NEW ORLEANS — Investigators confessed to being "astonished" by results of a randomized trial showing that patients with acute myeloid leukemia who have a poor response following induction therapy do just as well going on to immediate allogeneic transplant as they would if they had received an intensive salvage induction regimen to get them into remission before transplant.
The results come from the phase 3 ASAP Trial and were presented here at the American Society of Hematology annual meeting.
"We selected this to be in the plenary because it completely changes how we've traditionally thought about acute myeloid leukemia," commented press briefing moderator Mikkael A. Sekeres, MD, from the University of Miami Miller School of Medicine, who also serves as chair of the ASH Committee on Communications
"When we have a patient who has relapsed or refractory AML, that person is in a very, very difficult situation, and the mortality among those sort of patients is incredibly high," Sekeres commented. "So traditionally we've given them very high doses of chemotherapy to try to reduce the tumor burden — at least that's been the theory — to then get them successfully to a transplant."
This new finding "completely upends that, if these results hold," he said. The clinical implication is that "we no longer have to hospitalize these patients and give them very aggressive chemotherapy…[and] we don't introduce all the morbidity from giving them very high dose chemotherapy, which can actually prevent a transplant from happening if they get sick enough, and we can get them to a transplant quicker."
The ASAP trial was conducted in patients with an unfavorable risk AML who either had a poor response to first induction therapy or a relapse after first induction therapy.
They were randomly assigned to either a remission-induction strategy aiming for a better response prior to an allogeneic hematopoietic stem cell transplant (alloHCT), or a disease-control strategy consisting primarily of watchful waiting with low-dose cytarabine and single doses of mitoxantrone as needed, followed by sequential conditioning and alloHCT.
The results after 4 years of follow-up showed no differences in either leukemia-free survival or overall survival between patients who underwent additional chemotherapy with the remission-induction strategy and those who went straight to transplant, reported Johannes Schetelig, MD, MSc, from the Clinical Trials Unit at DKMS in Dresden, Germany.
"We expected non-inferiority — this was what we tested, and of course this was based on an assumption that we could get close or even somewhat better with respect to the primary endpoint, disease-free survival, after transplantation," he said.
"What we did not expect is that the early success, [complete response] on day 56 after transplantation, also translates into equal long-term benefit, so this is what I was really astonished about," Schetelig said at a press briefing prior to his presentation.
Less Intensive Approach
Schetelig explained that the rationale for the study was previous work by his group and others showing that alloHCT in patients with residual aplasia after first induction is feasible, with favorable outcomes compared with standard of care, and also on evidence that sequential conditioning based on high-dose cytarabine or melphalan plus reduced-intensity conditioning and alloHCT resulted in long-term control for relapsed or refractory AML.
He also gave details of the two treatment arms of the ASAP trial. The remission-inducing arm consisted of cytarabine (3 g/m2 for younger patients or 1 g/m2 for patients over age 60) twice daily on days 1-3 plus 10 mitoxantrone mg/m2 on days 3-5 and subsequent alloHCT. In the other group — disease control prior to sequential conditioning and alloHCT — watchful waiting was recommended, but low-dose cytarabine (LDAC) and single doses of mitoxantrone were permitted for disease control.
Although, as Schetelig noted, the statistical goal of the study was to show non-inferiority of the disease control arm, this less intensive strategy succeeded expectations for meeting the primary endpoint of disease-free survival (DFS; a maintained complete response) by day 56 after alloHCT.
In an intention-to-treat and per-protocol analysis, the respective rates of DFS at 56 days in the disease control group were 83.5% and 84.1%. In comparison, the respective rates in the remission-induction group were 81% and 81.3%.
In addition, after a median follow-up from randomization of 37 months, there were no differences in either leukemia-free survival or overall survival out to 4 years after DFS at day 56.
The disease-control strategy was also associated with significantly fewer adverse events grade 3 or greater (23% vs 64%, P < .001), and fewer days in hospital prior to transplant (mean 19 vs. 42, P < .001). There were no significant differences between the trial arms in either deaths within 28 days of randomization or time to discharge from hospital (28 days in each arm).
"These data support sequential conditioning and alloHCT without prior remission-induction chemotherapy whenever a stem cell donor is readily available," the researchers concluded.
"These results underline the importance of facilitating alloHCT as [the] most effective anti-leukemic therapy in patients with [relapsed or refractory] AML and stress the need for starting donor search at diagnosis," they added.
The study was sponsored by DKMS gemeinnützige GmbH. Schetelig disclosed honoraria from BeiGene, BMS, Janssen, AstraZeneca, AbbVie, and DKMS. Sekkeres reported no relevant financial relationships.
American Society of Hematology (ASH) 2022 Annual Meeting: Abstract 4. Presented December 10, 2022.
Blood Test 24 Hours After Starting Chemo Predicts AML Survival
Examining protein changes in peripheral blood cells just 24 hours after initiating chemotherapy for acute myeloid leukemia (AML) could predict 5-year overall survival, potentially allowing treatment to be changed, say Norwegian researchers.
They studied peripheral blood samples from patients with AML and healthy controls, finding that there were several clusters of cells that were different between the two groups, with one cell type expanded only in AML samples.
The results, published online January 7 in Nature Communications, revealed that patients with high levels of extracellular-signal-regulated kinase (ERK)1/2 in these cells at 24 hours had worse overall survival at both 2 years and 5 years.
"We believe that this protein is responsible for the cancer cells' resistance to chemotherapy and can be used to distinguish responders from nonresponders," said first author Benedicte Sjo Tislevoll, PhD Candidate, Centre for Cancer Biomarkers, Department of Clinical Science, University of Bergen, Bergen, Norway, in a statement.
She added: "We think that this is an important key in our understanding of cancer, and our aim is to use this information to change treatment early for patients who are not responding to therapy."
Study Details
AML is characterized by having numerous genetic aberrations and poor overall survival, the researchers say. Standard treatment for newly diagnosed fit patients is combination chemotherapy with an anthracycline and cytarabine.
While initial remission rates can reach as high as 80%, relapse is a "challenge" in over 40% of patients. It is estimated that up to 60% of patients with AML harbor mutations in signal transduction pathways, and changes in gene expression have been noted "within hours" of starting chemotherapy, including in those regulating cell death and survival.
Yet "when treating patients with leukemia, it is challenging to quickly follow if the patient is responding to therapy or not," said Tislevoll.
Tools to facilitate the early detection of responders and nonresponders "will be essential to improve cancer patient survival," by providing physicians with "patient-specific information to change treatment strategy early and avoid unnecessary adverse effects," the authors comment.
As the intratumor heterogeneity of AML underlines the needs of single-cell resolution, the researchers used mass spectrometry to study peripheral blood samples from 32 patients newly diagnosed with the disease who had started standardized induction chemotherapy in the previous 24 hours.
Samples were taken immediately before, 4 hours after, and 24 hours after the start of chemotherapy. In addition, four peripheral blood samples and three bone marrow samples from healthy volunteers were used as reference samples, and peripheral blood samples from a further seven healthy donors were used as a control group.
The samples were processed with 20 minutes of being taken in order to preserve the intracellular signaling networks, and were then stained with an antibody panel of 21 surface and 15 intracellular markers.
The median age of the patients was 56.3 years; 19 were male, 13 female.
Analyzing the peripheral blood samples, the researchers identified 10 metaclusters of cells that could differentiate the major healthy cell populations from AML blast cells. One of these, MC9, had a myeloid phenotype and was expanded in all AML patients and in the bone marrow of healthy individuals, but not in healthy peripheral blood.
A LASSO Cox regression model revealed that levels of phosphorylated (p-)ERK1/2 at 24 hours in MC9 cells was the most significant predictor of 2-year overall survival (adjusted P = .0004), and five-year overall survival (adjusted P = .0003).
Splitting the patient cohort by median p-ERK1/2 levels at 24 hours, the team found that patients with a high level in MC9 cells had significantly worse 2-year (P = .0048) and 5-year overall survival (P = .0015) than those with levels below the median.
A further Cox regression analysis taking into account European Leukemia Net 2017 risk classification, age, white blood cell count at the time of diagnosis, and allogeneic stem cell transplantation showed that peripheral ERK1/2 levels at 24 hours in MC9 cells were the only predictive marker for 5-year overall survival (P = .000581).
Interestingly, the degree of reduction in peripheral ERK1/2 levels between pretreatment assessment and 24 hours after starting chemotherapy was also predictive of 5-year overall survival (P = .0333).
The researchers also found that the second-most important marker was the level of p38 mitogen-activated protein kinase (MAPK) phosphorylation in MC9 cells 24 hours post-chemotherapy initiation, predicting both 2-year (adjusted P = .0013) and 5-year overall survival (adjusted P = .0005).
Further study showed that patients with high p-ERK1/2 levels 24 hours post-chemotherapy initiation had induction of MAPK target gene expression, alongside an increase in the p38 target MAPK activated protein kinase 2.
The study was supported by grants provided by EU ERA PerMed AML_PM, the Research Council of Norway, the Norwegian Cancer Society with Solveig & Ole Lunds Legacy, Øyvinn M ø lbach-Petersens Fund for Clinical Research, Western Norway Health Authorities, and Norwegian Health Authority South-East. It was partly supported by the Research Council of Norway through its Centres of the Excellence funding scheme. The authors report no relevant financial relationships.
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