Conference Coverage

Can AML patients be too old for cell transplantation?



How old is too old for a patient to undergo hematopoietic cell transplantation (HCT)? That’s the wrong question to ask, a hematologist/oncologist told colleagues at the virtual Acute Leukemia Forum of Hemedicus. Instead, he said, look at other factors such as disease status and genetics.

“Transplantation for older patients, even beyond the age of 70, is acceptable, as long as it’s done with caution, care, and wisdom. So we’re all not too old for transplantation, at least not today,” said Daniel Weisdorf, MD, professor of medicine and deputy director of the University of Minnesota Clinical and Translational Science Institute.

As he noted, acute myeloid leukemia (AML) is often fatal. Among the general population, “the expected survival life expectancy at age 75 is 98% at 1 year, and most people living at 75 go on to live more than 10 years,” he said. “But if you have AML, at age 75, you have 20% survival at 1 year, 4% at 3 years. And since the median age of AML diagnosis is 68, and 75% of patients are diagnosed beyond the age of 55, this becomes relevant.”

Risk factors that affect survival after transplantation “certainly include age, but that interacts directly with the comorbidities people accumulate with age, their assessments of frailty, and their Karnofsky performance status, as well as the disease phenotype and molecular genetic markers,” Dr. Weisdorf said. “Perhaps most importantly, though not addressed very much, is patients’ willingness to undertake intensive therapy and their life outlook related to patient-reported outcomes when they get older.”

Despite the lack of indications that higher age by itself is an influential factor in survival after transplant, “we are generally reluctant to push the age of eligibility,” Dr. Weisdorf said. He noted that recently published American Society of Hematology guidelines for treatment of AML over the age of 55 “don’t discuss anything about transplantation fitness because they didn’t want to tackle that.”

Overall survival (OS) at 1 year after allogenic transplants only dipped slightly from ages 51-60 to 71 and above, according to Dr. Weisdorf’s analysis of U.S. data collected by the Center for International Blood and Marrow Transplant Research for the time period 2005-2019.

OS was 67.6% (66.8%-68.3%) for the 41-50 age group (n = 9,287) and 57.9% (56.1%-59.8%) for the 71 and older group, Dr. Weisdorf found. Overall, OS dropped by about 4 percentage points per decade of age, he said, revealing a “modest influence” of advancing years.

His analysis of autologous transplant data from the same source, also for 2005-2019, revealed “essentially no age influence.” OS was 90.8% (90.3%-91.2%) for the 41-50 age group (n = 15,075) and 86.6% (85.9%-87.3%) for the 71 and older group (n = 7,247).

Dr. Weisdorf also highlighted unpublished research that suggests that cord-blood transplant recipients older than 70 face a significantly higher risk of death than that of younger patients in the same category. Cord blood “may be option of last resort” because of a lack of other options, he explained. “And it may be part of the learning curve of cord blood transplantation, which grew a little bit in the early 2000s, and maybe past 2010, and then fell off as everybody got enamored with the haploidentical transplant option.”

How can physicians make decisions about transplants in older patients? “The transplant comorbidity index, the specific comorbidities themselves, performance score, and frailty are all measures of somebody’s fitness to be a good candidate for transplant, really at any age,” Dr. Weisdorf said. “But we also have to recognize that disease status, genetics, and the risk phenotype remain critical and should influence decision making.”

However, even as transplant survival improves overall, “very few people are incorporating any very specific biological markers” in decision-making, he said. “We’ve gotten to measures of frailty, but we haven’t gotten to any biologic measures of cytokines or other things that would predict poor chances for doing well. So I’m afraid we’re still standing at the foot of the bed saying: ‘You look okay.’ Or we’re measuring their comorbidity index. But it is disappointing that we’re using mostly very simple clinical measures to decide if somebody is sturdy enough to proceed, and we perhaps need something better. But I don’t have a great suggestion what it should be.”

The Acute Leukemia Forum is held by Hemedicus, which is owned by the same company as this news organization.

Dr. Weisdorf disclosed consulting fees from Fate Therapeutics and Incyte Corp.

SOURCE: “The Ever-Increasing Upper Age for Transplant: Is This Evidence-Based?” Acute Leukemia Forum of Hemedicus, Oct. 15, 2020.

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