In cancer biology, tumor-promoting inflammation and an inflammatory microenvironment play a vital role in disease pathogenesis. In the past decade, aberrant innate immune activation and ...proinflammatory signaling within the malignant clone and the bone marrow (BM) microenvironment were identified as key pathogenic drivers of myelodysplastic syndromes (MDS). In particular, S100A9-mediated NOD-like receptor protein 3 (NLRP3) inflammasome activation directs an inflammatory, lytic form of cell death termed pyroptosis that underlies many of the hallmark features of the disease. This circuit and accompanying release of other danger-associated molecular patterns expands BM myeloid-derived suppressor cells, creating a feed-forward process propagating inflammasome activation. Furthermore, somatic gene mutations of varied functional classes license the NLRP3 inflammasome to generate a common phenotype with excess reactive oxygen species generation, Wnt/β-catenin–induced proliferation, cation flux-induced cell swelling, and caspase-1 activation. Recent investigations have shown that activation of the NLRP3 inflammasome complex has more broad-reaching importance, particularly as a possible disease-specific biomarker for MDS, and, mechanistically, as a driver of cardiovascular morbidity/mortality in individuals with age-related, clonal hematopoiesis. Recognition of the mechanistic role of aberrant innate immune activation in MDS provides a new perspective for therapeutic development that could usher in a novel class of disease-modifying agents.
Opinion statement
Lower risk myelodysplastic syndromes are typically characterized by an indolent disease course with a relatively low risk of transformation into acute myeloid leukemia. These ...patients are classically identified using the revised International Prognostic Scoring System and most likely its molecular version in the near future which may change the paradigm of treatment. The overall goals of care are symptomatic control to reduce transfusion requirements and improve quality of life. Symptomatic anemia is the most common indication to initiate disease-specific therapies after the optimization of supportive measures. Currently, erythropoiesis-stimulating agents remain the standard upfront therapy for anemia, and patients with del(5q) cytogenetic changes can benefit from lenalidomide monotherapy. Other therapeutic options after failure of upfront treatment include luspatercept, hypomethylating agents, and immunosuppressive therapies after taking into account of individualized disease features. Allogeneic hematopoietic stem cell transplant is the only potentially curative option and is usually reserved for medically fit patients with severe symptomatic cytopenias who failed all standard options and/or the disease is progressing toward higher risk categories. Fortunately, novel investigational therapies are rapidly emerging by targeting different biological processes contributing to MDS pathogenesis, and eligible patients should be managed in clinical trials if available.
Approximately 20% of patients with
-mutant myelodysplastic syndromes (MDS) achieve complete remission (CR) with hypomethylating agents. Eprenetapopt (APR-246) is a novel, first-in-class, small ...molecule that restores wild-type p53 functions in
-mutant cells.
This was a phase Ib/II study to determine the safety, recommended phase II dose, and efficacy of eprenetapopt administered in combination with azacitidine in patients with
-mutant MDS or acute myeloid leukemia (AML) with 20%-30% marrow blasts (ClinicalTrials.gov identifier: NCT03072043).
Fifty-five patients (40 MDS, 11 AML, and four MDS/myeloproliferative neoplasms) with at least one
mutation were treated. The overall response rate was 71% with 44% achieving CR. Of patients with MDS, 73% (n = 29) responded with 50% (n = 20) achieving CR and 58% (23/40) a cytogenetic response. The overall response rate and CR rate for patients with AML was 64% (n = 7) and 36% (n = 4), respectively. Patients with only
mutations by next-generation sequencing had higher rates of CR (69%
25%;
= .006). Responding patients had significant reductions in
variant allele frequency and p53 expression by immunohistochemistry, with 21 (38%) achieving complete molecular remission (variant allele frequency < 5%). Median overall survival was 10.8 months with significant improvement in responding versus nonresponding patients by landmark analysis (14.6
7.5 months;
= .0005). Overall, 19/55 (35%) patients underwent allogeneic hematopoietic stem-cell transplant, with a median overall survival of 14.7 months. Adverse events were similar to those reported for azacitidine or eprenetapopt monotherapy, with the most common grade ≥ 3 adverse events being febrile neutropenia (33%), leukopenia (29%), and neutropenia (29%).
Combination treatment with eprenetapopt and azacitidine is well-tolerated yielding high rates of clinical response and molecular remissions in patients with
-mutant MDS and oligoblastic AML.
Summary Background Clonal haemopoiesis of indeterminate potential (CHIP) is an age-associated genetic event linked to increased risk of primary haematological malignancies and increased all-cause ...mortality, but the prevalence of CHIP in patients who develop therapy-related myeloid neoplasms is unknown. We did this study to investigate whether chemotherapy-treated patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms. Methods We did a nested, case-control, proof-of-concept study to compare the prevalence of CHIP between patients with cancer who later developed therapy-related myeloid neoplasms (cases) and patients who did not develop these neoplasms (controls). We identified cases from our internal biorepository of 123 357 patients who consented to participate in the Total Cancer Care biobanking protocol at Moffitt Cancer Center (Tampa, FL, USA) between Jan 1, 2006, and June 1, 2016. We included all individuals who were diagnosed with a primary malignancy, were treated with chemotherapy, subsequently developed a therapy-related myeloid neoplasm, and were 70 years or older at either diagnosis. For inclusion in this study, individuals must have had a peripheral blood or mononuclear cell sample collected before the diagnosis of therapy-related myeloid neoplasm. Controls were individuals who were diagnosed with a primary malignancy at age 70 years or older and were treated with chemotherapy but did not develop therapy-related myeloid neoplasms. Controls were matched to cases in at least a 4:1 ratio on the basis of sex, primary tumour type, age at diagnosis, smoking status, chemotherapy drug class, and duration of follow-up. We used sequential targeted and whole-exome sequencing and described clonal evolution in cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available. The primary endpoint of this study was the development of therapy-related myeloid neoplasm and the primary exposure was CHIP. Findings We identified 13 cases and 56 case-matched controls. The prevalence of CHIP in all patients (23 33% of 69 patients) was higher than has previously been reported in elderly individuals without cancer (about 10%). Cases had a significantly higher prevalence of CHIP than did matched controls (eight 62% of 13 cases vs 15 27% of 56 controls, p=0·024; odds ratio 5·75, 95% CI 1·52–25·09, p=0·013). The most commonly mutated genes in cases with CHIP were TET2 (three 38% of eight patients) and TP53 (three 38% of eight patients), whereas controls most often had TET2 mutations (six 40% of 15 patients). In most (four 67% of six patients) cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available, the mean allele frequency of CHIP mutations had expanded by the time of the therapy-related myeloid neoplasm diagnosis. However, a subset of paired samples (two 33% of six patients) had CHIP mutations that decreased in allele frequency, giving way to expansion of a distinct mutant clone. Interpretation Patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms. The distribution of CHIP-related gene mutations differs between individuals with therapy-related myeloid neoplasm and those without, suggesting that mutation-specific differences might exist in therapy-related myeloid neoplasm risk. Funding Moffitt Cancer Center.
Mutations in the essential tumor suppressor gene, TP53, are observed in only 5–10% of acute myeloid leukemia (AML) cases, but are highly associated with therapy-related AML and cases with complex ...karyotype. The mutational status of TP53 is a critical prognostic indicator, with dismal outcomes consistently observed across studies. Response rates to traditional cytotoxic chemotherapy are poor and long-term survival after allogeneic hematopoietic stem cell transplant is rare. Therapy with hypomethylating agents has resulted in a modest improvement in outcomes over intensive chemotherapy, but durable responses are seldom observed. In view of the intrinsic resistance to standard chemotherapies conferred by mutations in TP53, novel treatment approaches are required. In this review, we examine the current treatment landscape in TP53 mutated AML and discuss emerging therapeutic approaches currently under clinical investigation.
-mutated (
) myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) have very poor outcome irrespective of the treatment received, including 40% responses (20% complete remission CR) with ...azacitidine (AZA) alone, short response duration, and a median overall survival (OS) of approximately 6 months. Eprenetapopt (APR-246), a novel first-in-class drug, leads to p53 protein reconformation and reactivates its proapoptotic and cell-cycle arrest functions.
This phase II study assessed the safety and efficacy of eprenetapopt in combination with AZA in untreated high or very high International Prognostic Scoring System-R
MDS and AML patients.
Fifty-two
patients (34 MDS, 18 AML including seven with more than 30% blasts) were enrolled. In MDS, we observed an overall response rate (ORR) of 62%, including 47% CR, with a median duration of response at 10.4 months. In AML, the ORR was 33% including 17% CR (27% and 0% CR in AML with less than and more than 30% marrow blasts, respectively). Seventy-three percent of responders achieved
next-generation sequencing negativity (ie, variant allele frequency < 5%). The main treatment-related adverse events were febrile neutropenia (36%) and neurologic adverse events (40%), the latter correlating with a lower glomerular filtration rate at treatment onset (
< .01) and higher age (
= .05), and resolving with temporary drug interruption without recurrence after adequate eprenetapopt dose reduction. With a median follow-up of 9.7 months, median OS was 12.1 months in MDS, and 13.9 and 3.0 months in AML with less than and more than 30% marrow blasts, respectively.
In this very high-risk population of
MDS and AML patients, eprenetapopt combined with AZA was safe and showed potentially higher ORR and CR rate, and longer OS than reported with AZA alone.
Somatic gene mutations are key determinants of outcome in patients with myelodysplastic syndromes (MDS) and secondary AML (sAML). In particular, patients with TP53 mutations represent a distinct ...molecular cohort with uniformly poor prognosis. The precise pathogenetic mechanisms underlying these inferior outcomes have not been delineated. In this study, we characterized the immunological features of the malignant clone and alterations in the immune microenvironment in patients with TP53-mutant and wild-type MDS or sAML. Notably, PDL1 expression is significantly increased in hematopoietic stem cells of patients with TP53 mutations, which is associated with MYC upregulation and marked downregulation of MYC's negative regulator miR-34a, a p53 transcription target. Notably, patients with TP53 mutations display significantly reduced numbers of bone marrow–infiltrating OX40+ cytotoxic T cells and helper T cells, as well as decreased ICOS+ and 4-1BB+ natural killer cells. Further, highly immunosuppressive regulatory T cells (Tregs) (ie, ICOShigh/PD-1−) and myeloid-derived suppressor cells (PD-1low) are expanded in cases with TP53 mutations. Finally, a higher proportion of bone marrow–infiltrating ICOShigh/PD-1− Treg cells is a highly significant independent predictor of overall survival. We conclude that the microenvironment of TP53 mutant MDS and sAML has an immune-privileged, evasive phenotype that may be a primary driver of poor outcomes and submit that immunomodulatory therapeutic strategies may offer a benefit for this molecularly defined subpopulation.
•Mutant TP53 MDS and sAML have altered regulation of select checkpoint molecules.•Targeting the proposed mir-34a-MYC-PDL1 circuit in patients with TP53 mutations represents a novel therapeutic strategy.
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Despite genetic heterogeneity, myelodysplastic syndromes (MDSs) share features of cytological dysplasia and ineffective hematopoiesis. We report that a hallmark of MDSs is activation of the NLRP3 ...inflammasome, which drives clonal expansion and pyroptotic cell death. Independent of genotype, MDS hematopoietic stem and progenitor cells (HSPCs) overexpress inflammasome proteins and manifest activated NLRP3 complexes that direct activation of caspase-1, generation of interleukin-1β (IL-1β) and IL-18, and pyroptotic cell death. Mechanistically, pyroptosis is triggered by the alarmin S100A9 that is found in excess in MDS HSPCs and bone marrow plasma. Further, like somatic gene mutations, S100A9-induced signaling activates NADPH oxidase (NOX), increasing levels of reactive oxygen species (ROS) that initiate cation influx, cell swelling, and β-catenin activation. Notably, knockdown of NLRP3 or caspase-1, neutralization of S100A9, and pharmacologic inhibition of NLRP3 or NOX suppress pyroptosis, ROS generation, and nuclear β-catenin in MDSs and are sufficient to restore effective hematopoiesis. Thus, alarmins and founder gene mutations in MDSs license a common redox-sensitive inflammasome circuit, which suggests new avenues for therapeutic intervention.
•Key biological features of MDSs are explained by NLRP3 inflammasome activation, which drives pyroptotic cell death and β-catenin activation.•Alarmin signals and founder gene mutations license this redox-sensitive inflammasome platform.
Although remarkable international efforts have been ongoing for over 17 years to improve upon azacitidine, representing the standard of care therapy for higher-risk myelodysplastic neoplasms (MDS), ...there still has not been a positive randomized trial in comparison to azacitidine. Real-world data from numerous trials have shown similar results with a median overall survival of 14-18 months, a 40%-50% overall response rate, and a complete remission rate close to 20%. Despite these outcomes, 6 randomized controlled trials have failed to improve outcomes in this patient population, although relevant issues in some of these studies included improper dose adjustments of the hypomethylating agent, lack of placebo- controlled studies, and lack of overall survival (OS) as a primary endpoint, among others. Critical updates in MDS management include the development of molecular prognostication models (eg, the molecular international prognostic scoring system), updates in classification systems highlighting significant overlap in patients with MDS-increased blasts and acute myeloid leukemia (most relevant to TP53 mutations), and refinement of response criteria. Although these paradigm-shifting studies have had great impact in MDS management, the current ongoing randomized phase 3 trials were initiated prior, and prognostic stratification remains via the revised international prognostic scoring system) and with bone marrow blast counts of <20%. Notably, azacitidine + venetoclax, azacitidine + sabatolimab, and azacitidine + magrolimab have shown exciting results in large, single-arm studies and have completed accrual in placebo-controlled, double-blind studies with OS as a primary endpoint. We all eagerly await the results of these studies.
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