Recurrent ECSIT mutation encoding V140A triggers hyperinflammation and promotes hemophagocytic syndrome in extranodal NK/T cell lymphoma

Hemophagocytic syndrome (HPS) is a fatal hyperinflammatory disease with a poorly understood mechanism that occurs most frequently in extranodal natural killer/T cell lymphoma (ENKTL). Through exome sequencing of ENKTL tumor-normal samples, we have identified a hotspot mutation (c.419T>C) in the evolutionarily conserved signaling intermediate in Toll pathway (ECSIT) gene, encoding a V140A variant of ECSIT. ECSIT-V140A activated NF-κB more potently than the wild-type protein owing to its increased affinity for the S100A8 and S100A9 heterodimer, which promotes NADPH oxidase activity. ECSIT-T419C knock-in mice showed higher peritoneal NADPH oxidase activity than mice with wild-type ECSIT in response to LPS. ECSIT-T419C-transfected ENKTL cell lines produced tumor necrosis factor (TNF)-α and interferon (IFN)-γ, which induced macrophage activation and massive cytokine secretion in cell culture and mouse xenografts. In individuals with ENKTL, ECSIT-V140A was associated with activation of NF-κB, higher HPS incidence, and poor prognosis. The immunosuppressive drug thalidomide prevented NF-κB from binding to the promoters of its target genes (including TNF and IFNG), and combination treatment with thalidomide and dexamethasone extended survival of mice engrafted with ECSIT-T419C-transfected ENKTL cells. We added thalidomide to the conventional dexamethasone-containing therapy regimen for two patients with HPS who expressed ECSIT-V140A, and we observed reversal of their HPS and disease-free survival for longer than 3 years. These findings provide mechanistic insights and a potential therapeutic strategy for ENKTL-associated HPS.

Lenalidomide plus dexamethasone is more effective than dexamethasone alone in patients with relapsed or refractory multiple myeloma regardless of prior thalidomide exposure

This analysis assessed the efficacy and safety of lenalidomide + dexamethasone in patients with relapsed or refractory multiple myeloma (MM) previously treated with thalidomide. Of 704 patients, 39% were thalidomide exposed. Thalidomide-exposed patients had more prior lines of therapy and longer duration of myeloma than thalidomide-naive patients. Lenalidomide + dexamethasone led to higher overall response rate (ORR), longer time to progression (TTP), and progression-free survival (PFS) versus placebo + dexamethasone despite prior thalidomide exposure. Among lenalidomide + dexamethasone-treated patients, ORR was higher in thalidomide-naive versus thalidomide-exposed patients (P = .04), with longer median TTP (P = .04) and PFS (P = .02). Likewise for dexamethasone alone-treated patients (P = .03 for ORR, P = .03 for TTP, P = .06 for PFS). Prior thalidomide did not affect survival in lenalidomide + dexamethasone-treated patients (36.1 vs 33.3 months, P > .05). Thalidomide-naive and thalidomide-exposed patients had similar toxicities. Lenalidomide + dexamethasone resulted in higher rates of venous thromboembolism, myelosuppression, and infections versus placebo + dexamethasone, independent of prior thalidomide exposure. Lenalido-mide + dexamethasone was superior to placebo + dexamethasone, independent of prior thalidomide exposure. Although prior thalidomide may have contributed to inferior TTP and PFS compared with thalidomide-naive patients, these parameters remained superior compared with placebo + dexamethasone; similar benefits compared with placebo + dexamethasone were not evident for thalidomide-exposed patients in terms of overall survival. Studies were registered at http://www.clinicaltrials.gov under NCT00056160 and NCT00424047.

New drugs in multiple myeloma

PURPOSE OF REVIEW

Advances in the understanding of multiple myeloma pathogenesis have led to the development of innovative targeted therapies and improved management of this aggressive hematological neoplasia. This review will focus on the clinical trials that have reinforced the use of these new agents. Also, we will briefly take a look at the newer drugs making their way out of the laboratory and into early phase studies.

RECENT FINDINGS

During the past decade new multiple myeloma therapies featuring bortezomib and lenalidomide have come to light, whereas known agents such as thalidomide and arsenic trioxide have been reintroduced as key factors in multiple myeloma management. These new agents and their combinations have shown increased response rates and have added more options for patients with multiple myeloma whose disease has become resistant to conventional therapy. With these drug therapies has come a more targeted approach to treatment enabling not only improved antimyeloma efficacy but also the use of decreased dosing enhancing the safety and tolerability of these regimens. Newer agents including the histone deacetylase, hsp90, mammalian target of rapamycin and Akt inhibitors are showing promise preclinically and are now being assessed in phase I/II trials.

SUMMARY

This new antimultiple myeloma arsenal has shown its worth in both the relapsed/refractory and frontline setting and provides valuable options for patients with this debilitating disease.

Treatment of plasma cell dyscrasias with lenalidomide

Lenalidomide is an immunomodulatory drug, structurally related to thalidomide, with pleiotropic activity including antiangiogenic and antineoplastic properties. It is the product of advances in our understanding of the biology of myeloma cells, their interactions with the microenvironment and of the underlying molecular pathways. In preclinical and clinical studies, lenalidomide was more potent and less toxic than thalidomide. Subsequent phase II and III studies confirmed the activity of lenalidomide either as a single agent or in combination with dexamethasone in relapsed or refractory myeloma patients, whereas combinations with chemotherapy induce high response rates and durable remissions. Lenalidomide has been used successfully as an upfront treatment either with high or low dose dexamethasone or with melphalan and prednisone, resulting in high overall response and complete response rates and excellent 1-year survival. Lenalidomide causes less neuropathy than thalidomide; however, the risk of thromboembolism is high, especially in patients treated with lenalidomide and steroids. In this review, we summarize the mechanisms of action, toxicity and clinical activity, and the current role of lenalidomide in patients with multiple myeloma or other related plasma cell disorders.

[New therapeutic strategies for multiple myeloma. Efficacy and cost-effectiveness analyses]

The objective of the present article is the review of the most important therapeutic innovations in the treatment of multiple myeloma in terms of efficacy and cost-effectiveness. Besides autologous transplant with peripheral-blood stem-cell, thalidomide establishes as one of the most powerful therapeutic tools in induction and maintenance treatment and together with lenalidomide and bortezomib as therapy for relapsing/refractory multiple myeloma. Considering, the last named situation thalidomide can be an adequate therapeutical option in combination with dexamethasone. Under a strictly pharmacoeconomic point of view, lenalidomide and bortezomib seem to be additional alternatives in patients previously treated with thalidomide.

Lenalidomide in myelodysplastic syndrome and multiple myeloma

The use of thalidomide is limited by adverse effects of sedation, constipation, neuropathy and thromboembolism. In order to discover more potent and less toxic immunomodulators than thalidomide, its chemical structure was modified and lenalidomide was formed. Lenalidomide is approved by the US FDA for the treatment of patients with low-risk myelodysplastic syndrome (MDS) with deletion 5q cytogenetic abnormality. Two studies and a case report have evaluated lenalidomide in these MDS patients and showed significantly higher cytogenetic responses and durable red blood cell transfusion independence. Lenalidomide should be the drug of choice for patients with low and intermediate-1 risk MDS (based on the International Prognostic Scoring System) with chromosome 5q31 deletion with or without other karyotype abnormalities. Lenalidomide, in combination with dexamethasone, has been compared with dexamethasone alone in patients with relapsed or refractory multiple myeloma (MM) in two studies (MM-009 in North America and MM-010 in Europe, Israel and Australia). In these two phase III trials, lenalidomide demonstrated impressive (58-59%) response rates with dexamethasone. Lenalidomide has also been shown to overcome thalidomide resistance in MM patients. Therefore, the lenalidomide plus dexamethasone regimen provides another treatment option, in addition to first line MM treatment regimens of bortezomib, thalidomide or high-dose dexamethasone, for the treatment of relapsed or refractory MM. Lenalidomide does not produce significant sedation, constipation or neuropathy, but does lead to significant myelosuppression, unlike thalidomide. The prescribing information has a black box warning for risk of myelosuppression, deep vein thrombosis/pulmonary embolism and teratogenicity. Administration of lenalidomide is recommended at a starting dose of 10 mg/day orally for deletion 5q in MDS patients. Significant risk of myelosuppression may lead to dose reduction in the majority of these patients. Clinical trials of relapsed and refractory MM have shown that lenalidomide is clinically efficacious at a dosage of 25 mg/day when administered in combination with dexamethasone. Lenalidomide should be continued until disease progression in both MDS and MM patients.

New drugs for myeloma

Although multiple myeloma remains incurable with conventional treatments, management of the disease has recently been transformed with the introduction of three novel agents, bortezomib, thalidomide, and lenalidomide. The proteasome inhibitor bortezomib is approved for the treatment of patients who have received one prior therapy; there is a growing body of clinical evidence showing its effectiveness alone and in combination in the frontline setting, with high response rates and consistently high rates of complete response. Thalidomide plus dexamethasone is approved as frontline treatment of multiple myeloma. Other combination regimens including thalidomide have demonstrated substantial activity in both relapsed and frontline settings. Recently, the thalidomide analogue lenalidomide has been approved, in combination with dexamethasone, for the treatment of patients who have received one prior therapy; this regimen has shown promising results in the frontline setting. These agents represent a new generation of treatments for multiple myeloma that affect both specific intracellular signaling pathways and the tumor microenvironment. Other novel, targeted therapies are also being evaluated in preclinical and clinical studies. Regimens incorporating bortezomib, thalidomide, lenalidomide, and other novel agents, together with commonly used conventional drugs, represent a promising future direction in myeloma treatment. At present, further investigation is required to assess the safety and activity of combinations integrating these other novel agents. However, bortezomib, thalidomide, and lenalidomide are now in widespread clinical use. This review therefore focuses on the extensive clinical data available from studies of these drugs in the treatment of newly diagnosed and advanced multiple myeloma.