Acute myeloid leukemia (AML) remains an extraordinarily deadly form of blood cancer, with fewer than 30% of affected adults expected to live for more than 3 years. But these statistics mark an improvement, thanks to advances in treatment options, with children especially likely to survive the disease.
For adult patients, "we've seen a series of remarkable and well-overdue advances in a space that had not changed much over the prior decades," hematologist/oncologist Thomas William LeBlanc, MD, associate professor of medicine at Duke University School of Medicine, Durham, North Carolina, said in an interview.
According to the National Cancer Institute, AML will be newly diagnosed in 20,800 patients in 2024, at a median age of 69, and will cause 11,220 deaths. As many as 70% of adult patients will reach complete remission, and 45% of those will live for more than 3 years and potentially be cured. As for children, the Leukemia & Lymphoma Society says the 5-year survival rate from 2012-2018 was 69% for those under 15 years old.
As the American Cancer Society notes, the goal of AML treatment "is to put the leukemia into complete remission (the bone marrow and blood cell counts return to normal), preferably a complete molecular remission (no signs of leukemia in the bone marrow, even using sensitive lab tests), and to keep it that way."
Chemotherapy Strategies Shift Over Time
In terms of the treatment of adults with AML, "targeted therapies, in addition to the expanding role of venetoclax, has really altered our approach to AML from diagnosis, including after relapse, and later in the disease," hematologist/oncologist Andrew M. Brunner, MD, of Harvard Medical School and Massachusetts General Hospital, Boston, said in an interview. "The ability to explore these options as monotherapy and in novel combinations has dramatically expanded our treatment options."
Much depends on the underlying genetic profile of the disease, he said. "There certainly have been gains in patient survival in AML, but those improvements remain fairly heterogeneous and dependent on the underlying genetic profile of the disease. For instance, advances in FLT3- and IDH1/2-mutated AML are a direct result of the improvements in targeted therapies directed at these mutations. Similarly, some molecular and cytogenetic subtypes of AML are particularly responsive to venetoclax-based regimens, and these regimens have been expanded to previously undertreated populations, particularly those over age 60."
Specifically, Dr LeBlanc said, the Food and Drug Administration has approved "3 different FLT3 inhibitors, 2 IDH1 inhibitors, 1 IDH2 inhibitor, a BCL-2 inhibitor, a smoothened/hedgehog pathway inhibitor, an oral maintenance chemotherapy/hypomethylating agent (CC-486/oral azacitidine), a CD33-targeting antibody-drug conjugate, and even a novel formulation of two older chemotherapies that improves efficacy in a poor prognosis subgroup (CPX-351/liposomal daunorubicin and cytarabine)."
There's also been a shift in treatment protocols for patients who were not fit for intensive chemotherapy. In the past, he said, it was standard "to give single-agent hypomethylating chemotherapy with azacitidine or decitabine, or in some contexts, low-dose chemotherapy with cytarabine. Today, many patients who are older and/or more frail are receiving novel therapies either alone or in combination, with greater efficacy and longer duration of response than previously seen with chemotherapy alone."
Outcomes Improve but Remain Grim in High-Risk Cases
As a result, Dr LeBlanc said, "we're definitely seeing much better outcomes in AML overall. It takes some time to prove this via outcomes data assessments in a large population, but I expect that registries will show significant improvements in overall survival in the coming years, owing to the many new FDA approvals in AML"
Dr LeBlanc highlighted national data from 2013-2019 showing that the 5-year relative survival rate from AML is 31.7%. That's up from 26% just a few years ago, and the numbers "always lag several years behind the current year of practice," he said. However, "the major area where we still have relatively poor outcomes and significant unmet needs remains the 'adverse risk' group of patients, particularly those who are older and/or not candidates for hematopoietic stem cell transplantation, which generally is the only potentially curative option for adverse-risk AML."
He went on to say that "this risk grouping includes those with TP53 mutations, most of which confer a particularly poor prognosis. Exciting therapies that many of us were hoping would prove effective in this subgroup have unfortunately failed in recent clinical trials. We still have a lot of work to do in adverse-risk AML particularly, and also for those whose leukemia has relapsed."
Mikkael Sekeres, MD, MS, chief of the Division of Hematology at the University of Miami Miller School of Medicine/Sylvester Comprehensive Cancer Center, agreed that more progress is needed, since survival rates are low even as lifespans improve. One key will be "better identifying subtypes of acute myeloid leukemia, and identifying the therapies that will benefit those people most," he said in an interview. On the other side, it's important to identify "when aggressive therapies aren't going to work in somebody and maybe turn toward less-aggressive approaches so we can maximize that person's quality of life."
What advice do AML experts have for their colleagues? Dr LeBlanc said "older patients are not often enough considered for allogeneic stem cell transplantation, which could potentially cure their AML when given as a consolidation treatment for those in remission. I have several patients who are healthy and in their 70s who have enormously benefited from transplants and are now being several years out from transplant with adverse risk AML and without relapse. They've had no significant impairments of their quality of life, including no significant graft vs. host disease."
Dr Sekeres highlighted the American Society of Hematology's guidelines for treating older adults with AML, which are currently being updated. It's crucial to order genetic testing "up front," he said. "I'm often pleasantly surprised when genetic testing returns and reveals that I have other treatment options."
However, it's crucial to understand a patient's priorities. "I've had patients who are 75 who say to me, 'Do everything under the sun to get rid of my leukemia, I want to live as long as possible.' And I've had patients who say, 'I want to see as little of doctors and nurses as I can. I want you to maximize my quality of life and keep me out of the hospital.' "
Dr Sekeres also noted that insurers may not cover some pill-based AML treatments such as venetoclax. "We work with our patients and assistance programs. For the most part, we're pretty successful at getting these drugs for our patients," he said.
In Pediatrics, Clinical Trials Are Crucial
AML in children is less well-known than in adults, since the number of cases is so small. The disease is diagnosed in about 500 children a year in the United States, according to St. Jude Children's Research Hospital, adding, however, that AML is "the most common second cancer among children treated for other cancers."
AML in children gained attention earlier this year when the 2-year-old daughter of a Boston Herald NFL reporter died of the disease following a bone marrow transplant and chemotherapy. Despite the agonies of her treatment, reporter Doug Kyed told a reporter that his daughter Hallie "was still able to find joy every day."
In an interview, hematologist/oncologist Sarah K. Tasian, MD, of Children's Hospital of Philadelphia, said researchers are discovering that pediatric AML is significantly different on from a biological perspective from adult AML. "We've come to understand a lot more about who these patients are, what makes these leukemias tick, and what their Achilles' heels are. Then we can align that with the clinical trials outcome data that we have."
About 80%-90% of pediatric patients with AML nationwide are enrolled in clinical trials, Dr Tasian said, and an international consortium called the Children's Oncology Group gathers data about genetics. About 60%-70% of patients will be cured, she added.
However, "we've kind of been stuck for about the last 20 years," she said. "A lot of improving the survival of patients has not been because we've been better at chemotherapy or using new chemo, but because we've gotten better at supportive care, at treating infections that can be fatal."
There haven't been major conflicts with insurers over coverage, she said, although drug shortages are a problem, especially in relapsed AML.
As for advice to colleagues, Dr Tasian counseled them to understand the importance of genetic testing and the expanding role of stem cell transplants. "We are now transplanting somewhere between 30% and 50% of children with AML, which is a higher rate than we used to do," she said. The number is up thanks to genetic testing that reveals which patients are most likely to benefit.
Also, she noted, "the chemotherapy that we get to these patients is really strong, and patients have a lot of complications. Really pay attention to supportive care."
Dr LeBlanc reported ties with AbbVie, Agios/Servier, Astellas, BMS/Celgene, Genentech, Pfizer, Incyte, Rige, Deverra, GSK, Jazz, and Seattle Genetics. Dr Sekeres discloses relationships with BMS and Kurome. Dr Tasian serves as the Leukemia & Lymphoma Society Pediatric Acute Leukemia consortium clinical trials leader and works with pharmaceutical companies on clinical trials under confidentiality agreements. Dr Brunner has no disclosures.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.