Abraham M. Varghese

Rituximab Plus Chlorambucil As First-Line Treatment for Chronic Lymphocytic Leukemia: Final Analysis of an Open-Label Phase II Study

PURPOSE Most patients with chronic lymphocytic leukemia (CLL) are elderly and/or have comorbidities that may make them ineligible for fludarabine-based treatment. For this population, chlorambucil monotherapy is an appropriate therapeutic option; however, response rates with chlorambucil are low, and more effective treatments are needed. This trial was designed to assess how the addition of rituximab to chlorambucil (R-chlorambucil) would affect safety and efficacy in patients with CLL. PATIENTS AND METHODS Patients with first-line CLL were treated with rituximab (375 mg/m(2) on day 1, cycle one, and 500 mg/m(2) thereafter) plus chlorambucil (10 mg/m(2)/d all cycles; day 1 through 7) for six 28-day cycles. For patients not achieving complete response (CR), six additional cycles of chlorambucil alone could be administered. The primary end point of the study was safety. RESULTS A total of 100 patients were treated with R-chlorambucil, with a median follow-up of 30 months. Median age of patients was 70 years (range, 43 to 86 years), with patients having a median of seven comorbidities. Hematologic toxicities accounted for most grade 3/4 adverse events reported, with neutropenia and lymphopenia both occurring in 41% of patients and leukopenia in 23%. Overall response rates were 84%, with CR achieved in 10% of patients. Median progression-free survival was 23.5 months; median overall survival was not reached. CONCLUSION These results compare favorably with previously published results for chlorambucil monotherapy, suggesting that the addition of rituximab to chlorambucil may improve efficacy with no unexpected adverse events. R-chlorambucil may improve outcome for patients who are ineligible for fludarabine-based treatments.

A randomized phase II trial of fludarabine, cyclophosphamide and mitoxantrone (FCM) with or without rituximab in previously treated chronic lymphocytic leukaemia.

Combination fludarabine (F), cyclophosphamide (C) and rituximab (R) is the standard front‐line therapy in chronic lymphocytic leukaemia (CLL), but appropriate treatment of relapsed/refractory CLL is less clear. Combined FC and mitoxantrone (M) has been reported to be effective in a single arm study, and rituximab when added to chemotherapy in CLL is synergistic. A randomized, two‐stage, Phase II trial of FCM and FCM‐R was conducted in relapsed CLL. The primary endpoint was response rate 2 months after therapy, assessed according to the 2008 International Workshop CLL criteria. In addition, minimal residual disease (MRD) in the marrow was studied 2 months after therapy, with MRD negativity defined as <0·01% CLL cells. Fifty‐two patients were entered, 26 in each arm. The overall response rates to FCM and FCM‐R were 58% and 65% respectively. Combined complete response (CR) and CR with incomplete marrow recovery [CR(i)] was 15% (95% confidence interval [CI]:4–35%) for FCM and 42% (95%CI:23–63%) for FCM‐R, with eight patients achieving MRD negativity (3 FCM; 5 FCM‐R). The toxicity of both regimens was acceptable. In conclusion, the addition of rituximab to FCM improves the response rates in relapsed CLL, resulting in more complete remissions and without additional safety concerns. Efficacy and safety should be fully tested in a randomized Phase III trial.

Assessment of Bone Marrow Response in Waldenström's Macroglobulinemia

In this study we used bone marrow flow cytometry and immunohistochemistry to evaluate response to fludarabine therapy in patients with Waldenströms macroglobulinemia (WM)/lymphoplasmacytic lymphoma. Responses in serum M protein were typically delayed with a median time to maximum response of 6 months following the completion of therapy (range, 0-18 months). In contrast, bone marrow responses occurred promptly in responding patients such that there were no detectable clonal B cells at the end of therapy in 55% of patients assessed. Persistent monoclonal plasma cells were, however, readily identified by CD138 immunohistochemistry, explaining the persistence of serum M protein in these patients. This simple observation has significant implications for the assessment of responses in WM as well as the design of future therapeutic strategies.

Eradicating Minimal Residual Disease in Chronic Lymphocytic Leukemia: Should This Be the Goal of Treatment?

Even though chronic lymphocytic leukemia (CLL) is the most prevalent leukemia of the Western world, the development of treatment approaches for CLL has lagged behind the development of approaches to various other hematologic malignancies for a variety of reasons. In recent years, the treatment approach to patients with CLL has evolved rapidly, with the addition of several new prognostic markers, highly effective immunochemotherapy combinations, and attainment of remission up to the point of the eradication of minimal residual disease (MRD). Highly sensitive methods now available to detect MRD can detect a single CLL cell in 104 leukocytes using either allele-specific oligonucleotide polymerase chain reaction or four-color or six-color flow cytometry. Over the past decade, several studies have examined the possible advantage of MRD eradication in CLL. This article reviews our current understanding of MRD eradication and analyzes whether it is a desirable goal in the routine clinical treatment of CLL, which will optimize the management of individual patients.

Heterogeneity of Histological Transformation Events in Waldenström's Macroglobulinemia (WM) and Related Disorders

Histological transformation, typically to diffuse large B-cell lymphoma (DLBCL) is reported to occur in 5%-10% of patients with WM and recent studies have highlighted a possible aetiological role for the nucleoside analogues. It is however becoming increasingly clear that histological transformation is a complex phenomenon and may include clonally unrelated disorders. In order to highlight this pathological heterogeneity we describe 5 patients with diverse histological progression events. These included EBV-associated events namely DLBCL, peripheral T-cell lymphoma and spontaneously resolving mucocutaneous ulcer. A further 2 patients demonstrated a localised plasma cell rich lesion simulating plasmacytoma and a de novo DLBCL arising in an unrelated B-cell clone. It is clear therefore that detailed pathological assessments are required in all suspected cases of transformation and that the pathological heterogeneity demonstrated by this study needs to be taken into account when potential aetiological factors are being assessed.

Oncolytic reovirus enhances rituximab-mediated antibody-dependent cellular cytotoxicity against chronic lymphocytic leukaemia

The naturally occurring oncolytic virus (OV), reovirus, replicates in cancer cells causing direct cytotoxicity, and can activate innate and adaptive immune responses to facilitate tumour clearance. Reovirus is safe, well tolerated and currently in clinical testing for the treatment of multiple myeloma, in combination with dexamethasone/carfilzomib. Activation of natural killer (NK) cells has been observed after systemic delivery of reovirus to cancer patients; however, the ability of OV to potentiate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) is unexplored. This study elucidates the potential of oncolytic reovirus for the treatment of chronic lymphocytic leukaemia (CLL), both as a direct cytotoxic agent and as an immunomodulator. We demonstrate that reovirus: (i) is directly cytotoxic against CLL, which requires replication-competent virus; (ii) phenotypically and functionally activates patient NK cells via a monocyte-derived interferon-α (IFNα)-dependent mechanism; and (iii) enhances ADCC-mediated killing of CLL in combination with anti-CD20 antibodies. Our data provide strong preclinical evidence to support the use of reovirus in combination with anti-CD20 immunotherapy for the treatment of CLL.

Development of EBV-associated diffuse large B-cell lymphoma in Waldenström macroglobulinemia and mantle cell lymphoma

Large cell transformation is a well-recognised late event in follicular lymphoma, mantle cell lymphoma (MCL), Waldenström macroglobulinemia (WM) and chronic lymphocytic leukemia (CLL). This is traditionally considered to be due to transformation of the underlying clone as a consequence of the acquisition of new genetic events. However, there is increasing evidence in CLL at least, that apparent histological ‘‘transformation’’ can occur as a consequence of the development of a de-novo diffuse large B-cell lymphoma (DLBCL) in a clonally unrelated population which is frequently associated with Epstein-Barr virus (EBV) [1,2]. Here we report the development of EBV-associated DLBCL in 2 patients with WM and MCL. An 80-year-old male patient was found to have mild anemia and an IgMk paraprotein during preoperative screening in 2003. His bone marrow was diffusely infiltrated by small lymphocytes and plasma cells and was associated with a reactive increase in mast cells. B-cells, identified on the basis of scatter characteristics and CD19 expression were monotypic (IgMkþ) and had the following immunophenotype: CD20þ CD38þ/7 CD57 CD107 CD22þ FMC7þ CD237 CD11aþ/7 CD79bþ. A diagnosis of WM was made [3]. He was not treated initially but subsequently received chlorambucil in 2004 and fludarabine in 2005 achieving partial responses in both instances. He then presented in August 2006 with abdominal distension and was found to have a heterogeneous mass in the mesentery close to small bowel loops without any other lymph node enlargement. He had a laparoscopic biopsy of the mesenteric mass, which showed histological features typical of DLBCL. This had the following immunophenotype: CD57CD107BCL2þCD20þCD79þBCL6þ/7 CD237 MUM-17 FOX-P17. EBV-associated latent membrane protein-1 (LMP-1) expression was demonstrable in a significant proportion of tumor cells. He was commenced on CVP-R but unfortunately suffered significant complications and finally succumbed to MRSA septicemia. A 62-year-old male patient originally presented in 1998 with peripheral blood lymphocytosis, lymphadenopathy and bone marrow infiltration and a diagnosis of MCL was made on the basis of a CD5þ CD107 CD20þ CD237 CD79þ BCL2þ immunophenotype and nuclear expression of cyclin D1 protein. He was initially treated with chlorambucil and achieved a good partial response. He relapsed in 2000 and was treated with CHOP, and again in 2003 when he was treated with FCR. He presented with a small bowel mass in May 2004, which showed the typical morphological features of DLBCL with a CD57 CD20þ CD79þ CD10þ BCL67 BCL2þ CD30þ immunophenotype. Cyclin D1 immunostaining was negative while LMP1 staining was clearly demonstrable in a significant proportion of tumor cells. Interphase FISH studies failed to demonstrate the t(11;14) although retrospective analysis confirmed its presence in the biopsy material from 1998. Unfortunately the patient succumbed to the

Results of the randomized phase IIB ARCTIC trial of low-dose rituximab in previously untreated CLL

ARCTIC was a multicenter, randomized-controlled, open, phase IIB non-inferiority trial in previously untreated chronic lymphocytic leukemia (CLL). Conventional frontline therapy in fit patients is fludarabine, cyclophosphamide and rituximab (FCR). The trial hypothesized that including mitoxantrone with low-dose rituximab (FCM-miniR) would be non-inferior to FCR. A total of 200 patients were recruited to assess the primary end point of complete remission (CR) rates according to IWCLL criteria. Secondary end points were progression-free survival (PFS), overall survival (OS), overall response rate, minimal residual disease (MRD) negativity, safety and cost-effectiveness. The trial closed following a pre-planned interim analysis. At final analysis, CR rates were 76 FCR vs 55% FCM-miniR (adjusted odds ratio: 0.37; 95% confidence interval: 0.19–0.73). MRD-negativity rates were 54 FCR vs 44% FCM-miniR. More participants experienced serious adverse reactions with FCM-miniR (49%) compared to FCR (41%). There are no significant differences between the treatment groups for PFS and OS. FCM-miniR is not expected to be cost-effective over a lifetime horizon. In summary, FCM-miniR is less well tolerated than FCR with an inferior response and MRD-negativity rate and increased toxicity, and will not be taken forward into a confirmatory trial. The trial demonstrated that oral FCR yields high response rates compared to historical series with intravenous chemotherapy.

Eradication of minimal residual disease improves overall and progression-free survival in patients with chronic lymphocytic leukaemia, evidence from NCRN CLL207: a phase II trial assessing alemtuzumab consolidation.

With immunochemotherapy, remission duration and survival in patients with chronic lymphocytic leukaemia is dependent on the level of minimal residual disease (MRD) after treatment. This phase II trial assessed alemtuzumab consolidation post‐chemotherapy in patients who responded with persistent low levels of detectable disease. Blood was screened for MRD using multi‐parameter flow cytometry, 6–24 months post‐chemotherapy. MRD‐positive participants received alemtuzumab 30 mg subcutaneously 3 times weekly for 6 weeks. Following a marrow assessment, MRD‐negative participants or non‐responders stopped therapy and MRD‐positive participants with 1 + log reduction had 6 more weeks of alemtuzumab. Alemtuzumab consolidation was received by 47 participants. One death and 19 of 22 serious adverse events reported from 17 (36%) participants were alemtuzumab‐related. MRD eradication from blood and bone marrow was achieved in 39 (83%) participants at the end of consolidation, with 18 (38%) remaining MRD‐negative in the blood 6 months later. Of the 18 participants who were MRD‐negative at 6 months, the median time to MRD relapse was 46 months, which was similar to patients who were MRD‐negative at baseline and were followed up. The 5‐year progression‐free survival (PFS) and overall survival (OS) of participants who were MRD‐negative at 6 months was significantly better than MRD‐positive participants [PFS: 78% vs. 39% (P = 0·010), OS: 89% vs. 64% (P = 0·029)].

Ofatumumab in advanced stage chronic lymphocytic leukaemia: results of the UK named patient compassionate use programme.

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