Project description:Hypomethylating agents (HMA) have played a pivotal role for treating myelodysplastic syndromes (MDS) over the past decade, inducing sustained hematological responses and delaying progression to leukemia. However, a vast majority of patients will experience treatment failure within 2 years, with poor prognoses and limited options, and management of this growing patient population remains unclear. Areas covered: With the introduction of new agents in the MDS field, a better understanding of the biology of MDS, and updated information on standard of care options (including allogeneic transplantation), we re-evaluate the global treatment strategy in MDS via novel agents, focusing in particular on investigational approaches for patients who fail to respond to HMA when applicable. This review aims to address two questions: what are reasonable alternatives to HMA in MDS, and what strategies can be used for patients experiencing HMA failure. Expert opinion/commentary: HMA therapy remains a mainstay of treatment, even if additional research is still warranted to maximize its benefits for the different groups of patients. The outcome of patients experiencing HMA failure remains grim, without standard of care, but several new approaches seem promising, as there is an increasing focus on studying treatments for patients refractory to HMA treatment.
Project description:Aberrant DNA methylation plays a pivotal role in tumor development and progression. DNA hypomethylating agents (HMA) constitute a class of drugs which are able to reverse DNA methylation, thereby triggering the re-programming of tumor cells. The first-generation HMA azacitidine and decitabine have now been in standard clinical use for some time, offering a valuable alternative to previous treatments in acute myeloid leukemia and myelodysplastic syndromes, so far particularly in older, medically non-fit patients. However, the longer we use these drugs, the more we are confronted with the (almost inevitable) development of resistance. This review provides insights into the mode of action of HMA, mechanisms of resistance to this treatment, and strategies to overcome HMA resistance including next-generation HMA and HMA-based combination therapies.
Project description:In the last decade, the treatment of higher-risk myelodysplastic syndromes (MDS) has revolved around the azanucleosides, azacitidine and decitabine, which at lower doses are postulated to work predominantly via their effects on inhibition of DNA methyltransferases and consequent DNA hypomethylation. For patients who relapse after, or do not respond to, hypomethylating agent therapy, the outcome is dismal, and new agents and approaches that have the potential to alter the natural history of these diseases are desperately needed. Allogeneic stem cell transplant is the only known potentially curative approach in MDS, but its applicability has been limited by the advanced age of patients and attendant comorbidities. There is now an increasing array of new agents under clinical investigation in MDS that aim to exploit our expanding understanding of molecular pathways that are important in the pathogenesis of MDS. This review focuses on a critical appraisal of novel agents being evaluated in higher-risk MDS that go beyond the conventional hypomethylating agent therapies approved by the US Food and Drug Administration.
Project description:We established acquired venetoclax resistant OCI-LY1R cell line by treating venetoclax sensitive parental OCI-Ly1 cell line with increasing doses of venetoclax up till 1µM. Parental OCI-Ly1 and venetoiclax-resistant OCI-Ly1R cells were treated with vehicle control or decitabine at 1uM for 3 days. We found that decitabine differantially regulated gene expression in venetoclax sensitive and resistant cells. With gene set enrichment analysis, we identified two pathways that were deregulated by decitabine in both cell lines.
Project description:APVO436 is a recombinant bispecific antibody designed to direct host cytotoxic T-cells to CD123-expressing blast cells in patients with hematologic malignancies. APVO436 showed promising tolerability and single-agent activity in relapsed or refractory (R/R) acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). The primary purpose of this post-hoc analysis was to evaluate the therapeutic and pharmacodynamic effects of APVO436 in 14 R/R AML/MDS patients who had failed treatment with hypomethylating agents (HMA) or venetoclax plus HMA prior to being enrolled in the APVO436 Phase 1 dose-escalation study that was recently completed. Eight of these 14 patients had R/R AML and had failed treatment with HMA (N=2) or venetoclax plus HMA (N=6). The remaining 6 patients had R/R MDS and had also failed treatment with HMA (N=5) or venetoclax plus HMA (N=1). They were treated with APVO436 at submicrogram dose levels >0.08 mcg/kg that were active in preclinical NOD/SCID mouse xenograft models of AML. APVO436 activated patients' T-cells as evidenced by reduced numbers of circulating CD123+CD34+ and CD33+CD34+ peripheral blasts. Single-agent activity was observed at dose levels ranging from 0.1 mcg/kg to 0.7 mcg/kg in 4 R/R AML patients (50%), including 3 patients with prolonged stable disease (SD) and one patient with complete remission (CR). Likewise, 3 MDS patients had SD (50%) and 3 additional MDS patients (50%) had a marrow CR at dose levels ranging from 0.1 mcg/kg to 0.8 mcg/kg. The median survival for the combined group of 14 R/R AML/MDS patients was 282 days. This early evidence of single-agent activity of APVO436 in R/R AML/MDS patients who failed HMA with or without venetoclax provides proof of concept supporting its in vivo immunomodulatory and anti-leukemic activity and warrants further investigation of its clinical impact potential.
Project description:First-line therapy for higher-risk myelodysplastic syndromes (MDS) includes decitabine (DAC) or azacitidine (AZA). Variables have not identified differential response rates between these. We assessed the influence of patient sex on outcomes including overall survival (OS) in 642 patients with higher-risk MDS treated with AZA or DAC. DAC-treated patients (35% of females, 31% of males) had marginally better OS than AZA-treated patients (p = .043), (median OS of 18.7 months versus 16.4 months), but the difference varied strongly by sex. Female patients treated with DAC had a longer median OS (21.1 months, 95% CI: 16.0-28.0) than female patients treated with AZA (13.2 months, 95% CI: 11.0-15.9; p = .0014), while for males there was no significant difference between HMAs (median OS 18.3 months with DAC versus 17.9 months for AZA, p = .59). The biological reason for this variability is unclear, but may be a consequence of differences in cytidine deaminase activity between men and women.
Project description: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.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.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.
Project description:Spliceosome mutations (SRSF2, SF3B1, U2AF1, ZRSR2), are encountered in ∼50% of secondary acute myeloid leukemia cases (sAML) and define a molecular subgroup with outcomes similar to sAML in de novo AML patients treated with intensive chemotherapy. Outcomes in patients with spliceosome mutations treated with hypomethylating agents in combination with venetoclax (HMA+VEN) remains unknown. The primary objective was to compare outcomes in patients with spliceosome mutations vs wild-type patients treated with HMA+VEN. Secondary objectives included analysis of the mutational landscape of the spliceosome cohort and assessing the impact of co-occurring mutations. We performed a retrospective cohort analysis of patients treated with HMA+VEN-based regimens at The University of Texas MD Anderson Cancer Center. A total of 119 patients (spliceosome mutated n = 39 [SRSF2, n = 24; SF3B1, n = 8; U2AF1, n = 7]; wild-type, n = 80) were included. Similar responses were observed between spliceosome and wild-type cohorts for composite complete response (CRc; 79% vs 75%, P = .65), and measurable residual disease-negative CRc (48% vs 60%, P = .34). Median overall survival for spliceosome vs wild-type patients was 35 vs 14 months (P = .58), and was not reached; 35 months and 8 months for patients with SRSF2, SF3B1, and U2AF1 mutations, respectively. IDH2 mutations were enriched in patients with SRSF2 mutations and associated with favorable outcomes (1- and 2-year overall survival [OS] of 100% and 88%). RAS mutations were enriched in patients with U2AF1 mutations and associated with inferior outcomes (median OS, 8 months). Comparable outcomes were observed between patients with vs without spliceosome mutations treated with HMA+VEN regimens, with specific co-mutation pairs demonstrating favorable outcomes.
Project description:Hypomethylating agents (HMAs) are the standard of care for patients with myelodysplastic syndrome (MDS). However, only around 50% of patients respond to these agents, and responses tend to be transient, with loss of response frequently happening within 2 years and being associated with very poor prognosis and limited therapeutic options. Identification of patients who will respond to HMAs is challenging. Mechanisms underlying resistance to HMAs are not clear yet. Recently, absence of response has been associated with increased cell-cycle quiescence among the hematopoietic progenitor cells. There are no standard-of-care options for patients after HMA failure. However, the increasing knowledge of MDS pathogenesis has led to the development of new potential therapies, including HMAs with longer half-life and exposure, inhibition of the antiapoptotic BCL2 protein with venetoclax or inhibition of immune-checkpoint regulatory proteins such as PD-1 or CTLA-4, innate immunity and targeting of CD33/CD3 with multiple monoclonal antibodies. In addition, multiple targeted agents are opening opportunities to treat subgroups of patients whose disease harbors mutations in TP53, IDH, FLT3, and genes involved in splicing machinery. Newer formulations of intensive chemotherapy and its different combinations may be considered a valid option in selected patients after HMA failure. Finally, decision making at the time of failure of response to HMAs should be personalized, taking into account that allogenic stem-cell transplantation remains the only therapeutic approach with curative potential in these patients. In the current review, we will focus on all the above aspects.
Project description: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.