Panagiotis D. Kottaridis

Role of nonmyeloablative allogeneic stem-cell transplantation after failure of autologous transplantation in patients with lymphoproliferative malignancies

PURPOSE Conventional allogeneic stem-cell transplantation (SCT) after a prior failed autograft is associated with a transplant-related mortality rate of 50% to 80%. The aim of the current study was to evaluate the safety and efficacy of sibling, HLA-matched, nonmyeloablative allogeneic SCT with donor lymphocyte infusion (DLI) in patients with lymphoid malignancy after failure of autologous SCT. PATIENTS AND METHODS A total of 38 patients with refractory, progressive, or relapsed disease after autologous SCT were entered onto this study. The conditioning regimen consisted of the humanized monoclonal antibody CAMPATH-1H, fludarabine, and melphalan. Fifteen of 35 assessable patients received DLI after SCT. RESULTS Sustained neutrophil engraftment was achieved in 37 recipients, and platelet engraftment was achieved in 35 patients. The estimated transplant-related mortality was 7.9% at day 100 and 20% at 14 months, the median duration of follow-up. Eight patients experienced grade I/II acute graft-versus-host disease (GVHD) after transplantation, but no grade III/IV GVHD was observed in this setting. However, grade III/IV GVHD occurred in seven patients who received DLI. The actuarial overall survival at 14 months was 53%, with a progression-free survival of 50%. DLI produced a further response in three of 15 recipients. CONCLUSION Nonmyeloablative allogeneic SCT after CAMPATH-1H-containing conditioning is a relatively safe option compared with conventional allogeneic transplantation for patients who have failed previous autologous SCT. The low incidence of early GVHD enabled the subsequent administration of DLI to improve further clinical responses in this poor-risk group of lymphoma and myeloma patients.

Flt3 mutations and leukaemia

It is now 20 years since a molecular classification of acute myeloid leukaemia (AML) was initiated through the recognition of a number of leukaemia-specific cytogenetic abnormalities and their role as independent prognostic factors (Bloomfield et al, 1984). The intensive study of some of these markers, in particular the fusion transcripts from chromosomal translocations, has provided considerable insight into the underlying disease pathogenesis through characterization of the resulting aberrant gene products and their biological and clinical consequences. This has now been incorporated into the recent World Health Organization (WHO) classification of haemopoietic and lymphoid neoplasms in which AML patients with four well-defined recurring cytogenetic abnormalities have been put together as a subgroup (Harris et al, 1999). In general, however, patients are divided into three different risk groups based on cytogenetics: those with favourable, intermediate or standard, and poor risk disease. In some centres, the response to initial therapy is also taken into account (Wheatley et al, 1999). This classification has paved the way for a move from the indiscriminate use of high-dose chemotherapy for all patients to a more risk-adapted treatment approach. Patients with favourable cytogenetics, i.e. t(15;17), t(8;21) and inv(16), have particularly benefited from an improved understanding of the molecular pathology of their disease through identification of potential therapeutic targets. For example, the addition of all-trans retinoic acid (ATRA) during induction chemotherapy for acute promyelocytic leukaemia (APL) patients with the PML ⁄RARa (promyelocytic leukaemia ⁄ retinoic acid receptor alpha) fusion gene has increased the 5-year survival a further 20–30% compared with chemotherapy alone (Tallman et al, 1997; Burnett et al, 1999). Patients with poor risk disease have adverse survival, which hardly exceeds 20% at 5 years (Grimwade et al, 1998). They often have complete or partial loss of genetic material, e.g. )7, )5, del(5q), del(3q) or complex karyotypes, abnormalities that are currently less suitable candidates for targeted therapy. Approximately two-thirds of newly diagnosed AML patients, however, have intermediate ⁄ standard risk disease; their remission rate is similar to that of patients with favourable disease, but their outcome is hampered by an increased relapse rate (Grimwade et al, 1998). Although some of these patients have identifiable cytogenetic abnormalities that may allow the development of novel therapies, the majority of patients, 50% of all patients, have a normal karyotype. There has therefore been much interest in identifying further molecular markers of leukaemia that could help to improve the prognostic stratification of patients. In addition, with clear evidence for a multistep pathogenesis from both mouse models of leukaemia and the variable outcome for patients within defined cytogenetic groups, knowledge of co-operating mutations may further assist in improving therapy. Mutations in growth factor receptors and their downstream signalling molecules have long been obvious candidates for causing dysregulation of the delicate balance between proliferation and differentiation in haemopoietic cells. Many years of searching have now started to bear fruit with the demonstration that acquired mutations in the tyrosine kinase receptor gene, FLT3, are common in AML and have a major impact on prognosis. This review will outline the current knowledge on these mutations and their biological and clinical significance in leukaemia.

Plerixafor plus granulocyte CSF can mobilize hematopoietic stem cells from multiple myeloma and lymphoma patients failing previous mobilization attempts: EU compassionate use data

Plerixafor was recently approved by the US Food and Drug Administration (FDA) and the European Medicines Evaluation Agency (EMEA) to enhance stem cell mobilization for autologous transplant in patients with lymphoma and multiple myeloma. In this study, we present the first European compassionate use experience in mobilization failures, patients who are hardest to remobilize but were not included in registration trials. A total of 56 consecutive patients from 15 centers in Spain and the United Kingdom were included: age 60 (33–69) years; 29 men (32 with myeloma and 24 with lymphoma); 2 lines of previous chemotherapy (1–10); 73 previously failed mobilization attempts with G-CSF (28), chemotherapy plus G-CSF (43) or G-CSF plus SCF(2). Overall, 71% of patients reached ⩾10 CD34+ cells per μL with plerixafor on day 5 after a 7.6-fold expansion from day 4. A total of 42 patients (75%) collected ⩾2 × 106, average 3.0±1.7 (0.4–10.6) CD34+ cells per kg with plerixafor plus G-CSF. There were no severe drug-related adverse events. In all, 35 patients (63%) underwent transplant, receiving an average of 3.1±1.2 (1.9–7.7) × 106 CD34+ cells per kg. All patients engrafted neutrophils (day 12; 13.4±0.8; 8–30) and platelets (day 15; 18.5±2.4; 8–33). In our experience, plerixafor offers an effective alternative to collect sufficient CD34+ cells for autologous SCT from patients who fail conventional mobilization methods, with good tolerance and a high success rate.

The role of Vδ2-negative γδ T cells during cytomegalovirus reactivation in recipients of allogeneic stem cell transplantation

Reactivation of cytomegalovirus (CMV) remains a serious complication after allogeneic stem cell transplantation, but the role of γδ T cells is undefined. We have studied the immune reconstitution of Vδ2negative (Vδ2neg) γδ T cells, including Vδ1 and Vδ3 subsets and Vδ2positive (Vδ2pos) γδ T cells in 40 patients during the first 24 months after stem cell transplantation. Significant long-term expansions of Vδ2neg but not Vδ2pos γδ T cells were observed during CMV reactivation early after transplantation, suggesting direct involvement of γδ T cells in anti-CMV immune responses. Similarly, significantly higher numbers of Vδ2neg γδ T cells were detected in CMV-seropositive healthy persons compared with seronegative donors; the absolute numbers of Vδ2pos cells were not significantly different. The expansion of Vδ2neg γδ T cells appeared to be CMV-related because it was absent in CMV-negative/Epstein-Barr virus-positive patients. T-cell receptor-δ chain determining region 3 spectratyping of Vδ2neg γδ T cells in healthy subjects and patients showed restricted clonality. Polyclonal Vδ2neg cell lines generated from CMV-seropositive healthy donors and from a recipient of a graft from a CMV-positive donor lysed CMV-infected targets in all cases. Our study shows new evidence for role of γδ T cells in the immune response to CMV reactivation in transplantation recipients.

Donor Lymphocyte Infusions Modulate Relapse Risk in Mixed Chimeras and Induce Durable Salvage in Relapsed Patients After T-Cell–Depleted Allogeneic Transplantation for Hodgkin's Lymphoma

PURPOSE Reduced-intensity conditioning has minimized nonrelapse-related mortality rates after allogeneic transplantation in patients with Hodgkins lymphoma, and relapse has now become the major cause for treatment failure. We aimed to assess the impact of donor lymphocyte infusions (DLIs) on relapse incidence when administered for mixed chimerism and their utility as salvage therapy when given for relapse. PATIENTS AND METHODS This study reports the outcomes of 76 consecutive patients with multiply relapsed or refractory Hodgkins lymphoma who underwent allogeneic transplantation that incorporated in vivo T-cell depletion. Forty-two patients had related donors and 34 had unrelated donors. DLIs were administered in a dose-escalating fashion to 22 patients for mixed chimerism (median time of first dose, 9 months post-transplantation) and to 24 patients for relapse. RESULTS Three-year donor lymphocyte-related mortality was 7%, relating mainly to the induction of graft-versus-host disease. Nineteen (86%) of 22 patients receiving donor lymphocytes for mixed chimerism converted to full donor status. Four-year relapse incidence was 5% in these 22 patients compared with 43% in patients who remained relapse free but full donor chimeras at 9 months post-transplantation (P = .0071). Nineteen (79%) of 24 patients receiving donor lymphocytes for relapse responded (14 complete responses, five partial responses). Four-year overall survival from relapse was 59% in recipients of donor lymphocytes, contributing to a 4-year overall survival from transplantation of 64% and a 4-year current progression-free survival of 59% in all 76 patients. CONCLUSION These data demonstrate the potential for allogeneic immunotherapy with donor lymphocytes both to reduce relapse risk and to induce durable antitumor responses in patients with Hodgkins lymphoma after hematopoietic stem-cell transplantation that incorporates in vivo T-cell depletion.

Respiratory virus infections in transplant recipients after reduced‐intensity conditioning with Campath‐1H: high incidence but low mortality

Summary. Respiratory virus infections can cause serious morbidity and mortality after conventional allogeneic stem cell transplantation. However, the incidence and outcome of these infections after reduced intensity conditioning has not been reported. Between 1997 and 2001, 35 episodes of respiratory virus infections were noted in 25 of 83 transplant recipients conditioned with fludarabine, melphalan and Campath‐1H, and 80% of them received early antiviral therapy. Parainfluenza virus (PIV) 3 was the commonest isolate (45·7%) followed by respiratory syncytial virus (37%). Patients with myeloma were more susceptible to these infections [odds ratio (OR) 4·1, P = 0·01] which were often recurrent in patients with severe acute or chronic graft‐versus‐host disease (GVHD) (OR 10·6, P = 0·03). Infection within the first 100 d (OR 5·0, P = 0·05) and PIV 3 (OR 9·2, P = 0·01) isolation were risk factors for developing lower respiratory infection. Although more than half of the episodes progressed to lower respiratory infection, the mortality was only 8%. This could have been due to early initiation of antiviral therapy, but the attenuation of pulmonary damage due to the reduced‐intensity conditioning, low incidence of GVHD and, paradoxically, the low CD4+ T‐cell subset in this setting might also have been contributory factors.

Impact of in vivo alemtuzumab dose before reduced intensity conditioning and HLA-identical sibling stem cell transplantation: pharmacokinetics, GVHD, and immune reconstitution

In vivo alemtuzumab reduces the risk of graft-versus-host disease (GVHD) and nonrelapse mortality after reduced intensity allogeneic transplantation. However, it also delays immune reconstitution, leading to frequent infections and potential loss of graft-versus-tumor responses. Here, we tested the feasibility of alemtuzumab dose deescalation in the context of fludarabine-melphalan conditioning and human leukocyte antigen (HLA)-identical sibling transplantation. Alemtuzumab was given 1-2 days before graft infusion, and dose reduced from 60 mg to 20 mg in 4 sequential cohorts (total n = 106). Pharmacokinetic studies were fitted to a linear, 2-compartment model in which dose reduction led to incomplete saturation of CD52 binding sites and greater antibody clearance. Increased elimination was particularly evident in the 20-mg group in patients who had CD52-expressing tumors at time of transplantation. The 20-mg dose was also associated with greater risk of severe GVHD (acute grade III-IV or chronic extensive) compared with > 20 mg (hazard ratio, 6.7; 95% CI, 2.5-18.3). In contrast, dose reduction to 30 mg on day -1 was associated with equivalent clinical outcomes to higher doses but better lymphocyte recovery at 12 months. In conclusion, alemtuzumab dose reduction to 30 mg is safe in the context of reduced intensity conditioning and HLA-identical sibling transplantation. This trial was registered at http://www.ncrn.org.uk as UKCRN study 1415.

Extended routine polymerase chain reaction surveillance and pre‐emptive antiviral therapy for cytomegalovirus after allogeneic transplantation

Pre‐emptive treatment strategies based on sensitive screening for cytomegalovirus (CMV) infection up to day +100 after allogeneic transplantation have been shown to reduce the incidence of CMV disease during the period of surveillance. However, the use of ganciclovir has been associated with delays in immune reconstitution and an increased incidence of late CMV disease after day +100. In the present study, 81 patients undergoing allogeneic transplantation received polymerase chain reaction (PCR)‐guided pre‐emptive therapy based on detection of CMV DNA by PCR on 2 consecutive weeks up to day +180. Thirty‐three of the 52 high‐risk patients (CMV‐seropositive donor or recipient) received a total of 45 treatment episodes up to day +100. Three of these patients (5·7%) developed CMV disease, with one fatality. Twelve of the surviving 44 high‐risk patients (27%) required pre‐emptive treatment between days +101 and +192, but none of these patients developed late CMV disease with a median follow‐up of 402 d (range 117–952 d). Antiviral therapy was stopped after a single negative PCR result with no subsequent episodes of CMV disease while patients remained off antiviral treatment. As all initial episodes of CMV DNA detection occurred within 60 d of transplantation, it may be possible to discontinue monitoring beyond day +100 in patients who have remained CMV PCR negative before this. Thus, we have confirmed that PCR‐guided pre‐emptive therapy results in a low incidence of CMV disease before day +100 and that discontinuing treatment on the basis of viral clearance as determined by CMV PCR appears to be safe practice. In addition, we have observed no episodes of late CMV disease with an extension of surveillance to 26 weeks.

The role of allogeneic SCT in primary myelofibrosis: a British Society for Blood and Marrow Transplantation study

Fifty-one patients with primary myelofibrosis (PMF) received allogeneic haematopoietic stem cell transplants from related (n=33) or unrelated (n=18) donors. Twenty-seven patients, 19–54 years old, were prepared with myeloablative regimens including CY plus BU (n=4) or TBI (n=23). Twenty-four patients, 40–64 years old, received reduced-intensity conditioning (RIC) regimens. All RIC regimens contained fludarabine, combined with melphalan (n=19) or BU (n=5), and alemtuzumab or anti-thymocyte globulin (ATG) in the majority (n=19). Four patients (17%) in the RIC group had primary graft failure. Previous splenectomy reduced time to engraftment in the RIC group (13 versus 20 days; P=0.008). For MA and RIC groups, respectively, at 3 years, overall survival rates were 44 and 31% (P=0.67), progression-free survival 44 and 24% (P=0.87), and actuarial relapse rates 15 and 46% (P=0.06). Non-relapse mortality at 3 years was 41% for the myeloablative and 32% for the RIC group. Acute GVHD occurred in 29 and 38% of patients in the myeloablative and RIC groups, respectively. Extensive chronic GVHD developed in 30 and 35% of evaluable patients, respectively.

HLA-mismatched unrelated donors are a viable alternate graft source for allogeneic transplantation following alemtuzumab-based reduced-intensity conditioning

The impact of human leukocyte antigen (HLA) mismatch after reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation (RIT) using unrelated donors (UD) is unclear, and may be modulated by T-cell depletion. We therefore examined outcomes of 157 consecutive patients undergoing RIT after uniform conditioning with fludarabine, melphalan, and alemtuzumab (FMC). Donors were 10/10 HLA-matched (MUDs, n = 107) and 6 to 9/10 HLA-matched (MMUDs, n = 50), with no significant differences in baseline characteristics other than increased cytomegalovirus seropositivity in MMUDs. Rates of durable engraftment were high. Graft failure rates (persistent cytopenias with donor chimerism) were similar (8% vs 3%, P = .21), though rejection (recipient chimerism) was more frequent in MMUDs (8% vs 0%, P < .01). There were no significant differences between donors in the incidences of acute graft-versus-host disease (GVHD; 20% vs 22% grade 2-4, respectively, P = .83), chronic extensive GVHD (3-year cumulative incidence [CI] 23% vs 24%, P = .56), or treatment-related mortality (1-year CI 27% vs 27%, P = .96). Furthermore, there was no difference in 3-year overall survival (OS; 53% vs 49%, P = .44). Mismatch occurred at the antigenic level in 40 cases. The outcome in these cases did not differ significantly from the rest of the cohort. We conclude that RIT using HLA-mismatched grafts is a viable option using FMC conditioning.