Maintenance is a important component of therapy for acute lymphoblastic leukemia, but it’s still a relatively new concept in the treat of patients with acute myeloid leukemia (AML).
The topic of AML maintenance “has become quite hot actually, recently, after languishing for years behind ALL, a disease where maintenance is absolutely critical to overall survival; we haven’t had that much to talk about it in AML until recently,” said, from Weill Cornell Medicine and The New York Presbyterian Hospital, both in New York.
Dr. Roboz discussed her approach to AML maintenance during the virtual.
The current AML treatment paradigm starts with remission induction via intensive or less-intensive therapies, followed by consolidation with chemotherapy or with autologous or allogeneic stem cell transplantation (SCT), with maintenance considered as a possibility for some patients.
“Strictly speaking, maintenance is the idea of keeping someone in remission, but we’ve gotten used to it that maintenance is postremission therapy that is different from what you had in your induction,” she noted. “That said, the exact nature of maintenance, while it most traditionally refers to an ongoing lower-intensity therapy, is a little bit complicated these days of what exactly constitutes maintenance.”
Current AML treatments generally fail to completely eliminate leukemic cells, so nearly all patients have remissions with minimal residual disease (MRD).
“You have a heterogeneous mix of leukemia stem cells, progenitors, blast cells, and you are in remission but there are still leftovers, and those leftovers result in disease relapse, and the goal of postremission therapy to basically target and hopefully eradicate the leftovers,” Dr. Roboz said.
Focusing on the postremission period is vital because most patients with AML will die within 1 year after disease relapse.
Many options, none great
National Comprehensive Cancer Networkrecommend a variety of approaches to postremission therapy for patients younger than 60 years with AML, including, depending on risk, either histone deacetylase inhibitors, gemtuzumab ozogamicin (Mylotarg), chemotherapy, and/or SCT, but none of these options, strictly speaking, is called maintenance, she noted.
For patients 60 years and older, “there’s also a likelihood of proceeding with hypomethylating [HMA]-based therapy in such a way that, if they’re responding to initial treatment, they get ongoing therapy with whatever HMA or hypomethylating-based regimen they’re responding to. So is that called maintenance? Is that called ongoing therapy? Continuing therapy? It’s a subject of some controversy,” she added.
For patients younger than 60, hematopoietic SCT has been the ultimate form of maintenance, and increasingly allogeneic SCT is being employed in the United States for patients older than 60 years, including those 70 years and older.
“That has been a good thing, because we’ve been able to offer more patients potentially curative therapy, but the problem is that allo transplant is not a free lunch either, and there are significant risks of nonrelapse mortality, especially for patients going into the transplant with other comorbidities,” Dr. Roboz said.
The majority of older patients may not be cured with transplant because of the use of reduced-intensity conditioning regimens with the result of extended disease-free survival but eventual relapse from residual disease.
“The question is, if you’re an older patient and you can’t get an ablative transplant and you do have residual disease, what’s the likelihood of actually being cured at 2 years, and do you really want to go through the headaches of having a transplant?” she said.