnosis of ALK-positive ALCL is therefore dependent on identification of T-cell ‘null’ phenotype, specific histological appearances with an underlying chromosomal translocation involving the ALK gene, expression of the ALK-fusion protein and uniform, strong CD30 expression (1, 9, 13). Incidence and risk factors
Anaplastic lymphoma kinase-positive ALCL represents approximately 3% of adult non-Hodgkin’s lymphoma (NHL) (14, 15) and 10–15% of childhood lymphomas (16). No con-
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sistent evidence of a causative agent for ALK-positive ALCL such as EBV, HTLV or environmental toxins has been discovered. Case reports of ALCL associated with HIV are published but none were ALK-positive ALCL (17). Breast implant associated ALCL are rarely ALK-positive (18). Anaplastic lymphoma kinase
Anaplastic lymphoma kinase (ALK) itself is an orphan tyrosine kinase which when deregulated becomes oncogenic. Although first described in ALCL, ALK is also implicated in non-small cell lung cancer (NSCLC) (19), neuroblastomas, acute myeloid leukaemia and diffuse large B-cell lymphoma (DLBCL). The ALK gene encodes a 1620-amino acid protein that undergoes post-translational N-linked glycosylation to a mature form weighing 220 kDa. It belongs to the insulin-receptor super-family and is closely related to the leucocyte tyrosine kinase (LTK) (20). The physiological role of ALK was established through invertebrate studies, murine knock-out models and cell-line experiments. Loss of ALK homologues in Caenorhabditis elegans and Drosophila Melanogaster result in defects in midgut development, neuronal wiring and plasticity via the Ras-mitogen-activated protein kinase pathway (MAP-K) (21, 22). In mammals, ALK expression is preferential in the central and peripheral nervous systems (23). In mice, the genomic deletion of ALK results in a minimal change in phenotype compared with wild type. Cell line studies show that constitutively active chimeric ALK receptors induce neuron differentiation and promote mitogenesis (24). Ligands for ALK are described in invertebrate (JEB, Jelly Belly) and mammalian models [Pleiotrophin (PTN) and Midkine (MK)]. ALK is in the family of ‘dependence-receptors’, defined as transmembrane proteins capable of inducing apoptosis in the absence of the required stimulus but which block apoptosis following binding to their ligand. Expression of these receptors creates cellular states of dependence on the associated ligands (25). Pathological ALK expression
In ALK translocations, genomic breakpoints are almost always located in the intron flanked by exons 16 and 17. Mechanisms for different transformations acting as oncogenes are demonstrated in studies where their expression is enforced in immortalised cells. Each translocation generates a different fusion protein consisting of a 50 -end partner fused to the 30 end ALK tyrosine kinase domain. In most cases, the 50 -end partners supply domains that promote dimerization and holo- and heterocomplex formation. These complexes allow ALK-fusion kinases to transphosphorylate themselves and interact and phosphorylate multiple adaptor proteins. The different chimeras from each of the translocations localise to distinct sub-cellular compartments and
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Eyre et al.
therefore might have discrepant disruptive effects on cellular homeostasis depending on their physical sub-cellular compartment (26). For example, in ALK-NPM1: NPM1 encodes a protein involved in the transport of pre-ribosomal particles and ribosome biogenesis, regulation of cell division, DNA repair, transcription and genomic stability. The NPM protein includes a nucleolar localisation signal and a dimerisation domain, favouring the generation of large homo-complexes and hetero-complexes of NPM and ALK activation. Nucleophosmin has a postulated role as either an oncogene or a tumour suppressor depending on its level of expression. In Npm1-knockout mice, NPM shows tumoursuppressor properties, controlling the maintenance of genomic stability and regulating p53 and ARF tumour-suppressor pathways. NPM overexpression also induces increased cell proliferation (27). The inappropriate compartmentalisation of NPM–ALK through heterodimerization with wild-type NPM might deregulate phosphorylation of key cell-division regulators and result in frequent numerical chromosome aberrations often seen in ALCL (28). NPM–ALK transcripts can be readily detected in cells of healthy individuals (29). ALK translocations might be relatively common but not sufficient to induce neoplastic transformation. Other molecular events might be required for such lymphoid cell transformation (28). ALK, CD30 and lymphoma
Aberrant ALK activity enhances cell proliferation, cytoskeletal rearrangements and cellular migration. Oncogenic ALK transformation is mediated by intracellular signalling cascades. ALK fusions activate the Ras–extracellular signal-regulated kinase (ERK) (30), the Janus kinase 3 (JAK3)–STAT3 (31) and the phosphatidylinositol 3-kinase (PI3K)–Akt pathways (32). The Sonic hedgehog signalling pathway (SHH/ GLI1) is overactive in ALK-positive ALCL (33). The Ras– ERK pathway is essential for ALCL proliferation, whereas the JAK3–STAT3 and PI3K–Akt pathways are vital primarily for cell survival and phenotypic changes (26). The first direct pathogenic role for NPM–ALK in human lymphomas was demonstrated using a retroviral gene transfer mouse model. NPM–ALK transformed bone-marrow precursors led to ALK-positive DLBCL (34). Using T-cell lineage-restricted promoters, transgenic mice have been established in which NPM–ALK expression leads to T-cell transformation (35). NPM–ALK engaged a series of adaptor molecules in both pre-malignant and transformed murine T-cells, and activated multiple pathways similar to human ALCL, including STAT3; required for the maintenance of the neoplastic phenotype (36). Human and murine ALK lymphomas show constitutively phosphorylated STAT3 (37) and NPM-ALK– positive BaF3 cells show STAT5 activation (38), confirming findings of molecular investigations. Evolving genomic and
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Future perspective for ALK-positive ALCL
high throughput proteomic technology will provide better insights into the molecular signatures of ALK-positive ALCL. In vitro studies revealed the functional relationship between ALK and CD30 (39). In ALK-positive ALCL, CD30 transcription is upregulated by ALK via the ERK1/2 pathway and by phosphorylated STAT3. The effect of CD30 engagement in ALCL cells is the activation of NFjB pathways, which result in apoptosis and p21-mediated cell-cycle arrest. It follows that anti-CD30 antibodies are of great interest in ALK-positive ALCL treatment. Staging and diagnosis
Staging for ALK-positive ALCL is by the standard Ann Arbor classification (40). Alongside an accurate history and examination, haematological and biochemical investigations include lactate dehydrogenase (LDH), virology (HBV, HCV, and HIV serology), bone marrow examination and wholebody Computerized Tomography (CT). There is emerging evidence for the value of Positron Emission Tomography (PET) in ALCL staging, although it is not currently considered a standard of care. The post-treatment value of PET is not yet clear (41). Prognosis
In contrast to other PTCLs, ALK-positive ALCLs are consistently shown to have better prognosis, (14, 15, 42, 43). The International Prognostic Index (IPI) (44) is useful in predicting outcome (45), as is the recent T-cell Prognostic Index (PIT) (46). CD56 expression is an independent predictor of poor outcome (47), as is raised beta-2-microglobulin (48). Although not routinely measured, serum soluble CD30 is a specific prognostic indicator; raised pre-treatment levels are associated with lower complete response (CR) and event free survival (EFS) (49). Translocations other than NPM-ALK have a similar prognosis, although concurrent c-MYC rearrangement produces an aggressive phenotype (50, 51). Clinical features and survival
Anaplastic lymphoma kinase-positive ALCL is an aggressive NHL most prevalent in children and young adults (mean age, 22.01 10.87 yr) with a male predominance [male/ female (M/F) ratio, 3.0] that is particularly apparent in the second-third decades (M/F ratio, 6.5). It typically presents with stage III–IV disease, systemic symptoms (75%) and extranodal involvement (60%) involving skin (21%), bone (17%), and soft tissues (17%). In contrast, ALK-negative ALCL presents in older individuals (mean 43.33 16.15 yr) and showed a lower M/F ratio (0.9), less stage III–IV disease and extranodal involvement.
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Future perspective for ALK-positive ALCL
Treatment in adults
There are no prospective randomized trials for adult ALKpositive ALCL. Prospective trial evidence has been obtained in paediatric series. A majority of evidence in adult patients is based on retrospective, historical ‘Grade C’ subgroup analyses, when the histopathological ‘ALK-positive ALCL’ entity was less clearly defined, inadvertently including cases of Hodgkin’s lymphoma (HL), ALK-negative ALCL and ALK-positive DLBCL in subgroups. First line
Most published first line regimens include an anthracycline; usually CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone). A retrospective analysis of 78 adult and paediatric ALCL found that most received anthracyclinebased chemotherapy (15). Overall survival (OS) of ALKpositive ALCL (53/78) was far superior to ALK-negative ALCL (71% vs. 15%). In patients with an age-adjusted IPI of 0–1, OS was 94% 5% compared with an OS 41% 12% for age-adjusted IPI ≥2. This underlines the observation that not all patients with ALK-positive ALCL do well. A retrospective analysis of patients with T-cell NHL by the German High Grade Non-Hodgkin’s Lymphoma Study Group (DSHNHL) (43), analysed 289 patients: ALK-positive ALCL (n = 78) and ALK-negative ALCL (n = 113). All participants were in prospective phase II or III trials treated with 6–8 cycles of CHOP-14 with or without etoposide (CHOEP-14 or 21). CHOEP was given at standard dose, as was Hi-CHOEP and Mega-CHOEP (dose-escalated CHOP plus etoposide); the latter required stem-cell rescue. Threeyear EFS and OS were 75.8% and 89.8% (ALK-positive ALCL), 50.0% and 67.5% (angioimmunoblastic TCL), 45.7% and 62.1% (ALK-negative ALCL), and 41.1% and 53.9% (PTCL-NOS), respectively. The IPI defined outcome accurately. In patients ≤60 yr with a normal LDH, etoposide improved 3-yr EFS: 75.4% vs. 51.0% (P = 0.003). Young ALK-positive ALCL patients seemed to particularly benefit from the addition of etoposide. In patients >60 yr, six cycles of CHOP-21 remained the standard. The majority in those with ALK-positive ALCL (85%) had a low to low-intermediate IPI. However, this was a retrospective subgroup analysis using patients from different trials so the finding of a benefit with etoposide should be regarded as hypothesis-generating. The superior outcome for ALK-positive ALCL compared to other PTCL is supported by evidence from the International PTCL Project (14); a multicentre worldwide registry. 12.1% (159/1314) patients had ALCL (55% ALK-positive, 45% ALK-negative). ALK-positive ALCL was clinically distinctive, presenting at a young age, with a superior prognosis to ALK-negative ALCL.
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A majority of patients were treated with an anthracyclinebased regimen (ALK-positive 95%; ALK-negative 88%). Five ALK-negative ALCL and six ALK-positive ALCL underwent autologous stem cell transplantation (ASCT) as part of their primary therapy. The overall response rate (ORR) to first line treatment was 76% in ALK-negative ALCL and 88% in ALK-positive ALCL. The 5-yr OS exceeded failure-free survival (FFS) in both ALK-positive (70% vs. 60%) and ALK-negative ALCL (49% vs. 36%), suggesting that salvage therapies were effective. Consistent with prior studies, the FFS (P = 0.015) and OS (P = 0.016) favoured ALK-positive ALCL. A subanalysis comparing ALK-negative and ALK-positive outcome relative to age found no difference in FFS or OS suggesting that age is a prominent factor driving outcome differences. Stage III disease had a better outcome than stage IV disease in ALKpositive ALCL and again, the IPI was effective in defining risk in ALK-negative and ALK-positive ALCL. 39% of ALK-positive ALCL had an IPI ≥3 and a 5-yr FFS of only 25%–30%. A subgroup analysis from M.D. Anderson of 135 T-cell NHL patients with ALCL (47) assessed 40 ALCL patients (ALK-positive ALCL:12; ALK-negative ALCL:19; unknown ALK:9). The median age was 49 yr with a male-to-female ratio 1.7:1. B symptoms were present in 33%. At 3 yr, the estimated OS was 83%. Most received CHOP (65%) including seven with ALK-positive disease, 11 ALK-negative disease, and eight unknown. The estimated 3-yr OS was 66% and 100% for ALK-negative ALCL and ALK-positive ALCL, respectively (P = 0.04), although numbers were small (52). The GELA group published a retrospective subgroup ALCL analysis from their prospective T-cell NHL trials (48). Overall, 138 patients with systemic ALCL on consensus review were analysed (46% ALK-positive, 54% ALKnegative). Median follow-up was 8 yr. ALK-positive ALCL cases were significantly younger (median 31.5 vs. 56 yr; P < 0.001), had a lower IPI [(IPI 3–5 23% ALK-positive vs. 48% ALK-negative (P = 0.030)] and lower PIT score [PIT 2–4 14% ALK-positive vs. 47% of ALK-negative (P = 0.003)]. b2-microglobulin was higher in ALK-negative patients. Nearly all patients received anthracycline-based chemotherapy, with 22 patients (ALK-positive n = 16; ALK-negative n = 6) undergoing ASCT as first-line consolidation. CR plus CRu (unconfirmed) was higher for ALKpositive than ALK-negative patients (86% vs. 68%; P = 0.01). 11 ALK-negative ALCL patients died during induction. 14 ALK-positive and 26 ALK-negative patients relapsed or progressed. The 8-yr PFS for ALK-positive and ALK-negative ALCL were 72% and 39% respectively (P < 0.001). The 8-yr OS were 82% and 49%, respectively (P < 0.001). The 8-yr OS was 86% for IPI 0–1, 66% for IPI 2, 46% for IPI 3, and 39% for IPI 4–5. Similar results were seen with the PIT score. In patients 40 yr, OS was significantly better if ALK-positive. No significant difference in outcome was found when the more intensive ACVBP (doxorubicin, cyclophosphamide, vindesine, bleomycin, prednisone, high dose methotrexate, etoposide, ifosfamide and low dose cytarabine) (n = 101) was compared with CHOP (n = 19) in those ≤65 yr. Several studies have evaluated ASCT consolidation in first remission. A small subgroup analysis of 202 patients with NHL who underwent ASCT as first line consolidation evaluated 15 patients with ALCL (seven ALK-positive). Patients received anthracycline-based induction followed by BEAM (carmustine (BCNU), etoposide, cytarabine, melphalan) ASCT. The 5-yr EFS and OS were both 87% (53). Patients all had a low IPI so it is unclear whether ASCT in CR1 improves outcome. A prospective study evaluating first line ASCT consolidation in PTCL (including ALK-positive ALCL) showed a significantly better outcome vs. other TcNHL (10-yr OS 62% vs. 21%, respectively) (54). Numbers in both studies were small and prone to bias. Upfront ASCT in ALK-positive ALCL is not considered a standard approach despite favourable results. Relapsed or refractory disease
Autologous stem cell transplantation after salvage chemotherapy is widely used to treat relapsed/refractory ALCL. A small series of 36 patients with PTCL showed that EFS in ALCL was 67% (P = 0.41) vs. 37% for other PTCLs after high dose melphalan and etoposide total-body irradiation (TBI) ASCT (55). Another study of 28 patients with PTCL looked at outcomes post-ASCT, the 3-yr OS and EFS were 69% and 50%. ALCL had a better 3-yr OS compared to non-ALCL histology (86% vs. 47%, P = 0.0122). In contrast to ASCT, allogeneic SCT (alloSCT) could add a graft-vs.-lymphoma (GVL) effect to the myeloablative or reduced intensity conditioning (RIC) regimen, potentially improving the therapeutic outcome. A retrospective analysis of 77 patients with PTCL who received an alloSCT, typically in the relapsed or refractory setting included 27 patients (median 12–55 yr) with ALCL. ALK status was available in 13 patients and eight were ALK-positive (56). Five-year EFS and OS for ALCL was 58% and 55%, respectively; comparable to the other PTCL subtypes. Chemo-resistant patients derived some benefit from alloSCT, with a 5-yr OS of 29% for the whole group, and successful use of donor lymphocyte infusion (DLI) implied a GVL effect. Chemoresistance at transplant and grade 3–4 acute graft-vs.-host disease (GVHD) were the strongest adverse prognostic factors. HLA-donor mismatch increased treatment-related mortality (TRM). RIC-alloSCT has not been exclusively assessed in ALK-positive ALCL but has been evaluated in relapsed PTCLs with 3-yr PFS of 64% and OS of 81%% in 17 patients, including four ALK-negative ALCL
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Future perspective for ALK-positive ALCL
(57). Despite the advent of novel agents, alloSCT in the refractory/relapsed ALK-positive ALCL may still offer the chance of cure. RIC-alloSCT may make this more feasible by reducing TRM. Novel approaches
Praletrexate is an anti-folate agent designed to be efficiently internalised by the reduced folate carrier (RFC). It displayed modest efficacy in relapsed PTCL in the PROPEL study (58). Only four of the 115 treated had ALK-positive ALCL. The ORR in 109 evaluable patients was 29% (CR 11%, PR 18%). Median PFS and OS were 3.5 and 14.5 months, respectively. Common grade 3/4 adverse events (AEs) were thrombocytopenia (32%), mucositis (22%), neutropenia (22%) and anaemia (18%). Praletrexate was subsequently licensed by the FDA in 2011 for relapsed PTCLs, including ALCL. Romidepsin is an HDAC1 inhibitor also approved by the FDA for relapsed PTCL. Only one ALK-positive ALCL patient was treated out of 130 patients in the pivotal phase II trial which showed an ORR of 25% (15% CR/CRu). The median PFS was 29 months. Those in CR/CRu for ≥12 months had significantly longer OS than those with CR/ CRu for 90% and an EFS of approximately 70%. Further international collaborative studies will seek to improve outcome while minimising the risk of late effects, refine risk stratification and identify strategies for high-risk groups which include the use of novel therapies. Management at relapse
Systemic ALCL relapse occurs in 25–30% of children. At present, evidence exists for a number of options, although there is no current gold standard, with a 30–60% rate of second continued remission. Children who relapse
REVIEW ARTICLE
Anaplastic lymphoma kinase-positive anaplastic large cell lymphoma: current and future perspectives in adult and paediatric disease Toby A. Eyre1, Dalia Khan1, Georgina W. Hall2, Graham P. Collins1 1
Department of Haematology, Oxford University Hospitals NHS Trust, Churchill Hospital, Oxford; 2Paediatric & Adolescent Haematology/ Oncology Unit, Oxford University Hospitals NHS Trust, Children’s Hospital, John Radcliffe Hospital, Oxford, UK
Abstract Anaplastic large cell lymphoma (ALCL) is a rare T-cell lymphoma seen in both adults and children. ALCL is associated with a characteristic chromosomal translocation, t(2;5)(p23;35) which fuses the anaplastic lymphoma kinase (ALK) gene on chromosome 2 with the nucleophosmin (NPM) gene on chromosome 5, resulting in a NPM-ALK fusion protein, ALK over-expression and constitutive tyrosine kinase activity. This aggressive lymphoma is more prevalent in males and can present with extranodal involvement (lung, skin and marrow infiltration) and haemophagocytic lymphohistocytosis. The long-term overall survival is approximately 70–90% in children and over 70% in adults. Staging systems and prognostic risk factors are different in both childhood and adult ALCL. Treatment in adults is typically anthracycline-based, with autologous stem cell transplantation (ASCT) salvaging patients in relapsed disease. There is evidence for ALL-like therapy or intensive, pulsed anthracycline-based induction in children. ASCT, allogeneic SCT and vinblastine maintenance are all considered reasonable options in relapsed childhood disease. The antiCD30 immunoconjugate Brentuximab Vedotin and the specific ALK inhibitor Crizotinib are changing the treatment paradigm in ALCL (ALK-positive or negative) and ALK-positive ALCL respectively. Both agents have shown encouraging responses in relapsed ALCL. It remains to be seen how these novel agents are used, but it is very possible that they may improve overall responses and survival in both children and adults. This review highlights the presentation, histopathological features, prognostic factors, and evidence-based treatment approaches in the first line and relapsed setting in ALK-positive ALCL. The review concludes by discussing the novel approaches using Brentuximab and Crizotinib which are being tested in clinical trials. Key words anaplastic large cell lymphoma; anaplastic lymphoma kinase; stem cell transplantation; Brentuximab; Crizotinib; vinblastine Correspondence Toby A. Eyre, Lymphoma Clinical Research Fellow, Department of Haematology and Early Phase Trials Unit, Churchill Hospital, Oxford OX3 7LE, UK. Tel: +44 (0) 1865 235886; Fax: +44 (0) 1865 235260; e-mail: [email protected] Accepted for publication 21 April 2014
Anaplastic large cell lymphomas (ALCL) are a subgroup of Peripheral T-Cell Lymphomas (PTCL) thought to derive from cytotoxic T cells. The 2008 WHO classification identifies three separate biological entities: (1) primary systemic ALK-positive ALCL (ALK-positive ALCL), primary systemic ALK-negative ALCL and primary cutaneous ALCL (2, 3). ALK-positive ALCL, by definition overexpresses an ALK-fusion gene, typically via t(2;5)(p23;35) which fuses the anaplastic lymphoma kinase (ALK) gene on chromosome 2 with the nucleophosmin (NPM) gene on chromosome 5,
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
doi:10.1111/ejh.12360
resulting in a NPM-ALK chimeric protein with constitutive tyrosine kinase activity (4, 5). Anaplastic large cell lymphomas presents at any age. Characterised by extranodal presentation and male predominance, ALCL is typically a chemo-sensitive disease with long-term OS rate of approximately 70–90% in both adults and children despite different treatment approaches. Although relapsed, refractory disease remains a challenge, impressive novel targeted therapy has made a huge impact and is likely to change the treatment paradigm in ALCL.
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Future perspective for ALK-positive ALCL
Laboratory investigations
There is a spectrum of morphological heterogeneity, but cells are often large, with ‘horse-shoe’ or ‘kidney-bean’ shaped nuclei with a prominent nucleolus and dispersed chromatin. Other subtypes such as small cell type and lymphohistocytic cell type are described (6). Although 90% of cases show T-cell receptor (TCR) clonal rearrangements, typical malignant T cells often have a ‘null’ phenotype. It is common for the neoplastic cells to lack CD3 and other commonly expressed T-cell surface markers are often underexpressed. Neoplastic cells strongly express CD30, lack CD15, and most express epithelial membrane antigen (EMA). Cytotoxic granule-associated antigen expression (TIA-1, Perforin, Granzyme) and a golgi pattern of reactivity for clusterin is often seen (7). The cytoplasmic and nuclear pattern of ALK expression depends on the nature of the ALK translocation. Typically, the classical NPM1-ALK translocation leads to nuclear and cytoplasmic ALK staining (8), although this specific translocation is not seen in 10–15% of cases (9). There are no clearly defined prognostic differences in tumours with variant ALK translocations. The ALK gene can be translocated onto other chromosomes, leading to different fusion proteins and various immunohistochemical patterns of ALK expression. For example in t(1;2)(q25;p23) (10) or inv(2) (p23;q35), (11) the ALK protein accumulates only in the cytoplasm. Moreover, in two large studies (6, 9) up to 20% of ALK-positive ALCL displayed cytoplasmic-only expression. Although it is possible to make the diagnosis by immunohistochemical assessment of ALK, EMA, CD30 and T-cell markers, the most sensitive test for ALK-positive ALCL is fluorescence in-situ hybridization (FISH) using an ALK-gene break-apart probe. If the precise ALK translocation is known, patients can also be assessed by real-time polymerase chain reaction (RT-PCR). Recently, gene expression profiling (GEP) has shown that ALK-positive ALCL, ALKnegative ALCL and PTCL-NOS are all distinct molecular entities (12). Lymph nodes typically display diffusely effaced architecture or sinusoidal and/or perivascular tumour involvement. The bone marrow is infiltrated in 10–30% of cases. Extranodal tissue infiltration can also provide the diagnosis. Diagnosis of ALK-positive ALCL is therefore dependent on identification of T-cell ‘null’ phenotype, specific histological appearances with an underlying chromosomal translocation involving the ALK gene, expression of the ALK-fusion protein and uniform, strong CD30 expression (1, 9, 13). Incidence and risk factors
Anaplastic lymphoma kinase-positive ALCL represents approximately 3% of adult non-Hodgkin’s lymphoma (NHL) (14, 15) and 10–15% of childhood lymphomas (16). No con-
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sistent evidence of a causative agent for ALK-positive ALCL such as EBV, HTLV or environmental toxins has been discovered. Case reports of ALCL associated with HIV are published but none were ALK-positive ALCL (17). Breast implant associated ALCL are rarely ALK-positive (18). Anaplastic lymphoma kinase
Anaplastic lymphoma kinase (ALK) itself is an orphan tyrosine kinase which when deregulated becomes oncogenic. Although first described in ALCL, ALK is also implicated in non-small cell lung cancer (NSCLC) (19), neuroblastomas, acute myeloid leukaemia and diffuse large B-cell lymphoma (DLBCL). The ALK gene encodes a 1620-amino acid protein that undergoes post-translational N-linked glycosylation to a mature form weighing 220 kDa. It belongs to the insulin-receptor super-family and is closely related to the leucocyte tyrosine kinase (LTK) (20). The physiological role of ALK was established through invertebrate studies, murine knock-out models and cell-line experiments. Loss of ALK homologues in Caenorhabditis elegans and Drosophila Melanogaster result in defects in midgut development, neuronal wiring and plasticity via the Ras-mitogen-activated protein kinase pathway (MAP-K) (21, 22). In mammals, ALK expression is preferential in the central and peripheral nervous systems (23). In mice, the genomic deletion of ALK results in a minimal change in phenotype compared with wild type. Cell line studies show that constitutively active chimeric ALK receptors induce neuron differentiation and promote mitogenesis (24). Ligands for ALK are described in invertebrate (JEB, Jelly Belly) and mammalian models [Pleiotrophin (PTN) and Midkine (MK)]. ALK is in the family of ‘dependence-receptors’, defined as transmembrane proteins capable of inducing apoptosis in the absence of the required stimulus but which block apoptosis following binding to their ligand. Expression of these receptors creates cellular states of dependence on the associated ligands (25). Pathological ALK expression
In ALK translocations, genomic breakpoints are almost always located in the intron flanked by exons 16 and 17. Mechanisms for different transformations acting as oncogenes are demonstrated in studies where their expression is enforced in immortalised cells. Each translocation generates a different fusion protein consisting of a 50 -end partner fused to the 30 end ALK tyrosine kinase domain. In most cases, the 50 -end partners supply domains that promote dimerization and holo- and heterocomplex formation. These complexes allow ALK-fusion kinases to transphosphorylate themselves and interact and phosphorylate multiple adaptor proteins. The different chimeras from each of the translocations localise to distinct sub-cellular compartments and
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Eyre et al.
therefore might have discrepant disruptive effects on cellular homeostasis depending on their physical sub-cellular compartment (26). For example, in ALK-NPM1: NPM1 encodes a protein involved in the transport of pre-ribosomal particles and ribosome biogenesis, regulation of cell division, DNA repair, transcription and genomic stability. The NPM protein includes a nucleolar localisation signal and a dimerisation domain, favouring the generation of large homo-complexes and hetero-complexes of NPM and ALK activation. Nucleophosmin has a postulated role as either an oncogene or a tumour suppressor depending on its level of expression. In Npm1-knockout mice, NPM shows tumoursuppressor properties, controlling the maintenance of genomic stability and regulating p53 and ARF tumour-suppressor pathways. NPM overexpression also induces increased cell proliferation (27). The inappropriate compartmentalisation of NPM–ALK through heterodimerization with wild-type NPM might deregulate phosphorylation of key cell-division regulators and result in frequent numerical chromosome aberrations often seen in ALCL (28). NPM–ALK transcripts can be readily detected in cells of healthy individuals (29). ALK translocations might be relatively common but not sufficient to induce neoplastic transformation. Other molecular events might be required for such lymphoid cell transformation (28). ALK, CD30 and lymphoma
Aberrant ALK activity enhances cell proliferation, cytoskeletal rearrangements and cellular migration. Oncogenic ALK transformation is mediated by intracellular signalling cascades. ALK fusions activate the Ras–extracellular signal-regulated kinase (ERK) (30), the Janus kinase 3 (JAK3)–STAT3 (31) and the phosphatidylinositol 3-kinase (PI3K)–Akt pathways (32). The Sonic hedgehog signalling pathway (SHH/ GLI1) is overactive in ALK-positive ALCL (33). The Ras– ERK pathway is essential for ALCL proliferation, whereas the JAK3–STAT3 and PI3K–Akt pathways are vital primarily for cell survival and phenotypic changes (26). The first direct pathogenic role for NPM–ALK in human lymphomas was demonstrated using a retroviral gene transfer mouse model. NPM–ALK transformed bone-marrow precursors led to ALK-positive DLBCL (34). Using T-cell lineage-restricted promoters, transgenic mice have been established in which NPM–ALK expression leads to T-cell transformation (35). NPM–ALK engaged a series of adaptor molecules in both pre-malignant and transformed murine T-cells, and activated multiple pathways similar to human ALCL, including STAT3; required for the maintenance of the neoplastic phenotype (36). Human and murine ALK lymphomas show constitutively phosphorylated STAT3 (37) and NPM-ALK– positive BaF3 cells show STAT5 activation (38), confirming findings of molecular investigations. Evolving genomic and
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Future perspective for ALK-positive ALCL
high throughput proteomic technology will provide better insights into the molecular signatures of ALK-positive ALCL. In vitro studies revealed the functional relationship between ALK and CD30 (39). In ALK-positive ALCL, CD30 transcription is upregulated by ALK via the ERK1/2 pathway and by phosphorylated STAT3. The effect of CD30 engagement in ALCL cells is the activation of NFjB pathways, which result in apoptosis and p21-mediated cell-cycle arrest. It follows that anti-CD30 antibodies are of great interest in ALK-positive ALCL treatment. Staging and diagnosis
Staging for ALK-positive ALCL is by the standard Ann Arbor classification (40). Alongside an accurate history and examination, haematological and biochemical investigations include lactate dehydrogenase (LDH), virology (HBV, HCV, and HIV serology), bone marrow examination and wholebody Computerized Tomography (CT). There is emerging evidence for the value of Positron Emission Tomography (PET) in ALCL staging, although it is not currently considered a standard of care. The post-treatment value of PET is not yet clear (41). Prognosis
In contrast to other PTCLs, ALK-positive ALCLs are consistently shown to have better prognosis, (14, 15, 42, 43). The International Prognostic Index (IPI) (44) is useful in predicting outcome (45), as is the recent T-cell Prognostic Index (PIT) (46). CD56 expression is an independent predictor of poor outcome (47), as is raised beta-2-microglobulin (48). Although not routinely measured, serum soluble CD30 is a specific prognostic indicator; raised pre-treatment levels are associated with lower complete response (CR) and event free survival (EFS) (49). Translocations other than NPM-ALK have a similar prognosis, although concurrent c-MYC rearrangement produces an aggressive phenotype (50, 51). Clinical features and survival
Anaplastic lymphoma kinase-positive ALCL is an aggressive NHL most prevalent in children and young adults (mean age, 22.01 10.87 yr) with a male predominance [male/ female (M/F) ratio, 3.0] that is particularly apparent in the second-third decades (M/F ratio, 6.5). It typically presents with stage III–IV disease, systemic symptoms (75%) and extranodal involvement (60%) involving skin (21%), bone (17%), and soft tissues (17%). In contrast, ALK-negative ALCL presents in older individuals (mean 43.33 16.15 yr) and showed a lower M/F ratio (0.9), less stage III–IV disease and extranodal involvement.
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Treatment in adults
There are no prospective randomized trials for adult ALKpositive ALCL. Prospective trial evidence has been obtained in paediatric series. A majority of evidence in adult patients is based on retrospective, historical ‘Grade C’ subgroup analyses, when the histopathological ‘ALK-positive ALCL’ entity was less clearly defined, inadvertently including cases of Hodgkin’s lymphoma (HL), ALK-negative ALCL and ALK-positive DLBCL in subgroups. First line
Most published first line regimens include an anthracycline; usually CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone). A retrospective analysis of 78 adult and paediatric ALCL found that most received anthracyclinebased chemotherapy (15). Overall survival (OS) of ALKpositive ALCL (53/78) was far superior to ALK-negative ALCL (71% vs. 15%). In patients with an age-adjusted IPI of 0–1, OS was 94% 5% compared with an OS 41% 12% for age-adjusted IPI ≥2. This underlines the observation that not all patients with ALK-positive ALCL do well. A retrospective analysis of patients with T-cell NHL by the German High Grade Non-Hodgkin’s Lymphoma Study Group (DSHNHL) (43), analysed 289 patients: ALK-positive ALCL (n = 78) and ALK-negative ALCL (n = 113). All participants were in prospective phase II or III trials treated with 6–8 cycles of CHOP-14 with or without etoposide (CHOEP-14 or 21). CHOEP was given at standard dose, as was Hi-CHOEP and Mega-CHOEP (dose-escalated CHOP plus etoposide); the latter required stem-cell rescue. Threeyear EFS and OS were 75.8% and 89.8% (ALK-positive ALCL), 50.0% and 67.5% (angioimmunoblastic TCL), 45.7% and 62.1% (ALK-negative ALCL), and 41.1% and 53.9% (PTCL-NOS), respectively. The IPI defined outcome accurately. In patients ≤60 yr with a normal LDH, etoposide improved 3-yr EFS: 75.4% vs. 51.0% (P = 0.003). Young ALK-positive ALCL patients seemed to particularly benefit from the addition of etoposide. In patients >60 yr, six cycles of CHOP-21 remained the standard. The majority in those with ALK-positive ALCL (85%) had a low to low-intermediate IPI. However, this was a retrospective subgroup analysis using patients from different trials so the finding of a benefit with etoposide should be regarded as hypothesis-generating. The superior outcome for ALK-positive ALCL compared to other PTCL is supported by evidence from the International PTCL Project (14); a multicentre worldwide registry. 12.1% (159/1314) patients had ALCL (55% ALK-positive, 45% ALK-negative). ALK-positive ALCL was clinically distinctive, presenting at a young age, with a superior prognosis to ALK-negative ALCL.
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A majority of patients were treated with an anthracyclinebased regimen (ALK-positive 95%; ALK-negative 88%). Five ALK-negative ALCL and six ALK-positive ALCL underwent autologous stem cell transplantation (ASCT) as part of their primary therapy. The overall response rate (ORR) to first line treatment was 76% in ALK-negative ALCL and 88% in ALK-positive ALCL. The 5-yr OS exceeded failure-free survival (FFS) in both ALK-positive (70% vs. 60%) and ALK-negative ALCL (49% vs. 36%), suggesting that salvage therapies were effective. Consistent with prior studies, the FFS (P = 0.015) and OS (P = 0.016) favoured ALK-positive ALCL. A subanalysis comparing ALK-negative and ALK-positive outcome relative to age found no difference in FFS or OS suggesting that age is a prominent factor driving outcome differences. Stage III disease had a better outcome than stage IV disease in ALKpositive ALCL and again, the IPI was effective in defining risk in ALK-negative and ALK-positive ALCL. 39% of ALK-positive ALCL had an IPI ≥3 and a 5-yr FFS of only 25%–30%. A subgroup analysis from M.D. Anderson of 135 T-cell NHL patients with ALCL (47) assessed 40 ALCL patients (ALK-positive ALCL:12; ALK-negative ALCL:19; unknown ALK:9). The median age was 49 yr with a male-to-female ratio 1.7:1. B symptoms were present in 33%. At 3 yr, the estimated OS was 83%. Most received CHOP (65%) including seven with ALK-positive disease, 11 ALK-negative disease, and eight unknown. The estimated 3-yr OS was 66% and 100% for ALK-negative ALCL and ALK-positive ALCL, respectively (P = 0.04), although numbers were small (52). The GELA group published a retrospective subgroup ALCL analysis from their prospective T-cell NHL trials (48). Overall, 138 patients with systemic ALCL on consensus review were analysed (46% ALK-positive, 54% ALKnegative). Median follow-up was 8 yr. ALK-positive ALCL cases were significantly younger (median 31.5 vs. 56 yr; P < 0.001), had a lower IPI [(IPI 3–5 23% ALK-positive vs. 48% ALK-negative (P = 0.030)] and lower PIT score [PIT 2–4 14% ALK-positive vs. 47% of ALK-negative (P = 0.003)]. b2-microglobulin was higher in ALK-negative patients. Nearly all patients received anthracycline-based chemotherapy, with 22 patients (ALK-positive n = 16; ALK-negative n = 6) undergoing ASCT as first-line consolidation. CR plus CRu (unconfirmed) was higher for ALKpositive than ALK-negative patients (86% vs. 68%; P = 0.01). 11 ALK-negative ALCL patients died during induction. 14 ALK-positive and 26 ALK-negative patients relapsed or progressed. The 8-yr PFS for ALK-positive and ALK-negative ALCL were 72% and 39% respectively (P < 0.001). The 8-yr OS were 82% and 49%, respectively (P < 0.001). The 8-yr OS was 86% for IPI 0–1, 66% for IPI 2, 46% for IPI 3, and 39% for IPI 4–5. Similar results were seen with the PIT score. In patients 40 yr, OS was significantly better if ALK-positive. No significant difference in outcome was found when the more intensive ACVBP (doxorubicin, cyclophosphamide, vindesine, bleomycin, prednisone, high dose methotrexate, etoposide, ifosfamide and low dose cytarabine) (n = 101) was compared with CHOP (n = 19) in those ≤65 yr. Several studies have evaluated ASCT consolidation in first remission. A small subgroup analysis of 202 patients with NHL who underwent ASCT as first line consolidation evaluated 15 patients with ALCL (seven ALK-positive). Patients received anthracycline-based induction followed by BEAM (carmustine (BCNU), etoposide, cytarabine, melphalan) ASCT. The 5-yr EFS and OS were both 87% (53). Patients all had a low IPI so it is unclear whether ASCT in CR1 improves outcome. A prospective study evaluating first line ASCT consolidation in PTCL (including ALK-positive ALCL) showed a significantly better outcome vs. other TcNHL (10-yr OS 62% vs. 21%, respectively) (54). Numbers in both studies were small and prone to bias. Upfront ASCT in ALK-positive ALCL is not considered a standard approach despite favourable results. Relapsed or refractory disease
Autologous stem cell transplantation after salvage chemotherapy is widely used to treat relapsed/refractory ALCL. A small series of 36 patients with PTCL showed that EFS in ALCL was 67% (P = 0.41) vs. 37% for other PTCLs after high dose melphalan and etoposide total-body irradiation (TBI) ASCT (55). Another study of 28 patients with PTCL looked at outcomes post-ASCT, the 3-yr OS and EFS were 69% and 50%. ALCL had a better 3-yr OS compared to non-ALCL histology (86% vs. 47%, P = 0.0122). In contrast to ASCT, allogeneic SCT (alloSCT) could add a graft-vs.-lymphoma (GVL) effect to the myeloablative or reduced intensity conditioning (RIC) regimen, potentially improving the therapeutic outcome. A retrospective analysis of 77 patients with PTCL who received an alloSCT, typically in the relapsed or refractory setting included 27 patients (median 12–55 yr) with ALCL. ALK status was available in 13 patients and eight were ALK-positive (56). Five-year EFS and OS for ALCL was 58% and 55%, respectively; comparable to the other PTCL subtypes. Chemo-resistant patients derived some benefit from alloSCT, with a 5-yr OS of 29% for the whole group, and successful use of donor lymphocyte infusion (DLI) implied a GVL effect. Chemoresistance at transplant and grade 3–4 acute graft-vs.-host disease (GVHD) were the strongest adverse prognostic factors. HLA-donor mismatch increased treatment-related mortality (TRM). RIC-alloSCT has not been exclusively assessed in ALK-positive ALCL but has been evaluated in relapsed PTCLs with 3-yr PFS of 64% and OS of 81%% in 17 patients, including four ALK-negative ALCL
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Future perspective for ALK-positive ALCL
(57). Despite the advent of novel agents, alloSCT in the refractory/relapsed ALK-positive ALCL may still offer the chance of cure. RIC-alloSCT may make this more feasible by reducing TRM. Novel approaches
Praletrexate is an anti-folate agent designed to be efficiently internalised by the reduced folate carrier (RFC). It displayed modest efficacy in relapsed PTCL in the PROPEL study (58). Only four of the 115 treated had ALK-positive ALCL. The ORR in 109 evaluable patients was 29% (CR 11%, PR 18%). Median PFS and OS were 3.5 and 14.5 months, respectively. Common grade 3/4 adverse events (AEs) were thrombocytopenia (32%), mucositis (22%), neutropenia (22%) and anaemia (18%). Praletrexate was subsequently licensed by the FDA in 2011 for relapsed PTCLs, including ALCL. Romidepsin is an HDAC1 inhibitor also approved by the FDA for relapsed PTCL. Only one ALK-positive ALCL patient was treated out of 130 patients in the pivotal phase II trial which showed an ORR of 25% (15% CR/CRu). The median PFS was 29 months. Those in CR/CRu for ≥12 months had significantly longer OS than those with CR/ CRu for 90% and an EFS of approximately 70%. Further international collaborative studies will seek to improve outcome while minimising the risk of late effects, refine risk stratification and identify strategies for high-risk groups which include the use of novel therapies. Management at relapse
Systemic ALCL relapse occurs in 25–30% of children. At present, evidence exists for a number of options, although there is no current gold standard, with a 30–60% rate of second continued remission. Children who relapse
