Lucio Morabito

Epigenetic regulation in myelodysplastic syndromes: implications for therapy

Introduction: Myelodysplastic syndromes (MDS), characterized by ineffective hematopoiesis and dysplasia in one or more lineages, produce life-threatening cytopenias and progress to acute myeloid leukemia (AML). Growing evidence suggests that targeting epigenetic mechanisms improves MDS/AML pathophysiology. Areas covered: This review provides an understanding of studies investigating novel agents published up to January 2011 aimed at normalizing and monitoring the epigenetic profile of the MDS cancer cell. The authors discuss how non-intensive epigenetic therapy can ‘re-programme’ gene expression patterns of abnormal hematopoiesis in MDS. Recently FDA-approved DNA-methyltransferase inhibitors, 5-azacytidine and 5-aza-2′-deoxycytidine or decitabine, represent frontline nonablative treatments, while combinations with histone deacetylase inhibitors show promising synergism in preclinical and Phase I/II trials in tumor suppressor gene re-expression and overall survival. Additional epigenetic mechanisms including non-encoding transcripts with inhibitory posttranscriptional regulatory functions, such as microRNAs, though not fully understood, present novel molecular and clinical implications in these disorders. Expert opinion: Alongside current single-agent epigenetic regimens, combination therapies represent potentially effective options for intermediate-2 and high-risk MDS. Methylation profiles and gene mutation predictors provide promising areas of development for monitoring MDS disease progression and outcome, while targeting microRNA dysregulation represents an important therapeutic goal.

Janus kinase 2 inhibitors in myeloproliferative disorders.

Importance of the field: JAK2 is an obligatory kinase for the proliferation and differentiation of erythroid cells and megakaryocytes thus representing a relevant therapeutic target for agents that specifically inhibit its activity particularly in myeloproliferative disorders (MPD) harboring JAK2V617F mutations. Areas covered in this review: We discuss the physiopathology of the JAK2 signaling pathway and review clinical trials of JAK2 inhibitors for the treatment of MPD using papers and meeting abstracts published up to September 2010. What the reader will gain: This review helps in understanding the potential role of JAK2 inhibitors in MPD clinical trials and provides a comprehensive review regarding their efficacy and safety in these disorders. Take home message: JAK2 inhibitors may prove to be useful only for suppressing disease manifestations. However, unlike drugs such as IFN which are capable of eliminating the malignant clone, JAK2 inhibitors are unable to eradicate the disease. In fact, results to date indicate that although these inhibitors reduce splenomegaly and alleviate constitutional symptoms irrespective of JAK2 mutational status, most have only a modest impact on the JAK2V617F allele burden. Considering the relevant risk of serious complications in patients undergoing splenectomy, these drugs could find a suitable indication in patients with myelofibrosis awaiting bone marrow transplantation.

Ixazomib for the treatment of multiple myeloma

Introduction: Proteasome inhibition is a mainstay in the treatment of multiple myeloma (MM). Bortezomib, the first proteasome inhibitor (PI) approved for MM therapy, has shown efficacy in relapsed/refractory patients and in the front-line setting. Among second-generation PIs, MLN9708 (ixazomib) is the first oral compound to be evaluated in MM treatment and has shown improvement in pharmacokinetic and pharmacodynamic parameters compared with bortezomib with a similar efficacy in the control of myeloma growth and in the prevention of bone loss. Areas covered: In this review, the authors discuss the rationale for use of PIs. They then summarize the clinical development of ixazomib in MM, from initial Phase I to Phase II studies as a monotherapy and in combination with other chemotherapeutics. Expert opinion: Preliminary data of Phase I/II trials showed that ixazomib had a good safety profile and exerted anti-myeloma activity as a single agent in relapsed/refractory patients. Furthermore, ixazomib also had efficacy in patients who were refractory to bortezomib. Its use in combination with lenalidomide and dexamethasone was shown to be an effective and well-tolerated regimen in up-front treatment leading to minimal residual disease negativity in a significant number of patients. Results of Phase III trials, evaluating ixazomib in induction or maintenance therapy, are awaited.

Italian external and multicentric validation of the MD Anderson Cancer Center nomogram and prognostic index for chronic lymphocytic leukaemia patients: Analysis of 1502 cases

We performed an external and multicentric validation of the nomogram and prognostic index (PI) proposed by the MD Anderson Cancer Center to prognostically stratify chronic lymphocytic leukaemia (CLL) patients in 1502 CLL cases. All six parameters involved in the nomogram and PI (age, sex, absolute lymphocyte count, number of lymph node groups, Rai stage and β2‐microglobulin) were independently associated with survival. The nomogram was accurate in predicting survival (c‐index = 0·82). According to the PI, 38·7% of patients were at low‐risk, 58·3% at intermediate‐risk and 3% at high‐risk. The estimated median survival times were: not reached for low‐risk, 13·4 years for intermediate‐risk and 3·4 years for high‐risk. The estimated median and 5‐year survival by PI were similar to those originally reported. The PI remained a predictor of survival when analysis was limited to 847 Rai stage 0 (P < 0·0001) and 151 clinical monoclonal B‐cell lymphocytosis (cMBL) cases (P = 0·033). Finally, the PI allowed prediction of time to therapy in all patients (P < 0·0001), in Rai 0 (P < 0·0001) and in cMBL cases (P = 0·044). Our results confirm the ability of the PI to predict prognosis, even in early stage disease cases. The study also extended the utility of the PI to cMBL cases.

An old drug with a new future: bendamustine in multiple myeloma

Introduction: Bendamustine is a unique bifunctional alkylating agent with promising activity in multiple myeloma (MM). It is currently licensed in Europe for use as frontline treatment with prednisolone for patients with MM who are unsuitable for transplantation and who are contraindicated for thalidomide and bortezomib therapy. Areas covered: Studies evaluating the safety and efficacy of bendamustine administered alone or in combination in both the upfront and relapse settings of MM patients, including those with renal insufficiency, were reviewed. The use of bendamustine as conditioning for autologous stem-cell transplantation and the possibility of stem-cell mobilization after bendamustine therapy are discussed. Expert opinion: Bendamustine seems to be efficacious either in monotherapy or in combination with other drugs in previously treated or untreated patients. This is due to its unique mechanism of action including its ability to activate apoptosis and inhibit mitotic checkpoints, making it potentially more effective than other alkylating agents. Moreover, it has an acceptable toxicity profile and is suitable for patients with renal impairment. Finally, this drug does not seem to compromise the possibility of achieving a stem-cell mobilization. Nonetheless, data from Phase III studies demonstrating its effectiveness in terms of overall survival are not yet available.

Lenalidomide in the treatment of chronic lymphocytic leukemia

Introduction: Insights into the role of the tumor microenvironment and of immune dysfunction in chronic lymphocytic leukemia (CLL) have opened the way for further augmenting the therapeutic armamentarium for CLL patients. In this respect, lenalidomide represents an exciting drug since it is able to eliminate CLL cells without immunosuppression. Areas covered: Mechanism of action and clinical trials of lenalidomide in CLL, and suggestions for its future utilization are reviewed. The most relevant papers and the meeting abstracts published up to July 2010 were used as sources for this review. This review will help readers understand the mechanism of action of lenalidomide and will provide a comprehensive summary regarding efficacy and safety of this drug in CLL patients. Expert opinion: Lenalidomide shows good activity against CLL. However, the toxicity profile is significant and can result in serious and potentially life-threatening side effects. Definitive data from ongoing trials will aid better definition of its status in CLL therapy. Moreover, clarification of the exact mechanism(s) of action in CLL will allow more precise use of lenalidomide and design of more efficacious combination therapies.

Bendamustine in multiple myeloma

The advent of high‐dose melphalan with autologous stem‐cell transplantation (ASCT), the availability of novel agents such as thalidomide, lenalidomide (immunomodulatory drugs or IMiDs) and bortezomib (proteasome inhibitor) and improvements in supportive care have allowed to increase overall survival in multiple myeloma (MM) patients; nevertheless, MM remains an incurable pathology. For this reason, newer agents are required for continued disease control. Bendamustine is an old drug rediscovered in the last decade. In fact, its unique mechanism of action with structural similarities to both alkylating agents and antimetabolities, but which is not cross‐resistant to alkylating agents, has reawakened interest in the use of this drug in the treatment of MM. Studies have proven the safety and efficacy of bendamustine administered alone or in combination with new drugs in both upfront and relapse/refractory settings of MM patients, including those with renal impairment. Moreover, bendamustine has been successfully used as conditioning for autologous stem‐cell transplantation. Finally, the use of bendamustine does not compromise peripheral blood stem‐cell collection. This drug is generally well tolerated, with the majority of adverse events being due to myelosuppression. Non‐haematological adverse events are infrequent and usually mild.

Role of new drugs incorporated into consolidation and maintenance therapy in transplant-eligible multiple myeloma patients

Introduction: Since in multiple myeloma (MM) patients the depth of response achieved with autologous stem-cell transplantation (ASCT) seems to correlate with the time to progression, various strategies have been undertaken to control disease and improve prognosis. Novel agents thalidomide, bortezomib and lenalidomide that have allowed deeper responses to be achieved in the induction phase have been tested following the ASCT as consolidation and maintenance treatments. Areas covered: Consolidation is generally a short-term treatment and aims to increase the depth of the response achieved with high-dose melphalan, whereas maintenance therapy consists of protracted therapy of either a fixed duration or until response and has the goal of prolonging duration of the first response. The goals of both treatments are the extension of progression-free survival and, hopefully, overall survival. This editorial will focus on the consolidation and maintenance strategies after ASCT for the treatment of MM. Expert opinion: The incorporation of new drugs into the continuum of MM care resulted in improved outcomes and long-term disease control. However, optimal consolidation and maintenance strategies are still to be defined in the light of newer drugs to be utilized for induction strategies.

Promising therapies for the treatment of chronic lymphocytic leukemia

Introduction: The combination schedule of fludarabine, cyclophosphamide and rituximab is the gold standard of therapy for younger, physically fit chronic lymphocytic leukemia (CLL) patients; it allows achieving high and durable complete response rates. Although treatment outcome has considerably improved with chemo-immunotherapy, most patients eventually relapse and CLL is still incurable. Thus, newer and more rationally developed drugs are needed to improve CLL therapy, particularly in cases of relapsed/refractory disease. Areas covered: The authors review preclinical and clinical data regarding newer CLL agents, currently undergoing examination, such as: signal transduction and cyclin-dependent kinase inhibitors, immunomodulatory agents, B-cell lymphoma 2 inhibitors, next generation mAbs, heat shock protein 90 and histone deacetylase inhibitors, and chimeric antigen receptor T-cell therapy. Expert opinion: Newer compounds with different mechanisms of action, such as B-cell receptor signal transduction inhibitors, lenalidomide, next generation mAbs and several pro-apoptotic molecules, have shown efficacy in relapsed or refractory CLL patients. Several studies are under way to investigate the efficacy of combinations of these novel drugs. Hopefully, the combined use of these molecules in risk-adapted treatment strategies will change the therapeutic approach in the near future and will pave the way for a long-term control of CLL.

Smoldering multiple myeloma: to treat or not to treat

Introduction: Smoldering multiple myeloma (SMM) is an asymptomatic disorder characterized by the presence of ≥ 30 g/l serum M-protein and/or ≥ 10% bone marrow plasma cell infiltration. The progression risk to active multiple myeloma (MM) is not uniform, and several prognostic parameters are useful for identifying patients at high risk of progression. A watch-and-wait approach has been the standard of care up to now. However, recently, it has been demonstrated that a subset of high-risk cases can benefit from early treatment with new drugs. Areas covered: In this editorial, we focus on SMM and evaluate the diagnostic work-up and the prognostic factors predicting progression to symptomatic MM. We also review the studies in which the role of early treatment has been evaluated for patients with SMM. Expert opinion: After the update performed by the International Myeloma Working Group regarding MM diagnosis, it is now time to change the therapeutic paradigm for this disease. While “ultra high-risk” myeloma should now be considered as active MM, for low-risk patients the “watch-and-wait” strategy is still recommended. More caution is needed for the high-risk group: physicians should continue monitoring patients using every tool now available while waiting for results from ongoing trials that will establish if this group will benefit from an early intervention.