Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

The role of lenalidomide in the treatment of patients with chromosome 5q deletion and other myelodysplastic syndromes

PURPOSE OF REVIEW

The aim of this article is to discuss the relevant pathobiologic effects of lenalidomide and the most recent clinical evidence to support its use in patients with myelodysplastic syndrome.

RECENT FINDINGS

Lenalidomide is an immunomodulatory agent with biological activity in several hematologic malignancies, including myelodysplastic syndrome. The precise mechanism yielding benefit in patients with myelodysplastic syndrome and 5q- syndrome is not clear, but various molecular and pathogenic targets have been identified. Enhancement of cellular immunity through T-cell and NK-cell activation and suppression of inflammatory cytokines and pro-angiogenic peptides upon lenalidomide treatment has been demonstrated in in-vitro models of myelodysplastic syndrome. Furthermore, lenalidomide induces a direct cytotoxic effect against 5q- clones in leukemia cell lines and enhances ligand-induced erythropoietin receptor signaling in erythroid progenitors. Clinical trials with lenalidomide in myelodysplastic syndrome have supported the in-vitro evidence of karyotype-dependent activity by demonstration of a high frequency of cytogenetic and pathologic responses in patients with myelodysplastic syndrome and deletion of chromosome 5q. Lenalidomide was approved for the treatment of transfusion-dependent patients with low to intermediate risk myelodysplastic syndrome and chromosome 5q deletion.

SUMMARY

Lenalidomide is an active immunomodulatory agent for the treatment of myelodysplastic syndrome with encouraging erythropoetic and cytogenetic remitting activity that is karyotype dependent.

Update of the decitabine experience in higher risk myelodysplastic syndrome and analysis of prognostic factors associated with outcome

BACKGROUND

Therapy for patients with myelodysplastic syndrome (MDS) with hypomethylating agents, like decitabine and 5-azacitidine, has produced favorable results. In this study, the authors update their experience with decitabine in patients with MDS and analyze the cytogenetic response patterns and prognostic factors associated with decitabine therapy.

METHODS

One hundred fifteen patients with higher risk MDS who received treatment with decitabine were reviewed. Patients received decitabine 100 mg/m(2) per course every 4 weeks in 3 different schedules: 1) 20 mg/m(2) intravenously daily x 5, 2) 20 mg/m(2) subcutaneously daily x 5, and 3) 10 mg/m(2) intravenously daily x 10. Decitabine was given for a median of >or=7 courses (range, 1-23 courses).

RESULTS

Overall, 80 patients (70%) achieved a response according to the modified International Working Group criteria (IWG): complete response (CR), 40 patients (35%); partial response, 2 patients (2%); bone marrow CR with or without other hematologic improvements (HI), 26 patients (23%); and other HI, 12 patients (10%). Cytopenias were improved in 50% of patients. The median remission duration was 20 months, and the median survival was 22 months. Mortality was 3% at 6 weeks and 7% at 3 months. In a multivariate analysis, poor prognostic factors for achieving IWG CR were MDS (vs chronic myelomonocytic leukemia), longer duration of MDS, and prior MDS therapy. For survival, independent adverse prognostic factors were chromosome 5 and/or 7 abnormalities, older age, and prior MDS therapy (excluding growth factors).

CONCLUSIONS

The longer term experience with decitabine in MDS was favorable. Pretreatment prognostic factors may predict the outcome of patients who receive decitabine therapy for MDS.

The role of decitabine in the treatment of myelodysplastic syndromes

Supportive care with red cell and platelet transfusions and use of growth factors has long been the standard of care for patients with myelodysplastic syndromes (MDS) ineligible for stem cell transplantation. Although these measures improve quality of life, their impact on the natural history of the disease is questionable. Recently, three new agents have been approved for the treatment of MDS. These include: 5-azacytidine, lenalidomide and, more recently, 5-aza-2 -deoxycytidine (decitabine). Decitabine is a hypomethylating agent that is incorporated into DNA and forms irreversible covalent adducts with DNA-methyltransferases. At high concentrations, this leads to cell death. At low concentrations, decitabine is considered to exert its anticancer effects by inducing DNA hypomethylation. This results in reactivation of epigenetically repressed genes, such as tumour suppressor genes and, potentially, cell differentiation. In a randomized, Phase III trial of decitabine versus best supportive care in patients with MDS, the overall response rate with decitabine was 17%, including 9% complete remissions. Patients at high risk had a statistically significant prolongation of time to acute myelogenous leukemia transformation or death. This experience has been followed by a study of low-dose decitabine using a five-times daily 1-h infusion schedule, with significant efficacy in patients with MDS observed. Ongoing studies are evaluating the activity and safety of the combination of decitabine with several histone deacetylase inhibitors and other indications. This article summarizes the experience in with decitabine in MDS.

Evaluation of recurring cytogenetic abnormalities in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are clinically heterogeneous, but the presence of specific cytogenetic abnormalities can predict disease manifestations, provide a basis for prognosis, and direct treatment. Conventional cytogenetic analysis is instrumental in identifying chromosomal abnormalities in MDS and novel genetic methods may provide supplementary information. Treatment with lenalidomide was recently shown to be effective in MDS, particularly in those cases with del(5q), resulting in durable cytogenetic remission and hematological responses. In this paradigm, diagnosis of the del(5q) abnormality would be essential to predicting response to therapy.

Myelodysplasia: when to treat and how

Myelodysplastic syndrome (MDS) is a disorder of hematopoietic stem cells characterized by ineffective hematopoiesis. The result is pancytopenia leading to transfusion-dependent anemia, an increased risk of infection or bleeding, and a potential to progress to acute myeloid leukemia (AML). MDS is most prevalent among older individuals, many of whom also suffer from other medical conditions. MDS is classified according to World Health Organization criteria and the International Prognostic Scoring System. Supportive care remains the mainstay of therapy. Those with low-risk MDS can often be monitored for an extended period of time without specific therapy, whereas those with intermediate- or high-risk MDS benefit from treatment. Currently, only azacitidine is approved for the treatment of MDS. Several new agents are being tested, including inhibitors of angiogenesis (thalidomide, lenalidomide), farnesyl transferase inhibitors (lonafarnib, tipifarnib), and DNA methyltransferase inhibitors (azacitidine, decitabine). Lenalidomide appears particularly effective in patients with low-risk MDS with the deletion of chromosome 5q31. Allogeneic stem cell transplantation is an alternative for high-risk MDS. With advances in transplantation techniques, this treatment can be offered to an increasing number of patients. However, it is necessary to assess each patient's disease individually and to evaluate prognostic factors, other treatment options, and the appropriateness and timing of transplantation.

Biological and prognostic significance of chromosome 5q deletions in myeloid malignancies

The presence of del(5q), either as the sole karyotypic abnormality or as part of a more complex karyotype, has distinct clinical implications for myelodysplastic syndromes (MDS) and acute myeloid leukemia. The 5q- syndrome, a subtype of low-risk MDS, is characterized by an isolated 5q deletion and <5% blasts in the bone marrow and can serve as a useful model for studying the role of 5q deletions in the pathogenesis and prognosis of myeloid malignancies. Recent clinical results with lenalidomide, an oral immunomodulatory drug, have shown durable erythroid responses, including transfusion independence and complete cytogenetic remissions in patients with del(5q) MDS with or without additional chromosomal abnormalities. These results indicate that lenalidomide can overcome the pathogenic effect of 5q deletion in MDS and restore bone marrow balance. The data provide important new insights into the pathobiology of 5q chromosomal deletions in myeloid malignancies.

Transfusion independence in patients with myelodysplastic syndromes

Anemia is the most common cytopenia associated with myelodysplastic syndromes (MDS). Current management relies on frequent red blood cell (RBC) transfusions and erythroid growth factors to alleviate symptoms. However, the dependence of patients with MDS on repeated RBC transfusions often results in significant clinical and economic consequences, poorer outcomes, and diminished health-related quality of life. In addition, the intensity and duration of RBC transfusion dependence can influence responses to treatment after disease progression. Erythropoietic growth factors may alleviate the need for RBC transfusions in some patients with MDS, although only a minority of patients experience responses. Emerging treatment strategies to reduce or eliminate the need for RBC transfusions in patients with MDS include immunomodulating drugs, immunosuppressive therapy, and differentiating agents. The immunomodulating drug lenalidomide in patients who have MDS with 5q deletion is unique among emerging approaches, in that cytogenetic remitting activity and durable erythroid responses have been achieved. Newer treatments have the potential to improve the care of patients with MDS by alleviating the clinical, economic, and quality-of-life consequences of long-term RBC transfusion dependence.

Activity of 9-nitro-camptothecin, an oral topoisomerase I inhibitor, in myelodysplastic syndrome and chronic myelomonocytic leukemia

BACKGROUND

Topoisomerase I inhibitors, like topotecan, have activity in myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). 9-Nitro-camptothecin (9-NC) is a new oral topoisomerase inhibitor with a good safety profile. The aims of the current study were to evaluate the activity and safety of 9-NC in MDS and CMML.

METHODS

Adults with a diagnosis of MDS (n = 12) and CMML (n = 32) received 9-NC 2 mg/m(2) orally daily 5 days a week, every 4 to 6 weeks.

RESULTS

Overall, 5 (11%) patients achieved complete response (CR), 7 (16%) had a partial response (PR), and 6 (14%) had hematologic improvement (HI), for an overall response rate of 41%. The response rate was similar in MDS and CMML. Severe (Grade 3-4) side effects included nausea and vomiting (7%), diarrhea (18%), other gastrointestinal toxicities (5%), and genitourinary toxicities (12%).

CONCLUSIONS

9-NC is active in MDS and CMML. The paucity of available therapies in CMML makes 9-NC a good candidate for further studies as a single agent, or in combination with decitabine, 5-azacitidine or cytarabine.

Clinical Cancer Advances 2005: major research advances in cancer treatment, prevention, and screening--a report from the American Society of Clinical Oncology

This year, for the first time, the American Society of Clinical Oncology (ASCO) is publishing Clinical Cancer Advances 2005: Major Research Advances in Cancer Treatment, Prevention, and Screening, an annual review of the most significant clinical research presented or published over the past year across all cancer types. ASCO embarked on this project to provide the public, patients, policymakers, and physicians with an accessible summary of the year's most important research advances. While not intended to serve as a comprehensive review, this report provides a year-end snapshot of research that will have the greatest impact on patient care. As you will read, there is much good news from the front lines of cancer research. These pages report on new chemotherapy regimens that sharply reduce the risk of recurrence for very common cancers; the "coming of age" of targeted cancer therapies; promising studies of drugs to prevent cancer; and improvements in quality of life for people living with the disease, among many other advances. Survival rates for cancer are on the rise, increasing from 50% to 64% over the last 30 years. Cancer still exacts an enormous toll, however. Nearly 1.4 million Americans will be diagnosed this year, and some 570,000 will die of the disease. Clearly, more research is needed to find effective therapies for the most stubborn cancer types and stages. We need to know more about the long-term effects of newer, more targeted cancer therapies, some of which need to be taken over long periods of time. And we need to devote far greater attention to tracking and improving the care of the nearly 10 million cancer survivors in the United States today. Despite these and other challenges, the message of this report is one of hope. Through the dedicated, persistent pursuit of clinical research and participation in clinical trials by people with cancer, we steadily uncover new and better ways of treating, diagnosing, and preventing a disease that touches the lives of so many. I want to thank the Editorial Board members, the Specialty Editors, and the ASCO Cancer Communications Committee for their dedicated work to develop this report, and I hope you find it useful.

Recent clinical studies of the immunomodulatory drug (IMiD) lenalidomide

Thalidomide is effective in the treatment of multiple myeloma. The immunomodulatory drug and thalidomide analogue lenalidomide is currently in late stage clinical development for MDS and multiple myeloma. This minireview highlights the course of initial and ongoing lenalidomide clinical development in oncology with reference to earlier thalidomide studies.

Update on supportive care and new therapies: immunomodulatory drugs, growth factors and epigenetic-acting agents

Patients with "low-risk" myelodysplastic syndrome (MDS) are mostly treated with approaches aiming to reduce the negative consequences of ineffective hematopoiesis. Transfusion therapy should be tailored to allow adequate oxygenation and optimal quality of life, and may lead to the need for iron chelation therapy. Growth factors (erythropoietin and granulocyte colony-stimulating factor [G-CSF]) may induce long-lasting improvement of hemoglobin levels and does not increase the risk for leukemic transformation. Growth factors should be offered to defined subgroups of patients. Immunosuppression with anti-thymoglobulin or cyclosporine A may be an alternative for younger patients with refractory anemia (RA). The new immunomodulating compound lenalidomide, CC5013, is very active in the 5q- syndrome and is under evaluation for other low-risk MDS subtypes. "High-risk" MDS is associated with poor survival and high risk for leukemic transformation. The DNA hypomethylating compounds azacytidine and decitabine may offer improved long-term outcomes in this group of patients, although there has so far been no effect on survival rates. The efficacy of farnesyl transferase inhibitors has been evaluated in a series of phase II trials. The overall response rate was low, but the majority of responses were CRs. Finally, a number of new drugs directed to various biological and genetic targets are entering clinical trials.