The evolving role of chemotherapy and hematopoietic cell transplants in Ph-positive acute lymphoblastic leukemia in adults.

The introduction of the tyrosine kinase inhibitors (TKI) into the treatment of patients with Ph or BCR-ABL1-positive acute lymphoblastic leukemia has revolutionized the treatment of this poor prognosis acute leukemia. The combination of TKI with chemotherapy has improved response rates and allowed more patients to proceed to allogeneic hematopoietic cell transplant (alloHCT). Older patients have excellent responses to TKI and corticosteroids or in combination with minimal chemotherapy. This raises the question as to whether patients require full-intensity chemotherapy with TKI to achieve molecular remissions. The pediatricians have proposed that cure is achievable without alloHCT in children. These results have suggested that many patients may not require traditional chemotherapy in addition to TKI to achieve remission, and that patients who achieve a negative minimal residual disease state may not require alloHCT. The data in support of these questions is presented here and a suggested future clinical trial design based on these data is proposed.

Pegylated-asparaginase during induction therapy for adult acute lymphoblastic leukaemia: toxicity data from the UKALL14 trial.

Safety and efficacy data on pegylated asparaginase (PEG-ASP) in adult acute lymphoblastic leukaemia (ALL) induction regimens are limited. The UK National Cancer Research Institute UKALL14 trial NCT01085617 prospectively evaluated the tolerability of 1000 IU/m2 PEG-ASP administered on days 4 and 18 as part of a five-drug induction regimen in adults aged 25-65 years with de novo ALL. Median age was 46.5 years. Sixteen of the 90 patients (median age 56 years) suffered treatment-related mortality during initial induction therapy. Eight of the 16 died of sepsis in combination with hepatotoxicity. Age and Philadelphia (Ph) status were independent variables predicting induction death >40 versus ⩽40 years, odds ratio (OR) 18.5 (2.02-169.0), P=0.01; Ph- versus Ph+ disease, OR 13.60 (3.52-52.36), P<0.001. Of the 74 patients who did not die, 37 (50.0%) experienced at least one grade 3/4 PEG-ASP-related adverse event, most commonly hepatotoxicity (36.5%, n=27). A single dose of PEG-ASP achieved trough therapeutic enzyme levels in 42/49 (86%) of the patients tested. Although PEG-ASP delivered prolonged asparaginase activity in adults, it was difficult to administer safely as part of the UKALL14 intensive multiagent regimen to those aged >40 years. It proved extremely toxic in patients with Ph+ ALL, possibly owing to interaction with imatinib.

Blinatumomab vs historical standard therapy of adult relapsed/refractory acute lymphoblastic leukemia.

We compared outcomes from a single-arm study of blinatumomab in adult patients with B-precursor Ph-negative relapsed/refractory acute lymphoblastic leukemia (R/R ALL) with a historical data set from Europe and the United States. Estimates of complete remission (CR) and overall survival (OS) were weighted by the frequency distribution of prognostic factors in the blinatumomab trial. Outcomes were also compared between the trial and historical data using propensity score methods. The historical cohort included 694 patients with CR data and 1112 patients with OS data compared with 189 patients with CR and survival data in the blinatumomab trial. The weighted analysis revealed a CR rate of 24% (95% CI: 20-27%) and a median OS of 3.3 months (95% CI: 2.8-3.6) in the historical cohort compared with a CR/CRh rate of 43% (95% CI: 36-50%) and a median OS of 6.1 months (95% CI: 4.2-7.5) in the blinatumomab trial. Propensity score analysis estimated increased odds of CR/CRh (OR=2.68, 95% CI: 1.67-4.31) and improved OS (HR=0.536, 95% CI: 0.394-0.730) with blinatumomab. The analysis demonstrates the application of different study designs and statistical methods to compare novel therapies for R/R ALL with historical data.

Impact of extracorporeal photopheresis on skin scores and quality of life in patients with steroid-refractory chronic GVHD.

There are few prospective studies evaluating the role of extracorporeal photopheresis (ECP) in chronic GVHD (cGVHD) and only occasional reports of the effect of ECP on patients' quality of life (QoL). We report a single-centre prospective study of patients undergoing fortnightly ECP for moderate or severe cGVHD. Response was assessed after 6 months of treatment using NIH scoring criteria and reduction in immunosuppression. QoL assessments were undertaken at baseline and at 6 months using the chronic GVHD symptom scale (cGVHD SS) and dermatology life quality index (DLQI). An intention-to-treat analysis showed that 19/38 (50%) of patients had a complete or partial response. Twenty-seven out of 38 patients completed 6 months of ECP treatment and 70% (19/27) had a complete or partial response. Eighty per cent of patients who completed 6 months of ECP treatment had a reduction in immunosuppression dose. A subset of patients completed QoL questionnaires. Seventeen out of 18 patients (94%) showed an improvement in scores. The mean cGVHD SS and mean DLQI score were both significantly lower after 6 months of ECP (22 compared with 36, P=0.012 and 3.4 compared with 6.9, P=0.009, respectively). This study confirms that ECP can lead to objective clinical responses and, in addition, may lead to an improvement in QoL in cGVHD.

High hyperdiploidy among adolescents and adults with acute lymphoblastic leukaemia (ALL): cytogenetic features, clinical characteristics and outcome.

High hyperdiploidy (HeH, 51-65 chromosomes) is an established genetic subtype of acute lymphoblastic leukaemia (ALL). The clinical and cytogenetic features as well as outcome of HeH among adolescents and adults have not been thoroughly investigated. Among 1232 B-cell precursor ALL patients (15-65 years) treated in the UKALLXII/ECOG2993 trial, 160 (13%) had a HeH karyotype, including 80 patients aged >24 years. The frequency of HeH was the same in Philadelphia chromosome (Ph)-positive and -negative cases, but Ph-positive patients were older. The cytogenetic profiles of Ph-positive and Ph-negative HeH cases were similar, although trisomy 2 was strongly associated with Ph-positive HeH. Overall, Ph-positive HeH patients did not have an inferior overall survival compared with Ph-negative patients (P=0.2: 50 vs 57% at 5 years). Trisomy of chromosome 4 was associated with a superior outcome in Ph-negative patients, whereas +5 and +20 were associated with an inferior outcome in Ph-positive and Ph-negative patients, respectively. All three markers retained significance in multivariate analysis adjusting for age and white cell count: hazard ratio for risk of death 0.47 (95% CI: 0.27-0.84) (P=0.01), 3.73 (1.51-9.21) (P=0.004) and 2.63 (1.25-5.54) (P=0.01), respectively. In conclusion, HeH is an important subtype of ALL at all ages and displays outcome heterogeneity according to chromosomal gain.

Treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia.

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is characterized by expression of oncogenic fusion product BCR-ABL1, resulting from reciprocal translocation between chromosomes 9 and 22 [t(9;22)(q34;q11.2)]. Previously perceived to confer poor outcome with at least 10 % lower chance of remission than standard-risk ALL. With the advent of targeted BCR-ABL specific tyrosine-kinase inhibitors (TKIs), higher remission rates were achieved, thus allowing more patients to proceed with the definitive treatment modality--allogeneic hematopoietic stem cell transplantation (alloHSCT). Prime challenges to treatment of Ph+ ALL include appropriate integration of TKIs into remission induction chemotherapeutic regimes, appropriate understanding and implementation of BCR-ABL monitoring for guiding therapeutic intervention(s), and minimizing transplant-related toxicities.

Evidence for a GVL effect following reduced-intensity allo-SCT in ALL: a British Society of Blood and Marrow Transplantation study.

Myeloablative allo-SCT decreases relapse incidence (RI) in ALL. Reduced intensity conditioning (RIC) may extend allo-SCT to older and less fit patients. Sixty-nine ALL patients reported to the BSBMT underwent fludarabine-based RIC allo-SCT, 38 from unrelated donors (UD). Forty-four patients received alemtuzumab. ALL was in CR in 64 patients (93%). This was a second or third SCT in 23 patients. Two-year OS and PFS were 36% and 32%, respectively. In multivariate analysis male recipients demonstrated better OS and PFS (hazard ratio (HR) = 0.42, P = 0.008 and HR = 0.45, P = 0.012, respectively). Two-year TRM was 29%: higher with younger age (HR = 0.97/year, P = 0.041), female recipient (HR = 2.55, P = 0.049) and increasing grade of acute GVHD (HR = 1.87, P = 0.001). Two-year RI was 38% and was lower in patients with acute and chronic GVHD (HR = 0.62 per increasing grade, P = 0.035 and HR = 0.52, P = 0.025, respectively). Long-term ALL-free survival is achievable following fludarabine-based RIC allo-SCT. The association between GVHD and decreased RI suggests the presence of a GVL effect.

The coagulopathy and thrombotic risk associated with L-asparaginase treatment in adults with acute lymphoblastic leukaemia.

The dramatic improvements seen in the outcome of paediatric patients with acute lymphoblastic leukaemia (ALL) have led to increasing incorporation of L-asparaginase (L-Asp) in adult treatment protocols. However, its use is associated with a disruption in the physiological balance between haemostatic and anticoagulant pathways, with the predominant clinical manifestation being thrombosis. Although L-Asp therapy is known to be associated with an acquired deficiency of antithrombin (AT), the concurrent depletion of fibrinogen and other haemostatic proteins means that the precise mechanism of thrombosis remains to be defined. In vitro coagulation assays are often prolonged but thrombosis rather than haemorrhage is the primary concern. Management of thrombotic events in these patients is based around agents that rely on AT for their anticoagulant effect, even though it is usually depleted. There is currently only limited evidence supporting the use of AT concentrates in either primary prevention or management following an established event. Evidence-based guidelines for prevention and management strategies are lacking.

Efficacy of bimonthly extracorporeal photopheresis in refractory chronic mucocutaneous GVHD.

Extracorporeal photopheresis (ECP) has become a recognised treatment for steroid-refractory chronic GVHD (cGVHD), but the optimal frequency and duration of treatment are yet to be established. We report on 82 consecutive patients with mucocutaneous cGVHD who received a bimonthly regimen of ECP treatment for two consecutive days, which could be subsequently tapered to a monthly regimen depending on response. Patients were steroid-refractory, steroid-dependent or steroid-intolerant, and 29 (35%) had multiorgan involvement. The median duration of treatment was 330 days (42-987). The median number of ECP cycles was 15 (1.5-32). Response was assessed by clinical assessment and reduction in immunosuppression after 6 months. 69/82 (84%) had completed 6 months of ECP and 65/69 (94%) had ≥ 50% improvement in symptoms and signs of cGVHD. A total of 77% of patients who completed 6 months of ECP had a reduction in immunosuppression dose and 80% had decreased their steroid dose (27.5% stopped, 30% had ≥ 75% reduction, 17.5% had ≥ 50% reduction and 25% had <50% reduction). OS at 3 years from the start of ECP was 69%. This study reports the largest series of patients receiving bimonthly ECP treatment for cGVHD, and confirms that ECP allows successful reduction of immunosuppression.

Standardized MRD quantification in European ALL trials: proceedings of the Second International Symposium on MRD assessment in Kiel, Germany, 18-20 September 2008.

Assessment of minimal residual disease (MRD) has acquired a prominent position in European treatment protocols for patients with acute lymphoblastic leukemia (ALL), on the basis of its high prognostic value for predicting outcome and the possibilities for implementation of MRD diagnostics in treatment stratification. Therefore, there is an increasing need for standardization of methodologies and harmonization of terminology. For this purpose, a panel of representatives of all major European study groups on childhood and adult ALL and of international experts on PCR- and flow cytometry-based MRD assessment was built in the context of the Second International Symposium on MRD assessment in Kiel, Germany, 18-20 September 2008. The panel summarized the current state of MRD diagnostics in ALL and developed recommendations on the minimal technical requirements that should be fulfilled before implementation of MRD diagnostics into clinical trials. Finally, a common terminology for a standard description of MRD response and monitoring was established defining the terms 'complete MRD response', 'MRD persistence' and 'MRD reappearance'. The proposed MRD terminology may allow a refined and standardized assessment of response to treatment in adult and childhood ALL, and provides a sound basis for the comparison of MRD results between different treatment protocols.

High incidence of avascular necrosis in adolescents with acute lymphoblastic leukaemia: a UKALL XII analysis.

Avascular necrosis (AVN) is a serious complication of acute lymphoblastic leukaemia (ALL) therapy. Little is known of the scope and magnitude of this problem among adults with ALL. We analysed the incidence and risk factors for AVN in 1053 patients on the UKALLXII/ECOG2993 study. AVN affected 99 joints in 42 patients at a median of 2.2 years post-diagnosis, giving a crude incidence rate of 4.0%. Statistically significant risk factors for the development of AVN were age and treatment with chemotherapy. Patients receiving prolonged chemotherapy without stem cell transplant were at significantly greater risk of developing AVN than stem cell transplant recipients (P<0.00005). The actuarial incidence of AVN was 29% at 10 years in patients <20 years old compared to 8% at 10 years in those >20 years old; P=0.0004; odds ratio 0.28 (95% CI=0.14-0.56).

Allogeneic haematopoietic stem cell transplant in Philadelphia-positive acute lymphoblastic leukaemia.

ALL in which the Philadelphia (Ph) chromosome is detected is one of the few diseases in which there is almost unequivocal agreement that a matched sibling allogeneic haematopoietic stem cell transplant in first CR is the most appropriate therapy for patients within certain age limits. Extension of allogeneic stem cell transplant to patients without matched sibling donors or to older individuals is increasingly possible due to unrelated donors, umbilical cord blood and reduced-intensity conditioning regimens. Here, we carefully review evidence supporting current practice and examine recent evidence relating to the use of newer allogeneic transplant technologies in Ph-pos ALL. We explore the burgeoning literature on the role of tyrosine kinase inhibitors in this disease and summarize their impact on the transplant practice.

Live attenuated measles virus induces regression of human lymphoma xenografts in immunodeficient mice.

Derivatives of the Edmonston-B strain of measles virus (MV-Ed) are safe, live attenuated measles virus (MV) vaccines that have been used worldwide for more than 30 years. The cytoreductive potential of MV-Ed has been investigated in murine models of both aggressive and indolent B-cell lymphoma in severe combined immunodeficient (SCID) mice. The rationale for these studies was generated by experience with viral fusogenic membrane glycoproteins as cytotoxic genes and the recognition of the potential of replicating viruses in the treatment of human malignancy. Intratumoral injection of both unmodified MV-Ed and a strain of MV-Ed genetically modified by the addition of a beta-galactosidase reporter gene (MVlacZ) induced regression of large established human lymphoma xenografts, in contrast to control therapy with UV-inactivated virus, in which all tumors progressed. The antitumor effect still occurred in the presence of passively transferred anti-MV antibody. Intravenous administration of MV also resulted in considerable slowing of tumor progression. Analysis of sections of residual tumor confirmed replication of MV within the tumors. Thus, the vaccine strain of MV mediates regression of large, established human B-cell lymphoma xenografts in SCID mice, and proof of principle is established that MV is oncolytic for lymphomas in vivo. Attenuated MVs may have value as a novel replicating-virus therapy for this group of disorders. (Blood. 2001;97:3746-3754)

A hyperfusogenic gibbon ape leukemia envelope glycoprotein: targeting of a cytotoxic gene by ligand display.

An important goal in cancer gene therapy is the development of novel targeted cytotoxic genes. The observation that transfection of a GaLV envelope glycoprotein lacking an R peptide into human cells results in considerable cell-cell fusion and subsequent cell death prompted us to explore the potential for using this fusogenic membrane glycoprotein (FMG) as a targeted cytotoxic gene. As proof of principle, we therefore displayed epidermal growth factor (EGF) on the N terminus of GaLV envelope glycoproteins both with and without an R peptide (GaLV R+ and GaLV R-). Transfection of the GaLVR+ envelope expression plasmids did not cause cell-cell fusion. The GaLV R+ envelopes were incorporated into retroviral vectors whose infectivity was investigated on EGF receptor-positive and -negative cells. The vector incorporating an N-terminally unmodified envelope was able to infect all human cell lines tested. Infectivity of the vector incorporating an envelope on which EGF was displayed was restricted on EGF receptor-positive cells (but not on EGF receptor-negative cells) and could be restored by protease cleavage of the displayed domain or competition with exogenous ligand. The cell-cell fusion capacity of the GaLV R- envelope glycoproteins (N-terminally unmodified and with N-terminal display of both EGF and insulin-like growth factor I [IGF-I]) was investigated by plasmid DNA transfection. While the N-terminally unmodified GaLV R- fused all human cell types tested, fusogenicity of GaLV R- on which EGF or IGF-I was displayed was considerably restricted on receptor-positive cells. "Reciprocal" competition experiments showed that fusogenicity could be restored by competition only with the relevant exogenous ligand. Thus the specificity of cell-cell fusion by a hyperfusogenic GaLV envelope glycoprotein can be regulated by N-terminal display of growth factor ligands. There is therefore significant potential for further development of the targeting of the cell-killing capability of this fusogenic viral glycoprotein by using strategies similar to those we have developed for the targeting of retroviral vectors.

Inverse targeting of retroviral vectors: selective gene transfer in a mixed population of hematopoietic and nonhematopoietic cells.

We previously reported that retroviral vectors displaying epidermal growth factor (EGF) as part of a chimeric envelope glycoprotein are sequestered upon binding to EGF receptor (EGFR)-positive target cells, leading to loss of infectivity. In the current study, we have displayed stem cell factor (SCF) on beta-galactosidase-transducing ecotropic and amphotropic retroviral vector particles as a factor Xa protease-cleavable N-terminal extension of the envelope glycoprotein. Viral incorporation of the SCF chimeric envelopes was demonstrated by immunoblotting of pelleted virions and their specific attachment to Kit receptors was demonstrated by flow cytometry. Gene transfer studies showed that when SCF was displayed on an amphotropic envelope, the infectivity of the SCF-displaying vectors was selectively inhibited on Kit-expressing cells, but could be restored by adding soluble SCF to block the Kit receptors or by cleaving the displayed SCF domain from the vector particles with factor Xa protease. The host range properties of EGF-displaying and SCF-displaying vectors were then compared in cell mixing experiments. When EGFR-positive cancer cells and Kit-positive hematopoietic cells were mixed and exposed to the different engineered vector particles, the cancer cells were selectively transduced by the SCF-displaying vector and the hematopoietic cells were selectively transduced by the EGF-displaying vector. Retroviral display of polypeptide growth factors can therefore provide the basis for a novel inverse targeting strategy with potential use for selective transduction of hematopoietic or nonhematopoietic cells (eg, cancer cells) in a mixed cell population.

Acquired skewing of X-chromosome inactivation patterns in myeloid cells of the elderly suggests stochastic clonal loss with age.

More frequent skewing of X-chromosome inactivation patterns (XCIPs) occurs in the white blood cells of elderly females; this study was performed to determine whether this occurs in myeloid or lymphoid lineages. XCIPs were analysed in purified neutrophils and T cells from 80 females > 75 years and the results were compared with 23 cord blood and 94 younger adult blood samples. The degree of XCIP skewing in cord blood and younger adult blood cells was similar, with 3-4% having > 90% expression of one allele. Skewing was markedly increased in the neutrophils of elderly females, with 33% having > 90% expression of one allele (P < 0.0001). Extreme skewing was present in only 9% of the elderly T-cell samples and no evidence of T-cell clonality was found by PCR analysis of the TCR gamma gene. The high level of acquired skewing of the XCIPs in myeloid cells of the elderly suggests that with time there is a change in stem cell usage with stochastic loss of some of the original stem cells. This has major implications for the use of XCIP analysis in the diagnosis of myeloid malignancies in the elderly and for gene therapy into haemopoietic stem cells.

Gene therapy for B cell lymphomas.

The use of genes or genetically modified cells for therapeutic benefit is likely to have a significant therapeutic role for patients with B cell lymphomas in the future. To date, most gene therapy strategies applicable to the therapy of these diseases have not reached the point of clinical study. Adoptive immunotherapy using donor leucocyte infusion to treat aggressive B cell neoplasms in immunosuppressed patients has, however, shown great promise clinically, and studies of idiotypic vaccination in patients with low grade B cell neoplasms are also under way. Results from in vitro and animal studies continue to suggest that it may become possible to use the immune system for therapeutic benefit, and many current basic research strategies in the gene therapy of B cell non-Hodgkin's lymphoma are based on immune modulation of T cells or tumour cells themselves. Other major approaches to gene therapy for B cell malignancies include the introduction of directly toxic or "suicide genes" into B cells or the chemoprotection of haemopoietic stem cells by the introduction of drug resistance genes. All of these approaches require efficient and accurate gene transfer as well as correct expression of the gene product within the target cell. Although some way from therapeutic use, specific targeting of gene delivery is an area of active investigation and will be of value in many of the gene therapy strategies applicable to B cell lymphomas.

G-CSF after peripheral blood stem cell transplantation in lymphoma patients significantly accelerated neutrophil recovery and shortened time in hospital: results of a randomized BNLI trial.

We have undertaken a prospective randomized study in 90 patients with relapsed or resistant lymphomas to assess the value of G-CSF (lenograstim) in the acceleration of myeloid recovery after peripheral blood stem cell transplantation (PBSCT). A common regimen of cyclophosphamide 1.5 g/m2 on day 1 and lenograstim 263 microg s.c. on days 2-10 with two aphereses on days 10 and 11 was used for stem cell mobilization. 77% of patients achieved an adequate PBSC collection in two harvests (> 2 x 10(8) MNC/kg or > 2 x 10(6) CD34+ cells/kg). 65 patients went on to receive high-dose BEAM chemotherapy and engraftment data was available for 62. 34 patients had been randomized to receive lenograstim 263 microg/d s.c. and 28 to no growth factor. The median time to ANC > 0.5 x 10(9)/l was 9 d in the lenograstim arm versus 12.5 d in the no-lenograstim arm (P=0.0001). This was associated with a median duration of time in hospital post PBSCT of 13 d in the lenograstim arm versus 15.5 d in the no-lenograstim arm (P=0.0002). Median days to platelet independence, platelet transfusions, incidence of infection and red cell transfusion were the same in both arms. These data indicate that lenograstim significantly accelerated myeloid recovery after PBSCT and shortened the duration of hospital stay.

Peripheral blood stem cell support does not accelerate haemopoietic recovery from miniBEAM chemotherapy.

Intermediate-dose salvage therapy is frequently given for relapsed and resistant lymphomas and is usually intensely myelosuppressive. In an attempt to reduce the haematological toxicity of miniBEAM, one of the commonly used salvage regimens, peripheral blood stem cell (PBSC) support was given to 21 consecutive patients who received miniBEAM chemotherapy. The outcome was compared with a non-randomised control group of consecutive patients who were similar to the supported group apart from the fact that it was not possible to collect PBSC before miniBEAM therapy. Apart from a small, marginally significant difference between the supported and unsupported groups in the number of days for which intravenous antibiotics were required, there were no other differences between the two groups in supportive care required and times to haematological recovery. In conclusion, PBSC support does not accelerate haematological recovery from miniBEAM therapy.