The emerging role of lenalidomide in the management of lymphoid malignancies

Lenalidomide, a novel immunomodulatory drug (IMiD), is a promising therapeutic strategy for patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and B-cell lymphomas. Biologically, the mechanisms responsible for lenalidomide activity are yet to be clearly defined. Based on preclinical models and early correlative studies conducted in parallel to clinical trials, lenalidomide has been found to enhance natural killer (NK)- and T-cell activity against tumor cells, alter the balance of pro- and anti-inflammatory cytokines in the tumor bed, inhibit angiogenesis, and, to a lesser degree, induce cell cycle arrest and apoptosis in cancer cells. Together, all of these biological effects appear to play a role in the activity observed in CLL or lymphoma patients treated with lenalidomide. Given the effect in NK- and T-cell function, lenalidomide is an alternative strategy to enhance the antitumor activity of monoclonal antibodies (mAbs). Clinical responses have been observed in patients with relapsed/refractory CLL, follicular lymphoma, small lymphocytic lymphoma, mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL) treated with lenalidomide single agent. The favorable toxicity profile and route of administration made the use of lenalidomide an attractive therapy for certain types of patients (i.e. elderly, chemotherapy unfit, etc.). The erratic but serious incidence of tumor lysis syndrome and/or tumor flare reactions provides challenges in the incorporation of lenalidomide in the management of previously untreated CLL or CLL/lymphoma patients with bulky adenopathy. Correlative studies and/or retrospective analysis of lenalidomide-treated patients had identified several biomarkers associated with clinical endpoints in CLL (i.e. changes in tumor necrosis factor alpha [TNF-α] or vascular endothelial growth factor [VEGF] levels) or DLBCL (non-GCB phenotype) patients, but need to be validated. Early studies evaluating the efficacy and toxicity of lenalidomide in combination with rituximab in previously untreated indolent lymphoma are promising and warrant further study. In addition, the evaluation of lenalidomide in the maintenance setting or in combination with other target-specific agents (i.e. proteasome inhibitors) in aggressive lymphomas is being addressed in ongoing clinical trials. In summary, lenalidomide is emerging as a biologically active and novel agent in the treatment of B-cell neoplasms. Future translational and clinical studies will further define the role of lenalidomide in the management of de novo or relapsed/refractory CLL or B-cell lymphomas and identify the subset of patients most likely to gain clinical benefit.

Treatment of diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma in all countries and all age groups. DLBCL is potentially curable, and the outcome of patients with DLBCL has completely changed with the introduction of therapy involving the monoclonal antibody rituximab in combination with chemotherapy. Nonetheless, relapse is detected after treatment with rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone in approximately 30% of patients. It has recently become clear that DLBCL represents a heterogeneous admixture of quite different entities. Gene expression profiling has uncovered DLBCL subtypes that have distinct clinical behaviors and prognoses; however, incorporation of this information into treatment algorithms awaits further investigation. Future approaches to DLBCL treatment will use this new genetic information to identify potential biomarkers for prognosis and targets for treatment.

Novel agents for diffuse large B-cell lymphoma

INTRODUCTION

Although diffuse large B-cell lymphoma (DLBCL) is commonly considered as a cancer with a high cure rate with conventional therapies recent studies demonstrate that different biological variants of DBLCL exist, and that patients with one DLBCL variant and DLBCL patients who relapse early following rituximab-based therapy have markedly poorer outcomes with conventional management strategies. Over the last decade, there has been an increasing exploration of novel therapies derived from improved understanding of DLBCL biology and tumor-host interactions.

AREAS COVERED

This review examines the biological basis for novel therapeutic approaches in DLBCL and the early clinical data on compounds derived from this research. A description of the expanding options of novel agents and combination therapies for patients with poor risk DLBCL is provided.

EXPERT OPINION

Several promising novel agents and novel therapeutic combinations are under development for patients with poor risk DLBCL. Carefully designed clinical trials that build on our improved understanding of DLBCL biology and utilize tissue samples to examine the activity of novel combination therapies should expand treatment options for DLBCL patients in the future.