Lenalidomide for del(5q) and Non-del(5q) Myelodysplastic Syndromes

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.

Lenalidomide treatment of myelodysplastic syndromes with chromosome 5q deletion: Results from the National Registry of the Italian Drug Agency

OBJECTIVE

The most typical cytogenetic aberration in myelodysplastic syndromes is del(5q), which, when isolated, is associated with refractory anaemia and good prognosis. Based on high rates of erythroid response and transfusion independence, Lenalidomide (LEN) became the standard treatment. This multi-centre study was designed to supplement Italian Registry data on LEN by addressing prescription, administration appropriateness, haematological and cytogenetic responses and disease evolution.

METHODS

MORE study was an observational, non-interventional, multi-centre, retrospective and prospective study. Cases were recruited from 45 Haematological Centres throughout Italy. Data were collected from the Italian National Registry for Lenalidomide administration and supplemented by a MORE data form.

RESULTS

Data from 190/213 patients were analysed. In all, 149 had been diagnosed by conventional cytogenetics (GROUP A) and 41 only by FISH (GROUP B). Overall erythroid response was obtained in 92.8% of cases. Overall cytogenetic remission was achieved in 22.6% of cases. Disease progression occurred in 15.6% of cases. Clonal cytogenetic evolution characterised progression to AML but not to higher risk MDS.

CONCLUSIONS

Erythroid response to Lenalidomide was similar in MDS with isolated del(5q) and with del(5q) plus one anomaly. Progression to AML or higher risk MDS showed different cytogenetic features.

Genome-wide association of white blood cell counts in Hispanic/Latino Americans: the Hispanic Community Health Study/Study of Latinos

Circulating white blood cell (WBC) counts (neutrophils, monocytes, lymphocytes, eosinophils, basophils) differ by ethnicity. The genetic factors underlying basal WBC traits in Hispanics/Latinos are unknown. We performed a genome-wide association study of total WBC and differential counts in a large, ethnically diverse US population sample of Hispanics/Latinos ascertained by the Hispanic Community Health Study and Study of Latinos (HCHS/SOL). We demonstrate that several previously known WBC-associated genetic loci (e.g. the African Duffy antigen receptor for chemokines null variant for neutrophil count) are generalizable to WBC traits in Hispanics/Latinos. We identified and replicated common and rare germ-line variants at FLT3 (a gene often somatically mutated in leukemia) associated with monocyte count. The common FLT3 variant rs76428106 has a large allele frequency differential between African and non-African populations. We also identified several novel genetic loci involving or regulating hematopoietic transcription factors (CEBPE-SLC7A7, CEBPA and CRBN-TRNT1) associated with basophil count. The minor allele of the CEBPE variant associated with lower basophil count has been previously associated with Amerindian ancestry and higher risk of acute lymphoblastic leukemia in Hispanics. Together, these data suggest that germline genetic variation affecting transcriptional and signaling pathways that underlie WBC development and lineage specification can contribute to inter-individual as well as ethnic differences in peripheral blood cell counts (normal hematopoiesis) in addition to susceptibility to leukemia (malignant hematopoiesis).

A calcium- and calpain-dependent pathway determines the response to lenalidomide in myelodysplastic syndromes

Despite the high response rates of individuals with myelodysplastic syndrome (MDS) with deletion of chromosome 5q (del(5q)) to treatment with lenalidomide (LEN) and the recent identification of cereblon (CRBN) as the molecular target of LEN, the cellular mechanism by which LEN eliminates MDS clones remains elusive. Here we performed an RNA interference screen to delineate gene regulatory networks that mediate LEN responsiveness in an MDS cell line, MDSL. We identified GPR68, which encodes a G-protein-coupled receptor that has been implicated in calcium metabolism, as the top candidate gene for modulating sensitivity to LEN. LEN induced GPR68 expression via IKAROS family zinc finger 1 (IKZF1), resulting in increased cytosolic calcium levels and activation of a calcium-dependent calpain, CAPN1, which were requisite steps for induction of apoptosis in MDS cells and in acute myeloid leukemia (AML) cells. In contrast, deletion of GPR68 or inhibition of calcium and calpain activation suppressed LEN-induced cytotoxicity. Moreover, expression of calpastatin (CAST), an endogenous CAPN1 inhibitor that is encoded by a gene (CAST) deleted in del(5q) MDS, correlated with LEN responsiveness in patients with del(5q) MDS. Depletion of CAST restored responsiveness of LEN-resistant non-del(5q) MDS cells and AML cells, providing an explanation for the superior responses of patients with del(5q) MDS to LEN treatment. Our study describes a cellular mechanism by which LEN, acting through CRBN and IKZF1, has cytotoxic effects in MDS and AML that depend on a calcium- and calpain-dependent pathway.

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.

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.

A phase I study of oral ARRY-614, a p38 MAPK/Tie2 dual inhibitor, in patients with low or intermediate-1 risk myelodysplastic syndromes

PURPOSE

Data suggest that activity of p38 MAPK and Tie2 kinases is dysregulated in myelodysplastic syndromes (MDS) and may be targets for novel therapies. A phase I study of ARRY-614, an oral dual inhibitor of p38 MAPK and Tie2, was conducted in patients with low or intermediate-1 International Prognostic Scoring System risk MDS to evaluate safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary responses by International Working Group 2006 criteria.

EXPERIMENTAL DESIGN

Forty-five patients received ARRY-614 either once daily or twice daily in dose escalation (400, 600, 900, or 1,200 mg once daily; 200 or 300 mg twice daily) or expansion cohorts.

RESULTS

The 300 mg twice daily schedule was not tolerated, and an MTD was not reached for once daily dosing. Treatment-related adverse events were primarily grade 1-2, with the most common being rash, diarrhea, dry skin, fatigue and anorexia. Interpatient PK variability was high, although exposure was sufficient to achieve reduction in p38 MAPK activation in bone marrow and in the levels of circulating biomarkers. Disease responses were observed in 14 of 44 (32%) evaluable patients, 13 (93%) of whom had previously been treated with a hypomethylating agent. Responses were observed in all lineages, with 5 patients experiencing bilineage responses. Three of 25 red blood cell transfusion-dependent (TD) patients achieved transfusion independence (TI) and 5 of 7 platelet TD patients achieved TI.

CONCLUSIONS

ARRY-614 was well tolerated and has sufficient activity to warrant further evaluation in this patient population. We recommend 1,200 mg once daily as the optimal dose for further study.

High level of full-length cereblon mRNA in lower risk myelodysplastic syndrome with isolated 5q deletion is implicated in the efficacy of lenalidomide

Downregulation of cereblon (CRBN) gene expression is associated with resistance to the immunomodulatory drug lenalidomide and poor survival outcomes in multiple myeloma (MM) patients. However, the importance of CRBN gene expression in patients with myelodysplastic syndrome (MDS) and its impact on lenalidomide therapy are not clear. In this study, we evaluate cereblon expression in mononuclear cells isolated from bone marrow [23 lower risk MDS patients with isolated 5q deletion (5q-), 37 lower risk MDS patients with chromosome 5 without the deletion of long arms (non-5q-), and 24 healthy controls] and from peripheral blood (38 patients with 5q-, 52 non-5q- patients and 25 healthy controls) to gain insight into, firstly, the role of cereblon in lower risk MDS patients with or without 5q deletion and, secondly, into the mechanisms of lenalidomide action. Patients with 5q- lower risk MDS have the highest levels of CRBN mRNA in comparison with both lower risk MDS without the deletion of long arms of chromosome 5 and healthy controls. CRBN gene expression was measured using the quantitative TaqMan real-time PCR. High levels of CRBN mRNA were detected in all lenalidomide responders during the course of therapy. A significant decrease of the CRBN mRNA level during lenalidomide treatment is associated with loss of response to treatment and disease progression. These results suggest that, similar to the treatment of MM, high levels of full-length CRBN mRNA in lower risk 5q- patients are necessary for the efficacy of lenalidomide.

Analysis of the efficacy of lenalidomide in patients with intermediate-1 risk myelodysplastic syndrome without 5q deletion

The aim of this study was to evaluate the efficacy and adverse effects of lenalidomide in the treatment of intermediate-1 risk non-5q deletion [non-del (5q)] myelodysplastic syndrome (MDS). A total of 30 patients with MDS were classified through G-banding chromosome karyotype analysis and fluorescence in situ hybridization (FISH). According to the International Prognostic Scoring System scores, among the 30 patients, 23 and seven cases had scores of 0.5 and 1.0, respectively. Lenalidomide (Revlimid^®), 10 mg/day) was administered for 21 days every 28 days. All 30 cases were treated with lenalidomide for at least three cycles, including 20 cases with four cycles. The patients did not require erythropoietin, cyclosporine or iron chelation treatments. Statistical analysis was performed using SPSS statistical software version 13.0, and comparisons among groups were conducted using a t-test. The efficacy of lenalidomide was demonstrated in patients with intermediate-1 risk non-del (5q) MDS. Peripheral blood cell counts were improved following treatment, and absolute neutrophil, haemoglobin and platelet counts increased following 2–4 cycles of treatment. All patients became stable having undergone three cycles of treatment; however, 17 patients with chromosomal abnormalities had no cytogenetic response to the treatment, as confirmed through the FISH test. Patients with intermediate-1 risk non-del (5q) MDS treated with lenalidomide did not achieve complete haematological remission, although they demonstrated haematological improvement.

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.