Reduced intensity conditioning and allogeneic stem cell transplantation after salvage therapy integrating alemtuzumab for patients with relapsed peripheral T-cell non-Hodgkin's lymphoma

Allogeneic Hematopoietic Stem Cell Transplantation for Mature T/NK-Cell Lymphomas in Children

Mature T/NK-cell lymphomas (MTCLs) are a heterogeneous group of lymphoproliferative disorders, relatively rare in adults and children. Allogeneic hematopoietic stem cell transplantation (HSCT) can be considered in some cases as a consolidation and is the first choice for refractory forms and relapses. We retrospectively analyzed 19 pediatric patients with MTCL who received allogeneic hematopoietic stem cell transplantation from a haploidentical or unrelated donor on the αβ T cell depletion platform. Among the studied patients, cutaneous T-cell lymphoma was diagnosed in 5, hepatosplenic γδT-cell lymphoma in 4, ALK-positive anaplastic large cell lymphoma in 9 patients, and 1 had nasal T/NK cell lymphoma. All patients received myeloablative conditioning based on treosulfan or total body irradiation. Non-relapse mortality was 5%, the cumulative incidence of relapse or progression at 5 years was 27%, 5-year event-free survival was 67%, and 5-year overall survival was 78%. Thus, our data support that allogeneic αβ T-cell-depleted HSCT can provide long-term overall survival of children with high-risk mature T-cell lymphomas.

Comparison of Allogeneic Stem Cell Transplant and Autologous Stem Cell Transplant in Refractory or Relapsed Peripheral T-Cell Lymphoma: A Systematic Review and Meta-analysis

IMPORTANCE

Hematopoietic stem cell transplant (HSCT) is an advisable option for refractory or relapsed peripheral T-cell lymphoma (R/R-PTCL), but whether allogeneic HSCT or autologous HSCT is more beneficial is unknown.

OBJECTIVE

To compare the effectiveness and safety of allogeneic HSCT vs autologous HSCT in patients with R/R-PTCL.

DATA SOURCES

A systematic search of the PubMed, Embase, the Cochrane Central Register of Controlled Trials, Wanfang, and China National Knowledge Infrastructure databases with the search items refractory or relapsed peripheral T-cell lymphoma, ASCT/autologous stem-cell transplantation, allo-HSCT/allogeneic stem-cell transplantation, therapeutic effect, and treatment was conducted for articles published from January 12, 2001, to October 1, 2020.

STUDY SELECTION

After duplicate and irrelevant publications were discarded, 329 were ineligible according to the inclusion (clinical trials or retrospective studies with >10 samples) and exclusion criteria (articles without overall survival [OS], progression-free survival [PFS], and transplantation-related mortality [TRM]). Thirty trials were included in the meta-analysis. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

DATA EXTRACTION AND SYNTHESIS

Data on study design, individual characteristics, and outcomes were extracted. All statistics were pooled by applying a random-effects model.

MAIN OUTCOMES AND MEASURES

The prespecified main outcomes were OS, PFS, and TRM.

RESULTS

Of 6548 articles, data extracted from the 30 studies (including 880 patients who underwent allogeneic HSCT and 885 who underwent autologous HSCT) were included in this meta-analysis. In the allogeneic HSCT group, a 3-year OS of 50% (95% CI, 41%-60%) and PFS of 42% (95% CI, 35%-51%), a 5-year OS of 54% (95% CI, 47%-62%) and PFS of 48% (95% CI, 40%-56%), and a 3-year TRM of 32% (95% CI, 27%-37%) were observed. In the autologous HSCT group, a 3-year OS of 55% (95% CI, 48%-64%) and PFS of 41% (95% CI, 33%-51%), a 5-year OS of 53% (95% CI, 44%-64%) and PFS of 40% (95% CI, 24%-58%), and a 3-year TRM of 7% (95% CI, 2%-23%) were observed.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, OS and PFS were similar in the allogeneic HSCT and autologous HSCT groups; however, allogeneic HSCT was associated with specific survival benefits among patients with R/R-PTCL.

The rapidly changing landscape in mature T-cell lymphoma (MTCL) biology and management

Historical advances in the care of patients with non-Hodgkin lymphoma (NHL) have been restricted largely to patients with B-cell lymphoma. The peripheral T-cell lymphomas (PTCLs), which are rare and heterogeneous in nature, have yet to experience the same degree of improvement in outcome over the past 20 to 30 years. It is estimated that there are approximately 80,000 and 14,000 cases, respectively, of NHL and Hodgkin lymphoma per year in the United States. As a subgroup of NHL, the PTCLs account for 6% to 10% of all cases of NHL, making them exceedingly rare. In addition, the World Health Organization 2017 classification describes 29 distinct subtypes of PTCL. This intrinsic diversity, coupled with its rarity, has stymied progress in the disease. In addition, most subtypes carry an inferior prognosis compared with their B-cell counterparts, an outcome largely attributed to the fact that most treatment paradigms for patients with PTCL have been derived from B-cell neoplasms, a radically different disease. In fact, the first drug ever approved for patients with PTCL was approved only a decade ago. The plethora of recent drug approvals in PTCL, coupled with a deeper understanding of the molecular pathogenesis of the disease, has stimulated the field to pursue new avenues of research that are now largely predicated on the development of novel, targeted small molecules, which include a host of epigenetic modifiers and biologics. There is an expectation these advances may begin to favorably challenge the chemotherapy paradigms that have been used in the T-cell malignancies.

Allogeneic stem cell transplantation for patients with relapsed or refractory T-cell lymphoma: efficacy of lymphoma-directed conditioning against advanced disease

Salvage chemotherapy induces disease remissions in patients with relapsed or refractory (r/r) T-cell lymphomas, but fails to provide lasting tumor control. We analyzed the outcome after peripheral blood stem and bone marrow transplantation (PBSCT, n = 80; BMT, n = 4) from matched related (MRD, n = 22) or matched and unmatched unrelated donors (MUD and MMD, n = 53 and n = 9, respectively) following conditioning with fludarabine, busulfan, and cyclophosphamide (FBC) for 84 consecutive patients with r/r T-cell malignancies. At start of conditioning LDH was elevated in 50% of cases, and residual tumor (PD, SD, PR) was detectable in 84% of patients. In total, 38% (95% CI 33-44) of the patients were alive and disease-free after a median observation time of 14.5 (range 1.8 to 114) months. Univariate and multivariate analyses identified low ECOG status, as well as occurrence of acute GvHD as favorable factors for outcome. Lymphoma-directed conditioning with fludarabin, busulfan and cyclophosphamid (FBC-12), and allogeneic stem cell transplantation resulted in long-term survival for a proportion of patients with r/r peripheral T-cell lymphoma, including those with PR and SD only after salvage therapy.

New developments in the treatment of peripheral T-cell lymphoma - role of Belinostat

Peripheral T-cell lymphomas (PTCL) represent a heterogeneous group of rare malignancies that with the exception of anaplastic lymphoma kinase expressing anaplastic large cell lymphoma, share a poor outcome after standard (eg, anthracycline-based) chemotherapy. Most patients are either refractory to initial therapy or eventually relapse. Randomized studies for relapsed/refractory PTCL are not available, however, recently published data show that conventional chemotherapy has very limited efficacy in the salvage setting. Thus, novel drugs are urgently needed to improve the outcome in this setting. Belinostat, a pan-histone deacetylase inhibitor, has demonstrated meaningful efficacy and a favorable toxicity profile in two single-arm Phase II trials on 153 patients with relapsed/refractory PTCL. The conclusive results led to an accelerated approval by the US Food and Drug Administration. The present review summarizes the clinical data available for belinostat, its current role, and future perspectives.

Upfront allogeneic stem-cell transplantation for patients with nonlocalized untreated peripheral T-cell lymphoma: an intention-to-treat analysis from a single center

BACKGROUND

Peripheral T-cell lymphomas (PTCLs) are rare and heterogeneous diseases with dismal outcome when treated with chemotherapy alone. Because allogeneic stem-cell transplantation (allo-SCT) can cure relapse/refractory patients, we hypothesized that upfront allo-SCT may provide a better outcome. Therefore, all patients that presented with advanced PTCL in our institution at diagnosis were scheduled to undergo upfront allo-SCT after induction chemotherapy.

PATIENTS AND METHODS

The aim of the present work was to assess the feasibility and toxicity of upfront allo-SCT. From 2004 to 2012, 49 newly diagnosed PTCL patients were scheduled to receive upfront allo-SCT. A human leukocyte antigen-matched donor was found for 42 patients: related to the patient in 15 cases, unrelated in 20 cases, and suitable cord blood units were used in 7 cases.

RESULTS

After induction chemotherapy, 17 patients reached complete remission and 29 (60%) proceeded to upfront allo-SCT. For all patients, the 1 and 2-year overall survival (OS) rates were 59% [95% confidence interval (CI) 47-75] and 55% (95% CI 43-71), respectively. The most frequent reason we did not proceed to allo-SCT was disease progression or insufficient response after induction. For transplanted patients, the 1- and 2-year OS were 76% (95% CI 62-93) and 72.5% (95% CI 58-91), respectively. Toxicity-related mortality (TRM) 1 year after allo-SCT was only 8.2% (95% CI 0-18.5). The 2-year progression-free survival (PFS) rate of patients who did not proceed to allo-SCT (n = 20) was below 30%. The disease status at the time of transplantation was a strong predictive marker for both PFS and OS in transplant patients.

CONCLUSIONS

Upfront allo-SCT in PTCLs is feasible with low TRM, and it provides long-term disease control. However, one-third of patients remain chemo-refractory and, thus, new therapeutic approaches are warranted. The role of upfront allo-SCT compared with other therapeutic approaches in PTCLs requires investigation in randomized studies.

Treatment options for patients with relapsing and refractory peripheral T-cell lymphoma

SUMMARY 

Peripheral T-cell lymphomas are rare malignancies that with the exception of ALK-expressing anaplastic large cell lymphoma show a poor outcome after conventional (anthracycline-based) chemotherapy. The median overall survival ranges between approximately 9–42 months. Most patients are refractory or relapsing, and need salvage treatment. Several strategies have been investigated for this setting, but data are sparse. Autologous and allogeneic stem cell transplantation can induce long-term remissions and cure in a subset of chemosensitive patients. In addition, novel agents are available and under investigation to improve the outcome in this challenging group of diseases.

Allogeneic stem-cell transplantation for peripheral T-cell lymphoma: a systemic review and meta-analysis

Peripheral T-cell lymphoma (PTCL) comprises a heterogeneous group of mature T-cell tumors with a poor prognosis; allogeneic stem cell transplantation (allo-SCT) may offer a potential way of cure for these patients though the optimal type and timing of transplantation remain to be defined. We performed a systemic review and meta-analysis examining the efficacy and safety of allo-SCT for PTCL. The pooled 3-year overall survival (OS) of PTCL patients treated with allo-SCT was 49.6% (95% confidence interval, CI: 41.7-57.5%). A meta-analysis of 3-year OS in allo-SCT and autologous SCT (auto-SCT) showed no statistical difference. The rates of pooled acute graft-versus-host disease (GVHD; grade 2/4) and chronic GVHD were 26.7% (95% CI: 21.4-32.9%) and 29.9% (95% CI: 24.3-36.1%), respectively. The pooled 100-day treatment-related mortality was 24.2% (95% CI: 17.2-33.0%). Of the total study patients (n = 299), 48.5% were reported dead after allo-hematopoietic SCT, with disease progression as the first cause of death in PTCL patients. Although most studies included were retrospective and their sample size was small, existing data suggested that the group of PTCL patients receiving allo-SCT was to a great degree homogeneous regarding OS, mortality without relapse, death rate and the incidence of GVHD. The most common cause of death was disease progression. The present data did not show a difference in OS between allo- and auto-SCT in PTCL patients, but large prospective studies are needed to provide a more comprehensive understanding of the role of allo-SCT in the treatment of PTCL patients.

Therapeutic options in relapsed or refractory peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas with a very poor prognosis. Current therapies, based on historical regimens for aggressive B-cell lymphomas, have resulted in insufficient patient outcomes. The majority of patients relapse rapidly, and current 5-year overall survival rates are only 10-30%. It is evident that new approaches to treat patients with PTCL are required. In recent years, prospective studies in PTCL have been initiated, mainly in patients with relapsed/refractory disease. In some of these, selected histologic subtypes have been evaluated in detail. As a consequence, numerous new therapies have been developed and shown activity in PTCL, including: agents targeting the immune system (e.g. brentuximab vedotin, alemtuzumab, lenalidomide); histone deacetylase inhibitors (romidepsin, belinostat); antifolates (pralatrexate); fusion proteins (denileukin diftitox); nucleoside analogs (pentostatin, gemcitabine); and other agents (e.g. alisertib, plitidepsin, bendamustine, bortezomib). A variety of interesting novel combinations is also emerging. It is hoped that these innovative approaches, coupled with a greater understanding of the clinicopathologic features, pathogenesis, molecular biology, and natural history of PTCL will advance the field and improve outcomes in this challenging group of diseases. This review summarizes the currently available clinical evidence on the various approaches to treating relapsed/refractory PTCL, including the role of stem cell transplantation, with an emphasis on potential new drug therapies.

Efficacy of a dose-intensified CHOP (Double-CHOP) regimen for peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare and heterogeneous group of non-Hodgkin lymphomas, often resulting in poor prognoses. The CHOP chemotherapy regimen, which includes cyclophosphamide, doxorubicin, vincristine and prednisone, has been used previously to treat other types of lymphomas. Here, we examined the efficacy and safety of a dose-intensified CHOP regimen (Double-CHOP), which was followed by autologous stem-cell transplantation (ASCT) or high-dose methotrexate (HDMTX), in PTCL patients. Twenty-eight PTCL patients, who received 3 courses of Double-CHOP at our institution, were retrospectively studied from 1996 to 2012. Patients with anaplastic lymphoma kinase-positive anaplastic large-cell lymphoma (ALK+-ALCL) were excluded from this study. The median age of patients was 58 years (range: 17-69). They had low-intermediate (n=11), high-intermediate (n=10) or high (n=7) risk according to the International Prognostic Index (IPI). The overall complete remission (CR) rate following Double-CHOP treatment was 68%. Of the CR patients, 10 successfully tolerated a consolidated high-dose chemotherapy followed by ASCT and 7 received HDMTX. A single case of treatment-related mortality was recorded during the study. On a median 31-month follow-up, the estimated 3- or 5-year overall survival (OS) rates were 68 or 63%, respectively, while 3- or 5-year relapse-free survival (RFS) rates after CR were 60 or 43%, respectively. Although this study included elderly and excluded low-risk IPI and ALK+-ALCL patients, OS results were superiorly favourable, indicating the efficacy of this Double-CHOP regimen. However, an effective treatment strategy for refractory or relapsing patients needs to be validated and established.

How to predict the outcome in mature T and NK cell lymphoma by currently used prognostic models?

To select an appropriate prognostic model in the treatment of mature T- and natural killer (NK) -cell lymphoma (peripheral T-cell lymphoma (PTCL) and NK-/T-cell lymphoma (NKTCL)) is crucial. This study investigated the usefulness of Ann Arbor staging classification International prognostic index (IPI), prognostic index for T-cell lymphoma (PIT) and International peripheral T-cell lymphoma Project score (IPTCLP). Between 2000 and 2009, 176 patients (122 males) with PTCL and NKTCL were diagnosed and treated from a single institute in Taiwan. The correlation between complete response (CR) rate, 3-year overall survival (OS), early mortality rate and four prognostic models was analyzed. Thirty-one patients received hematopoietic stem cell transplantation (HSCT) and were analyzed separately. Three-year OS rate was 34.7%, and anaplastic large-cell lymphoma harbored better outcome than others. IPI score had the lowest Akaike information criterion value (1081.197) and was the best score in predicting OS and early mortality (P=0.009). Ann Arbor stage classification can predict CR rate more precisely (P=0.006). OS was significantly better in patients who received HSCT, even in patients with unfavorable features compared with chemotherapy alone. All prognostic models were useful to evaluate the outcome of patients with PTCL and NKTCL but IPI score did best in predicting OS in PTCL and PIT score in NKTCL. This study also supported the role of HSCT in patients with high-risk or refractory PTCL or NKTCL.

Current status of allogeneic transplantation for aggressive non-Hodgkin lymphoma

PURPOSE OF REVIEW

To provide a succinct update on the role of allogeneic stem cell transplantation (allo-SCT) in the management of patients with aggressive lymphomas. To clarify the indications for allogeneic transplantation vis-à-vis autologous transplant and to discuss the rationale and potential benefits of reduced intensity conditioning (RIC), nonmyeloablative (NMA) transplant, T-cell depletion and variations in graft vs. host disease (GVHD) prophylaxis.

RECENT FINDINGS

Considerable effort has been spent in developing transplant regimens with reduced toxicity and reduced GVHD. The role of allogeneic transplantation has also been redefined in light of advances in lymphoma classification, diagnostic methods, particularly PET scan and advances in transplant technology. Haplo and umbilical cord blood SCT allow identification of a donor for nearly all patients.

SUMMARY

In diffuse large B-cell lymphoma, the outcome of allo-SCT depends on patient characteristics and chemosensitivity. It is useful after failure of auto-SCT and in partial responses to salvage therapy. Allo-SCT may be the treatment of choice for advanced T-cell and natural killer cell lymphoma and for adult T-cell leukemia-lymphoma. Prophylactic or preemptive donor lymphocyte infusion may be useful, but requires controlled studies. RIC and NMA conditioning have reduced early toxicity but are associated with increased risk for disease recurrence. Promising data have been reported from a novel conditioning regimen combining NMA with ibritumomab tiuxetan. T-cell depletion reduces chronic GVHD but has some increase in rate of recurrence. Rapamycin may be associated with reduction in risk for disease recurrence.

Guidelines for the management of mature T-cell and NK-cell neoplasms (excluding cutaneous T-cell lymphoma)

The peripheral T-cell neoplasms are a biologically and clinically heterogeneous group of rare disorders that result from clonal proliferation of mature post-thymic lymphocytes. Natural killer (NK) cell neoplasms are included in this group. The World Health Organization classification of haemopoietic malignancies has divided this group of disorders into those with predominantly leukaemic (disseminated), nodal, extra-nodal or cutaneous presentation. They usually affect adults and are more commonly reported in males than in females. The median age at diagnosis is 61 years with a range of 17-90 years. Although some subtypes may follow a relatively benign protracted course most have an aggressive clinical behaviour and poor prognosis. Excluding anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL), which has a good outcome, 5-year survival for other nodal and extranodal T-cell lymphomas is about 30%. Most patients present with unfavourable international prognostic index scores (>3) and poor performance status. The rarity of these diseases and the lack of randomized trials mean that there is no consensus about optimal therapy for T- and NK-cell neoplasms and recommendations in this guideline are therefore based on small case series, phase II trials and expert opinion.

Reduced-intensity allogeneic hematopoietic cell transplantation using fludarabine-melphalan conditioning for treatment of mature T-cell lymphomas

Among non-Hodgkin's lymphoma subtypes, T-cell phenotype confers a poor clinical prognosis. For more aggressive histologies, patients frequently present with advanced disease that is inherently chemoresistant. For cutaneous histologies, disease progresses less rapidly, but is debilitating and often incurable in the long term. Here we report the retrospective analysis of data from 27 patients with mature T-cell lymphoma treated with salvage allogeneic haematopoietic cell transplantation at the City of Hope, Duarte, CA, USA, using a reduced-intensity fludarabine/melphalan conditioning regimen between the years 2001 and 2008. Eleven of the twenty-seven patients had cutaneous T-cell lymphoma (CTCL). The majority of patients had advanced disease at the time of transplant (17/27 or 63%). Median follow-up was 36 months. We observed a 2-year OS of 55%, a PFS of 47% and a cumulative incidence of relapse/progression and non-relapse mortality (NRM) of 30 and 22%, respectively. For CTCL, patients had a 2-year PFS of 45% and NRM of 27% compared with patients with other histologies, who had a PFS of 62% and NRM of 19%. Overall, our results suggest that meaningful long-term survival rates and disease control can be achieved with acceptable non-relapse mortality in patients with mature T-cell lymphomas, including CTCL using reduced-intensity conditioning with melphalan and fludarabine.

Impact of autologous and allogeneic stem cell transplantation in peripheral T-cell lymphomas

Peripheral T/NK-cell lymphomas (PTCLs) are rare malignancies characterized by poor prognosis. So far, no standard therapy has been established, due to the lack of randomised studies. High-dose therapy and autologous stem cell transplantation (HDT-autoSCT) have shown good feasibility with low toxicity in retrospective studies. In relapsing and refractory PTCL several comparison analyses suggest similar efficacy for PTCL when compared with aggressive B-cell lymphoma. In the upfront setting, prospective data show promising results with a long-lasting overall survival in a relevant subset of patients. Achieving a complete remission at transplantation seems to be the most important prognostic factor. Allogeneic stem cell transplantation (alloSCT) has been investigated only as salvage treatment. Especially when using reduced intensity conditioning regimen, eligible patients seem to benefit from this approach. To define the role for upfront stem cell transplantation a randomised trial by the German High-Grade Non-Hodgkin Lymphoma Study Group comparing HDT-autoSCT and alloSCT will be initiated this year.

Hematopoietic stem cell transplantation in peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCL) are a rare entity with a dismal outcome. After conventional chemotherapy they showed a worse prognosis compared with B-cell non-Hodgkin's lymphoma (NHL), except for anaplastic lymphoma-kinase (ALK)-positive anaplastic large cell lymphomas (ALCL). High-dose chemotherapy followed by autologous stem cell transplantation (SCT) has been evaluated in relapsed patients as well as in the upfront setting. Available data showed an advantage for patients who received transplant as first line treatment whereas results of autografting at relapse have been satisfactory only for ALK-positive ALCLs compared to other PTCL subtypes. Based upon preliminary results, allogeneic SCT can be also considered as an alternative strategy in these lymphomas. Whether or not the postulated graft-versus-lymphoma effect may overcome the poor prognosis of T-cell NHL patients has to be established.

Hepatosplenic gammadelta T-cell lymphoma: A case report

A 53-year-old man complained of weight loss, night sweats, and splenomegaly. The patient was diagnosed with stage IV hepatosplenic gammadelta T-cell non-Hodgkin's lymphoma, a highly aggressive and rare form of peripheral T-cell lymphoma. After completing CHOP chemotherapy, the patient relapsed. He did not respond to subsequent alemtuzumab therapy.

High-dose chemotherapy and autologous stem cell transplantation for peripheral T-cell lymphoma: complete response at transplant predicts survival

Although the role of high dose chemotherapy (HDT) and autologous stem cell transplantation (ASCT) in the treatment of aggressive lymphoma has been established in several large prospective studies, its effectiveness in patients with peripheral T cell lymphoma (PTCL) has not been defined. We aimed to evaluate the efficacy of HDT and ASCT and prognostic factors for survival in patients with PTCL. We retrospectively analyzed the results of 40 PTCL patients treated with HDT and ASCT at Asan Medical Center between January 1995 and December 2005. Twenty patients had PTCL-U (peripheral T cell lymphoma, unspecified), 10 had extranodal natural killer/T cell lymphoma, 5 had anaplastic large cell lymphoma, 3 had angioimmunoblastic T cell lymphoma, 1 had hepatosplenic gammasigma T cell lymphoma, and 1 had disseminated mycosis fungoides. Disease status at transplant was complete response (CR)1 in 3 patients, CR2 or greater in 8, partial remission in 25, and refractory in 4. At a median follow-up of 16 months (range, 5 to 135 months) for surviving patients, the median overall survival (OS) was 11.5 months and the 1-year probability of survival was 46.1%. The median event free survival (EFS) was 3.6 months (95% confidence interval, 2.5 to 4.8 months). Ten patients (25%) remain alive without evidence of disease. The median OS of 11 patients with CR at ASCT was not reached; of these, 7 patients (63.6%) were alive with CR. In multivariate analysis, CR at ASCT was a prognostic factor for EFS (P = 0.025) and OS (P = 0.027) and normal lactate dehydrogenase (LDH) at ASCT was a prognostic factor for improved OS (P = 0.025). Chemosensitive patients with PTCL who achieved CR before ASCT seem to benefit from HDT and ASCT. Pretransplant values of LDH had potential to predict the survival.

Alemtuzumab in T-cell lymphoproliferative disorders

The humanized monoclonal antibody alemtuzumab binds to the CD52 antigen, a glycoprotein which is widely expressed on normal and malignant B and T lymphocytes. Recently it has been demonstrated in a number of clinical trials that alemtuzumab has clinical activity in mature T-cell diseases such as T-prolymphocytic leukaemia and cutaneous T-cell lymphoma, inducing responses in up to two thirds of heavily pre-treated relapsed/refractory patients. Response was associated with improved survival. The toxicity profile for the antibody is manageable. The major complications are infusional reactions associated with initial injections, and prolonged lymphopenia associated with reactivation of viruses. Future studies will be directed towards alternative (subcutaneous) routes and schedules of administration, use as first-line therapy, combination strategies, and role of alemtuzumab to purge minimal residual bone-marrow disease prior to stem-cell transplantation.

The Role of High-Dose Therapy in Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of non-Hodgkin's lymphomas. With few exceptions (eg, anaplastic large-cell lymphoma expressing the anaplastic lymphoma kinase), PTCLs have generally been reported to have a worse prognosis compared with B-cell lymphomas. Despite the poor outcome after conventional therapy, the impact of high-dose therapy with autologous or allogeneic stem cell transplantation (SCT) in these rare diseases is poorly defined mainly because of the lack of prospective PTCL-restricted studies. Most data exist for high-dose therapy with autologous SCT in relapsing or refractory disease. Because most studies showed similar results for PTCL compared with aggressive B-cell lymphomas in which high-dose therapy with autologous SCT is accepted as standard therapy, this approach seems appropriate in relapsing or refractory PTCL. Results for high-dose therapy with autologous SCT as first-line therapy mainly rely on studies on aggressive lymphomas that also included lymphomas of the T-cell phenotype. Our own recently published PTCL-restricted prospective study confirmed the feasibility with only moderate toxicity and a good response rate. Overall, patients with a good remission status after induction therapy exhibited a high complete response rate after transplantation, and at least a subgroup of patients remained in long-term remission. The greatest uncertainty exists for the impact of allogeneic SCT after high-dose therapy. In refractory or relapsing PTCL, this approach might improve the outcome for eligible patients, especially when using reduced-intensity conditioning. Overall, because data on high-dose therapy for PTCL are limited, larger and randomized studies are necessary to definitely confirm the preliminary results.