Venetoclax and hypomethylating agent therapy in high risk myelodysplastic syndromes: a retrospective evaluation of a real-world experience

LC-MS/MS method for the quantitation of decitabine and venetoclax in rat plasma after SPE: Application to pharmacokinetic study

This study developed a novel, sensitive and selective LC-MS/MS method for the concurrent determination of DCB and VTX in rat plasma using encorafenib as internal standard (IS). To identify DCB, VTX, and IS, the positive multiple reaction monitoring (MRM) mode was used. Chromatographic separation was carried out using a reversed-phase Agilent Eclipse plus C18 column (100 mm × 2.1 mm, 3.5 µm) and an isocratic mobile phase made up of water with 0.1% formic acid and acetonitrile (50:50, v/v, pH 3.2) at a flow rate of 0.30 mL/min for 3.0 min. Prior to analysis, the DCB and VTX with the IS were extracted from plasma using the solid-phase extraction (SPE) method. High recovery rates for DCB, VTX and IS were achieved using the C18 cartridge without interference from plasma endogenous. The developed method was validated as per the FDA guidelines over a linear concentration range in rat plasma from 5-3000 and 5-1000 ng/mL for DCB and VTX, respectively with r2 ≥ 0.998. For both drugs, the lower limits of detection (LLOD) were 2.0 ng/mL. After the HLOQ sample was injected, less than 20% of the LLOQ of DCB, VTX, and less than 5% of the IS carry-over in the blank sample was attained. The overall recoveries of DCB and VTX from rat plasma were in the range of 90.68-97.56%, and the mean RSD of accuracy and precision results was ≤6.84%. For the first time, the newly developed approach was effectively used in a pharmacokinetic study on the simultaneous oral administration of DCB and VTX in rats that received 15.0 mg/kg of DCB and 100.0 mg/kg of VTX.

15-days duration of venetoclax combined with azacitidine in the treatment of relapsed/refractory high-risk myelodysplastic syndromes: A retrospective single-center study

The treatment of patients with refractory and/or relapsed (R/R) high-risk myelodysplastic syndrome (HR-MDS) remains a daunting clinical challenge. Venetoclax is a selective BCL-2 inhibitor, which combined with hypomethylating agents (HMAs), increased responses and prolonged survival in unfit and previously untreated acute myeloid leukemia. We performed a retrospective study of patients with R/R HR-MDS receiving combination azacytidine (AZA) plus 15-days duration of venetoclax (VEN-15d) in order to determine their efficacy and toxicity in this context. We showed that the overall response rate was 57.2% (20/35) and the median over survival was 14 months in R/R MDS. The most common treatment-emergent adverse events were peripheral blood cytopenias and infectious complications. Our retrospective study showed that the real-world experience of treating R/R MDS with AZA plus VEN-15d highlights an encouraging response rate with myelosuppression being the major toxicity. Of note, VEN-15d with AZA may salvage patients failing to respond optimally to HMAs and reduce the disease-burden for subsequent allogeneic stem cell transplantation in our analysis. These data of combination AZA plus VEN-15d in R/R MDS warrant further prospective evaluation in clinical trials.

Novel Therapies in Myelodysplastic Syndrome: Where Do Venetoclax and Isocitrate Dehydrogenase Inhibitors Fit in?

ABSTRACT

Myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal hematopoietic stem cell disorders with treatment approaches tailored to the presence of cytopenias, disease risk, and molecular mutation profile. In higher-risk MDSs, the standard of care are DNA methyltransferase inhibitors, otherwise referred to as hypomethylating agents (HMAs), with consideration for allogeneic hematopoietic stem cell transplantation in appropriate candidates. Given modest complete remission rates (15%-20%) with HMA monotherapy and median overall survival of approximately 18 months, there is much interest in the investigation of combination and targeted treatment approaches. Furthermore, there is no standard treatment approach in patients with progression of disease after HMA therapy. In this review, we aim to summarize the current evidence for the B-cell lymphoma-2 inhibitor, venetoclax, and a variety of isocitrate dehydrogenase inhibitors in the treatment of MDSs along with discussing their potential role in the treatment paradigm of this disease.

Azacitidine Is Synergistically Lethal with XPO1 Inhibitor Selinexor in Acute Myeloid Leukemia by Targeting XPO1/eIF4E/c-MYC Signaling

Acute myeloid leukemia (AML) is a high-mortality malignancy with poor outcomes. Azacitidine induces cell death and demonstrates treatment effectiveness against AML. Selinexor (KPT-330) exhibited significant benefits in combination with typical induction treatment for AML patients. Here, we explore the antitumor effect of KPT-330 combined with AZA in AML through CCK-8, flow cytometry, RT-qPCR, western blot, and RNA-seq. Our results showed that KPT-330 combined with AZA synergistically reduced cell proliferation and induced apoptosis in AML primary cells and cell lines. Compared to the control, the KPT-330 plus AZA down-regulates the expression of XPO1, eIF4E, and c-MYC in AML. Moreover, the knockdown of c-MYC could sensitize the synergy of the combination on suppression of cell proliferation and promotion of apoptosis in AML. Moreover, the expression of XPO1 and eIF4E was elevated in AML patient cohorts, respectively. XPO1 and elF4E overexpression was associated with poor prognosis. In summary, KPT-330 with AZA exerted synergistic effects by suppressing XPO1/eIF4E/c-MYC signaling, which provided preclinical evidence for further clinical application of the novel combination in AML.

Navigating the contested borders between myelodysplastic syndrome and acute myeloid leukemia

Myelodysplastic syndrome and acute myeloid leukemia are heterogeneous myeloid neoplasms which arise from the accumulation of mutations in a myeloid stem cell or progenitor that confer survival or growth advantages. These disease processes are formally differentiated by clinical, laboratory, and morphological presentations, especially with regard to the preponderance of blasts in the peripheral blood or bone marrow (AML); however, they are closely associated through their shared lineage as well as their existence on a spectrum with some cases of MDS displaying increased blasts, a feature that reflects more AML-like behavior, and the propensity for MDS to transform into AML. It is increasingly recognized that the distinctions between these two entities result from the divergent patterns of genetic alterations that drive each of them. Mutations in genes related to chromatin-remodeling and the spliceosome are seen in both MDS and AML arising out of antecedent MDS, while mutations in genes related to signaling pathways such as RAS or FLT3 are more typically seen in AML or otherwise are a harbinger of transformation. In this review, we focus on the insights into the biological and genetic distinctions and similarities between MDS and AML that are now used to refine clinical prognostication, guide disease management, and to inform development of novel therapeutic approaches.

Poly (ADP-ribose) polymerase-1 (PARP1) as a therapeutic target in acute myeloid leukemia and myelodysplastic syndrome

Poly(ADP‐ribose) polymerase 1 (PARP1) is a key mediator of various forms of DNA damage repair and plays an important role in the progression of several cancer types. The enzyme is activated by binding to DNA single-strand and double-strand breaks. Its contribution to chromatin remodeling makes PARP1 crucial for gene expression regulation. Inhibition of its activity with small molecules leads to the synthetic lethal effect by impeding DNA repair in the treatment of cancer cells. At first, PARP1 inhibitors (PARPis) were developed to target breast cancer mutated cancer cells. Currently, PARPis are being studied to be used in a broader variety of patients either as single agents or in combination with chemotherapy, antiangiogenic agents, ionizing radiation, and immune checkpoint inhibitors. Ongoing clinical trials on olaparib, rucaparib, niraparib, veliparib, and the recent talazoparib show the advantage of these agents in overcoming PARPi resistance and underline their efficacy in targeted treatment of several hematologic malignancies. In this review, focusing on the crucial role of PARP1 in physiological and pathological effects in myelodysplastic syndrome and acute myeloid leukemia, we give an outline of the enzyme’s mechanisms of action and its role in the pathophysiology and prognosis of myelodysplastic syndrome/acute myeloid leukemia and we analyze the available data on the use of PARPis, highlighting their promising advances in clinical application.

Low-dose decitabine plus venetoclax is safe and effective as post-transplant maintenance therapy for high-risk acute myeloid leukemia and myelodysplastic syndrome

Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are usually associated with poor outcomes, especially in high-risk AML/MDS. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative option for patients suffering from high-risk AML/MDS. However, many patients relapse after allo-HSCT. Novel therapy to prevent relapse is urgently needed. Both the BCL-2 inhibitor venetoclax (VEN) and the hypomethylating agent decitabine (DEC) possess significant antitumor activity effects against AML/MDS. Administration of DEC has been shown to ameliorate graft-versus-host disease (GVHD) and boost the graft-versus-leukemia (GVL) effect post-transplantation. We therefore conducted a prospective study (ChiCTR1900025374) to examine the tolerability and efficacy of a maintenance therapy of low-dose decitabine (LDEC) plus VEN to prevent relapse after allo-HSCT for high-risk AML/MDS patients. Twenty patients with high-risk AML (n = 17) or high-risk MDS (n = 3) post-transplantation were recruited. Approximately day 100 post-transplantation, all patients received LDEC (15 mg/m2 for 3 d) followed by VEN (200 mg) on d 1-21. The cycle interval was 2 mo, and there was 10 cycles. The primary end points of this study were rates of overall survival (OS) and event-free survival (EFS). The secondary endpoints included adverse events (AEs), cumulative incidence of relapse (CIR), nonrelapse mortality (NRM), incidences of acute GVHD (aGVHD) and chronic GVHD (cGVHD), and incidences of viral infection after allo-HSCT. Survival outcomes were assessed using Kaplan-Meier analysis. The median follow-up was 598 (149-1072) d. Two patients relapsed, 1 died, and 1 is still alive after the second transplant. The 2-y OS and EFS rates were 85.2% and 84.7%, respectively. The median 2-y EFS time was 525 (149-1072) d, and 17 patients still had EFS and were alive at the time of this writing. The most common AEs were neutropenia, anemia, thrombocytopenia, neutropenic fever, and fatigue. Grade 2 or 3 AEs were observed in 35% (7/20) and 20% (4/20) of the patients, respectively. No grade >3 AEs were observed. aGVHD (any grade) and cGVHD (limited or extensive) occurred in 55% and 20% of patients, respectively. We conclude that LDEC + VEN can be administered safely after allo-HSCT with no evidence of an increased incidence of GVHD, and this combination decreases the relapse rate in high-risk AML/MDS patients. This novel maintenance therapy may be a promising way to prevent relapse in high-risk AML/MDS patients.

Management of the Older Patient with Myelodysplastic Syndrome

No two diagnoses of myelodysplastic syndrome are genuinely alike, owing to differing and dynamic mutational topography and epigenetic aberrancy. Consequently, no two patients with myelodysplastic syndrome are identical and disease-specific and patient-specific factors are considered in formulating the optimal treatment, which includes few that are disease modifying. Age itself should not be an absolute contraindication to therapy, including intensive therapy such as allogeneic hematopoietic stem cell transplantation, which is the only curative therapy. However, age associates with an increased prevalence of frailty and comorbidities that must be considered and may preclude a path to cure. Palliative therapies are the mainstay for many patients with myelodysplastic syndrome, which is a disease of older adults with the majority of patients diagnosed at age ≥ 75 years. The older patient requires heightened attention to end organ function/reserve and drug-drug interactions as well as insurance, income, cost, and socioeconomic and psychosocial issues that influence management. Many prior studies have included relatively younger populations or have not specifically performed high-quality subgroup analyses of older patients. In this review, we discuss the available standard-of-care therapies for myelodysplastic syndrome as they specifically relate to the older population and assess the emerging therapeutics that may further the pursuit for personalized treatment and improve both the outcomes and quality of life of the older patient with myelodysplastic syndrome.

The potential of proliferative and apoptotic parameters in clinical flow cytometry of myeloid malignancies

Standardization of the detection and quantification of leukocyte differentiation markers by the EuroFlow Consortium has led to a major step forward in the integration of flow cytometry into classification of leukemia and lymphoma. In our opinion, this now enables introduction of markers for more dynamic parameters, such as proliferative and (anti)apoptotic markers, which have proven their value in the field of histopathology in the diagnostic process of solid tumors and lymphoma. Although use of proliferative and (anti)apoptotic markers as objective parameters in the diagnostic process of myeloid malignancies was studied in the past decades, this did not result in the incorporation of these biomarkers into clinical diagnosis. This review addresses the potential of these markers for implementation in the current, state-of-the-art multiparameter analysis of myeloid malignancies. The reviewed studies clearly recognize the importance of proliferation and apoptotic mechanisms in the pathogenesis of bone marrow (BM) malignancies. The literature is, however, contradictory on the role of these processes in myelodysplastic syndrome (MDS), MDS/myeloproliferative neoplasms, and acute myeloid leukemia. Furthermore, several studies underline the need for the analysis of the proliferative and apoptotic rates in subsets of hematopoietic BM cell lineages and argue that these results can have diagnostic and prognostic value in patients with myeloid malignancies. Recent developments in multiparameter flow cytometry now allow quantification of proliferative and (anti)apoptotic indicators in myeloid cells during their different maturation stages of separate hematopoietic cell lineages. This will lead to a better understanding of the biology and pathogenesis of these malignancies.

Decitabine combined with low dose idarubicin and cytarabine (D-IA) followed by allo-HSCT improves acute myeloid leukemia and higher-risk myelodysplastic syndrome patient outcomes: results from a retrospective study

Treatment for acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) ineligible for intensive chemotherapy is a major challenge for clinicians. We enrolled 154 patients ineligible for intensive chemotherapy who were prescribed D-IA regimen (decitabine 15-20 mg/m² days 1 to 3-5, followed by idarubicin 3 mg/m² for 5-7 days and cytarabine 30 mg/m² for 7-14 days). For AML and MDS patients, the overall response rate after two cycles was 66.4% and 76.6%, respectively, and the 2-year overall survival rates were 29% and 31%, respectively. Fourteen (13.1%) AML and five (10.6%) MDS patients underwent allo-HSCT after complete remission. The allo-HSCT group survival time was significantly longer than the control group (median survival time not reached in HSCT group, 13 and 18.5 months in non-HSCT AML and MDS group). We concluded that D-IA regimen was effective and well tolerated for patients with AML or higher-risk MDS ineligible for intensive chemotherapy.

Venetoclax-based chemotherapy in acute and chronic myeloid neoplasms: literature survey and practice points

Venetoclax (VEN), a small-molecule inhibitor of B cell leukemia/lymphoma-2, is now FDA approved (November 2018) for use in acute myeloid leukemia (AML), specific to newly diagnosed elderly or unfit patients, in combination with a hypomethylating agent (HMA; including azacitidine or decitabine) or low-dose cytarabine. A recent phase-3 study compared VEN combined with either azacitidine or placebo, in the aforementioned study population; the complete remission (CR) and CR with incomplete count recovery (CRi) rates were 28.3% and 66.4%, respectively, and an improvement in overall survival was also demonstrated. VEN-based chemotherapy has also shown activity in relapsed/refractory AML (CR/CRi rates of 33-46%), high-risk myelodysplastic syndromes (CR 39% in treatment naïve, 5-14% in HMA failure), and blast-phase myeloproliferative neoplasm (CR 25%); in all instances, an additional fraction of patients met less stringent criteria for overall response. Regardless, venetoclax-induced remissions were often short-lived (less than a year) but long enough to allow some patients transition to allogeneic stem cell transplant. Herein, we review the current literature on the use of VEN-based combination therapy in both acute and chronic myeloid malignancies and also provide an outline of procedures we follow at our institution for drug administration, monitoring of adverse events and dose adjustments.

Characteristics of a Novel Target Antigen Against Myeloma Cells for Immunotherapy

Despite the availability of therapeutic treatments, multiple myeloma is an incurable haematological disorder. In this study, we aimed to clarify the role of CXorf48 as a therapeutic target in multiple myeloma. Based on a previously identified HLA-A*24:02-restiricted epitope from this novel cancer/testis antigen, we characterized the activities of cytotoxic T lymphocytes (CTLs) specific to this antigen against myeloma cells and evaluated the effects of demethylating agents in increasing antigen expression and enhancing the cytotoxic activity of CTLs. CXorf48 expression was examined by reverse transcription polymerase chain reaction (RT-PCR) using nine myeloma cell lines. Cell lines with low CXorf48 expression were treated by demethylating agents (DMAs), 5-azacytidine (5-aza), and 5-aza-2’-deoxycytidine (DAC) to evaluate gene expression using quantitative RT-PCR. Furthermore, CXorf48-specific CTLs were induced from peripheral blood mononuclear cells of HLA-A*24:02-positive healthy donors to evaluate antigen recognition using ELISpot and ⁵¹Cr cytotoxicity assays. CXorf48 was widely expressed in myeloma cells, and gene expression was significantly increased by DMAs. Furthermore, CXorf48-specific CTLs recognized DMA-treated myeloma cells. These findings suggest that CXorf48 is a useful target for immunotherapy, such as vaccination, in combination with demethylating agents for the treatment of patients with myeloma.