FTY720 increases CD74 expression and sensitizes mantle cell lymphoma cells to milatuzumab-mediated cell death

Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy with a short median survival despite multimodal therapy. FTY720, an immunosuppressive drug approved for the treatment of multiple sclerosis, promotes MCL cell death concurrent with down-modulation of phospho-Akt and cyclin D1 and subsequent cell-cycle arrest. However, the mechanism of FTY720-mediated MCL cell death remains to be fully clarified. In the present study, we show features of autophagy blockage by FTY720 treatment, including accumulation of autolysosomes and increased LC3-II and p62 levels. We also show that FTY720-induced cell death is mediated by lysosomal membrane permeabilization with subsequent translocation of lysosomal hydrolases to the cytosol. FTY720-mediated disruption of the autophagic-lysosomal pathway led to increased levels of CD74, a potential therapeutic target in MCL that is degraded in the lysosomal compartment. This finding provided rationale for examining combination therapy with FTY720 and milatuzumab, an anti-CD74 mAb. Treatment of MCL cell lines and primary tumor cells with FTY720 and milatuzumab resulted in statistically significant enhanced cell death, which was synergistic in blastic variant MCL cell lines. Significant in vivo therapeutic activity of combination treatment was also demonstrated in a preclinical, in vivo model of MCL. These findings support clinical evaluation of this combination in patients with MCL.

Combination anti-CD74 (milatuzumab) and anti-CD20 (rituximab) monoclonal antibody therapy has in vitro and in vivo activity in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy with a median survival of 3 years despite chemoimmunotherapy. Rituximab, a chimeric anti-CD20 monoclonal antibody (mAb), has shown only modest activity as single agent in MCL. The humanized mAb milatuzumab targets CD74, an integral membrane protein linked with promotion of B-cell growth and survival, and has shown preclinical activity against B-cell malignancies. Because rituximab and milatuzumab target distinct antigens and potentially signal through different pathways, we explored a preclinical combination strategy in MCL. Treatment of MCL cell lines and primary tumor cells with immobilized milatuzumab and rituximab resulted in rapid cell death, radical oxygen species generation, and loss of mitochondrial membrane potential. Cytoskeletal distrupting agents significantly reduced formation of CD20/CD74 aggregates, cell adhesion, and cell death, highlighting the importance of actin microfilaments in rituximab/milatuzumab-mediated cell death. Cell death was independent of caspase activation, Bcl-2 family proteins or modulation of autophagy. Maximal inhibition of p65 nuclear translocation was observed with combination treatment, indicating disruption of the NF-κB pathway. Significant in vivo therapeutic activity of combination rituximab and milatuzumab was demonstrated in a preclinical model of MCL. These data support clinical evaluation of combination milatuzumab and rituximab therapy in MCL.

Phase 2 trial of rituximab and bortezomib in patients with relapsed or refractory mantle cell and follicular lymphoma

BACKGROUND

In vitro studies in mantle cell lymphoma (MCL) cell lines and patient-derived cells have demonstrated synergistic apoptosis with combined rituximab and bortezomib (R-bortezomib) compared with single-agent bortezomib. Therefore, the authors of this report evaluated R-bortezomib in a preclinical model and in a phase 2 clinical trial.

METHODS

A Hu-MCL-severe combined immunodeficiency (SCID) model engrafted with the Jeko cell line was treated with R-bortezomib, bortezomib, or rituximab. Twenty-five patients with relapsed follicular lymphoma (n = 11) and MCL (n = 14) received 375 mg/m(2) rituximab on Days 1 and 8 and 1.3 to 1.5 mg/m(2) bortezomib on Days 1, 4, 8, and 11 every 21 days for a median of 3 cycles (range, 1-5 cycles).

RESULTS

R-bortezomib resulted in a statistically significant improvement in overall survival in Hu-MCL-SCID mice. In the clinical trial, the overall response rate was 40% in all 25 patients, 55% in patients with follicular lymphoma, and 29% in patients with MCL. The estimated 2-year progression-free survival (PFS) rate was 24% (95% confidence interval [CI], 10%-53%) in all patients and 60% (95% CI, 20%-85%) in responding patients. Thirteen patients (52%) developed grade 3 neurotoxicity, which consisted of constipation/ileus, sensory or motor neuropathy, or orthostatic hypotension. Patients who were heterozygous for the CD32a (Fcγ receptor IIa) 131 histidine (H) to arginine (R) polymorphism had a significantly decreased PFS (P = .009) after R-bortezomib compared with HH and RR homozygotes.

CONCLUSIONS

R-bortezomib had significant activity in patients with relapsed or refractory follicular lymphoma and MCL, although an unexpectedly high incidence of grade 3 neurologic toxicity was a potential limiting factor with this combination.

The clinical application of monoclonal antibodies in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) represents the most prevalent adult leukemia. Treatment with chemotherapy over the past 3 decades has been palliative. The introduction of therapeutic antibodies has increased the number of treatment options for this disease. Despite this increase, our true understanding of the mechanism of action of antibody therapy in CLL remains limited. Rituximab, a CD20 antibody, is currently widely used in combination-based strategies for both previously untreated symptomatic CLL and as salvage therapy. Recent data suggest that the addition of rituximab to fludarabine with or without cyclophosphamide prolongs survival in younger patients with CLL. Other improved CD20 antibodies with promising clinical activity, including ofatumumab and GA-101, are coming forward. Alemtuzumab, a CD52 antibody, likewise has demonstrated benefit in both symptomatic, previously untreated CLL and in patients with relapsed disease but has less selectivity. Development of other therapeutic antibodies targeting alternative B-cell-specific antigens in CLL has been less successful, although many promising candidate antibodies and/or small modular immune pharmaceuticals (SMIPs) are coming forward. In addition, recent efforts to combine currently applied therapeutic antibodies with other biologic and targeted therapies with efficacy in CLL offers the potential to move toward alternative non-chemotherapy-based treatment approaches.

New targets of therapy in T-cell lymphomas

T-cell lymphomas (TCL) are characterized by poor response to chemotherapy and generally poor outcome. While molecular profiling has identified distinct biological subsets and therapeutic targets in B-cell lymphomas, the molecular characterization of TCL has been slower. Surface markers expressed on malignant T-cells, such as CD2, CD3, CD4, CD25, and CD52 were the first TCL-specific therapeutic targets to be discovered. However, the presence of these receptors on normal T-cells means that monoclonal antibody (mAb)- or immunotoxin (IT)-based therapy in TCL inevitably results in variable degrees of immunosuppression. Thus, although some mAbs/IT have significant activity in selected subsets of TCL, more specific agents that target signaling pathways preferentially activated in malignant T-cells are needed. One such novel class of agents is represented by the histone deacetylase (HDAC) inhibitors. These molecules selectively induce apoptosis in a variety of transformed cells, including malignant T-cells, both in vitro and in vivo. Several HDAC inhibitors have been studied in TCL with promising results, and have recently been approved for clinical use. Immunomodulatory drugs, such as interferons and Toll Receptor (TLR) agonists have significant clinical activity in TCL, and are particularly important in the treatment of primary cutaneous subtypes (CTCL). Although most classical cytotoxic drugs have limited efficacy against TCL, agents that inhibit purine and pyrimidine metabolism, known as nucleoside analogues, and novel antifolate drugs, such as pralatrexate, are highly active in TCL. With improved molecular profiling of TCL novel pharmacological agents with activity in TCL are now being discovered at an increasingly rapid pace. Clinical trials are in progress and these agents are being integrated in combination therapies for TCL, both in the relapsed/refractory setting as well as front line.

The novel deacetylase inhibitor AR-42 demonstrates pre-clinical activity in B-cell malignancies in vitro and in vivo

Background

While deacetylase (DAC) inhibitors show promise for the treatment of B-cell malignancies, those introduced to date are weak inhibitors of class I and II DACs or potent inhibitors of class I DAC only, and have shown suboptimal activity or unacceptable toxicities. We therefore investigated the novel DAC inhibitor AR-42 to determine its efficacy in B-cell malignancies.

Principal Findings

In mantle cell lymphoma (JeKo-1), Burkitt's lymphoma (Raji), and acute lymphoblastic leukemia (697) cell lines, the 48-hr IC₅₀ (50% growth inhibitory concentration) of AR-42 is 0.61 µM or less. In chronic lymphocytic leukemia (CLL) patient cells, the 48-hr LC₅₀ (concentration lethal to 50%) of AR-42 is 0.76 µM. AR-42 produces dose- and time-dependent acetylation both of histones and tubulin, and induces caspase-dependent apoptosis that is not reduced in the presence of stromal cells. AR-42 also sensitizes CLL cells to TNF-Related Apoptosis Inducing Ligand (TRAIL), potentially through reduction of c-FLIP. AR-42 significantly reduced leukocyte counts and/or prolonged survival in three separate mouse models of B-cell malignancy without evidence of toxicity.

Conclusions/Significance

Together, these data demonstrate that AR-42 has in vitro and in vivo efficacy at tolerable doses. These results strongly support upcoming phase I testing of AR-42 in B-cell malignancies.

Methylation of histone H3 and H4 by PRMT5 regulates ribosomal RNA gene transcription

In an effort to understand the epigenetic regulation of ribosomal RNA gene (rDNA) expression we have previously demonstrated the role of DNA methyltransferases and methyl CpG binding proteins in rRNA synthesis. Here, we studied the role of protein arginine methyltransferase PRMT5 and the two methylated histones H3R8Me2 and H4R3Me2, in rDNA expression in Epstein Barr virus- transformed primary B-cells (LCLs) and in HeLa cells responding to serum-regulated growth. Chromatin immunoprecipitation assay showed that histones H3 and H4 associated with rRNA promoters were differentially methylated at arginine residues 8 and 3, respectively, depending on its transcriptional activity. Association of PRMT5 and methylated H3 with the unmethylated promoters in resting B-cells was significantly reduced in rapidly growing LCLs. Unlike PRMT5 and H3R8Me2, histone H4 associated with both methylated and unmethylated rRNA promoters in resting B-cells was methylated at the R3 residue. However, a dramatic decrease in R3 methylation of H4 recruited to the unmethylated rRNA promoters was observed in LCLs while it remained unaltered in the fraction bound to the methylated promoters. Differential interaction of PRMT5 and methylation of H3 and H4 associated with the rRNA promoters was also observed when serum starved HeLa cells were allowed to grow in serum replenished media. Ectopic expression of PRMT5 suppressed activity of both unmethylated and methylated rRNA promoter in transient transfection assay whereas siRNA mediated knockdown of PRMT5 increased rRNA synthesis in HeLa cells. These data suggest a key role of PRMT5 and the two methylated histones in regulating rRNA promoter activity.

FTY720 shows promising in vitro and in vivo preclinical activity by downmodulating Cyclin D1 and phospho-Akt in mantle cell lymphoma

PURPOSE

Despite the progress that has been made in the treatment of mantle cell lymphoma (MCL), all patients invariably relapse with the currently available therapies. Because of the absence of curative therapy for MCL, we explored FTY720 as a novel agent against MCL.

EXPERIMENTAL DESIGN

The cytotoxic effect of FTY720 in primary MCL tumor cells and cell lines were evaluated in vitro. The effects of FTY720 on caspase activation, generation of reactive oxygen species, and modulation of Cyclin D1 and Akt, which are implied in the pathogenesis of MCL, were investigated. The in vivo efficacy of FTY720 was evaluated in a Jeko-severe combined immunodeficient xenograft model of human MCL.

RESULTS

FTY720 mediated time- and dose-dependent cytotoxicity in primary MCL tumor cells and MCL cell lines in vitro. FTY720-induced cytotoxicity occured independent of caspase activation but dependent on the generation of ROS in MCL. In addition, FTY720 treatment resulted in the time-dependent downmodulation of Cyclin D1 and accumulation of cells in G(0)-G(1) and G(2)-M phases of the cell cycle with concomitant decrease in S-phase entry. Furthermore, concentrations of FTY720 that induced cytotoxicity led to decreased phospho-Akt in primary MCL cells and cell lines. Most importantly, the in vivo therapeutic activity of FTY720 was shown in severe combined immunodeficient mice engrafted with the Jeko MCL cell line.

CONCLUSIONS

These results provide the first evidence for a potential use of FTY720 in targeting key pathways that are operable in the pathogenesis of MCL and warrant further investigation of FTY720 in clinical trials to treat patients with MCL.

Abstract 1584: Targeting protein arginine methyltransferase 5 (PRMT5) enzyme over expression in high grade astrocytomas

High grade astrocytomas are aggressive brain tumors that are associated with a dismal prognosis and are incurable with a median survival of less than 15 months despite intensive multimodal therapy. The linability to effectively target grade III and grade IV (glioblastoma multiforme, GBM) astrocytomas highlights the need for novel therapeutic approaches. Recent studies have shown that epigenetic regulation of chromatin plays a central role in the control of cell growth, differentiation, and survival. Chromatin remodeling enzymes like histone deacetylases, DNA methyltransferases and protein arginine methyltransferase 5 (PRMT5) are involved in silencing tumor suppressor gene (TSG) expression and may contribute towards cellular transformation. PRMT5 silences the transcription of key regulatory genes by symmetric di-methylation (S2Me) of arginine (R) residues on histone proteins (H4R3 and H3R8) and works more efficiently when associated with other co-repressor enzymes. Eight patient-derived GBM cell lines and 45 primary GBM tumors showed abundant expression of PRMT5 protein. Confocal microscopy and immunohistochemical staining showed the PRMT5 signal to localize primarily to the nucleus. Normal brain tissue, normal human astrocytes and low/intermediate grade astrocytomas failed to show PRMT5 expression. The degree of PRMT5 over expression inversely correlated with survival of GBM patients (r=-0.57, p=0.0001) and correlated with proliferation of GBM cell lines (r=0.81, p<0.0001). Elevated PRMT5 expression was observed in high grade astrocytomas that spontaneously develop in a pre-clinical mouse model of GBM employing conditional Nf1, TP53 and PTEN haploinsufficiency. Small inhibitory RNAs (siRNA) specific for PRMT5 led to loss of PRMT5 protein expression and S2Me of H4R3, a histone target of PRMT5. PRMT5 inhibition led GBM cell lines to cell cycle arrest, apoptosis, and complete loss of cell migratory activity. Apoptosis occurred independent of caspase and p53 pathways. Furthermore, PRMT5 knockdown led GBM cell lines to become sensitized to the toxic effects of temazolomide, a drug frequently used to manage patients with GBM. We utilized gene microarray analysis of cDNA isolated from siRNA (or control RNA) treated GBM cells to identify potential targets of PRMT5 and identified the TSG ST7 and three chemokine transcripts (RANTES, IP10, CXCL11) to be upregulated with PRMT5 knockdown. We used chromatin immuno precipitation to show that siRNA treatment led to loss of PRMT5 recruitment on ST7 and chemokine gene promoters that coincided with restoration of transcriptional and translational activity leading to marked elevation in protein expression. PRMT5 knock-down led to secretion of all chemokines into growth medium. These findings identify PRMT5 as an independent prognostic factor for GBM and an attractive therapeutic target for high grade astrocytomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1584.

Combination bortezomib and rituximab treatment affects multiple survival and death pathways to promote apoptosis in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a distinct histologic subtype of B cell non-Hodgkins lymphoma (NHL) associated with an aggressive clinical course. Inhibition of the ubiquitin-proteasome pathway modulates survival and proliferation signals in MCL and has shown clinical benefit in this disease. This has provided rationale for exploring combination regimens with B-cell selective immunotherapies such as rituximab. In this study, we examined the effects of combined treatment with bortezomib and rituximab on patient-derived MCL cell lines (Jeko, Mino, SP53) and tumor samples from patients with MCL where we validate reversible proteasome inhibition concurrent with cell cycle arrest and additive induction of apoptosis. When MCL cells were exposed to single agent bortezomib or combination bortezomib/rituximab, caspase dependent and independent apoptosis was observed. Single agent bortezomib or rituximab treatment of Mino and Jeko cell lines and patient samples resulted in decreased levels of nuclear NFkappaB complex(es) capable of binding p65 consensus oligonucleotides, and this decrease was enhanced by the combination. Constitutive activation of the Akt pathway was also diminished with bortezomib alone or in combination with rituximab. On the basis of in vitro data demonstrating additive apoptosis and enhanced NFkappaB and phosphorylated Akt depletion in MCL with combination bortezomib plus rituximab, a phase II trial of bortezomib-rituximab in patients with relapsed/refractory MCL is underway.

High-Dose Therapy with Autologous Transplantation for Aggressive Non-Hodgkin's Lymphoma: The Bologna Experience

Patients with aggressive non-Hodgkin's lymphoma (NHL) who relapse after initial therapy have a poor prognosis and with standard dose salvage therapy the outlook remains poor. In this work we examine the patient characteristics and outcome of patients with aggressive NHL treated with HDT and autologous transplantation at our Institute from 1982 to 1999. A retrospective analysis was performed examining patient characteristics, prior chemotherapy regimens, pretransplant disease status, HDT regimen, source of stem cells, time for hematopietic recovery, complications of transplantation, response rates, overall survival (OS) and relapse-free survival (RFS). One hundred and thirty-four patients with aggressive NHL were treated with estimated 10-year OS and RFS rates of 50% and 66%, respectively. Disease status (sensitive vs. refractory) pre-HDT was the most powerful predictive parameter for OS and RFS, at both univariate and multivariate analysis. For the entire cohort, transplant-related mortality was only 3.5% without evidence of second malignancies. Our results confirm that HDT with autologous transplantation is associated with a durable RFS in a remarkable proportion of aggressive NHL patients with very low global early and late toxicity. Improved patient selection, transplant timing, ongoing improvements in supportive care, and selected phase III trials should increase outcomes further.

Effectiveness of Fludarabine, Idarubicin and Cyclophosphamide (FLUIC) Combination Regimen for Young Patients with Untreated Non-Follicular Low-Grade Non-Hodgkin's Lymphoma

In the last years, fludarabine (FLU) alone or in combination with other drugs has been reported to be effective in the treatment of previously untreated low-grade non-Hodgkin's lymphomas (LG-NHL). We report on the therapeutic efficacy and toxicity of a combination of FLU, idarubicin and cyclophosphamide (FLUIC regimen) in untreated non-follicular LG-NHL. We administered a three-drug combination of FLU (25 mg/m2 i.v. on days 1 to 3), idarubicin (14 mg/m2 i.v. on day 1) and cyclophosphamide (200 mg/m2 i.v. on days 1 to 3) to treat 41 young, previously untreated patients with non-follicular LG-NHL. Chemotherapy was repeated every 4 weeks for a total of 6 cycles. Among 41 patients, 24 (59%) were diagnosed with small lymphocytic, 10 (24%) with immnocytoma, and 7 (17%) with marginal zone subtypes. Nineteen (46%) patients achieved complete response (CR) and 21 (51%) partial response, while the remaining 1 (3%) showed no benefit from the treatment. With respect to histology, we observed CR rates of 38% for the small lymphocytic subtype, 40% for the immunocytoma subtype, and 86% for the marginal zone subtype. Estimated 42-month overall survival and relapse-free survival rates were 64% and 100%, respectively. Hematologic grade 3-4 toxicity was seen in 9 (22%) patients; no opportunistic infection or death was associated with administration of the FLUIC regimen. These preliminary data suggest that FLUIC is a very active, well-tolerated regimen for young, untreated patients with advanced non-follicular LG-NHL.

Role of anemia in survival of patients with elderly aggressive non-Hodgkin's lymphoma after chemotherapy

Baseline anemia is a relevant prognostic factor in the overall population of non-Hodgkin's lymphoma (NHL) patients, and studies focusing on elderly NHL are awaited. We conducted a pooled analysis of a cohort of comparable patients enrolled (1993 - 2001) in three multicenter clinical trials on use of a MACOP-B-like regimen (VNCOP-B) for front-line treatment of elderly aggressive NHL. Models of Cox's proportional hazards regression analysis of prognostic value of pre-/post-treatment hemoglobin values in terms of 5-year overall survival included age, sex, initial tumor staging and response to treatment. Of the 168 patients screened, 16 were excluded due to missing data or lack of 5-year follow-up. In addition to achievement of complete/partial remission (adjusted relative risk [RR], 0.215; p = 0.0001) and advanced stage (II-IV vs. I - II; adjusted RR, 1.55; p = 0.0023), post-treatment hemoglobin values were an independent predictor of survival (adjusted RR per 1-g/dL increment, 0.76; p = 0.0041). In the present analysis, pretreatment hemoglobin values were associated with only marginal risk reduction (adjusted RR per 1-g/dL increment, 0.985; p = 0.049). Post-treatment hemoglobin values appear to provide a strong independent predictor of 5-year survival in elderly aggressive NHL, supporting the potential role of anemia correction in this group of patients.

Discordant response to chemotherapy: An unusual patternof fluoro-deoxy-d-glucose uptake in heavily pre-treated lymphoma patients

In recent years a number of studies have been published showing strong value of positron emission tomography using 18-Fluorine 2-fluoro-deoxy-D-glucose (FDG-PET) in term of diagnosis, response to treatment, disease recurrence and prognostic indicator in early restaging. This study observed 17 patients who presented contemporary disease progression in some localizations as well as regression in others (PROG + REG pattern); this investigation assessed that this unusual pattern of FDG uptake lead to an unfavorable prognosis. Among 1280 FDG-PET scans performed between August 2003 and December 2004 on patients affected by lymphoma with suspected recurrence, attention was focused on 17 patients presenting a PROG + REG pattern. At follow-up (4 months) only 1/17 (6%) patient was in complete remission after salvage therapy, while 6/17 (35%) had stable disease and 10/17 (59%) had rapid progression of the disease. This study further strengthens the role of FDG-PET in lymphoma patients follow-up, as it can provide useful information to better differentiate those cases who may benefit from conventional treatments from others in whom additional treatment would provide avoidable toxicity.

Value of oxaliplatin treatment in heavily pretreated patients with non-Hodgkin's lymphoma

In order to assess the efficacy and toxicity profile of oxaliplatin, a third generation platinum derivate active against several solid tumors, we carried out a study in a group of heavily pretreated patients with non-Hodgkin's lymphoma (NHL). Between August 2003 and May 2004, 19 pretreated patients were enrolled in a phase II trial and were treated with oxaliplatin. The drug was administered intravenously on day 1 of a 21-day schedule, at a dose of 130 mg/m2 for a total of 6 cycles. One (5%) patient achieved complete remission (CR) and 5 patients (27%) had partial response (PR), thus giving an overall response rate of 32%. The patient in CR suffered from an aggressive B NHL. One of the 5 patients in PR had an aggressive B NHL, whereas the remaining 4 had an indolent B NHL. The treatment was well tolerated with minimal hematologic and extrahematologic toxicity. These data suggest and confirm the efficacy and low toxicity of oxaliplatin in the treatment of patients with heavily pretreated NHL. Further trials using oxaliplatin alone or in combination with other conventional drugs are needed.

Role of [18F]Fluorodeoxyglucose Positron Emission Tomography Scan in the Follow-Up of Lymphoma

Purpose

In lymphoma, [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) is routinely used for initial staging, early evaluation of treatment response, and identification of disease relapse. However, there are no prospective studies investigating the value of serial FDG-PET over time in patients in complete remission.

Patients and Methods

All patients with lymphoma who achieved the first complete remission were prospectively enrolled onto the study and scheduled for serial FDG-PET scans at 6, 12, 18, and 24 months; further scans were then carried out on an annual basis. Overall, the population included 421 patients (160 patients with Hodgkin's lymphoma [HL], 183 patients with aggressive non-Hodgkin's lymphoma [NHL], and 78 patients with indolent follicular NHL). All patients had a regular follow-up evaluation, including complete clinical and laboratory evaluation, and final assessment of any suspect FDG-PET findings using other imaging procedures (computed tomography [CT] scan) and/or biopsy and/or clinical evolution. FDG-PET findings were reported as positive for relapse, inconclusive (when equivocal), or negative for relapse.

Results

PET enabled documentation of lymphoma relapse in 41 cases at 6 months, in 30 cases at 12 months, in 26 cases at 18 months, in 10 cases at 24 months, and in 11 cases at more than 36 months. All 36 patients with inconclusive positive PET underwent biopsy; only 12 (33%) of 36 patients had a concomitant suggestion of positivity on CT. A lymphoma relapse was diagnosed in 24 (66%) of 36 patients.

Conclusion

Our results confirm FDG-PET as a valid tool for follow-up of patients with HL and NHL. In patients with inconclusive positive results, histologic confirmation plays an important role in identifying true relapse.

Pretransplantation positron emission tomography scan is the main predictor of autologous stem cell transplantation outcome in aggressive B-cell non-Hodgkin lymphoma

BACKGROUND

Limited data exist about the role of second-line chemotherapy response assessed by positron emission tomography (PET) as a prognostic factor in patients with aggressive non-Hodgkin Lymphoma (NHL) who undergo autologous stem cell transplantation (ASCT). The objective of this analysis was to investigate the main determinants of prognosis in patients with aggressive B-cell NHL who undergo ASCT, focusing on the impact of pretransplantation PET, secondary age-adjusted International Prognostic Index (sAA-IPI) score, histology, and previous response to first-line chemotherapy.

METHODS

Seventy-five patients with diffuse, large B-cell lymphoma or grade 3 follicular lymphoma who were treated at the author' institution with second-line chemotherapy (combined ifosfamide, etoposide, and epirubicin [IEV]) followed by ASCT between September 2002 and September 2006 were included. All patients were evaluated by PET after 1 to 3 courses of IEV chemotherapy before ASCT, and all patients received a conditioning regimen of combined carmustine, etoposide, cytosine arabinoside, and melphalan. The prognostic impact of pretransplantation PET, sAA-IPI score, histology, and previous response to first-line chemotherapy was evaluated by univariate and multivariate analyses.

RESULTS

Seventy-two of 75 patients underwent ASCT. In a univariate analysis for progression-free survival (PFS) and overall survival (OS), a significant association was observed with pretransplantation PET (PFS, P< .00001; OS, P< .01) and previous first-line response (PFS, P= .02; OS, P= .04). In the multivariate framework, pretransplantation PET was identified as the only independent prognostic factor (PFS, P< .001; OS, P= .01).

CONCLUSIONS

The current data indicated that pretransplantation PET is the main prognostic predictor in patients with aggressive B-cell NHL who are scheduled for ASCT.

A phase II trial of CHOP chemotherapy followed by yttrium 90 ibritumomab tiuxetan (Zevalin) for previously untreated elderly diffuse large B-cell lymphoma patients

BACKGROUND

A prospective, single-arm, open-label, nonrandomized phase II combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus radioimmunotherapy trial was conducted to evaluate the efficacy and safety in untreated elderly diffuse large B-cell lymphoma (DLBCL) patients.

PATIENTS AND METHODS

From February 2005 to April 2006, in our institute we treated 20 eligible elderly (age > or =60 years) patients with previously untreated DLBCL using a novel regimen consisting of six cycles of CHOP chemotherapy followed 6-10 weeks later by (90)Y ibritumomab tiuxetan.

RESULTS

The overall response rate to the entire treatment regimen was 100%, including 95% complete remission (CR) and 5% partial remission. Four (80%) of the five patients who achieved less than a CR with CHOP improved their remission status after radioimmunotherapy. With a median follow-up of 15 months, the 2-year progression-free survival was estimated to be 75%, with a 2-year overall survival of 95%. The (90)Y ibritumomab tiuxetan toxicity included grade > or =3 hematologic toxicity in 12 of 20 patients; the most common grade > or =3 toxic effects were neutropenia (12 patients) and thrombocytopenia (7 patients). Transfusions of red blood cells and/or platelets were given to one patient.

CONCLUSION

This study has established the feasibility, tolerability, and efficacy of this regimen for elderly patients with DLBCL.

Phase II trial of proteasome inhibitor bortezomib in patients with relapsed or refractory cutaneous T-cell lymphoma

PURPOSE

To determine the antitumor activity of the proteasome inhibitor bortezomib in patients with cutaneous T-cell lymphoma (CTCL) or peripheral T-cell lymphoma unspecified (PTCLU) with isolated skin involvement.

PATIENTS AND METHODS

From May 2005 to June 2006 at our institute, we treated patients with previously pretreated CTCL or PTCLU using bortezomib as a single agent, at a dose of 1.3 mg/m2 intravenously on days 1, 4, 8, and 11, every 21 days for a total of six cycles.

RESULTS

Fifteen patients were registered, of whom 12 (10 CTCL, all mycosis fungoides, and two PTCLU with isolated skin involvement) were assessable. The overall response rate was 67%, with two (17%) complete remissions and six (50%) partial remissions. The remaining four patients had disease progression. Histologically, the responder patients were seven with CTCL and one with PTCLU with isolated skin involvement. All responses were durable, lasting from 7 to 14 or more months. Overall, the drug was well tolerated, with no grade 4 toxicity. The most common grade 3 toxicities were neutropenia (n = 2), thrombocytopenia (n = 2), and sensory neuropathy (n = 2).

CONCLUSION

This study suggests that bortezomib was well tolerated and has significant single-agent activity in patients with cutaneous T-cell lymphoma.

Alemtuzumab (Campath-1H) in the treatment of chronic lymphocytic leukemia

Alemtuzumab (Campath-1H) is a humanized IgG1 monoclonal antibody that targets the human CD52 antigen. CD52 is expressed by a variety of lymphoid neoplasms and most human mononuclear cell subsets. In 2001, alemtuzumab was approved for marketing in the United States and Europe for use in patients with fludarabine-refractory chronic lymphocytic leukemia (CLL). In heavily pretreated patients with CLL, the overall response rate (ORR) is approximately 35%, and in previously untreated patients the ORR is greater than 80%, with a recent randomized study suggesting it is superior to alkylator-based therapy. Importantly, alemtuzumab is effective in patients with high-risk del(17p13.1) and del(11q22.3) CLL. Alemtuzumab combination studies with fludarabine and/or monoclonal antibodies such as rituximab have demonstrated promising results. Alemtuzumab is also being studied in CLL patients as consolidation therapy for treatment of minimal residual disease, in preparation for stem cell transplantation and to prevent acute and chronic graft versus host disease. Alemtuzumab is frequently associated with acute 'first-dose' reactions when administered intravenously, but is much better tolerated when administered subcutaneously without loss of therapeutic efficacy. Additional potential adverse events associated with alemtuzumab administration include myelosuppression as well as profound cellular immune dysfunction with the associated risk of viral reactivation and other opportunistic infections. Additional studies detailing the mechanism of action of alemtuzumab as well as new strategies for prevention of opportunistic infections will aid in the future therapeutic development of this agent.

Histological verification of positive positron emission tomography findings in the follow-up of patients with mediastinal lymphoma

BACKGROUND AND OBJECTIVES

Follow-ups of patients with mediastinal lymphoma are not accurate if they rely on computed tomography (CT). Positron emission tomography (PET) has been suggested to be useful in several lymphoma settings, such as initial staging, evaluation of residual masses after therapy, and assessment of response early in the course of treatment. The aim of this retrospective study was to verify the reliability of positive PET scans of the mediastinum in following up patients with mediastinal lymphoma, using histological findings as a comparison.

DESIGN AND METHODS

From January 2002 to July 2005, 151 patients with mediastinal lymphoma (57 with Hodgkin's disease [HD] and 94 with aggressive non-Hodgkin's lymphoma [NHL]) were followed-up after the end of front-line treatment. Patients with a positive PET scan of the mediastinum underwent CT scanning and surgical biopsy.

RESULTS

In 30 (21 HD and 9 NHL) out of 151 patients (20%) a suspicion of lymphoma relapse was raised based on positive mediastinal PET scanning. Histology confirmed this suspicion in 17 (10 HD and 7 NHL) out of 30 patients (57%), whereas either benign (9 fibrosis, 3 sarcoid-like granulomatosis) or unrelated neoplastic conditions (1 thymoma) were demonstrated in the remaining 13 patients (43%). SUVmax was significantly higher among patients who had signs of relapse (17 true positive cases) than among those who stayed in remission (13 false positive cases), the median values being 5.95 (range, 3.5-26.9) and 2.90 (range, 1.4-3.3), respectively (p=0.01).

INTERPRETATION AND CONCLUSIONS

We suggest that a positive PET scan of the mediastinum of a patient being followed-up for a mediastinal lymphoma should not be considered sufficient for diagnostic purposes in view of its lack of discrimination. Histological confirmation can safely be carried out with various biopsy techniques, the choice of which should be made on the basis of the findings of the clinical and imaging studies of the individual case.

18F-FDG PET in mucosa-associated lymphoid tissue (MALT) lymphoma

To evaluate the sensitivity of 18-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET) in patients with mucosa-associated lymphoid tissue (MALT) lymphoma. A total of 32 patients with a histological diagnosis of extra-nodal MALT lymphoma were referred to the PET Centers in the last 2 years (2003 - 2004) and scanned with 18F-FDG-PET following standard procedures. Overall, the results of 50 18F-FDG-PET scans performed in either active disease state or in complete remission were reviewed. Sites of primary disease included stomach, lung, parotid, skin, orbit, mandible, esophagus and uterus. This study retrospectively enrolled 26 patients with known active disease. 18F-FDG-PET was true positive (TP) in 21/26 patients and false negative (FN) in 5/26. Sensitivity of 18F FDG-PET for extra-nodal MALT was 81%. The data show that 18FDG-PET is a useful diagnostic tool in order to stage, restage or monitor disease in patients with extra-nodal MALT lymphoma.