Patel, Shyam A

Acute myeloid leukemia (AML) pathogenesis is deeply rooted in the concept of clonal evolution, in which hematopoietic stem cells experience an initial genetic insult, followed by the sequential acquisition of mutations leading to various disease phenotypes. Through natural selection, a malignant clone can diversify and propagate with time. Aside from clonal evolution, a number of time-honored principles of molecular oncology account for the initiation and maintenance of AML. These principles include loss of heterozygosity, genomic instability, epigenomic disruption, deregulation of signaling pathways, anti-apoptotic mechanisms, and oncogene addiction. Such tenets of cancer biology not only explain AML cellular behavior but also may inform target validation in AML. Herein, we highlight the current state of targeted therapeutics, including the 14 novel agents (beyond 7+3 chemotherapy) approved by the Food and Drug Administration, in the context of these tenets and discuss future prospects by leveraging current knowledge of AML genomics. Such therapeutic concepts, including synthetic lethality, are especially relevant to TP53-mutant AML, as there are no unique therapies that have received regulatory approval for this subset to date. We emphasize the emerging role of single-cell genomics and multi-omics toward better understanding of AML biology and development of future successful AML therapies.

ABSTRACT Age‐related changes in human hematopoietic stem cells (HSCs) often form the basis for clonal hematopoiesis (CH), which presages the development of overt myeloid neoplasm with variable risk. CH can also arise after exposure to chemotherapy, radiotherapy, or immune interventions. In this study, we performed clinico‐genomic profiling of therapy‐related CH (t‐CH) ( n = 67) versus de novo CH ( n = 123) from a multidisciplinary CHIP Clinic. The most enriched mutations in t‐CH were TET2 (26.2%), DNMT3A (22.4%), and TP53 (8.4%). Median latency period from the time of initial exposure to the diagnosis of t‐CH was 6.96 ± 1.10 years. Patients with t‐CH had inferior event‐free survival compared to de novo CH (median 29.9 months versus 122.1 months, p = 0.0045). Overall survival was also shorter in t‐CH versus de novo CH (median 55.3 months vs. 129.2 months, p = 0.043). Genes that imparted significantly increased risk for progression from t‐CH to overt therapy‐related myeloid neoplasm (t‐MN) included JAK2 (relative risk (RR) 9.42, p = 0.0001), RUNX1 (RR 7.11, p = 0.001), EZH2 (RR 7.11, p = 0.001), and TET2 (RR 13.4, p = 0.01). Clonal dynamic modeling of patients with t‐CH who progressed to overt t‐MN showed an increase in the relative clonal fraction and new clonal outgrowth. In the t‐CH cohort, higher mean variant allele frequency was observed in progressors versus non‐progressors (77.1% vs. 30.6%, p = 0.017). This study sheds light onto outcomes for CH based on differing clinical ontogeny and has implications for previvorship for secondary malignancies.

SummaryFrom a historical perspective, the treatment landscape of myelodysplastic syndromes/neoplasms (MDS) has experienced a standstill in terms of new approvals by the U.S. Food and Drug Administration up until the recent 5 years. The widespread availability of comprehensive genome sequencing has shed insight into human MDS biology toward the goal of rational therapeutic design. This new knowledge has inspired the development of investigational therapies that extend beyond the scope of traditional erythropoiesis‐stimulating agents and hypomethylating agents. We describe how these contemporary treatment options are changing the management paradigms for lower‐risk and higher‐risk MDS, based on the landmark trial data. We discuss investigational therapies in the MDS pipeline, such as venetoclax, emavusertib, canakinumab and olutasidenib. We highlight challenges and solutions to the successful translation of emerging therapies based on our improved understanding of the biology of MDS, including the genomics of MDS with mutated TP53. We discuss how the identification of biomarkers of response to therapeutics may help guide clinical trial design for certain subsets of patients. Finally, we discuss how multicentre randomized trials can help facilitate the clinical rollout of emerging MDS therapeutics.