Recent years have seen tremendous advances in treating acute myeloid leukemia (AML), largely because of progress in understanding the genetic basis of the disease. The US Food and Drug Administration ...approved 7 agents for AML in the last 2 years: the first new drugs in decades. In this review, the authors discuss these new approvals in the backdrop of an overall strategy for treating AML today. Treating AML in the modern era requires: 1) access to and use of upfront genetic and cytogenetic testing, not only to describe prognosis but also to help identify the best available therapy; 2) effectively working new therapies into a conventional backbone of treatment, including transplantation; and 3) continued commitment to clinical trials designed to capitalize on advances in genetics and immunology to foster the next wave of drug approvals.
Novel drugs for acute myeloid leukemia (AML) improve outcomes for patients and should be carefully incorporated into an overall treatment plan. Critical to the development of successful future treatments for AML will be an increased understanding of the clonal architecture and biology of the disease, the development of additional molecularly targeted agents, and advances in immunology, cell therapy, and transplantation.
Mutations in the gene encoding isocitrate dehydrogenase 1 ( IDH1) occur in 6 to 10% of patients with acute myeloid leukemia (AML). Ivosidenib (AG-120) is an oral, targeted, small-molecule inhibitor ...of mutant IDH1.
We conducted a phase 1 dose-escalation and dose-expansion study of ivosidenib monotherapy in IDH1-mutated AML. Safety and efficacy were assessed in all treated patients. The primary efficacy population included patients with relapsed or refractory AML receiving 500 mg of ivosidenib daily with at least 6 months of follow-up.
Overall, 258 patients received ivosidenib and had safety outcomes assessed. Among patients with relapsed or refractory AML (179 patients), treatment-related adverse events of grade 3 or higher that occurred in at least 3 patients were prolongation of the QT interval (in 7.8% of the patients), the IDH differentiation syndrome (in 3.9%), anemia (in 2.2%), thrombocytopenia or a decrease in the platelet count (in 3.4%), and leukocytosis (in 1.7%). In the primary efficacy population (125 patients), the rate of complete remission or complete remission with partial hematologic recovery was 30.4% (95% confidence interval CI, 22.5 to 39.3), the rate of complete remission was 21.6% (95% CI, 14.7 to 29.8), and the overall response rate was 41.6% (95% CI, 32.9 to 50.8). The median durations of these responses were 8.2 months (95% CI, 5.5 to 12.0), 9.3 months (95% CI, 5.6 to 18.3), and 6.5 months (95% CI, 4.6 to 9.3), respectively. Transfusion independence was attained in 29 of 84 patients (35%), and patients who had a response had fewer infections and febrile neutropenia episodes than those who did not have a response. Among 34 patients who had a complete remission or complete remission with partial hematologic recovery, 7 (21%) had no residual detectable IDH1 mutations on digital polymerase-chain-reaction assay. No preexisting co-occurring single gene mutation predicted clinical response or resistance to treatment.
In patients with advanced IDH1-mutated relapsed or refractory AML, ivosidenib at a dose of 500 mg daily was associated with a low frequency of grade 3 or higher treatment-related adverse events and with transfusion independence, durable remissions, and molecular remissions in some patients with complete remission. (Funded by Agios Pharmaceuticals; ClinicalTrials.gov number, NCT02074839 .).
The majority of patients with acute myeloid leukemia (AML) die from disease recurrence and historically, treatment options in both the relapsed and refractory settings of this disease have been ...limited. However, new insights into the molecular characterization and biology of relapsed and refractory AML have led to novel therapeutics and improvement in outcomes in these settings. The current understanding of mechanisms of disease resistance and status of treatment options both currently available and under exploration in relapsed and refractory AML are summarized in this review.
The rapid approval of multiple therapeutic agents since 2017 has led to improvement in selected populations such as isocitrate dehydrogenase and fms-like tyrosine kinase 3-mutated relapsed and refractory AML with agents such as enasidenib, ivosidenib, and gilteritinib. Despite these advancements, the only current curative approach remains allogeneic transplantation and only for those minority of patients that are candidates. However, encouraging results are being seen with a multitude of novel small molecular inhibitors and immunotherapeutic approaches currently in clinical trials both as single agents and combination strategies in both upfront and relapsed/refractory AML.
Continued advancements in the knowledge of various mechanisms of relapse and resistance in AML are ongoing, leading to the realization that diverse treatment strategies are needed to both prevent and manage relapsed and refractory disease.
T-cell bispecific antibodies (T-BsAbs) are a new class of cancer immunotherapy drugs that can simultaneously bind to tumor-associated antigens on target cells and to the CD3 subunit of the T-cell ...receptor (TCR) on T cells. In the last decade, numerous T-BsAbs have been developed for the treatment of both hematological malignancies and solid tumors. Among them, blinatumomab has been successfully used to treat CD19 positive malignancies and has been approved by the FDA as standard care for acute lymphoblastic leukemia (ALL). However, in many clinical scenarios, the efficacy of T-BsAbs remains unsatisfactory. To further improve T-BsAb therapy, it will be crucial to better understand the factors affecting treatment efficacy and the nature of the T-BsAb-induced immune response. Herein, we first review the studies on the potential mechanisms by which T-BsAbs activate T-cells and how they elicit efficient target killing despite suboptimal costimulatory support. We focus on analyzing reports from clinical trials and preclinical studies, and summarize the factors that have been identified to impact the efficacy of T-BsAbs. Lastly, we review current and propose new approaches to improve the clinical efficacy of T-BsAbs.
Ivosidenib (AG-120) is an oral, targeted agent that suppresses production of the oncometabolite 2-hydroxyglutarate via inhibition of the mutant isocitrate dehydrogenase 1 (IDH1; mIDH1) enzyme. From a ...phase 1 study of 258 patients with IDH1-mutant hematologic malignancies, we report results for 34 patients with newly diagnosed acute myeloid leukemia (AML) ineligible for standard therapy who received 500 mg ivosidenib daily. Median age was 76.5 years, 26 patients (76%) had secondary AML, and 16 (47%) had received ≥1 hypomethylating agent for an antecedent hematologic disorder. The most common all-grade adverse events were diarrhea (n = 18; 53%), fatigue (n = 16; 47%), nausea (n = 13; 38%), and decreased appetite (n = 12; 35%). Differentiation syndrome was reported in 6 patients (18%) (grade ≥3 in 3 9%) and did not require treatment discontinuation. Complete remission (CR) plus CR with partial hematologic recovery (CRh) rate was 42.4% (95% confidence interval CI, 25.5% to 60.8%); CR 30.3% (95% CI, 15.6% to 48.7%). Median durations of CR+CRh and CR were not reached, with 95% CI lower bounds of 4.6 and 4.2 months, respectively; 61.5% and 77.8% of patients remained in remission at 1 year. With median follow-up of 23.5 months (range, 0.6-40.9 months), median overall survival was 12.6 months (95% CI, 4.5-25.7). Of 21 transfusion-dependent patients (63.6%) at baseline, 9 (42.9%) became transfusion independent. IDH1 mutation clearance was seen in 9/14 patients achieving CR+CRh (5/10 CR; 4/4 CRh). Ivosidenib monotherapy was well-tolerated and induced durable remissions and transfusion independence in patients with newly diagnosed AML. This trial was registered at www.clinicaltrials.gov as #NCT02074839.
•In patients with newly diagnosed mIDH1 AML (median age, 76 years), ivosidenib monotherapy achieved median overall survival of 12.6 months.•The CR/CRh rate was 42.4%; mutation clearance in 64% patients with CR/CRh suggests that ivosidenib alters the biology of mIDH1 AML.
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The treatment landscape in acute myeloid leukemia (AML) is rapidly evolving, with multiple new therapies approved in recent years. However, the prognosis for patients with high-risk genetic subsets ...of AML remains poor, and the development of more effective treatment options for these patients is ongoing. Three of these high-risk AML patient subsets include TP53-mutated AML, FLT3-internal tandem duplication (ITD)-mutated AML, and AML harboring rearrangements affecting the KMT2A locus (KMT2A-r AML). The prognosis for TP53-mutated AML remains poor with both intensive and targeted regimens, including those incorporating the BCL-2 inhibitor, venetoclax. Allogeneic hematopoietic stem cell transplantation is the only potentially curative therapy for these patients, but posttransplant relapse rates remain high. Patients with FLT3-ITD-mutated AML continue to have suboptimal outcomes with standard therapies and experience high rates of relapse following transplant. KMT2A-r AML is also associated with poor outcomes with current treatment approaches, and effective standards of care are lacking for patients with relapsed/refractory disease. This article discusses current treatment approaches, along with the investigational agents being explored for the treatment of these 3 AML subsets, focusing primarily on agents that are further along in development.
CD33 is a transmembrane protein that is found on cells of myeloid lineage. It is also intensely expressed on acute myeloid leukemia (AML) progenitor cells but not on normal stem cells. It ...internalizes on binding and dimerization, making it a specific and ideal target for AML therapeutics and drug delivery. Several targeted therapies have been tested and many are still currently in development. Gemtuzumab ozogamicin was the first and only CD33‐directed antibody‐drug conjugate to be US Food and Drug Administration approved for AML. Other targeted agents have not achieved such success. Promising new strategies include cellular therapy mechanisms and linker molecules. This is an exciting target that requires a considerable amount of precision to yield clinical benefit.
Ivosidenib (AG-120) and enasidenib (AG-221) are targeted oral inhibitors of the mutant isocitrate dehydrogenase (mIDH) 1 and 2 enzymes, respectively. Given their effectiveness as single agents in ...mIDH1/2 relapsed or refractory acute myeloid leukemia (AML), this phase 1 study evaluated the safety and efficacy of ivosidenib or enasidenib combined with intensive chemotherapy in patients with newly diagnosed mIDH1/2 AML. Ivosidenib 500 mg once daily and enasidenib 100 mg once daily were well tolerated in this setting, with safety profiles generally consistent with those of induction and consolidation chemotherapy alone. The frequency of IDH differentiation syndrome was low, as expected given the concurrent administration of cytotoxic chemotherapy. In patients receiving ivosidenib, the frequency and grades of QT interval prolongation were similar to those observed with ivosidenib monotherapy. Increases in total bilirubin were more frequently observed in patients treated with enasidenib, consistent with this inhibitor's known potential to inhibit UGT1A1, but did not appear to have significant clinical consequences. In patients receiving ivosidenib (n = 60) or enasidenib (n = 91), end-of-induction complete remission (CR) rates were 55% and 47%, respectively, and CR/CR with incomplete neutrophil or platelet recovery (CR/CRi/CRp) rates were 72% and 63%, respectively. In patients with a best overall response of CR/CRi/CRp, 16/41 (39%) receiving ivosidenib had IDH1 mutation clearance and 15/64 (23%) receiving enasidenib had IDH2 mutation clearance by digital polymerase chain reaction; furthermore, 16/20 (80%) and 10/16 (63%), respectively, became negative for measurable residual disease by multiparameter flow cytometry. This trial was registered at www.clinicaltrials.gov as #NCT02632708.
Initial therapy for acute myeloid leukemia (AML) remained stagnant for approximately four decades despite advances in improved understanding of pathogenesis and prognostication of the disease. ...Treatment has typically consisted of an anthracycline combined with continuous infusion of cytarabine for 7 days, the “7 + 3” regimen. Attempts have been made to improve on this regimen with modest improvements in response rates but no change in overalll survival, until the recent introduction of mutation-specific agents. However, the re-vamping of the delivery of both daunorubicin and cytarabine in a liposomal encapsulation, known as CPX-351, did show improvements of overall survival compared to traditional 7 + 3 in newly diagnosed secondary and therapy-related AML in patients aged 60–75. This led to the Food and Drug Administration (FDA) approval of the agent for both of these subtypes of AML in August of 2017. Herein we will review the rationale and preclinical development of CPX-351 and discuss the pivotal studies that led to its FDA approval.
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