Novel agents in indolent lymphomas

Phase 1 Study Evaluating Pharmacokinetics and Tolerability of Ofatumumab Combined With Bendamustine in Patients With Indolent B-Cell Non-Hodgkin's Lymphoma

The pharmacokinetics (PK) and safety of ofatumumab and bendamustine alone and in combination were evaluated in patients with treatment-naive or relapsed indolent B-cell non-Hodgkin lymphoma (iNHL). Patients were randomly assigned to ofatumumab and bendamustine or ofatumumab alone. Ofatumumab PK concentration profiles and parameters were similar, alone or in combination with bendamustine. A decrease of 14% in the maximum observed plasma concentration (C_max ) and 15% in the area under the plasma concentration-time curve (AUC) from time 0 to the last measurable concentration sampling time (AUC_last ) was observed for ofatumumab coadministered with bendamustine, which was not considered clinically relevant. Bendamustine PK concentration profiles and parameters were similar with or without ofatumumab. The most frequent treatment-related adverse event was infusion-related reaction in 53% in the combination arm and 47% in the ofatumumab arm. No relevant drug-drug interaction was observed between ofatumumab and bendamustine. Ofatumumab alone or in combination with bendamustine had a manageable safety profile.

Efficacy and safety of ofatumumab and bendamustine followed by ofatumumab maintenance in patients with relapsed indolent non-Hodgkin lymphoma after prior rituximab

In indolent non-Hodgkin's lymphoma (iNHL), patients treated with rituximab, alone or in combination with various chemotherapeutic agents eventually relapse. This study evaluated the combination of ofatumumab and bendamustine, followed by maintenance ofatumumab in patients with relapsed iNHL with prior sensitivity to rituximab. Among the 49 patients enrolled, 24.5% achieved a complete response (CR) and 42.9% achieved a partial response (PR), with an overall response rate of 67.3% at the end of the induction therapy. Additionally, six patients with PR during induction phase achieved CR during the maintenance phase. Treatment-related adverse event was observed in 95.9% patients. The most common hematologic and biochemical abnormalities were decrease in lymphocytes (85.7%) and increase in glucose (91.8%), respectively. Overall, 42.9% progressed and 14.3% died during the study. Thus, ofatumumab in combination with bendamustine, followed by ofatumumab maintenance, was effective in the treatment of patients with iNHL with a manageable safety profile (NCT01294579).

Assessment of bendamustine-induced genotoxicity in eukaryotic cells

Bendamustine, an anticancer drug with alkylating properties, is widely used to treat hematological malignancies. Since the nitrogen mustard family alkylators induce DNA damages and have been associated with an elevated risk of second malignancy, current study evaluates the cytotoxic, mutagenic, and recombinogenic effects of bendamustine by using, respectively the mitotic index assay, the in vitro mammalian cell micronucleus test (Mnvit) and the chromosome aberration (CA) test in human peripheral lymphocytes, and the in vivo homozygotization assay in Aspergillus nidulans, which detects the loss of heterozygosity (LOH) due to somatic recombination. Bendamustine (6.0 µg/ml, 9.0 µg/ml, and 12.0 µg/ml) induced a statistically significant concentration-related increase in the frequencies of micronuclei and a significant reduction in the cytokinesis block proliferation index (CBPI) rates when compared to negative control. In the CA test, bendamustine significantly increased the frequencies of structural aberrations at the three tested concentrations when compared to the negative control. Aspergillus nidulans diploids, obtained after bendamustine treatment (6.0 µg/ml, 12.0 µg/ml, and 24.0 µg/ml), produced, after haploidization, homozygotization index (HI) rates higher than 2.0 and significantly different from the negative control. Since bendamustine showed genotoxic effects in all tested concentrations, two of them corresponding to the peak plasma concentrations observed in cancer patients treated with bendamustine, data provided in the current research work may be useful to identify the most appropriate dosage regimen to achieve the efficacy and safety of this anticancer medication.

Superior efficacy of rituximab-based chemoimmunotherapy as an initial therapy in newly diagnosed patients with B cell indolent lymphomas: long-term results from a single center in China

Background

Rituximab has been confirmed to improve the survival of patients with B cell indolent non-Hodgkin lymphomas (B-iNHLs) in Western world as previously reported, however, it is rarely reported in Chinese cohort. This study is to investigate the efficacy and safety of rituximab-based chemoimmunotherapy and select subpopulations most sensitive to the regimen in Chinese B-iNHL patients.

Methods

334 B-iNHL patients from our center were retrospectively assessed.

Results

Patients received R-based chemoimmunotherapy showed significantly higher rates of overall response (OR) (93.0 % vs. 53.4 %, P < 0.001) and complete response (CR) (63.3 % vs. 16.0 %, P < 0.001) compared with the patients received other therapies. Survival analysis showed that rituximab-based chemoimmunotherapy could obviously improve the progression-free survival (PFS) (110 vs. 49 months, P = 0.001) and overall survival (OS) (120 vs. 72 months, P < 0.001) in patients with B-iNHLs. Interestingly, in chronic lymphocytic leukemia (CLL) patients, we found that the patients with β2-microglobulin (β2-MG) < 3.5 mg/L, lactate dehydrogenase (LDH) < 220 U/L, zeta-chain-associated protein kinase 70 (ZAP-70) negative, and non high-risk genetic abnormality could achieve more benefits from R-based regimens with higher CR rate (P = 0.003, 0.029, 0.013 and 0.038, respectively). Meanwhile, more CLL patients achieved minimal residual disease (MRD) negative after rituximab-based treatment (46.5 % vs. 10.3 %, P < 0.001). Moreover, CLL patients with MRD < 1 %, LDH < 220 U/L, complete remission (CR) or partial remission (PR), β2-MG < 3.5 mg/L and non high-risk cytogenetic abnormality showed superior outcome compared to the controls (P = 0.001, 0.000, 0.000, 0.001 and 0.013, respectively). No other side-effects increased in chemoimmunotherapy group except the elevation of grade 3–4 neutropenia.

Conclusions

Our results demonstrate the superior efficacy of rituximab–based chemoimmunotherapy as an initial therapy in Chinese cohort with newly diagnosed B-iNHLs and further identify subpopulations that are more sensitive to R-based chemoimmunotherapy in CLL group.

New targeted therapies for indolent B-cell malignancies in older patients

Molecularly targeted agents have become an established component of the treatment of indolent B-cell malignancies (iNHL). iNHL disproportionately affects older adults, so treatments that have excellent tolerability and efficacy across multiple lines of therapy are in demand. The numbers and classes of targeted therapies for iNHL have proliferated rapidly in recent years; classes of agents that show promise for older patients with iNHL include anti-CD20 antibodies, phosphatidyl-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway inhibitors, immunomodulators, proteasome inhibitors, epigenetic modulators, and immunotherapies. Here, we review the proposed mechanisms of action, efficacy, and tolerability of novel agents for iNHL, with an emphasis on their applicability to older patients.

Kinetics of hematogones in bone marrow samples from patients with non-Hodgkin lymphomas treated with rituximab-containing regimens: a flow cytometric study

Treatment with rituximab, either alone or in combination with antiblastic drugs, causes significant depletion of circulating B-lymphocytes and modifications of B cell maturation in the bone marrow. In the present study, we analyzed the kinetics of hematogones in bone marrow samples from 55 patients suffering from non-Hodgkin lymphomas and treated with rituximab-containing regimens. Maturation arrest at the level of stage 2 hematogones, along with complete depletion of naïve, mature B-lymphocytes, was observed as short-term effects (2 months after completion of chemo-immunotherapy). Further bone marrow samples, obtained 12 months after the last rituximab infusion in 21 patients undergoing long-term follow-up and treated with rituximab maintenance therapy, showed complete normalization of B-lymphocyte ontogeny. Hypogammaglobulinemia developed in 26 patients, and was still observed in nine of the 21 patients undergoing long-term follow-up. Our study provides novel data on hematogone kinetics in the setting of patients with non-Hodgkin lymphomas treated with chemo-immunotherapy containing rituximab and with rituximab maintenance. Our observations show that hypogammaglobulinemia can persist in a significant percentage of patients, despite complete recovery of B-lymphocyte ontogeny.

Blinatumomab for the treatment of B-cell lymphoma

INTRODUCTION

Blinatumomab is a bispecific T-cell engager (BiTE) molecule that recruits cytotoxic T cells to target tumor B cells by linking the CD3 and CD19 antigens. Among the various formats of bispecific antibodies developed in the past 50 years, the BiTE class is remarkable for its low effector-to-target ratio, high tissue penetration and singular ability to activate T cells independent of MHC class I presentation or costimulation. Blinatumomab has been studied in patients with relapsed or refractory non-Hodgkin's lymphoma (NHL) and B-precursor acute lymphoblastic leukemia (B-ALL).

AREAS COVERED

This article reviews the current literature on blinatumomab including its pharmacology, preclinical findings, clinical trials in B-cell NHL and, to a lesser extent, Phase II studies in B-ALL. The authors discuss the potential future directions in light of other new competing therapies for NHL and unmet clinical needs in the market.

EXPERT OPINION

The recent approval of blinatumomab for B-ALL symbolizes a breakthrough for BiTE technology with prospective application in the targeted therapy of other cancers. Although blinatumomab seems an unlikely option for treating indolent lymphoma due to toxicity, the need for long-term continuous infusion therapy and multiple promising well-tolerated oral agents, it holds promise for aggressive NHL patients whose diseases are refractory to current standard approaches. Larger trials are needed to demonstrate blinatumomab's curative potential in aggressive histologies.

Target Therapy in Hematological Malignances: New Monoclonal Antibodies

Apart from radio- and chemotherapy, monoclonal antibodies (MoAbs) represent a new, more selective tool in the treatment of hematological malignancies. MoAbs bind with the specific antigens of the tumors. This interaction is a basis for targeted therapies which exhibit few side effects and significant antitumor activity. This review provides an overview of the functional characteristics of MoAbs, with some examples of their clinical application. The promising results in the treatment of hematological malignancies have led to the more frequent usage of MoAbs in the therapy. Development of MoAbs is a subject of extensive research. They are a promising method of cancer treatment in the future.

Clinical factors associated with response or survival after chemotherapy in patients with Waldenström macroglobulinemia in Korea

Waldenström's macroglobulinemia (WM) is a B-cell proliferative malignancy characterized by immunoglobulin M monoclonal gammopathy and bone marrow infiltration by lymphoplasmacytic cells. Clinical features and cytogenetics of WM in Asia including Republic of Korea remain unclear. Moreover, no study has reported treatment outcomes in patients with WM treated with novel agent combined with conventional chemotherapy. This study investigated clinical features and assessed treatment outcomes with novel agent and conventional chemotherapy in Republic of Korea. Data from all (n = 71) patients with newly diagnosed WM at 17 hospitals who received chemotherapy between January 2005 and December 2012 were collected retrospectively. The median age of patients was 66 years (range: 37–92 years) and male to female ratio was 5 : 1. Patients treated with novel agent combined chemotherapy displayed higher overall response rate (ORR) compared to conventional chemotherapy alone (92.9% versus 52.6%, P = 0.006). The 5-year overall survival rate was 62.6% (95% confidence interval: 34.73–111.07). Use of novel agents produced higher ORR but survival benefit was not apparent due to the small number of patients and short follow-up duration. Further studies are needed to confirm the efficacy of novel agents in patients with WM.