Treatment of Advanced Myelodysplastic Syndrome With Demethylating Agents: Azacitidine

Azacitidine Monotherapy in Patients With Treatment-Naïve Higher-risk Myelodysplastic Syndrome: A Systematic Literature Review and Meta-analysis

BACKGROUND

The global incidence of myelodysplastic syndromes (MDS) has been estimated as 0.06 to 0.26/100,000. Since their introduction, hypomethylating agents have played a central role in the treatment of MDS, with heterogeneous real-world outcomes.

MATERIALS AND METHODS

We assessed and synthesized clinical outcomes of azacitidine (AZA) monotherapy in treatment-naïve patients with higher-risk MDS. A systematic literature review was conducted by searching MEDLINE, Embase, and CENTRAL to identify randomized clinical trials (RCTs) and observational studies, both prospective and retrospective, reporting complete remission (CR), partial remission (PR), overall survival (OS), duration of response (DOR), time-to-response (TTR), and myelosuppressive adverse events (AEs) for patients treated with AZA monotherapy. Noncomparative meta-analyses were used to summarize effects.

RESULTS

The search identified 3250 abstracts, of which 34 publications describing 16 studies (5 RCTs, 3 prospective, and 8 retrospective observational) were included. Across all studies, pooled CR was 16%; PR was 6%; Median OS was 16.4 months; median DOR was 10.1 months; median TTR was 4.6 months. Proportions of grade 3/4 anemia and thrombocytopenia AEs were 10% and 30%.

CONCLUSIONS

The effectiveness and efficacy of AZA monotherapy-as measured by CR and median OS-was limited. These findings highlight a significant unmet medical need for effective treatments for patients with higher-risk MDS.

Azacitidine regulates DNA methylation of GADD45γ in myelodysplastic syndromes

Background

Myelodysplastic syndrome (MDS) is a heterogeneous clonal disease originated from hematopoietic stem cells. Epigenetic studies had demonstrated that DNA methylation and histone acetylation were abnormal in MDS. Azacitidine is an effective drug in the treatment of demethylation.

Methods

RT‐PCR was performed to determine GADD45γ in 15 MDS clinical samples. Myelodysplastic syndrome cell lines SKM‐1 and HS‐5 were transfected with GADD45γ eukaryotic expression vector and/or GADD45γ shRNA interference plasmid, and treated with azacitidine. Proliferation and apoptosis were examined by CCK‐8 and Western blot analysis to confirm the function role of GADD45γ and azacitidine. The methylation level of GADD45γ gene was detected by bisulfite conversion and PCR.

Results

This study found that GADD45γ gene was down‐expressed in MDS patients' bone marrow and MDS cell lines, and the down‐regulation of GADD45γ in MDS could inhibit MDS cell apoptosis and promote proliferation. Azacitidine, a demethylation drug, could restore the expression of GADD45γ in MDS cells and inhibit the proliferation of MDS cells by inducing apoptosis, which was related to prognosis and transformation.

Conclusion

This study indicated that GADD45γ was expected to become a new target of MDS‐targeted therapy. The findings of this study provided a new direction for the research and development of new MDS clinical drugs, and gave a new idea for the development of MDS demethylation drug to realize precise treatment.

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.

Characterization of acute myeloid leukemia based on levels of global hydroxymethylation

5hmC levels vary considerably in patients with AML. High levels of 5hmC independently correlate with inferior overall survival in AML.

Synergistic effect of 5-azacytidine and NF-κB inhibitor DHMEQ on apoptosis induction in myeloid leukemia cells

Constitutive NF-κB activation characterizes a subset of myeloid leukemia (ML) cells. Recent reports have indicated that DNA methyltransferase (DNMT) inhibitors are alternative candidates for the treatment of ML. However, the optimal use of DNMT as a chemotherapeutic agent against ML has yet to be established. In this report, we examined the effect of the NF-κB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) and its combinational use with the DNMT inhibitor 5-azacytidine (AZA) in ML cell lines. DHMEQ alone induced cell death in ML cell lines with NF-κB activation, although the response varied among the cell lines. The addition of DHMEQ enhanced the effect of AZA on the viability and apoptosis induction of ML cell lines. The treatment of ML cell lines with AZA marginally induced NF-κB binding activity, although the treatment induced NF-κB protein. These results indicate the potential usefulness of DHMEQ and its combinational use with AZA in the treatment of ML, although the molecular effect by AZA on the NF-κB pathway awaits further study.

When to transplant MDS, and what to do when transplant fails

Allogeneic hematopoietic stem cell transplantation (HCT) is still the only treatment modality with curative potential for patients with myelodysplastic syndromes. While early transplant-related mortality has improved during the last years, relapse risk following HCT still remains high, especially in older patients undergoing reduced-intensity conditioning. Therefore, when considering allogeneic HCT, in the absence of randomized data, emphasis should be put on patient selection and optimization of the pre-transplant and post-transplant period. In addition to a thorough comorbidity evaluation, risk stratification considering age, cytogenetics, grade of cytopenia, disease-related quality of life, as well as discussion of available treatment alternatives, are mandatory to decide when and how to perform allogeneic HCT. Since therapeutic options are often limited in patients relapsing after HCT, preventing relapse through maintenance strategies or minimal residual disease-directed therapy remains a central goal of current clinical research.

Safety and efficacy of 5-azacytidine treatment in myelodysplastic syndrome patients with moderate and mild renal impairment

Myelodysplastic syndrome (MDS) patients with renal impairment (RI) were not assessed in the approval trials of 5-azacytidine, thus the optimal use of 5-azacytidine in such patients is currently undefined. We retrospectively analyzed 42 IPSS intermediate-2 and high-risk patients with moderate, mild or no RI undergoing 5-azacytidine therapy in a non-trial setting. We demonstrate that patients in all three groups achieved comparable responses and had similar overall and event-free survival. Likewise, both treatment toxicity and dose adjustments were not significantly influenced by renal function status. A transient but reversible decline in glomerular filtration rate was observed in patients either with or without RI, without affecting the therapeutic schedule. Our results provide the first evidence that 5-azacytidine is effective and well-tolerated in patients with mild and moderate RI and, if confirmed by prospective randomized studies, advocate that such patients can be managed in an analogous fashion to patients with normal renal function.