Advances in targeted therapy for acute myeloid leukemia.

Acute myeloid leukemia (AML) is a clonal malignancy characterized by genetic heterogeneity due to recurrent gene mutations. Treatment with cytotoxic chemotherapy has been the standard of care for more than half of a century. Although much progress has been made toward improving treatment related mortality rate in the past few decades, long term overall survival has stagnated. Exciting developments of gene mutation-targeted therapeutic agents are now changing the landscape in AML treatment. New agents offer more clinical options for patients and also confer a more promising outcome. Since Midostaurin, a FLT3 inhibitor, was first approved by US FDA in 2017 as the first gene mutation-targeted therapeutic agent, an array of new gene mutation-targeted agents are now available for AML treatment. In this review, we will summarize the recent advances in gene mutation-targeted therapies for patients with AML.

The KDM2B- let-7b -EZH2 axis in myelodysplastic syndromes as a target for combined epigenetic therapy.

Both DNA and histone methylation are dysregulated in the myelodysplastic syndromes (MDS). Based on preliminary data we hypothesized that dysregulated interactions of KDM2B, let-7b and EZH2 signals lead to an aberrant epigenetic landscape. Gene expression in CD34+ cells from MDS marrows was analyzed by NanoString miR array and validated by real-time polymerase chain reaction (PCR). The functions of KDM2B, let-7b and EZH2 were characterized in myeloid cell lines and in primary MDS cells. Let-7b levels were significantly higher, and KDM2B and EZH2 expression was lower in primary CD34+ MDS marrow cells (n = 44) than in healthy controls (n = 21; p<0.013, and p<0.0001, respectively). Overexpression of let-7b reduced EZH2 and KDM2B protein levels, and decreased cells in S-phase while increasing G0/G1 cells (p = 0.0005), accompanied by decreased H3K27me3 and cyclin D1. Silencing of KDM2B increased let-7b expression. Treatment with the cyclopentanyl analog of 3-deazaadenosine, DZNep, combined with the DNA hypomethylating agent 5-azacitidine, decreased levels of EZH2, suppressed methylation of di- and tri-methylated H3K27, and increased p16 expression, associated with cell proliferation. Thus, KDM2B, via let-7b/EZH2, promotes transcriptional repression. DZNep bypassed the inhibitory KDM2B/let-7b/EZH2 axis by preventing H3K27 methylation and reducing cell proliferation. DZNep might be able to enhance the therapeutic effects of DNA hypomethylating agents such as 5-azacitidine, currently considered standard therapy for patients with MDS.

Randomized phase 2b study of pralatrexate versus erlotinib in patients with stage IIIB/IV non-small-cell lung cancer (NSCLC) after failure of prior platinum-based therapy.

INTRODUCTION: Pralatrexate, a folate analogue targeting dihydrofolate reductase, has antitumor activity in non-small-cell lung cancer (NSCLC). This randomized phase 2b trial was designed to further evaluate pralatrexate activity in NSCLC by estimating overall survival (OS) relative to erlotinib in patients with relapsed/refractory disease. METHODS: In 43 centers across 6 countries, patients were randomized 1:1 to receive intravenous pralatrexate 190 mg/m on days 1 and 15 of a 28-day cycle, or oral erlotinib 150 mg/day. The primary objective was to estimate OS in all patients and prespecified subgroups using relative comparisons of hazard ratios (HRs). Secondary endpoints included progression-free survival, response rate, and safety. Key eligibility criteria included: (1) ≥1 prior platinum-based therapy, (2) Eastern Cooperative Oncology Group performance status of 0 to 1, and 3) a smoking history of 100 cigarettes or more. RESULTS: A total of 201 patients were randomized. A trend toward improvement in OS favoring pralatrexate was observed with an HR of 0.84 (95% confidence interval: 0.61-1.14) in the intent-to-treat population. This favorable survival result was seen in most prespecified subgroups for pralatrexate. The largest reduction in the risk of death was observed in patients with nonsquamous cell carcinoma (n = 107; HR = 0.65; 95% confidence interval: 0.42-1.0). The most common grade 3 to 4 adverse event in the pralatrexate arm was mucositis (23%). Discontinuation of pralatrexate for any grade of mucositis was 21%. CONCLUSIONS: Pralatrexate demonstrated a trend toward improved survival relative to erlotinib in patients with advanced NSCLC. Future studies should include a mucositis management plan to improve tolerability and maximize treatment benefit.

Hematologic responses of patients with MDS to antithymocyte globulin plus etanercept correlate with improved flow scores of marrow cells.

Myelodysplastic syndrome (MDS) comprises a spectrum of heterogeneous diseases. Most patients present with ineffective hematopoiesis. The pathophysiology involves immune-mediated effects, cytokine dysregulation, and apoptosis, among others. We treated 14 transfusion-requiring patients with MDS, 10 with refractory anemia (RA) and four with RA with excess blasts (RAEB) with a 4-day course of antithymocyte globulin (ATG) followed by intermittent etanercept for 4 months. Among 13 evaluable patients, five are red blood cell and platelet transfusion independent for intervals extending beyond 2 years, and two have normalized their peripheral blood parameters. One additional patient showed a transient rise of platelet and neutrophil counts, for an overall response rate of 46%. Responding patients showed striking improvements in marrow cell abnormalities as characterized by flow cytometry. These data show that a combination of ATG plus etanercept offers effective palliative therapy for unselected patients with MDS. Further trials incorporating these two agents are warranted.