A phase 2 study of lenalidomide monotherapy in patients with deletion 5q acute myeloid leukemia: Southwest Oncology Group Study S0605

Selective CK1α degraders exert antiproliferative activity against a broad range of human cancer cell lines

Molecular-glue degraders are small molecules that induce a specific interaction between an E3 ligase and a target protein, resulting in the target proteolysis. The discovery of molecular glue degraders currently relies mostly on screening approaches. Here, we describe screening of a library of cereblon (CRBN) ligands against a panel of patient-derived cancer cell lines, leading to the discovery of SJ7095, a potent degrader of CK1α, IKZF1 and IKZF3 proteins. Through a structure-informed exploration of structure activity relationship (SAR) around this small molecule we develop SJ3149, a selective and potent degrader of CK1α protein in vitro and in vivo. The structure of SJ3149 co-crystalized in complex with CK1α + CRBN + DDB1 provides a rationale for the improved degradation properties of this compound. In a panel of 115 cancer cell lines SJ3149 displays a broad antiproliferative activity profile, which shows statistically significant correlation with MDM2 inhibitor Nutlin-3a. These findings suggest potential utility of selective CK1α degraders for treatment of hematological cancers and solid tumors.

Human leukocyte antigen (HLA) alleles as predictive factors for benefit from lenalidomide in acute myeloid leukemia (AML)

OBJECTIVES

Lenalidomide is an active agent in acute myeloid leukemia (AML); response rates are about 15-30%. There are no well-defined predictive factors for benefit from lenalidomide in AML. One of the mechanisms of lenalidomide is natural killer (NK) cell activation; hence human leukocyte antigen (HLA) class I alleles (serving as killer immunoglobulin-like receptor ligands) could play a predictive role. We here evaluate the same when lenalidomide was used as a bridge to transplant.

METHODS

Consecutive AML patients started on lenalidomide as bridge to transplant between Aug-2013 to Aug-2018 were included in this single centre retrospective analysis. The starting dose and schedule of lenalidomide were at the discretion of the treating clinician. Lenalidomide was scheduled to be stopped about 2-4 weeks prior to planned transplant admission (or was stopped earlier if there was intolerance). For this study, event was defined as progression/relapse while on lenalidomide or within 4 weeks of stopping the drug. The primary endpoint was event free survival (EFS). Those who underwent transplant without an event were censored on the day of transplant. Toxicities and post-transplant outcomes were secondary endpoints.

RESULTS

Twelve patients (8 males, median age 29 years) were included. At start of lenalidomide, 7 had complete remission (CR)-1 (measurable residual disease or MRD by flow cytometry was positive in 3, negative in 3, and 1 unknown), 4 CR-2 (all MRD negative) and 1 active disease. In the whole cohort, median EFS was not reached with projected 3 year EFS being 80%. There was a significantly reduced risk of event with HLA A*24 (0% vs 75%, P=0.018) or with HLA B*40 (0% vs 60%, P=0.045). Only 1 patient needed discontinuation due to toxicities (cytopenias). Among patients who underwent transplant, grade II-IV acute graft versus host disease (GVHD) was seen in 83%.

CONCLUSIONS

This is first study to show that HLA alleles may have a bearing on the effect of lenalidomide in AML and could serve as predictive biomarkers. These findings need to be confirmed in larger prospective studies.

Cancer therapies based on targeted protein degradation - lessons learned with lenalidomide

For decades, anticancer targeted therapies have been designed to inhibit kinases or other enzyme classes and have profoundly benefited many patients. However, novel approaches are required to target transcription factors, scaffolding proteins and other proteins central to cancer biology that typically lack catalytic activity and have remained mostly recalcitrant to drug development. The selective degradation of target proteins is an attractive approach to expand the druggable proteome, and the selective oestrogen receptor degrader fulvestrant served as an early example of this concept. Following a long and tragic history in the clinic, the immunomodulatory imide drug (IMiD) thalidomide was discovered to exert its therapeutic activity via a novel and unexpected mechanism of action: targeting proteins to an E3 ubiquitin ligase for subsequent proteasomal degradation. This discovery has paralleled and directly catalysed myriad breakthroughs in drug development, leading to the rapid maturation of generalizable chemical platforms for the targeted degradation of previously undruggable proteins. Decades of clinical experience have established front-line roles for thalidomide analogues, including lenalidomide and pomalidomide, in the treatment of haematological malignancies. With a new generation of 'degrader' drugs currently in development, this experience provides crucial insights into class-wide features of degraders, including a unique pharmacology, mechanisms of resistance and emerging therapeutic opportunities. Herein, we review these past experiences and discuss their application in the clinical development of novel degrader therapies.

Addition of lenalidomide to intensive treatment in younger and middle-aged adults with newly diagnosed AML: the HOVON-SAKK-132 trial

Lenalidomide, an antineoplastic and immunomodulatory drug, has therapeutic activity in acute myeloid leukemia (AML), but definitive studies about its therapeutic utility have been lacking. In a phase 3 study, we compared 2 induction regimens in newly diagnosed patients age 18 to 65 years with AML: idarubicine-cytarabine (cycle 1) and daunorubicin and intermediate-dose cytarabine (cycle 2) without or with lenalidomide (15 mg orally on days 1-21). One final consolidation cycle of chemotherapy or autologous stem cell transplantation (auto-SCT) or allogeneic SCT (allo-SCT) was provided according to a prognostic risk and minimal residual disease (MRD)-adapted approach. Event-free survival (EFS; primary end point) and other clinical end points were assessed. A second random assignment in patients in complete response or in complete response with incomplete hematologic recovery after cycle 3 or auto-SCT involved 6 cycles of maintenance with lenalidomide (10 mg on days 1-21) or observation. In all, 392 patients were randomly assigned to the control group, and 388 patients were randomly assigned to lenalidomide induction. At a median follow-up of 41 months, the study revealed no differences in outcome between the treatments (EFS, 44% ± 2% standard error and overall survival, 54% ± 2% at 4 years for both arms) although in an exploratory post hoc analysis, a lenalidomide benefit was suggested in SRSF2-mutant AML. In relation to the previous Dutch-Belgian Hemato-Oncology Cooperative Group and Swiss Group for Clinical Cancer Research (HOVON-SAKK) studies that used a similar 3-cycle regimen but did not pursue an MRD-guided approach, these survival estimates compare markedly more favorably. MRD status after cycle 2 lost prognostic value in intermediate-risk AML in the risk-adjusted treatment context. Maintenance with lenalidomide showed no apparent effect on relapse probability in 88 patients randomly assigned for this part of the study.

Phase I study of ADI-PEG20 plus low-dose cytarabine for the treatment of acute myeloid leukemia

Most acute myeloid leukemia (AML) cells are argininosuccinate synthetase‐deficient. Pegylated arginine deiminase (ADI‐PEG20) monotherapy depletes circulating arginine, thereby selectively inducing tumor cell death. ADI‐PEG20 was shown to induce complete responses in ~10% of relapsed/refractory or poor‐risk AML patients. We conducted a phase I, dose‐escalation study combining ADI‐PEG20 and low‐dose cytarabine (LDC) in AML patients. Patients received 20 mg LDC subcutaneously twice daily for 10 days every 28 days and ADI‐PEG20 at 18 or 36 mg/m² (dose levels 1 and 2) intramuscularly weekly. An expansion cohort for the maximal tolerated dose of ADI‐PEG20 was planned to further estimate the toxicity and preliminary response of this regimen. The primary endpoints were safety and tolerability. The secondary endpoints were time on treatment, overall survival (OS), overall response rate (ORR), and biomarkers (pharmacodynamics and immunogenicity detection). Twenty‐three patients were included in the study, and seventeen patients were in the expansion cohort (dose level 2). No patients developed dose‐limiting toxicities. The most common grade III/IV toxicities were thrombocytopenia (61%), anemia (52%), and neutropenia (30%). One had an allergic reaction to ADI‐PEG20. The ORR in 18 evaluable patients was 44.4%, with a median OS of 8.0 (4.5‐not reached) months. In seven treatment‐naïve patients, the ORR was 71.4% and the complete remission rate was 57.1%. The ADI‐PEG20 and LDC combination was well‐tolerated and resulted in an encouraging ORR. Further combination studies are warranted. (This trial was registered in ClinicalTrials.gov as a Ph1 Study of ADI‐PEG20 Plus Low‐Dose Cytarabine in Older Patients With AML, NCT02875093).

A phase I study of lenalidomide plus chemotherapy with idarubicin and cytarabine in patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome

Patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) have poor outcomes and hematopoietic cell transplantation (HCT) is the only curative treatment. New targeted therapies improved survival in select patients with specific mutations, however management of patients without these molecular alterations is an unmet need. We conducted a phase one study of lenalidomide in combination with cytarabine/idarubicin salvage chemotherapy in patients with R/R AML and high‐risk myelodysplastic syndromes. A total of 33 patients were enrolled in the study (30 AML, 3 MDS), and treated at three dose levels with 3 + 3 design. Dose‐limiting toxicity (DLT) was seen in eight patients, including four hematologic DLTs. The most commonly observed non‐hematologic serious adverse events were febrile neutropenia, rash, sepsis and renal injury. Dose level −1, consisting of 25 mg/d lenalidomide D1‐21, 1 g/m² cytarabine D5‐8, and 8 mg/m² idarubicin D5‐7 was determined to be the maximum tolerated dose. Note, 15/33 (45%) of patients were able to receive pre‐planned 21 days of lenalidomide. Overall, 18 patients achieved complete remission (CR) (n = 14) or CR with incomplete count recovery (CRi) (n = 4) with total CR/CRi rate of 56%. The 1‐year and 2‐year overall survival (OS) were 24% and 10%, respectively. Among responders, 10/18 underwent allogeneic HCT and had a 1‐year OS of 40%. There was no molecular pattern associated with response. These data demonstrate that the combination had clinical activity in R/R AML. This regimen should be further investigated for patients who relapsed after HCT, and as a bridge therapy to HCT. (ClinicalTrials.gov identifier: NCT01132586).

Loss of 5q in myeloid malignancies - A gain in understanding of biological and clinical consequences

Hemizygous interstitial or terminal deletion of the long arm of chromosome 5 [del(5q)] is a recurrent cytogenetic abnormality in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). These deletions cause loss of a large contiguous chromosomal region encompassing more than 30 genes, which results in disease through haploinsufficiency of one or more genes including RPS14. In MDS, del(5q) in isolation is a lower-risk cytogenetic anomaly and is sometimes associated with a unique clinicopathological phenotype, but in AML it represents a higher-risk lesion, often denoting secondary AML arising from prior MDS. Lenalidomide effectively targets the del(5q)-bearing clone in MDS, resulting in sustained erythroid transfusion independence in most patients and cytogenetic remission in a subset of treated patients. Since the initial regulatory approval of lenalidomide for del(5q) MDS in 2005, translational research endeavors in del(5q)-associated myeloid malignancies have improved our understanding of how allelic haploinsufficiency underlies both the hematological phenotype and selective sensitivity to lenalidomide therapy. This review will focus on the molecular pathogenesis of del(5q) in myeloid malignancies, clinical development of lenalidomide and emerging data on lenalidomide-refractory del (5q) MDS, and possible novel targeted therapeutic strategies.

Hypomethylating agent based combinations in higher risk myelodysplastic syndrome

For over a decade the hypomethylating agents (HMA) azacitidine and decitabine have been the mainstay of therapy for myelodysplastic syndrome (MDS). There is a critical need to improve frontline therapy, given that only up to half of high-risk MDS patients will respond to HMA therapy, and responses are short-lived. Currently, a key strategy has been to combine HMAs with other novel agents to improve patient outcomes. While synergy of agents is the goal of combination therapy, combinations often come at the cost of increased side effects that are often intolerable in this vulnerable population. The purpose of this review is to critically examine clinically relevant HMA combinations and discuss the future of MDS management.

One plus one does not always equal two, especially with regard to hypomethylating agents: the question of synergy of azacitidine and lenalidomide for treatment of relapsed acute myeloid leukemia and myelodysplastic syndromes post allogeneic hematopoietic stem cell transplant

Key paper evaluation: Craddock C, et al. Combination Lenalidomide and Azacitidine: A Novel Salvage Therapy in Patients Who Relapse After Allogeneic Stem-Cell Transplantation for Acute Myeloid Leukemia. J Clin Oncol. 2019; 37: 580-8. Allogeneic hematopoietic stem cell transplant (allo-HSCT) is the only potentially curative treatment for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, most patients relapse after allo-HSCT and treatment options are limited. Craddock et al. reported recently in the Journal of Clinical Oncology results from a small phase Ib study combining azacitidine (AZA) and lenalidomide (LEN) for treatment of 29 patients (24 AML and 5 MDS patients) who relapsed after allo-HSCT. Overall response rate was 24%. Patients who received ≥3 cycles of treatment had a higher response rate and responders had a better survival compared to non-responders (27 months vs. 10 months; p = 0.004). Combination treatment was well tolerated with three cases of graft-versus-host disease. While this study suggests a potential synergistic effect of LEN + AZA combination therapy, many questions remain. Efficacy and safety should be confirmed in larger, ideally randomized, studies. Further research on mechanism of action of this combination, comparison with other treatment combinations (e.g. AZA + venetoclax) and use during other disease stages are needed.

Sequential azacitidine and lenalidomide for patients with relapsed and refractory acute myeloid leukemia: Clinical results and predictive modeling using computational analysis

BACKGROUND

Patients with relapsed and refractory (R/R) acute myeloid leukemia (AML) have limited treatment options. Genomically-defined personalized therapies are only applicable for a minority of patients. Therapies without identifiable targets can be effective but patient selection is challenging. The sequential combination of azacitidine with high-dose lenalidomide has shown activity; we aimed to determine the efficacy of this genomically-agnostic regimen in patients with R/R AML, with the intention of applying sophisticated methods to predict responders.

METHODS

Thirty-seven R/R AML/myelodysplastic syndrome patients were enrolled in a phase 2 study of azacitidine with lenalidomide. The primary endpoint was complete remission (CR) and CR with incomplete blood count recovery (CRi) rate. A computational biological modeling (CBM) approach was applied retrospectively to predict outcomes based on the understood mechanisms of azacitidine and lenalidomide in the setting of each patients' disease.

FINDINGS

Four of 37 patients (11%) had a CR/CRi; the study failed to meet the alternative hypothesis. Significant toxicity was observed in some cases, with three treatment-related deaths and a 30-day mortality rate of 14%. However, the CBM method predicted responses in 83% of evaluable patients, with a positive and negative predictive value of 80% and 89%, respectively.

INTERPRETATION

Sequential azacitidine and high-dose lenalidomide is effective in a minority of R/R AML patients; it may be possible to predict responders at the time of diagnosis using a CBM approach. More efforts to predict responses in non-targeted therapies should be made, to spare toxicity in patients unlikely to respond and maximize treatments for those with limited options.

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 the treatment of acute myeloid leukemia: a systematic review and meta-analysis

Background

Lenalidomide is effective for the treatment of low-risk myelodysplastic syndromes with deletion 5q abnormalities. However, whether lenalidomide leads to a significant improvement in treatment response and overall survival (OS) in cases of acute myeloid leukemia (AML) remains controversial. A systematic review and a meta-analysis were performed to evaluate the efficacy and safety of lenalidomide in the treatment of AML.

Methods

Clinical studies were identified from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and ClinicalTrials.gov. Efficacy outcomes included overall response rate (ORR), complete remission (CR), and OS. Safety was evaluated based on the incidence of grade 3 and 4 treatment-related adverse events (AEs).

Results

Eleven studies were included in our meta-analysis; collectively these studies featured 407 AML patients. Pooled estimates for overall ORR and CR were 31% (95% CI: 26%–36%) and 21% (95% CI: 16%–27%), respectively. Thrombocytopenia, anemia, neutropenia, and infection were the most common grade 3 and 4 AEs.

Conclusion

Lenalidomide may have some clinical activity in AML, but the population that would benefit from lenalidomide and incorporating lenalidomide into combination drug strategies need to be better defined.

IMiDs mobilize acute myeloid leukemia blasts to peripheral blood through downregulation of CXCR4 but fail to potentiate AraC/Idarubicin activity in preclinical models of non del5q/5q- AML

Treatment for acute myeloid leukemia (AML) remains suboptimal and many patients remain refractory or relapse upon standard chemotherapy based on nucleoside analogs plus anthracyclines. The crosstalk between AML cells and the BM stroma is a major mechanism underlying therapy resistance in AML. Lenalidomide and pomalidomide, a new generation immunomodulatory drugs (IMiDs), possess pleiotropic anti-leukemic properties including potent immune-modulating effects and are commonly used in hematological malignances associated with intrinsic dysfunctional BM such as myelodysplastic syndromes and multiple myeloma. Whether IMiDs may improve the efficacy of current standard treatment in AML remains understudied. Here, we have exploited in vitro and in vivo preclinical AML models to analyze whether IMiDs potentiate the efficacy of AraC/Idarubicin-based standard AML chemotherapy by interfering with the BM stroma-mediated chemoresistance. We report that IMiDs do not exert cytotoxic effects on either non-del5q/5q- AML cells nor BM-MSCs, but they enhance the immunomodulatory properties of BM-MSCs. When combined with AraC/Idarubicin, IMiDs fail to circumvent BM stroma-mediated resistance of non-del5q/5q- AML cells in vitro and in vivo but induce robust extramedullary mobilization of AML cells. When administered as a single agent, lenalidomide specifically mobilizes non-del5q/5q- AML cells, but not healthy CD34⁺ cells, to peripheral blood (PB) through specific downregulation of CXCR4 in AML blasts. Global gene expression profiling supports a migratory/mobilization gene signature in lenalidomide-treated non-del5q/5q- AML blasts but not in CD34⁺ cells. Collectively, IMiDs mobilize non-del5q/5q- AML blasts to PB through CXCR4 downregulation, but fail to potentiate AraC/Idarubicin activity in preclinical models of non-del5q/5q- AML.

Comparable outcomes of patients eligible vs ineligible for SWOG leukemia studies

Patients may be deemed ineligible for a clinical trial for reasons that do not directly impact efficacy or safety. We identified reasons for ineligibility and compared outcomes of ineligible with eligible patients treated on Southwest Oncology Group (SWOG) Leukemia Committee protocols. Patients enrolled in SWOG phase 2, 2/3, or 3 protocols open since 2005 were analyzed for eligibility status, reasons for ineligibility, baseline characteristics, Eastern Cooperative Oncology Group (ECOG) performance status (PS), serious adverse events (SAEs), complete remission (CR) status, and overall survival. A total of 2361 patients were enrolled in the 13 included studies. Of these, 247 (10%) were deemed ineligible; 78 were excluded from analyses, and 169 were included. Of the 169 included in analyses, 60% (101/169) were excluded due to missing baseline documentation. Baseline characteristics comparing ineligible to eligible patients were similar, with the exception of ECOG PS for S0325 (P = .02) and S0530 (P = .002). In multivariable analyses, neither the proportion of patients with ECOG PS ≥ 2 (P = .12) nor the rate of grade 5 SAEs (P = .62) differed between groups. There was no difference in survival between eligible and ineligible patients (P = .25), and CR rates were similar, with the exception of S0325 (P < .001) and S0703 (P = .004). The findings of this study suggest that nonessential eligibility criteria can be less restrictive, thus expanding patient enrollment and avoiding protocol deviations. The clinical trials included in this study were registered at www.clincialtrials.gov as #NCT00085709, #NCT00066794, #NCT00070499, #NCT00109837, #NCT00093418, #NCT00492856, #NCT00337168, #NCT00352365, #NCT00658814, #NCT00792948, #NCT00945815, #NCT00840177, and #NCT01522976.

Beyond the Edge of Hypomethylating Agents: Novel Combination Strategies for Older Adults with Advanced MDS and AML

Higher-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) of the elderly exhibit several commonalities, including first line treatment with hypomethylating agents (HMA) like azacitidine (AZA) or decitabine (DAC). Until today, response to treatment occurs in less than 50 percent of patients, and is often short-lived. Moreover, patients failing HMA have a dismal prognosis. Current developments include combinations of HMA with novel drugs targeting epigenetic or immunomodulatory pathways. Other efforts focus on the prevention of resistance to HMA using checkpoint inhibitors to enhance immune attack. This review focuses on recent advances in the field of HMA-based front-line therapies in elderly patients with myeloid diseases.

A phase I study of lenalidomide plus chemotherapy with mitoxantrone, etoposide, and cytarabine for the reinduction of patients with acute myeloid leukemia

Patients with relapsed AML have a poor prognosis and limited responses to standard chemotherapy. Lenalidomide is an immunomodulatory drug that may modulate anti-tumor immunity. We performed a study to evaluate the safety and tolerability of lenalidomide with mitoxantrone, etoposide and cytarabine (MEC) in relapsed/refractory AML. Adult patients with relapsed/refractory AML were eligible for this phase I dose-escalation study. We enrolled 35 patients using a "3 + 3" design, with a 10 patient expansion cohort at the maximum tolerated dose (MTD). Lenalidomide was initially given days 1-14 and MEC days 4-8; due to delayed count recovery, the protocol was amended to administer lenalidomide days 1-10. The dose of lenalidomide was then escalated starting at 5 mg/d (5-10-25-50). The primary objective was tolerability and MTD determination, with secondary outcomes including overall survival (OS). The MTD of lenalidomide combined with MEC was 50 mg/d days 1-10. Among the 35 enrolled patients, 12 achieved complete remission (CR) (34%, 90%CI 21-50%); 30-day mortality was 6% and 60-day mortality 13%. The median OS for all patients was 11.5 months. Among 17 patients treated at the MTD, 7 attained CR (41%); the median OS was not reached while 12-month OS was 61%. Following therapy with MEC and lenalidomide, patient CD4+ and CD8+ T-cells demonstrated increased inflammatory responses to autologous tumor lysate. The combination of MEC and lenalidomide is tolerable with an RP2D of lenalidomide 50 mg/d days 1-10, yielding encouraging response rates. Further studies are planned to explore the potential immunomodulatory effect of lenalidomide and MEC.

Trends in Clinical Investigation for Myelodysplastic Syndromes

Myelodysplastic syndrome (MDS) paradigms have been dramatically changed over the last 10 years by major breakthroughs on both pathophysiologic and therapeutic aspects. It is currently a field of intense clinical investigation as new challenges have emerged in both low-risk and high-risk populations. In low-risk MDS, long-term control of anemia is a major issue, and second-line treatments after failure of erythropoiesis-stimulating agents are warranted. Several promising therapies are available, and there are many open questions on how to select the most adapted agent and/or sequence of agents in a specific individual. For high-risk MDS patients, improvement of frontline treatment (namely hypomethylating agents) and identification of valid treatments for relapsed/refractory patients are of paramount importance. This review attempts to define these challenges, summarize the results of the most recent and promising investigational strategies in the field, and to describe the future directions.

Randomized study of continuous high-dose lenalidomide, sequential azacitidine and lenalidomide, or azacitidine in persons 65 years and over with newly-diagnosed acute myeloid leukemia

Therapy of acute myeloid leukemia in older persons is associated with poor outcomes because of intolerance to intensive therapy, resistant disease and co-morbidities. This multi-center, randomized, open-label, phase II trial compared safety and efficacy of three therapeutic strategies in patients 65 years or over with newly-diagnosed acute myeloid leukemia: 1) continuous high-dose lenalidomide (n=15); 2) sequential azacitidine and lenalidomide (n=39); and 3) azacitidine only (n=34). The efficacy end point was 1-year survival. Median age was 76 years (range 66–87 years). Thirteen subjects (15%) had prior myelodysplastic syndrome and 41 (47%) had adverse cytogenetics. One-year survival was 21% [95% confidence interval (CI): 0, 43%] with high-dose lenalidomide, 44% (95%CI: 28, 60%) with sequential azacitidine and lenalidomide, and 52% (95%CI: 35, 70%) with azacitidine only. Lenalidomide at a continuous high-dose schedule was poorly-tolerated resulting in a high rate of early therapy discontinuations. Hazard of death in the first four months was greatest in subjects receiving continuous high-dose lenalidomide; hazards of death thereafter were similar. These data do not favor use of continuous high-dose lenalidomide or sequential azacitidine and lenalidomide over the conventional dose and schedule of azacitidine only in patients aged 65 years or over with newly-diagnosed acute myeloid leukemia. (clinicaltrials.gov identifier: 01358734).

Innovative strategies for adverse karyotype acute myeloid leukemia

PURPOSE OF REVIEW

Adverse karyotype acute myeloid leukemia is a disease particularly of older patients, but also observed in younger patients. Despite all efforts, standard chemotherapy is still generally applied in fit patients, as already for decades, and for nearly all different subtypes of acute myeloid leukemia. Lack of more specifically targeted therapy and the often older age of the patients are complicating treatment, and in the subgroup of patients achieving a complete remission, the strikingly high frequency of relapse is a characteristic of this disease. This review aims to give an overview of current treatment approaches as well as emerging therapies.

RECENT FINDINGS

Currently, the approach of a targeted therapy specific to the genetic and/or epigenetic aberrations detected in the individual patient is still not possible, and a 'one treatment fits all' course of action is still used, with allografting as curative consolidation. However, first immunotherapeutic approaches are emerging as treatment options and first phase 1 and 2 studies are described.

SUMMARY

Treatment of acute myeloid leukemia with adverse karyotype is still not individualized, most treatment options currently not being curative. This can change in the near future, but recent findings will have to be implemented into larger phase 3 studies before being standard of care.

A Phase II Study of Arginine Deiminase (ADI-PEG20) in Relapsed/Refractory or Poor-Risk Acute Myeloid Leukemia Patients

Exogenous arginine is required for growth in some argininosuccinate synthetase (ASS)-deficient cancers. Arginine deiminase (ADI) inhibits growth in various ASS-deficient cancers by depleting arginine. The efficacy of pegylated ADI (ADI-PEG20) in relapsed/refractory/poor-risk acute myeloid leukemia (AML) was evaluated in 43 patients in a prospective, phase II trial (NCT01910012 (10/07/2013), https://clinicaltrials.gov/ct2/show/NCT01910012?term = ADI-PEG20&rank = 12). Despite almost all pre-treatment tumor samples showing ASS deficiency, the best response among 21 evaluable patients was complete response (CR) in 2 (9.5%) and stable disease in 7 (33.3%), yielding a disease control rate (DCR) of 42.9%. The response durations of the two patients with CR were 7.5 and 8.8 months. DCR was correlated with a median of 8 weeks of arginine depletion to ≤10 μM. Using whole transcriptome sequencing, we compared gene expression profiling of pre- and post-treatment bone marrow samples of the two responders and three non-responders. The expression levels of some markers for AML subtypes and c-MYC regulated genes were considered potential predictors of response to ADI-PEG20. These results suggest that ASS deficiency is a prerequisite but not a sufficient condition for response to ADI-PEG20 monotherapy in AML. Predictive biomarkers and mechanistic explorations will be critical for identifying appropriate patients for future AML trials of ADI-PEG20.

Immunotherapeutic Concepts to Target Acute Myeloid Leukemia: Focusing on the Role of Monoclonal Antibodies, Hypomethylating Agents and the Leukemic Microenvironment

Intensive chemotherapeutic protocols and allogeneic stem cell transplantation continue to represent the mainstay of acute myeloid leukemia (AML) treatment. Although this approach leads to remissions in the majority of patients, long-term disease control remains unsatisfactory as mirrored by overall survival rates of approximately 30%. The reason for this poor outcome is, in part, due to various toxicities associated with traditional AML therapy and the limited ability of most patients to tolerate such treatment. More effective and less toxic therapies therefore represent an unmet need in the management of AML, a disease for which therapeutic progress has been traditionally slow when compared to other cancers. Several studies have shown that leukemic blasts elicit immune responses that could be exploited for the development of novel treatment concepts. To this end, early phase studies of immune-based therapies in AML have delivered encouraging results and demonstrated safety and feasibility. In this review, we discuss opportunities for immunotherapeutic interventions to enhance the potential to achieve a cure in AML, thereby focusing on the role of monoclonal antibodies, hypomethylating agents and the leukemic microenvironment.

Outcome of patients treated for myelodysplastic syndromes with 5q deletion after failure of lenalidomide therapy

While lenalidomide (LEN) is the standard of care for the lower-risk myelodysplastic syndromes (MDS) patients with deletion 5q, 35% will not respond to or do not tolerate the drug. Moreover, most of the patients will lose their response after a few years. Defining the outcome of patients with LEN failure and determining the impact of subsequent therapies is therefore important to develop alternative strategies. Based on an international collaboration, we were able to compile a total of 392 patient cases of lower-risk MDS patients with 5q deletion and to analyze their outcome after failure of lenalidomide. The median survival following LEN failure was 23 months. We observed a negative impact on survival of advanced age, higher bone marrow blast count at LEN initiation, progression after LEN failure, and unfavorable cytogenetics. Among the treatment strategies, we observed a relatively prolonged survival of patients treated subsequently with hypomethylating agents and only a limited impact on survival of allogeneic transplantation. In conclusion, our work stresses the relatively short survival of this group of patient and defines the expected baseline for the needed future investigations in this group of patients.

Lenalidomide combined with intensive chemotherapy in acute myeloid leukemia and higher-risk myelodysplastic syndrome with 5q deletion. Results of a phase II study by the Groupe Francophone Des Myélodysplasies

Patients with acute myeloblastic leukemia or higher risk myelodysplastic syndromes with 5q deletion (generally within a complex karyotype) respond poorly to intensive chemotherapy and have very poor survival. In this population, we evaluated escalating doses of lenalidomide combined with intensive chemotherapy in a phase II study. Treatment consisted of daunorubicin (45 mg/m²/day, days 1–3 in cohort 1, escalated to 60 mg/m²/day, days 1–3 in cohorts 2 and 3) combined with cytosine arabinoside (200 mg/m²/day, days 1–7) and lenalidomide (10 mg/day, days 1–21 in cohorts 1 and 2, escalated to 25 mg/day, days 1–21 in cohort 3). Eighty-two patients with 5q deletion were enrolled, including 62 with acute myeloblastic leukemia, 62/79 (78%) of whom had a complex karyotype (median 7 cytogenetic abnormalities, all but 2 of them monosomal) and three had unknown karyotypes. Thirty-eight patients (46%) achieved complete remission and the overall response rate was 58.5%. Among the 62 patients with a complex karyotype, 27 achieved complete remission (44%) and 21 had cytogenetic responses. A lower response rate was observed in patients with acute myeloblastic leukemia but other pretreatment factors, including cytogenetic complexity and treatment cohort, did not significantly influence response. Fifteen patients underwent allogeneic stem cell transplantation, including 11 patients in first remission. The 1-year cumulative incidence of relapse was 64.6% and the median overall survival was 8.2 months. By comparison with conventional intensive chemotherapy, the treatment protocol we used appeared to produce higher hematologic and cytogenetic complete remission rates in patients with very poor cytogenetics, but response duration was short in this very poor risk population, highlighting the need for better post-induction strategies. Clinical trial registry number: NCT00885508

A phase 2 trial of high dose lenalidomide in patients with relapsed/refractory higher-risk myelodysplastic syndromes and acute myeloid leukaemia with trilineage dysplasia

Limited therapies exist for patients with refractory and relapsed (RR) higher-risk myelodysplastic syndromes (HR-MDS) and acute myeloid leukaemia with trilineage dysplasia (AML-TD). High dose (HD) lenalidomide (50 mg) has activity as frontline therapy in elderly AML but there is limited data in the RR setting. This phase II trial included patients with RR HR-MDS or AML-TD at 2 doses of lenalidomide (15 or 50 mg) on days 1-28 of 42-day cycles. The primary endpoint was response rate using the 2006 International Working Group criteria. Overall survival (OS) was estimated by Kaplan-Meier methods. Of 27 patients enrolled, 59% had HR-MDS and 31% AML-TD. No patient had isolated del5q; 41% had poor-risk karyotype. Of 9 patients treated at 15 mg, 56% completed ≥2 cycles with no responses. Of 18 patients treated at 50 mg, 39% completed ≥2 cycles and 11% responded but all experienced grade 3/4 neutropenic fever/infection. The 60-day mortality rate was 30%. Median OS was 114 days with 19% surviving ≥1 year. The study was terminated due to lack of robust clinical activity. In conclusion, lenalidomide at 15 mg is ineffective in RR myeloid malignancies. Continous high dosing schedules are poorly tolerated and minimally active. Further evaluation should be considered in upfront intensive chemotherapy-ineligible patients.

Treatment patterns and comparative effectiveness in elderly acute myeloid leukemia patients (age 70 years or older): the Lyon-university hospital experience

The treatment of very elderly patients (≥70 years) with acute myeloid leukemia remains controversial. We present here 302 patients seen over a 14-year period in order to understand the real-world treatment patterns and outcomes in this patient population. Less than 25% of patients achieved a complete remission. The median overall survival was 12.4, 11.5 and 2.6 months, with a 3-year rates of 27%, 17% and 6%, for non-acute promyelocytic leukemia patients receiving intensive chemotherapy, lower-intensity therapy or best supportive care (BSC), respectively. In all ages, results were not significantly different among patients receiving low-intensity therapy and intensive chemotherapy, but significantly worse in those treated with BSC only. Similarly, intensive chemotherapy and low-intensity therapy gave better survival rates than BSC in patients with favorable- or intermediate-risk cytogenetics and in those with unfavorable cytogenetics (p < 0.0001 and p = 0.04, respectively).

Secondary Adult Acute Myeloid Leukemia: a Review of Our Evolving Understanding of a Complex Disease Process

OPINION STATEMENT

Secondary AML (s-AML) encompasses AML evolving from myelodysplasia (AML-MDS) and treatment-related AML (t-AML) after exposure to chemotherapy, radiation, or environmental toxins. S-AML has traditionally been considered a devastating disease, affecting a vulnerable population of heavily pretreated, older adults. A limited understanding of disease pathogenesis/heterogeneity and lack of effective treatments have hampered overall improvements in patient outcomes. With the recent understanding that the secondary nature of sAML does not by itself incur a poor prognosis and incorporation of cytogenetics and molecular genetics into patient care and the advancement of treatment, including improved supportive care, novel chemotherapeutics agents, and nonmyeloablative conditioning regimens as part of allogeneic hematopoietic cell transplantation (HCT), modest gains in survival and quality of life are beginning to be seen among patients with s-AML.

The safety of treatment options for elderly people with acute myeloid leukemia

INTRODUCTION

Life expectancy in elderly patients with acute myeloid leukemia (AML) is a function of age, disability, and co-morbidity, combined with leukemia characteristics. There is currently no consensus regarding the optimal therapeutic strategy for older adults with AML. Although selected older adults with AML can benefit from intensive therapies, recent evidence supports the use of lower-intensity therapies in most patients and emphasizes the importance of tolerability and quality of life.

AREAS COVERED

Results of the current clinical trials and safety data are reviewed.

EXPERT OPINION

Treatment recommendations for elderly patients with AML need to be individualized. In order to avoid toxicities, hematologists should collaborate more with geriatricians to identify clues of vulnerability in elderly patients through the study of functional physical, physiological, cognitive, social, and psychological parameters.

Are we curing more older adults with acute myeloid leukemia with allogeneic transplantation in CR1?

PURPOSE OF REVIEW

Despite the fact that acute myeloid leukemia (AML) is most common in older adults aged at least 60 years, curative therapy remains elusive in this population. Here we examine the data for predicting which patients are candidates for 'curative therapy', available therapeutic options, and the utilization of reduced intensity allogeneic stem cell transplantation in first remission.

RECENT FINDINGS

Incorporation of geriatric assessment tools to assess patient frailty, in addition to evaluation of comorbid conditions, improves patient selection for intense therapy. The majority of patients eligible for and treated with induction chemotherapy achieve complete remission, and overall survival in the older AML population is superior after allogeneic stem cell transplant. However, population-based studies continue to demonstrate the undertreatment or lack of treatment of older AML patients.

SUMMARY

New patient assessment tools, ability to offer more successful outcomes after induction chemotherapy, and improved survival after allogeneic transplantation has not yet translated to increased 'curative' treatment on a population level of older AML patients. It is critical that the tools and therapies available be put into practice while older patient enrollment in well designed therapeutic clinical trials which include the option of allogeneic transplantation is increased.

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.

Expanding role of lenalidomide in hematologic malignancies

Lenalidomide is an immunomodulatory agent that has been approved by the US Food and Drug Administration for treatment of multiple myeloma, deletion 5q myelodysplastic syndrome, and mantle cell lymphoma. In addition, it has clinical activity in lymphoproliferative disorders and acute myeloid leukemia. The mode of action includes immunomodulatory, anti-inflammatory, antiangiogenic, and antiproliferative mechanisms. The antitumor effect is a result of direct interference of key pathways in tumor cells and indirect modulation of the tumor microenvironment. There has been no recent collective review on lenalidomide in multiple myeloma, myelodysplastic syndrome/acute myeloid leukemia, and lymphoma. This review summarizes the results of current clinical studies of lenalidomide, alone and in combination with other agents, as a therapeutic option for various hematologic malignancies.

Sequential azacitidine and lenalidomide in patients with high-risk myelodysplastic syndromes and acute myeloid leukaemia: a single-arm, phase 1/2 study

BACKGROUND

The standard of care for myelodysplastic syndromes is hypomethylating agents such as azacitidine. However, responses to azacitidine are generally temporary, and outcomes after hypomethylating agent failure are dismal. Therefore, the development of more effective treatments is crucial to improve outcomes in patients with myelodysplastic syndromes. We aimed to assess azacitidine and lenalidomide in patients with high-risk myelodysplastic syndromes and acute myeloid leukaemia.

METHODS

We did this single-arm phase 1/2 study at the University of Texas MD Anderson Cancer Center, TX, USA. Patients of any age were eligible for phase 1 and 2a if they had relapsed or refractory acute myeloid leukaemia or myelodysplastic syndrome with bone marrow blasts more than 10%. For phase 2b, eligible participants were previously untreated with myelodysplastic syndrome with an International Prognostic Scoring System (IPSS) score of intermediate-1 or higher with up to 30% blasts. All participants received 75 mg/m(2) azacitidine once a day for days 1-5 for each 28 day cycle. We gave patients oral lenalidomide for 5 or 10 days starting on day 6. We assessed seven lenalidomide doses in a 3 + 3 phase 1 design (n=28). The primary endpoint in phase 1 was the maximum tolerated dose, and the primary endpoint in phase 2 was overall survival. Outcome analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01038635.

FINDINGS

Between Dec 30, 2009, and June, 17, 2013, we enrolled 88 patients (28 in phase 1 and 60 in phase 2). One patient unexpectedly died in the phase 1 study at the highest dose level, six more patients were recruited with no further serious adverse events. We recorded no dose-limiting toxic effects, and the maximum tolerated dose of lenalidomide in combination with azacitidine in patients with acute myeloid leukaemia and myelodysplastic syndrome was initially established at 50 mg per day for 10 days. In the first 20 patients in phase 2, we noted a high rate of myelosuppression and myelosuppression-related toxic effects; therefore, we amended the lenalidomide dose to 25 mg per day for 5 days. We also adjusted the inclusion criteria to include patients with less than 30% blasts to focus mainly on patients with myelodysplastic syndromes. Median overall survival was 75 weeks (IQR 25-not reached) for the 40 patients in phase 2b. The most common grade 3-4 adverse events overall were neutropenic fever (n=27) and pneumonia (n=18).

INTERPRETATION

We have identified a safe and active sequential treatment combination of azacitidine and lenalidomide for patient with myelodysplastic syndrome and have preliminary evidence that this dose is also safe for patients with acute myeloid leukaemia.

FUNDING

MD Anderson Cancer Center and Celgene.

Beyond hypomethylating agents failure in patients with myelodysplastic syndromes

PURPOSE OF REVIEW

Although hypomethylating agents (HMAs) significantly improve outcomes in myelodysplastic syndromes (MDS), only half the patients achieve objective responses, and most responders lose response within 1-2 years. Azacitidine prolongs survival by a median of only 9.5 months. Failure of HMA therapy is associated with a very dismal prognosis. Therefore, novel therapeutic approaches are clearly needed.

RECENT FINDINGS

The sequential use of the alternative HMA after failure of first line HMA is associated with modest efficacy. The improved understanding of the biologic underpinnings of the disease have opened the door to study investigational agents that target disrupted molecular pathways critical to the pathogenesis of MDS. Combination treatment strategies using an azacitidine backbone are demonstrating promising early results. Expanding the applicability of allogeneic stem cell transplantation (alloSCT), the only curative modality, by reducing toxicity and relapse rates is another area of active research.

SUMMARY

Sequential switching to the alternative HMA, clinical trials of novel targeted therapies, azacitidine-based combination therapeutic strategies, and improvements in the alloSCT platform are the main directions in improving outcomes of MDS post HMA failure.

Higher-risk myelodysplastic syndromes with del(5q): is sequential azacitidine-lenalidomide combination the way to go?

High-risk myelodysplastic syndromes (HR-MDS) and acute myeloid leukemia (AML) with deletions of long arm of chromosome 5 (del[5q]) are characterized by rapid progression and poor survival. The majority of these patients are elderly with comorbidities, therefore limiting the use of intensive therapies which, even if used, unfortunately yield low responses. While azacitidine prolongs survival in patients with HR-MDS by a median of 9.5 months, responses only occur in less than half of the patients, and azacitidine therapy is not curative, with most patients relapsing within 2 years. Therefore, strategies to improve outcomes in these patients are needed. Azacitidine and lenalidomide both have meaningful single-agent clinical activity in HR-MDS and AML with del(5q). Early-phase trials in HR-MDS without del(5q) suggest increased activity with a concurrent azacitidine-lenalidomide combination. In this article, we review the results of a Phase I trial of a sequential azacitidine-lenalidomide combination approach in patients with HR-MDS and AML with del(5q) abnormality.

Trial Watch: Lenalidomide-based immunochemotherapy

Lenalidomide is a synthetic derivative of thalidomide currently approved by the US Food and Drug Administration for use in patients affected by multiple myeloma (in combination with dexamethasone) and low or intermediate-1 risk myelodysplastic syndromes that harbor 5q cytogenetic abnormalities. For illustrative purposes, the mechanism of action of lenalidomide can be subdivided into a cancer cell-intrinsic, a stromal, and an immunological component. Indeed, lenalidomide not only exerts direct cell cycle-arresting and pro-apoptotic effects on malignant cells, but also interferes with their physical and functional interaction with the tumor microenvironment and mediates a robust, pleiotropic immunostimulatory activity. In particular, lenalidomide has been shown to stimulate the cytotoxic functions of T lymphocytes and natural killer cells, to limit the immunosuppressive impact of regulatory T cells, and to modulate the secretion of a wide range of cytokines, including tumor necrosis factor α, interferon γ as well as interleukin (IL)-6, IL-10, and IL-12. Throughout the last decade, the antineoplastic and immunostimulatory potential of lenalidomide has been investigated in patients affected by a wide variety of hematological and solid malignancies. Here, we discuss the results of these studies and review the status of clinical trials currently assessing the safety and efficacy of this potent immunomodulatory drug in oncological indications.

Hypomethylating agents and chemotherapy in MDS

Until recently, the treatment of higher risk myelodysplastic syndrome was based on [1] Intensive chemotherapy using anthracycline-AraC combinations, leading to a lower complete remission rates and a shorter CR duration compared with de novo AML [2], low dose chemotherapy with limited CR rate mainly restricted to patients with normal karyotype. Azacitidine was the first drug to significantly improve survival in higher risk MDS, although it is not curative. Thus, the survival improvement obtained with azacitidine must be the starting point for combination studies, and for utilization of this drug in other situations (before allo SCT, or after chemotherapy or allo SCT as maintenance treatment).

Myelodysplastic syndromes: toward a risk-adapted treatment approach

Several classification and scoring systems have been developed in myelodysplastic syndromes (MDS to predict the risk of progression to acute myeloid leukemia and survival. These prognostication models have been also used to inform therapeutic decision-making in a risk-adapted fashion. Patient-related factors such as age, comorbidities, and functional status have to be considered as well. Here we review a risk-guided therapeutic approach for the management of MDS patients. It is anticipated that the improved understanding of the complex pathogenesis of MDS and the recent discovery of important molecular lesions will be translated into novel therapeutic approaches. Additionally, some prognostic aberrations are expected to be incorporated into the prognostic tools with the goal of improving their prognostic precision and therefore allow for a more informed therapeutic decision-making based on the individual's risk profile.

5-azacitidine in the treatment of myelodysplastic syndrome and acute myeloid leukemia

SUMMARY Epigenetic dysregulation is one of the key mechanisms driving leukemogenesis in myelodysplastic syndromes (MDS) and acute myeloid leukemia. Over the last decade, the introduction of epigenetic targeted drugs, such as hypomethylating agents, has changed the paradigm of treatment, in particular for high-risk MDS. 5-azacitidine is one of the lead compounds of this new class of drugs and was registered for treatment of MDS in the USA in 2004 and for high-risk MDS in Europe in 2009. 5-azacitidine is able to trigger hematological responses and is the first therapy demonstrating an overall survival benefit for high-risk MDS patients as compared with conventional care regimens. In this review, we present the biological and pharmacological basis of the drug, an update on the clinical results and clinical research in MDS and acute myeloid leukemia, and discuss future developments in the field.

Lenalidomide monotherapy and in combination with cytarabine, daunorubicin and etoposide for high-risk myelodysplasia and acute myeloid leukaemia with chromosome 5 abnormalities

Patients with high risk myelodysplasia (HR-MDS) and acute myeloid leukaemia (AML) with chromosomal changes involving deletion of the long arm of chromosome 5 (del5q), especially with complex karyotype, rarely have a durable response to combination chemotherapy. In the subgroup with monosomal karyotype there are no long term survivors (Fang et al., 2011) [1]. Recent experience indicates that the incidence of del5q in AML is ~20–30%, with only 20–25% of patients achieving complete remission (CR) (Farag et al., 2006) [2]. Additionally, therapy has significant toxicity, with induction death rates ~20% even in younger patients (Juliusson et al., 2009) [3]. This lack of efficacy provides the clinical rationale for combination/sequential therapy with Lenalidomide and combination chemotherapy. Dose dependent haematological toxicity is the major safety concern with such a combination protocol. Therefore we conducted a phase 2 study, AML Len5 (ISRCTN58492795), to assess safety, tolerability and efficacy of lenalidomide monotherapy, followed by lenalidomide with intensive chemotherapy in patients with primary/relapsed/refractory high risk MDS or AML with abnormalities of chromosome 5.

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.

Combination of azacitidine and lenalidomide in myelodysplastic syndromes or acute myeloid leukemia-a wise liaison?

Treatment options for older patients with advanced myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) are limited and the prognosis remains poor, thereby warranting development of novel therapies. Aberrant epigenetic modifications, including altered DNA methylation, seem to contribute to the pathogenesis of these patients. In fact, hypomethylating agents (HMA) like azacitidine have been successfully used in clinical trials and achieved approval from health authorities. There is now growing evidence suggesting that the combination of drugs with different mechanisms of action might offer a potential benefit to these patients. This is especially done with the intention to synergize the positive effects of each drug on the defective hematopoiesis while sparing potential side effects and toxicities. Combination of HMA with histone deacetylase inhibitors, although mechanistically very tempting, have not yielded convincing improvement of the results in the majority of trials compared to single agent HMA treatment. Currently, combination therapies of azacitidine with lenalidomide appear to be promising thus making them an appealing option for treatment in these patients.