Treatment with lenalidomide does not appear to increase the risk of progression in lower risk myelodysplastic syndromes with 5q deletion. A comparative analysis by the Groupe Francophone des Myelodysplasies

Lenalidomide in Transfusion-Dependent IPSS Low- or Intermediate-1-Risk Myelodysplastic Syndromes and Isolated Del(5q): Results of a European Postauthorization Safety Surveillance Study

BACKGROUND

This noninterventional postauthorization safety study assessed the safety and effectiveness of lenalidomide in patients with transfusion-dependent, International Prognostic Scoring System (IPSS) Low- or Intermediate (Int)-1-risk myelodysplastic syndromes (MDS) associated with isolated deletion of 5q (del[5q]) who were treated in routine care.

PATIENTS AND METHODS

Eligible adult patients in the lenalidomide cohort had transfusion-dependent, IPSS Low- or Int-1-risk MDS and isolated del(5q) and had received ≥ 1 dose of lenalidomide between 2014 and 2022. The primary endpoint was the 24-month cumulative incidence of acute myeloid leukemia (AML) progression. Overall survival (OS) was estimated by Kaplan-Meier analysis and safety data were collected.

RESULTS

In total, 296 patients received ≥ 1 dose of lenalidomide (lenalidomide cohort, safety population) and 277 had received ≥ 1 complete cycle of lenalidomide (primary population). In the safety population, 44.3% of patients completed 3-year follow-up and 55.1% discontinued, with 33.1% discontinuing due to death. In the primary population, 24-month cumulative incidence of AML progression was 12.7% (95% confidence interval, 8.9%-17.1%) and estimated OS probability was 78.3% at 24 months and 63.9% at 36 months. Grade 3/4 treatment-emergent adverse events were experienced by 67.2% of the safety population, and these led to discontinuation in 35.5% of patients. There were no new safety signals.

CONCLUSION

These real-world data support the established benefit-risk profile of lenalidomide in transfusion-dependent IPSS Low- or Int-1-risk MDS with isolated del(5q).

Transfusion independence after lenalidomide discontinuation in patients with del(5q) myelodysplastic neoplasm: a HARMONY Alliance study

Lenalidomide (LEN) can induce red blood cell-transfusion independence (RBC-TI) in 60-70% of del(5q) myelodysplastic neoplasm (MDS) patients. Current recommendation is to continue LEN in responding patients until failure or progression, with likelihood of toxicity and a high cost for healthcare systems. This HARMONY Alliance study investigated the outcome of MDS del(5q) patients who discontinued LEN while RBC-transfusion independent. We enrolled 118 patients with IPSS-R low-intermediate risk. Seventy patients (59%) discontinued LEN for intolerance, 38 (32%) per their physician decision, nine (8%) per their own decision and one (1%) for unknown reasons. After a median follow-up of 49 months from discontinuation, 50/118 patients lost RBC-TI and 22/30 who underwent cytogenetic re-evaluation lost complete cytogenetic response. The median RBC-TI duration was 56 months. In multivariate analysis, RBC-TI duration after LEN discontinuation correlated with low transfusion burden before LEN therapy, treatment ≥ 12 LEN cycles, younger age and higher Hb level at LEN withdrawal. Forty-eight patients were re-treated with LEN for loss of response and 28 achieved again RBC-TI. These data show that stopping LEN therapy in MDS del(5q) patients who reached RBC-TI allows prolonged maintenance of TI in a large subset of patients.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

Efficacy and Safety of Lenalidomide for Treatment of Low-/Intermediate-1-Risk Myelodysplastic Syndromes with or without 5q Deletion: A Systematic Review and Meta-Analysis

Background

Lenalidomide could effectively induce red blood cell (RBC) transfusion independence (TI) in patients with lower-risk (Low/Intermediate-1) myelodysplastic syndrome (MDS) with or without 5q deletion. However whether lenalidomide ultimately improves the overall survival (OS) of lower-risk MDS patients and reduces the progression to AML remains controversial.

Method

A meta-analysis was conducted to examine the efficacy and safety of lenalidomide in the treatment of lower-risk MDS. Efficacy was assessed according to erythroid hematologic response (HI-E), cytogenetic response (CyR), OS and AML progression. Safety was evaluated based on the occurrence rates of grades 3–4 adverse events (AEs).

Results

Seventeen studies were included consisting of a total of 2160 patients. The analysis indicated that the overall rate of HI-E was 58% with 95% confidence interval (CI) of 43–74%. The pooled estimates for the rates of CyR, complete CyR, and partial CyR were 44% (95% CI 19–68%), 21% (95% CI 13–30%) and 23% (95% CI 15–32%), respectively. The patients with 5q deletion had significantly higher rate of HI-E and CyR than those without 5q deletion (P = 0.002 and 0.001, respectively). The incidences of grades 3–4 neutropenia, thrombocytopenia, leukopenia, anemia, deep vein thrombosis, diarrhea, fatigue and rash were 51% (95% CI 30–73%), 31% (95% CI 20–42%), 9% (95% CI 5–13%), 7% (95% CI 2–12%), 3% (95% CI 2–5%), 3% (95% CI 1–5%), 2% (95% CI 1–4%) and 2% (95% CI 1–3%), respectively. Lenalidomide significantly improved OS (HR: 0.62, 95% CI 0.47–0.83, P = 0.001) and lowered the risk of AML progression in del(5q) patients (RR: 0.61, 95% CI 0.41–0.91, P = 0.014).

Conclusions

In spite of the AEs, lenalidomide could be effectively and safely used for the treatment of lower-risk MDS patients with or without 5q deletion.

Subsequent primary malignancies and acute myelogenous leukemia transformation among myelodysplastic syndrome patients treated with or without lenalidomide

The few studies that have examined rates of acute myeloid leukemia (AML) transformation in lenalidomide‐treated myelodysplastic syndrome (MDS) patients have been limited to deletion 5q MDS. The association between lenalidomide and subsequent primary malignancies (SPMs) in MDS patients has not been evaluated previously. We conducted a retrospective cohort study to evaluate the risk of both SPM and AML in association with lenalidomide. A cohort of MDS patients (n = 1248) treated between 2004 and 2012 at Moffitt Cancer Center were identified, and incident cases of SPM and AML transformation were ascertained. Using a nested case–control design, MDS controls were 1:1 matched to SPM (n = 41) and AML (n = 150) cases, on age and date of MDS diagnosis, gender, follow‐up time, IPSS, and del (5q). Associations between lenalidomide and (1) SPM incidence and (2) AML transformation were estimated with hazards ratios (HR) and 95% confidence intervals (CIs) in the cohort and odds ratios (OR) in the case–control analysis. SPM incidence did not differ significantly between cohort MDS patients treated with (0.7 per 100 person‐years) or without lenalidomide (1.4 per 100 person‐years) (HR = 1.04, 95% CI = 0.40–2.74), whereas a significantly reduced SPM risk was observed in the case–control sample (OR = 0.03, 95% CI = <0.01–0.63). Lenalidomide was not associated with AML transformation in the cohort analysis (HR = 0.75, 95% CI = 0.44–1.27) or in the case–control analyses (OR = 1.16, 95% CI = 0.52–2.56), after adjustment for potential confounders. Lenalidomide was not associated with increased risk of SPM or AML transformation in a large cohort of MDS patients mostly including nondeletion 5q MDS.

Durable response to lenalidomide in a patient with myelodysplastic syndrome associated with isolated 5q deletion and JAK2 V617F mutation despite discontinuation of treatment

Loss of a section of the long arm of chromosome 5, as a sole cytogenetic abnormality, characterizes a rare type of myelodysplastic syndrome [del(5q) MDS] and the co-existence of the JAK2 V617F mutation occurs in a small subset of these cases. Patients with isolated del(5q) MDS have a relatively favorable prognosis, with transformation to acute myeloid leukemia occurring in <10%, and their disease responds well to lenalidomide. However the optimal therapeutic approach for patients with del(5q) MDS in coexistence with the JAK2 V617F mutation, which is common to myeloproliferative neoplasms, remains to be elucidated. The present study reports a 77-year-old, transfusion-dependent female patient diagnosed with del(5q) MDS and a concomitant JAK2 V617F mutation. The patient was started on 10 mg lenalidomide daily for 21 days in a 28 day-cycle and within the first month of treatment, the patient became transfusion-independent. The only toxicity observed was grade 3 neutropenia, which was managed with transient treatment discontinuation and dose reduction on restart (5 mg). The patient achieved a complete cytogenetic and molecular response (normal karyotype and undetected JAK2 V617F mutation) within 6 months of treatment. However, 12 months post treatment initiation and while on hematological, cytogenetic and molecular response, the patient was unwilling to continue on treatment and lenalidomide was discontinued. The patient remains in hematological response, which lasts for >5 years despite treatment discontinuation. The present case highlights the coexistence of the JAK2 V617F mutation in del(5q) MDS and suggests that lenalidomide treatment is beneficial and effective for these patients, leading to complete hematological, cytogenetic and molecular response. Hematological response may be sustained for long periods of time, even following the discontinuation of the treatment.

Effect of lenalidomide treatment on clonal architecture of myelodysplastic syndromes without 5q deletion

Non-del(5q) transfusion-dependent low/intermediate-1 myelodysplastic syndrome (MDS) patients achieve an erythroid response with lenalidomide in 25% of cases. Addition of an erythropoiesis-stimulating agent could improve response rate. The impact of recurrent somatic mutations identified in the diseased clone in response to lenalidomide and the drug's effects on clonal evolution remain unknown. We investigated recurrent mutations by next-generation sequencing in 94 non-del(5q) MDS patients randomized in the GFM-Len-Epo-08 clinical trial to lenalidomide or lenalidomide plus epoetin β. Clonal evolution was analyzed after 4 cycles of treatment in 42 cases and reanalyzed at later time points in 18 cases. The fate of clonal architecture of single CD34(+)CD38(-) hematopoietic stem cells was also determined in 5 cases. Mutation frequency was >10%: SF3B1 (74.5%), TET2 (45.7%), DNMT3A (20.2%), and ASXL1 (19.1%). Analysis of variant allele frequencies indicated a decrease of major mutations in 15 of 20 responders compared with 10 of 22 nonresponders after 4 cycles. The decrease in the variant allele frequency of major mutations was more significant in responders than in nonresponders (P < .001). Genotyping of single CD34(+)CD38(-) cell-derived colonies showed that the decrease in the size of dominant subclones could be associated with the rise of founding clones or of hematopoietic stem cells devoid of recurrent mutations. These effects remained transient, and disease escape was associated with the re-emergence of the dominant subclones. In conclusion, we show that, although the drug initially modulates the distribution of subclones, loss of treatment efficacy coincides with the re-expansion of the dominant subclone. This trial was registered at www.clinicaltrials.gov as #NCT01718379.

[Management of myelodysplastic syndromes]

Myelodysplastic syndromes are heterogeneous diseases whose molecular characteristics have only been identified in recent years. Better identification of prognostic factors, larger access to allogeneic stem cell transplantation and the advent of new drugs notably hypomethylating agents (azacitidine, decitabine) and lenalidomide have improved patient outcome.

Early lenalidomide treatment for low and intermediate-1 International Prognostic Scoring System risk myelodysplastic syndromes with del(5q) before transfusion dependence

Lenalidomide is approved for the treatment of transfusion-dependent (TD) del(5q) myelodysplastic syndromes (MDS). However, few data are available in patients with transfusion-independent (TI) del(5q) MDS. In the first, observational, part of this 2-part study, we assessed the impact of transfusion dependence on overall survival (OS) and non-leukemic death in untreated del(5q) MDS patients who were TD (n = 136), TI with hemoglobin (Hb) ≥10 mg/dL (n = 88), or TI with Hb <10 mg/dL (n = 96). In the second, interventional, part we assessed the quality-of-life (QoL) benefits and clinical efficacy of lenalidomide (10 mg/day) in 12 patients with TI del(5q) MDS and Hb <10 mg/dL. In the untreated population, OS was significantly longer in TI than in TD patients (TI [Hb ≥10 g/dL], 108 months; TI [Hb <10 g/dL], 77 months; TD, 44 months). Transfusion dependence also negatively impacted non-leukemic death rates. In the interventional part of the study, baseline Hb levels were found to correlate significantly with physical (R = 0.666, P = 0.035) and fatigue (R = 0.604, P = 0.049) QoL scores. Median physical QoL scores improved significantly after 12 weeks' treatment with lenalidomide (+12.5; P = 0.020). Evaluable TI patients experienced early increases in Hb levels, and all attained an erythroid response. Our findings suggest that TI patients with moderate anemia may benefit from early treatment with lenalidomide.

Treatment of Patients With Myelodysplastic Syndrome With Lenalidomide in Clinical Routine in Austria

BACKGROUND

Lenalidomide has demonstrated remarkable efficacy for therapy of lower-risk myelodysplastic syndromes (MDS) associated with 5q(-). The present evaluation aimed to describe the characteristics and outcomes of low-risk MDS patients treated with lenalidomide in Austria.

PATIENTS AND METHODS

For this retrospective, multicenter, observational analysis of MDS patients who received lenalidomide, data were collected at various hospitals in Austria over a period of 3 years. MDS classification, previous and current MDS therapies, and outcome and safety of lenalidomide were evaluated.

RESULTS

Forty-six percent of the patients (n = 23) had a 5q(-) syndrome, while 12% (n = 6) exhibited 5q(-) plus additional aberrations or isolated 5q(-) but ≥ 5% blasts in the bone marrow (10%, n = 5). The remaining 32% of patients (n = 16) had MDS with other World Health Organization classifications. Seventy percent belonged to lower International Prognostic Scoring System risk classes. Sixteen centers participated, involving a total of 50 patients. Most frequently used lenalidomide doses were 10 mg and 5 mg on days 1 to 21 of a 28-day cycle. Seventy-five percent of the patients received 11 months of treatment, with a median therapy period of 3.5 months; median follow-up was 3.9 months (range, 0-26 months). Response rate, defined as transfusion independence during the 2 months after lenalidomide therapy, was 64%. Median overall survival was not reached.

CONCLUSION

Lenalidomide was well tolerated and is an effective and well-tolerated option for therapy of patients with 5q(-) syndrome but also lower-risk MDS patients with other World Health Organization classifications in clinical practice.

Polish experience of lenalidomide in the treatment of lower risk myelodysplastic syndrome with isolated del(5q)

Background

Lenalidomide has been approved for the treatment of lower-risk myelodysplastic syndrome (MDS) with 5q deletion (del(5q)). We present for the first time a retrospective analysis of low-risk MDS with isolated del5q treated with lenalidomide, outside the clinical trials.

Methods

36 red blood cell (RBC) transfusion-dependent patients have been included in the study. Patients received lenalidomide 10 mg/day on days 1–21 of 28-day cycles.

Results

91.7 % of patients responded to lenalidomide treatment: 72.2 % achieved erythroid response, 19.4 % achieved minor erythroid response and 8.4 % of patients did not respond to treatment. Response depended on number of previous treatment lines (p = 0.0101), International Prognostic System Score (IPSS; p = 0.0067) and RBC transfusion frequency (p = 0.0139). Median duration of response was 16 months (range 6–60 months). Treatment was well tolerated. We observed hematological toxicity (grade 3 and 4): neutropenia in 16 (44.4 %) patients and thrombocytopenia in 9 (25 %) patients. Two patients (5.5 %) progressed to high-risk MDS and two subsequent progressed to acute myeloid leukemia. A Kaplan-Meier estimate for overall survival at 5 years in the study group was 79.0 ± 8.8 %.

Conclusions

Lenalidomide in this group of patients was beneficial for the treatment of RBC transfusion-dependency with well-known safety profile.

New therapeutic approaches in myelodysplastic syndromes: Hypomethylating agents and lenalidomide

Recent advances in the treatment of myelodysplastic syndromes have come from the use of the hypomethylating agents decitabine and azacitidine as well as the immunomodulatory drug lenalidomide. Their clinical benefit has been demonstrated by randomized phase III clinical trials, mostly in high-risk and del(5q) myelodysplastic syndromes, respectively. Neither drug, however, appears to eradicate myelodysplastic stem cells, and thus they currently do not represent curative options. Here, we review data from both clinical and translational research on those drugs to identify their molecular and cellular mechanisms of action and to delineate paths for improved treatment allocation and further therapeutic advances in myelodysplastic syndromes.

In patients with myelodysplastic syndromes with del(5q), factors other than age and sex contribute to the prognostic advantage, which diminishes over time

This study aimed to determine the extent to which the prognostic advantage of myelodysplastic syndromes (MDS) with del(5q) is due to the more favourable age and sex distribution of patients in that group when compared to other MDS subtypes. A total of 1912 MDS patients from the Duesseldorf registry with less than 5% blasts in the bone marrow were evaluable and had complete covariates. As endpoints, overall survival and progression to acute myeloid leukaemia (AML) were considered. Cox models were computed for both outcomes. A multivariate Cox model for survival confirmed higher age and male sex as risk factors. In addition, we found a survival advantage of 9·1 years for MDS del(5q) patients compared to refractory cytopenia with unilineage dysplasia, while the survival advantage of MDS del(5q) over refractory cytopenia with multilineage dysplasia was 18·6 years. Considering progression to AML, we did not find any significant differences between the World Health Organization classification subtypes. Our analyses show that the higher survival probabilities of MDS del(5q) patients are not only due to age and sex, although higher age and male sex were also important risk factors. Interestingly, it seems that the survival advantage of MDS del(5q) decreases over time.

Clinical utility of lenalidomide in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of acquired clonal hematopoietic disorders characterized by peripheral blood cytopenias, paradoxical BM hypercellularity, ineffective hematopoiesis, and increased risk of leukemic transformation. Risk stratification, using different prognostic scores and markers, is at the core of MDS management. Deletion 5q [del(5q)] MDS is a distinct class of MDS characterized by the haploinsufficiency of specific genes, microRNAs, and proteins, which has been linked to increased sensitivity to the drug lenalidomide. Phase II and III clinical trials have demonstrated the efficacy of lenalidomide in improving clinical outcomes of patients with del(5q) MDS, including reduction in red blood cell transfusion requirements and improvements in quality of life. Lenalidomide has also demonstrated some activity in non-del(5q) lower-risk MDS as well as higher-risk MDS, especially in combination with other agents. In this paper, we review the pathogenesis of del(5q) MDS, the proposed mechanisms of action of lenalidomide, the major clinical trials that documented the activity of lenalidomide in different MDS populations, potential predictors of benefit from the drug and suggested mechanisms of resistance, and the use of combination strategies to expand the clinical utility of lenalidomide in MDS.

Myelodysplastic syndromes

Myelodysplastic syndromes are clonal marrow stem-cell disorders, characterised by ineffective haemopoiesis leading to blood cytopenias, and by progression to acute myeloid leukaemia in a third of patients. 15% of cases occur after chemotherapy or radiotherapy for a previous cancer; the syndromes are most common in elderly people. The pathophysiology involves cytogenetic changes with or without gene mutations and widespread gene hypermethylation at advanced stages. Clinical manifestations result from cytopenias (anaemia, infection, and bleeding). Diagnosis is based on examination of blood and bone marrow showing blood cytopenias and hypercellular marrow with dysplasia, with or without excess of blasts. Prognosis depends largely on the marrow blast percentage, number and extent of cytopenias, and cytogenetic abnormalities. Treatment of patients with lower-risk myelodysplastic syndromes, especially for anaemia, includes growth factors, lenalidomide, and transfusions. Treatment of higher-risk patients is with hypomethylating agents and, whenever possible, allogeneic stem-cell transplantation.

Choosing treatment options for patients with relapsed/refractory multiple myeloma

Multiple myeloma (MM) is a clonal plasma cell disorder that is still incurable using conventional treatments. Over the last decade, advances in front-line therapy have led to an increase in survival, but there are still some doubts in the case of relapsed/refractory disease. We searched the PubMed database for articles on treatment options for patients with relapsed/refractory MM published between 1996 and 2013. These treatments included hematopoietic cell transplantation (HCT), rechallenges using previous chemotherapy regimens, and trials of new regimens. The introduction of new agents such as the immunomodulatory drugs (IMIDs) thalidomide and lenalidomide, and the first-in-its-class proteasome inhibitor bortezomib, has greatly improved clinical outcomes in patients with relapsed/refractory MM, but not all patients respond and those that do may eventually relapse or become refractory to treatment. The challenge is therefore to select the optimal treatment for each patient by balancing efficacy and toxicity. To do this, it is necessary to consider disease-related factors, such as the quality and duration of responses to previous therapies, and the aggressiveness of the relapse, and patient-related factors such as age, comorbidities, performance status, pre-existing toxicities and cytogenetic patterns. The message from the trials reviewed in this article is that the new agents may be used to re-treat relapsed/refractory disease, and that the sequencing of their administration should be modulated on the basis of the various disease and patient-related factors. Moreover, our understanding of the pharmacology and molecular action of the new drugs will contribute to the possibility of developing tailored treatment.

Lenalidomide as a disease-modifying agent in patients with del(5q) myelodysplastic syndromes: linking mechanism of action to clinical outcomes

Deletion of the long arm of chromosome 5, del(5q), is the most prevalent cytogenetic abnormality in patients with myelodysplastic syndromes (MDS). In isolation, it is traditionally associated with favorable prognosis compared with other subtypes of MDS. However, owing to the inherent heterogeneity of the disease, prognosis for patients with del(5q) MDS is highly variable depending on the presence of factors such as additional chromosomal abnormalities, >5 % blasts in the bone marrow (BM), or transfusion dependence. Over recent years, the immunomodulatory drug lenalidomide has demonstrated remarkable efficacy in patients with del(5q) MDS. Advances in the understanding of the pathogenesis of the disease have suggested that lenalidomide targets aberrant signaling pathways caused by haplosufficiency of specific genes in a commonly deleted region on chromosome 5 (e.g., SPARC, RPS14, Cdc25C, and PP2A). As a result, the agent specifically targets del(5q) clones while also promoting erythropoiesis and repopulation of the bone marrow in normal cells. This review discusses recent developments in the understanding of the mechanism of action of lenalidomide, and how this underlies favorable outcomes in patients with del(5q) MDS. In addition, we discuss how improved understanding of the mechanism of disease will facilitate clinicians’ ability to predict/monitor response and identify patients at risk of relapse.

Current and emerging treatment options for patients with relapsed myeloma

Multiple myeloma (MM) is a neoplastic disorder. It results from proliferation of clonal plasma cells in bone marrow with production of monoclonal proteins, which are detectable in serum or urine. MM is clinically characterized by destructive bone lesions, anemia, hypercalcemia and renal insufficiency. Its prognosis is severe, with a median survival after diagnosis of approximately 3 years due to frequent relapses. Treatments for patients with relapsed/refractory MM include hematopoietic cell transplantation, a rechallenge using a previous chemotherapy regimen or a trial of a new regimen. The introduction of new drugs such as thalidomide, lenalidomide and bortezomib has markedly improved MM outcomes. When relapse occurs, the clinician's challenge is to select the optimal treatment for each patient while balancing efficacy and toxicity. Patients with indolent relapse can be first treated with a 2-drug or a 3-drug combination. Patients with more aggressive relapse often require therapy with a combination of multiple active agents. Autologous stem cell transplantation should be considered as salvage therapy at first relapse for patients who have cryopreserved stem cells early in the disease course. The aim of this review is to provide an overview on the pharmacological and molecular action of treatments used for patients with relapsed/refractory multiple myeloma.

Current therapy of myelodysplastic syndromes

After being a neglected and poorly-understood disorder for many years, there has been a recent explosion of data regarding the complex pathogenesis of myelodysplastic syndromes (MDS). On the therapeutic front, the approval of azacitidine, decitabine, and lenalidomide in the last decade was a major breakthrough. Nonetheless, the responses to these agents are limited and most patients progress within 2 years. Allogeneic stem cell transplantation remains the only potentially curative therapy, but it is associated with significant toxicity and limited efficacy. Lack or loss of response after standard therapies is associated with dismal outcomes. Many unanswered questions remain regarding the optimal use of current therapies including patient selection, response prediction, therapy sequencing and combinations, and management of resistance. It is hoped that the improved understanding of the underpinnings of the complex mechanisms of pathogenesis will be translated into novel therapeutic approaches and better prognostic/predictive tools that would facilitate accurate risk-adaptive therapy.

How we treat lower-risk myelodysplastic syndromes

Lower-risk myelodysplastic syndromes (MDSs) are defined as having low or intermediate 1 risk by the International Prognostic Scoring System and are characterized mainly by anemia in most cases. Supportive care--primarily red blood cell transfusions--remains an important component of their treatment, but exposes patients to insufficient correction of anemia, alloimmunization, and organ iron overload (for which the role of iron chelation remains debated). Treatment aimed at preventing anemia recurrence should therefore be used whenever possible. Erythropoiesis stimulating agents remain the first-line treatment of anemia in most lower-risk MDS without del(5q), whereas anemia of low-risk MDS with del 5q responds to lenalidomide in two-thirds of the cases, but this drug should be used cautiously because profound cytopenias may occur initially. Treatment after failure of those first-line therapies are disappointing overall, with many patients eventually requiring long-term transfusions, but encouraging results have been reported with hypomethylating agents and lenalidomide. Selected patients respond to antithymocyte globulins, and thrombopoietin receptor agonists are under investigation in lower-risk MDS with thrombocytopenia. Some patients, while remaining at a "lower risk" MDS level, have severe cytopenias and/or poor prognostic factors, found using newer prognostic parameters, or resistance to treatment, making them urgent candidates for more intensive approaches, including allogeneic stem cell transplantation.

Lenalidomide does not increase AML progression risk in RBC transfusion-dependent patients with Low- or Intermediate-1-risk MDS with del(5q): a comparative analysis

Data comparing long-term outcomes in lenalidomide-treated and untreated patients with myelodysplastic syndromes (MDS) with del(5q) are limited. We evaluated clinical outcomes of 295 lenalidomide-treated patients from two clinical trials (MDS-003 and MDS-004) and 125 untreated red blood cell (RBC) transfusion-dependent patients with del(5q) Low- or Intermediate-1 (Int-1)-risk MDS from a large multicenter registry. Risk factors for acute myeloid leukemia (AML) progression and mortality were assessed using Cox proportional hazards models with left truncation to adjust for study entry differences between cohorts. Baseline characteristics were well balanced across cohorts, except for a higher RBC transfusion burden in lenalidomide-treated patients (median, 6 vs 2 units/8 weeks). Median follow-up was 4.3 years from first dose for lenalidomide-treated patients and 4.6 years from diagnosis for untreated patients. Two-year cumulative AML progression incidences were 6.9% (95% confidence interval (CI): 3.3–13.9) and 12.1% (95% CI: 7.0–20.3) and 2-year overall survival (OS) probabilities were 89.9% (95% CI: 84.1–96.0) and 74.4% (95% CI: 66.1–83.7), respectively. AML progression risk was similar in both cohorts (hazard ratio (HR) 0.969, P=0.930); however, lenalidomide treatment was associated with significant improvement in survival (HR 0.597, P=0.012), after adjusting for all other covariates. In conclusion, lenalidomide treatment does not increase AML progression risk, but instead confers a possible survival benefit in RBC transfusion-dependent patients with del(5q) Low- or Int-1-risk MDS.

Secondary primary malignancies in multiple myeloma: an old NEMESIS revisited

The treatment of myeloma has undergone extraordinary improvements in the past half century. These advances have been accompanied by a concern for secondary primary malignancies (SPMs). It has been known for decades that extended therapy with alkylating chemotherapy agents, such as melphalan, carries an increased risk of therapy-related myelodysplastic syndrome and/or acute myeloid leukemia (t-MDS/AML), with a cumulative risk as high as 10–15%. High-dose chemotherapy with autologous stem cell support became widely accepted for myeloma in the 1990s. Despite the use of high doses of melphalan, the risk of t-MDS/AML with this procedure is estimated to be less than 5%, with much of this risk attributable to pretransplant therapy. Recently, lenalidomide has come under scrutiny for its possible association with SPMs. It is too soon to declare a causal relationship at this time, but there appears to be an increased number of SPMs in reports from several studies using lenalidomide maintenance. Current studies should be amended and future studies planned to better define the risk of SPMs and the risk factors and mechanisms for its development. Patients should be educated regarding this potential concern but the current use of lenalidomide should not generally be altered until further data are available.

Update on immunomodulatory drugs (IMiDs) in hematologic and solid malignancies

INTRODUCTION

Thalidomide and its analogs [small molecule immunomodulatory drugs (IMiDs®)] are among the most successful new therapeutic agents of recent years. Thalidomide is now an integral part of multiple myeloma (MM) therapy. Lenalidomide has been approved for the treatment of patients with relapsed MM and 5q-myelodysplastic syndromes (MDS). Currently, more than 400 clinical trials are evaluating the activity of lenalidomide, alone or in combination with other conventional or novel therapies, in newly diagnosed MM and 5q-MDS. Based on their broad range of actions within the tumor microenvironment, IMiDs are currently also evaluated in a wide variety of additional hematologic and solid malignancies.

AREAS COVERED

This paper reviews the historic development of thalidomide and its derivatives and presents novel insights into their mode of action. Moreover, it discusses up-to-date clinical trials investigating IMiDs and potential future research and therapeutic perspectives in MM and other malignancies.

EXPERT OPINION

Although IMiDs have emerged as powerful agents for the treatment of hematologic and solid tumors, more preclinical and clinical studies are urgently needed both to increase our knowledge of their mechanisms of action, and to optimize their clinical use, in order to further improve the patient's quality of life and survival.